UNIVERSE - discovering the expansion?

-   2439 -   UNIVERSE  -  discovering the expansion?     One of the biggest scientific surprises in astronomy was the recent discovery that space itself is expanding. And, expanding the Universe at an ever increase rate.  Distant galaxies recede from us and from one another more quickly than the nearby ones, as though the fabric of space itself is being stretched by some dark form of energy.
- 
-

-
-------------------------- 2439 -   UNIVERSE  -  discovering the expansion? 
-
-  Today President Donald Trump announced the formation of the United States Space Command.  It puts the U.S. military in charge of securing space for peace.  It s  a new frontier that needs to secured for good and not for evil. We are learning more and more about space.  Now we need to take good care of it.
- 
-    Expanding into space is not the same as expanding space. How can the space itself be expanding at an ever increase rate?  How can distant galaxies recede from us and from one another more quickly than the nearby ones, as though the fabric of space itself is being stretched by some dark form of energy?
-
-  On the largest scales, the matter and energy densities of the Universe has been dropping for billions of years, and continues to do so as time goes on. And if we look to large enough distances, we find galaxies that are being pushed away so rapidly by the expansion of space that nothing we send out today will ever reach them, not even at the speed of light.
-
-  How do we comprehend this ever expanding space?  The original conception of space, thanks to Isaac Newton, was that space was fixed, absolute and unchanging. It was a stage where masses could exist and attract.
-
-  When Newton first conceived of the Universe, he pictured space as a grid. It was an absolute, fixed entity filled with masses that gravitationally attracted one another. But when Einstein came along, he recognized that this imaginary grid was not fixed, was not absolute and was not at all like Newton had imagined.
-
-  Einstein pictured space that was like a fabric, and the fabric itself was curved, distorted and forced to evolve over time by the presence of matter and energy. Einstein’s equations stated that the matter and energy within space determined how this spacetime fabric was curved.
-
-  But if all you had within your spacetime was a bunch of masses, they would inevitably collapse to form a black hole, imploding the entire Universe into a single point.   Einstein didn’t like that idea, so he added a “fix” in the form of a “cosmological constant“.
-
-  If there were this extra term representing extra energy permeating empty space, it could repel all of these masses and hold the Universe static. It would prevent a gravitational collapse. By adding this extra feature, Einstein could make the Universe exist in a near-constant state for all eternity.
-
-  Not everyone was so wedded to the idea that the Universe needed to be static. One of the first solutions was by a physicist named Alexander Friedmann. He showed that if you didn’t add this extra cosmological constant, and you had a Universe that was filled with anything energetic, that is matter, radiation, dust, fluid, etc. ,  there would be two classes of solutions: one for a contracting Universe and one for an expanding Universe.  But, none could be balanced into a “static existence“.
-
-   The mathematics tells you about the possible solutions, but you need to look to the physical Universe to find which one of these describes what is happening. That came in the 1920s, thanks to the work of Edwin Hubble.
-
-   Hubble was the first to discover that individual stars could be measured in other galaxies, determining their distance. By combining those measurements with the work of Vesto Slipher, which showed that these objects had their atomic signatures shifted, and this incredible result popped out.
-
-  A plot of the apparent expansion rate (y-axis) vs. distance (x-axis) is consistent with a Universe that expanded faster in the past, but is still expanding today. This is a modern version of, extending thousands of times farther than, Hubble’s original work.
-
-  Either all of relativity was wrong, we were at the center of the Universe and everything was moving symmetrically away from us, or relativity was right, Friedmann was right, and the farther away a galaxy was from us, on average, the faster it appeared to recede from our perspective. With one fell swoop, the expanding Universe went from being an idea to being the leading idea describing our Universe.
-
-  The way the expansion works is a little counterintuitive. It’s as though the fabric of space itself is getting stretched over time, and all the objects within that space are being dragged apart from one another.
-
-   The farther away an object is from another, the more “stretching” occurs, and so the faster they appear to recede from each other. If all you had was a Universe filled uniformly and evenly with matter, that matter would simply get less dense and would see everything expand away from everything else as time went on.
-
-  But the Universe isn’t perfectly even and uniform. It has overdense regions, like planets, stars, galaxies and clusters of galaxies. It has underdense regions, like great cosmic voids where there are virtually no massive objects present at all.
-
-  The reason for this is that there are other physical phenomena at play besides the Universe’s expansion. On small scales, like animal-sized and below, electromagnetism and nuclear forces dominate. On larger scales, like that of planets, solar systems and galaxies, gravitational forces dominate. The big competition on the largest scales of all, on the scale of the entire Universe, is between the Universe’s expansion and the gravitational attraction of all the matter and energy present within.
-
-  On the largest scales, the Universe expands and galaxies recede from each other. But on smaller scales, gravitation overcomes the expansion, leading to the formation of stars, galaxies and clusters of galaxies.  On the largest scales of all, the expansion wins.
-
-  The most distant galaxies are expanding away so quickly that no signals we send out, even at the speed of light, will ever reach them. The superclusters of the Universe, these long, filamentary structures lined with galaxies and stretching for over a billion light years, are being stretched and pulled apart by the Universe’s expansion.
-
-  In the relatively short term, they will cease to exist. And even the Milky Way’s nearest large galaxy cluster, the Virgo cluster, at just 50 million light years away, will never pull us into it. Despite a gravitational pull that’s more than a thousand times as powerful as our own, the expansion of the Universe will drive all of this apart.
-
-  A large collection of many thousands of galaxies makes up our nearby neighborhood within 100,000,000 light years. The Virgo cluster itself will remain bound together, but the Milky Way will continue to expand away from it as time goes on.
-
-  There are also smaller scales, where the expansion has been overcome, at least locally. The Virgo cluster itself will remain gravitationally bound. The Milky Way and all the local group galaxies will stay bound together, and eventually merge under their own gravity.
-
-   Earth will remain orbiting the Sun at the same distance, Earth itself will remain the same size, and the atoms making up everything on it will not expand. Why? Because the expansion of the Universe only has any effect where another force, whether gravitational, electromagnetic or nuclear, hasn’t overcome it. If some force can successfully hold an object together, even the expanding Universe can’t affect a change.
-
-  The orbits of the planets in the system are unchanging with the expansion of the Universe, due to the binding force of gravity overcoming any effects of that expansion.
The reason for this is subtle, and is related to the fact that the expansion itself isn’t a force, but rather a rate.
-
-   Space is really still expanding on all scales, but the expansion only affects things cumulatively. There is a certain speed that space will expand at between any two points, but if that speed is less than the escape velocity between those two objects, if there’s a force binding them, there’s no increase in the distance between them.
-
-  And if there’s no increase in distance, that impetus to expand has no effect. At any instant, it’s more than counteracted, and so it never gets the additive effect that shows up between the unbound objects. As a result, stable, bound objects can survive unchanged for eternity in an expanding Universe.
-
-  Whether bound by gravity, electromagnetism or any other force, the sizes of stable, held-together objects will not change even as the Universe expands. If you can overcome the cosmic expansion, you’ll stay bound forever.
-
-  As long as the Universe has the properties we measure it to have, this will remain the case forever. Dark energy may exist and cause the distant galaxies to accelerate away from us, but the effect of the expansion across a fixed distance will never increase.
-
-  The fabric of space itself may still be expanding everywhere, but it doesn’t have a measurable effect on every object. If some force binds you together strongly enough, the expanding Universe will have no effect on you. It’s only on the largest scales of all, where all the binding forces between objects are too weak to defeat the speedy Hubble rate, that expansion occurs at all.
-
-  Fortunately our new Space Force will not have to deal with expanding space, only with expanding into space.  Good Luck.
-
-  August 29, 2019                                                                                                                                                                                                                                           
----------------------------------------------------------------------------------------
-----  Comments appreciated and Pass it on to whomever is interested. ----
---   Some reviews are at:  --------------     http://jdetrick.blogspot.com ----- 
--  email feedback, corrections, request for copies or Index of all reviews
---  to:  ------    jamesdetrick@comcast.net  ------  “Jim Detrick”  -----------
-  https://plus.google.com/u/0/  -- www.facebook.com  -- www.twitter.com
 ---------------------               Thursday, August 29, 2019         --------------------
-----------------------------------------------------------------------------------------

GRAVITY - traveling at the speed of light?

-   2438  -    GRAVITY  -  traveling at the speed of light?  If the Sun went dark instantaneously we would not know it until 8 minutes later., when the last bit of light reached us. The same delay would occur with gravity.  If the Sun disappeared altogether the Earth would continue to orbit for another 8 minutes before it would shoot off into space in a straight line.
- 
-

-
-------------------------- 2438 -    GRAVITY  -  traveling at the speed of light?
-
-  Why Does Gravity Travel at the Speed of Light?
-
-  Two neutron stars collide; the resulting gravitational wave spread at the speed of light. (Request a separate Review if you want to learn what neutron stars are?)  The dead cores of these two stars collided 130 million years ago in a galaxy somewhat far away.
-
-  The collision was so extreme that it caused a wrinkle in space-time, called a gravitational wave. That gravitational wave and the light from the stellar explosion traveled together across the cosmos. They arrived at Earth simultaneously at 6:41 a.m. Eastern on August 17, 2019.
-
-  This detection proved to astronomers that their theory that gravity traveled at the speed of light was correct.  We all know light obeys a speed limit of 186,000 miles per second. Nothing travels faster. But why should gravity travel at the same speed?
-
-  Albert Einstein’s general relativity, or theory of gravity,  predicted gravitational waves, like light waves,  existed a century ago.  At the same time Einstein overthrew Isaac Newton’s idea of “absolute time.”
-
-   Newton thought time marched onward everywhere at an identical pace regardless of how we perceived it. Regardless of our own motion through space.  By that line of thinking, one second on Earth is one second near a black hole (which Newton didn’t know existed).  That is regardless of the influence of gravity or the curvature of space.
-
-  Newton thought gravity acted instantaneously. Distance didn’t matter.  But,  then Einstein showed that time is relative. It changes with speed and in the presence of gravity.
-
-  One of the ramifications of his theory is that you can’t have simultaneous actions at a distance. So information of any kind has a finite speed, whether it’s a photon, the light-carrying particle, or a graviton, which carries the force of gravity.  Which also has not yet been discovered, except in theory.
-
-  In relativity, there is a ‘speed of information’ , the maximum speed that you can send information from one point to another,”  In electromagnetism, when you shake an electron, it creates a change in the electric field that spreads out at the speed of light. Gravity works the same way. Shake a mass and the change in the gravitational field, the gravitational wave,  propagates at that same speed.
-
-  So the fact that the speed of gravitational waves is equal to the speed of electromagnetic waves is simply because they both travel at the speed of information.
-
-  There’s an easy way to picture this.  If the Sun went dark instantaneously we would not know it until 8 minutes later., when the last bit of light reached us.
-
-  The same delay would occur with gravity.  If the Sun disappeared altogether the
Earth would continue to orbit for another 8 minutes before it would shoot off into space in a straight line.
-
-  The same would occur at different times for the other planets, the comets and the asteroids.
-
-  What is gravity really?  If there is no mass there is no gravity.  We understand electromagnetism pretty well.  Otherwise I would not be typing this.  But, what is holding me in my chair is still much more mysterious.  May you live in interesting times.
-
-  See Review 2014 that lists 12 more Reviews about Gravity, and the property of space - time.
-
-  August 27, 2019                                                                                                                                                                                                                                           
----------------------------------------------------------------------------------------
-----  Comments appreciated and Pass it on to whomever is interested. ----
---   Some reviews are at:  --------------     http://jdetrick.blogspot.com ----- 
--  email feedback, corrections, request for copies or Index of all reviews
---  to:  ------    jamesdetrick@comcast.net  ------  “Jim Detrick”  -----------
-  https://plus.google.com/u/0/  -- www.facebook.com  -- www.twitter.com
 ---------------------               Tuesday, August 27, 2019         --------------------
-----------------------------------------------------------------------------------------

COFFEE - my morning coffee

-   2437  -  COFFEE  -  my morning coffee .    Where did your morning coffee come from?  You may be surprised?  It is not just Starbucks.
-
-

-
---------------------  2437  -  COFFEE  -  my morning coffee
-
-  Your morning coffee started with a goat.  Yep.  Way back in 900 A.D. in Ethiopia a herdsman noticed his goat was unusually alert and a little jittery.  He also noticed that the goat was eating some red berries off a bush.  He tried a few berries himself.  Sure enough the herdsman and the goat were soon jumping around together.
-
-  The Arabs were the ones to discover, in  1400 A.D., that it was not the berry but the seed inside that was so invigorating.  And, medieval Arabs were the first to consume a coffee beverage.  They separated the bean from the pulp and skin, crushed it, and mixed it  with water to make a drink called qahwa or, in Turkish, kahveh.
-
-  The Arabs learned how to roast the beans and controlled the trade of coffee beans fighting to maintain the monopoly.  You could be put to death for smuggling a coffee plant.
-
-   But word of the "wine of Araby" spread. At first, Europeans were suspicious. Many called it the "bitter invention of Satan," and priests urged parishioners to resist drinking in the sin. It wasn't until Pope Clement VIII tasted coffee in 1600, and gave it a thumbs-up, that coffee began to lose the taint of being evil to being good to the last drop.
-
-  By 1700, hundreds of coffeehouses graced Europe, and the Dutch had broken the Arab monopoly on the coffee trade, smuggling seedlings to the Indonesian islands of Java and Sumatra.
-
-  Not long after, the king of France received a coffee plant as a gift from the mayor of Amsterdam, and a seedling from that plant, taken to Martinique around 1720,  gave rise to the coffee of Central and South America.
-
-  Looking for a way to make his coffee faster, in 1901 an Italian named Luigi Bezzera patented a machine that forced steam through the grounds, and espresso was born.
Espresso was much stronger coffee. And when coffee pioneers used excess steam to warm milk before mixing it with their coffee, they discovered that steamed milk is frothy, foamy, and has a pleasant flavor all its own leading to lattes and cappuccinos.
-
-   Today, humans down more than 500,000,000,000 cups of coffee every year.  That is why I own stock in Starbucks.
-
-  August 22, 2019.                                                                               791                                                                           
----------------------------------------------------------------------------------------
-----  Comments appreciated and Pass it on to whomever is interested. ----
---   Some reviews are at:  --------------     http://jdetrick.blogspot.com ----- 
--  email feedback, corrections, request for copies or Index of all reviews
---  to:  ------    jamesdetrick@comcast.net  ------  “Jim Detrick”  -----------
-  https://plus.google.com/u/0/  -- www.facebook.com  -- www.twitter.com
 ---------------------   Thursday, August 22, 2019  -------------------------
-----------------------------------------------------------------------------------------

GALAXIES - what rotating galaxies tell us?

-   2436  -  GALAXIES  -  what rotating galaxies tell us?  The conclusion is that most of what contributes to the galaxy’s weight does not shine.  We call it “Dark Matter“.  The weight of Dark Matter is 10 times greater than the weight of what we see.  (Do not believe “truth” without evidence.  Is 95% of the Universe really Dark Matter?)
- 
-

-
-------------------------- 2436  -  GALAXIES  -  what rotating galaxies tell us? 
-
-  What rotating galaxies tell us about the Universe?  The Whirlpool Galaxy, M51 or NGC5194, is a beautiful image available to you with binoculars, telescope, or googling.  It is in the constellation Canes Venatici, The Hunting Dogs,  just below the end of the handle of the Big Dipper.
-
-   It is spectacular because you see the galaxy head on, and it is entwined with another galaxy, NGC5195, causing intense spiral arms.  It is 60,000,000 light years away, appears four times wider than Saturn in the night sky (499 arc seconds  versus 126 arc seconds)
-
-  Making a spectrum of the light can tell us the chemical composition of the light source.  It amounts to setting a prism in front of the telescope.  Spectrum lines are the fingerprint for each chemical element.  Each element’s atom has a unique quantum ladder structure for the electrons orbiting its nucleus.
-
-    When an electron drops to a lower energy level in this ladder it emits a unique frequency of light that is equal to the difference in the two energy levels divided by Planck’s Constant.
-
-  For example:  A hydrogen atom has four energy levels for the single electron that orbits its nucleus.  Beyond the forth level the electron escapes the Electromagnetic Force holding it to the nucleus and becomes a free electron.
-
-  Less the one electron the nucleus becomes a  positive ion.  If the electron drops in energy from the 4th level to the 1st level ( ground level), the difference in energy is 13.6 electron volts. 
-
-  The frequency of the photon emitted by the electron is equal to the difference in energy level / Planck’s Constant.
-
------------------  f = E / h
-
------------------  h = 4.136 * 10^-15 electron volts * seconds
-
------------------  f = 13.6 eV / 4.136 * 10^-15 eV * seconds
-
------------------  f = 3.29 * 10^15 cycles/second
-
------------------  Wavelength = c / f
-
------------------  Wavelength = 3*10^8 m/sec / 3.29 * 10^15 cycles/second  =  91.4 nanometers / cycle.
-
-  c = the speed of light.  I use 3*10^8 meters per second.  The more accurate number is 299,792,458 meters per second.
-
-  91.4 nanometers is the spectral line you would see on a spectrograph that is far into the Ultraviolet.( 400 nanometers is visible violet light).
-
-   In 1924 Harvard College Observatory had already archived 250,000 of star spectrographs.  From these astronomers learned that not all stars contained the same elements.  And, that the color (peak frequency) of the spectrum could be used to tell the temperature of each star.
-
-  Annie Jump Cannon was collecting these spectrograph in 1895.  In 1924 Cecilia Payne started classifying the elements that she saw in Annie’s spectrums.  Cecilia was the first to recognize that the lines in the spectrograph represented the quantum energy leaps of electrons jumping between energy shells of each atom.
-
-   Cecilia noted that in the coolest stars the calcium spectral line was strong.  In the hottest stars the calcium line was weak.  If a star is cool most of the calcium atoms will be at their lowest quantum energy state.  If the star is hot then many quantum energy levels are activated and many electrons are moved to higher energy levels.
-
-   Cecilia made mathematical calculations based on the strength / weakness of spectral lines to determine the temperature of the star.  Her analysis agreed closely with the color estimate of a star’s temperature done previously.
-
-  The more modern analysis of the spectrographs of galaxies have given us even more spectacular discoveries.   The Whirlpool Galaxy is facing us head on so we can not easily measure its rotational velocity.  We know that our Milky Way galaxy rotates at 250,000 meters / second (559,000 miles per hour) and completes one orbit in 225,000,000 years. 
-
-  Many other galaxies, over 100, have been studied that have their disks near orthogonal to the axis of rotation.  When we study these galaxies we can detect the Doppler effect of one side of the disk moving toward us (blue shift) and the other side moving away from us (redshift). 
-
-  For example: the galaxy NGC7541 spectrograph was taken.  It was enlarged to 5.5 feet in length and atomic hydrogen spectrum line looked like a “z” on the graph only 1/10 of an inch high.
-
-   The light from the side of the galaxy moving toward us was blue shifted to 253.5 nanometers wavelength from center.  The light form the side of the galaxy moving away from us was redshifted to 284 nanometers wavelength from center .  The center of the galaxy was redshifted to 270 nanometers.  The width of the galaxy is 160 arc seconds, or 130,000 lightyears.  Our Milky Way is 100,000 lightyears across.
-
-  Looking at the center of the little “z” we can see that the center of the galaxy is redshifted to 270 nanometers.  The velocity of the galaxy moving away from us can be calculated as:
-
------------------   delta wavelength/original wavelength = velocity / speed of light
-
------------------  dw / Wo = v / c
-
------------------  386.3*10^-9m / 656.3*10^-9 * 3*10^5 km/sec = v
-
------------------  v = 59% the speed of light
-
------------------  v = 177,000 km/sec. (396,000,000 mph)
-
-  Looking backwards in time we see the galaxy at 63% the age of the Universe, 8.6 billion years old, or 5.1 billion years ago (1/1+dw/Wo).  It is traveling away from us at 396 million miles per hour due to the expansion of the Universe.
-
-  That is the center of the NGC7541 galaxy that is moving away.  At the same time the side of the galaxy moving toward us has blue shifted to 253.5 nanometers wavelength us is moving 184,123 km/sec.  The side of the disk moving away from is redshifted to 284 nanometers moving 170,181 km/sec.  So, the orbital velocity at a radius of 32,600 light years, which is 3.08*10^20 meters, is moving + or - 6,971 km/sec velocity
-
-   We measure the redshift of stars half way out from the center.  The wavelength of hydrogen is 656.3 nanometers.  It is redshifted to 253.5 nanometers, stretched 402.8 nanometers.  The ratio delta wavelength over original wavelength, dw/Wo, is 61%.  Which means it is traveling 61% the speed of light or .61*300,000 kilometers/second = 184,123 km/sec.   The other side of the galaxy disk is redshifted to 284 nanometers.  This ratio is 56.7% or 170,181 km/sec.  The difference is 18,283 km/sec or + or- 6,971 km/sec.  Therefore the rotational velocity of stars half way out from the center of the galaxy is 6,971 km/sec ( 15,600,000 mph)
-
-  This is half way out from the center of the galaxy where the circumference for one orbit is 1.938*10^21 meters.  At this orbital velocity it will take 2.78*10^14 seconds or 8,800,000 years to complete one orbit.  By comparison our Milky Way has a 225,000,000 year period.
-
-   The distance out from the center is 10,000 parsecs (32,600 lightyears).  There are 3.1*10^16 meters in a kilo parsec.  So the radius is 3.1*10^20 meters.  The circumference is 2*pi*radius = 19.47*10^20 meters.  Distance = rate * time.  Time = 19.47*10^20 meters / 9,142 km/sec = 2.13 *10^14 seconds.  There are 3.16*10^7 seconds in a year.  The period of one rotation is 67,400,000 years.
-
-  Now that we know the period of one orbit we can calculate the mass of the galaxy.  Using Kepler’s law that period squared = radius cubed:
-
----------------  p^2 = 4*pi^2*radius^3 / G*(m+M)
-
----------------  G = 6.67*10^-11 m^3/(kg*sec^2)
-
----------------  Interior Mass = 2.237*10^44 kilograms
-
----------------  Mass of the Sun = 1.9891*10^30 kilograms
-
----------------  Mass at 32 LY from center of Galaxy = 1.12 * 10^14 solar masses.
-
-  We can repeat these same calculations at a distance of 20,000 parsecs from the center of the galaxy.  That is 65,200 light years out from the center where the stars fade away.  For comparison our Milky Way radius is 50,000 lightyears.  The total interior mass of the galaxy inside this radius is:
-
----------------  Mass at 65 LY from center of Galaxy = 4.83 * 10^14 solar masses.
-
-  Another approach to these calculations is to realize that the galaxy is not flying apart.  Therefore, the centripetal force must equal the force of gravity.
-
--------------- Centripetal force = m*v^2/R
-
--------------- Centripetal force = mass*velocity^2/Radius
-
--------------- Gravity force = G*M*m/R^2
-
--------------- Gravity force = Gravitational Constant * product of masses/Radius^2
-
---------------    Set these to forces equal to each other and solve for Mass:
-
--------------- Mass  =  v^2*R/G
-
-  At 32,600 light years radius the velocity is:
-
--------------- v = 6,971 km /sec
-
--------------- R = 3.09*10^20 meters
-
--------------- Mass = 1.13*10^14 solar mass
-
-  At 65,200 light years radius the velocity is:
-
--------------- v = 10,188 km /sec
-
--------------- R = 6.17*10^20 meters
-
--------------- Mass = 4.83*10^14 solar mass
-
-  Either method of calculation tells us that the farther out from the center of the galaxy the rotational velocity remains essentially the same and the interior mass of the galaxy grows immensely, over 430%.  The farther out from the center there is less starlight but there is more mass.
-
-    The conclusion is that most of what contributes to the galaxy’s weight does not shine.  We call it “Dark Matter“.  The weight of Dark Matter is 10 times greater than the weight of what we see.  (Do not believe “truth” without evidence.  Is 95% of the Universe really Dark Matter?)
-
-  Is there another explanation?  What else could cause the flat rotation curves in galaxies?  Over 100 galaxies have been studied and the results are consistent.  Could it be that Kepler’s and Newton’s laws have to be modified for large masses or large accelerations?
-
-   Recall the Newton’s laws for gravity did not hold at high velocities approaching the speed of light.  Einstein’s General Theory of Relativity modified these equations to make them more accurate at high velocities, which are changes of space versus time.
-
-  One proposal is the F=ma needs to be modified at high accelerations.  Force = mass * acceleration  needs to be changed to F=m*a^2/ao.  Where “ao” is a constant that represents the acceleration needed to take us from rest at the Big Bang to the speed of light in the lifetime of the Universe ( 13.7 billion years).  “F=ma” may work fine for the Solar System and not work well at all for galaxies that are 100,000 times bigger.
-
-  If Newton’s laws of physics need to be changed then we do not need Dark Matter.  Mordehae Milgrom, an Israeli physicists, published this idea in 1981.  Jacob Bekenstein, a friend of his, republished the theory on March 25, 2004, with much more mathematical support for the calculations.  The theory is called MOND, for modified Newtonian dynamics.
-
-  Astronomers are pursuing both theories.  Trying to find Dark Matter and trying the math of MOND on gravitational lensing and other gravity effects that must explain theory with evidence.
-
-   You do not modify Newton’s laws that have lasted 300 years with out extraordinary evidence.  We have more to learn.  Funny how that happens.
-
-   A redshift of z indicates the Universe has expanded by 1+z since the radiation was emitted.  z = dw/Wo.  If z=2, 1+z = 3, the Universe has grown by a factor of 3 times.
-
-  Gravity is a weak force compared to the other three forces.  A good illustration is to observe that it takes 200 feet for gravity to pull a falling man off a 200 foot building, but, the electromagnetic force at ground level can stop him in less than a tenth of an inch.
-
-  See Review  #373 “How to Weigh a Galaxy”
-
-  August 21, 2019                                                                               662                                                                                                                                                             
----------------------------------------------------------------------------------------
-----  Comments appreciated and Pass it on to whomever is interested. ----
---   Some reviews are at:  --------------     http://jdetrick.blogspot.com ----- 
--  email feedback, corrections, request for copies or Index of all reviews
---  to:  ------    jamesdetrick@comcast.net  ------  “Jim Detrick”  -----------
-  https://plus.google.com/u/0/  -- www.facebook.com  -- www.twitter.com
 ---------------------               Thursday, August 22, 2019         --------------------
-----------------------------------------------------------------------------------------

CONSTANTS - the constants of nature

-   2435  -  -  CONSTANTS  - the constants of nature.  We think there are only 31  Constants of Nature, but 3 are especially important in adding totally new dimensions to our understanding of the Universe.  These are the constants of gravity, the speed of light, and the quantum, as in Quantum Mechanics.
- 
-

-
-------------------------- 2435  -  CONSTANTS  - the constants of nature
-
-  The only Constant in the world is “change“.  Well, Physics disagrees.  Physics has some “Constants”.  Constants that we think are the same everywhere in the Universe.
-
-  There are 31 of these Constants of Nature, but 3 are especially important in adding totally new dimensions to our understanding of the Universe.  These are the constants of gravity, the speed of light, and the quantum, as in Quantum Mechanics.
-
- As an illustrations of Constants of Nature let’s start with pi.  Every circle, everywhere, always has a diameter and a circumference that is pi times that diameter.  Pi is about 3.14.  It is a unitless number.  It is also an irrational number.
-
-  Rational Real Numbers are integers.  Irrational Real Numbers are fractions whose decimals neither terminate nor eventually repeat.  So, pi is approximately 3.14.  Actually, it is a constant number that “ goes on forever “. 
-
--------------------------   Pi = 3.141716254254.……… ……………………… 
-
- Archimedes calculated that pi lay between 223/71 and 220/70 about 250 B.C.  In 1603 pi was calculated to 10 decimal places, a record at the time.  In 1768 Johann Lambert proved mathematically pi to be an irrational number.
-
-   In 1873 pi was calculated to 707 decimal places by hand, except the mathematician made a mistake at the 528th decimal point and all that followed was wrong.  In 2002 Japanese scientists using computers calculated pi to 1.24 trillion decimal places.  This number is never ending and getting us off track.
-
-   The point is the number pi is constant, to whatever accuracy we are able to calculate it.  Every circle, everywhere, always has a geometry dictated by the constant number pi.
-
-  In 1687 Isaac Newton defined the laws of motion for all objects.  Objects in motion with constant velocity have no net force acting on them.  Objects at rest or in constant motion are in their natural state.  The force that changes an objects constant velocity is equal to its mass times its acceleration (F = m*a).
-
-   The greater the mass the greater the force needed to accelerate it.  For every force of action there is an equal and opposite force of reaction (F1 = -F2).  For all of these laws to work we can assume the three Constants of Nature to be zero.
-
-  Newton’s laws of motion contained the measurement of distance and time (dx & dt), and their ratio, constant velocity ( The first derivative v = dx/dt).  The rate of change of velocity is acceleration (The second derivative a = d^2x/ dt^2).  These are the elements of space and time but they do not consider the effects of gravity, velocity near the speed of light, or quanta.  Therefore,
-
---------------------------  G = 0,        1/c = 0,        h = 0.
-
- Then Newton added his 4th law of gravity and introduced the constant G as a Constant of Gravity.  He assumed that gravity would be the same everywhere in the Universe.  The Force of Gravity is equal to the Natural Constant, G, times the product of the masses and the inverse of the square of the distance between them.

--------------------------   F = G * m1*m2 / d^2
-
-    In 1798 Henry Cavendish performed the first experiment to determine an accurate calculation for G.  Henry constructed a delicate torsion balance, suspending a light rod on a one yard length of wire.  At the ends of the light rod were 2 inch diameter lead balls.
-
-   Henry calibrated this torsion balance with tiny forces at right angles to the rod to twist the wire.  Then he brought two larger lead balls, 8 inches in diameter, almost in contact with the smaller lead balls.
-
-   The gravitational force between the two masses produced a twist in the wire.  The angle of the amount of twist allowed Henry to calculate a force of:
-----------------------------------   1 / 2,000,000kilogram meter / second^2. 
-
-  He knew the masses and the distances between their centers. 
-
--------------------------  Calculating G = R*d^2/m1*m2,
-
--------------------------  Henry got G  = .000000000667 m^3/kg*sec^2.  A very tiny value.
-
-------------------------- G = 6.673 * 10^-11 m^3 / kg * sec^2
-
- Newton’s calculation of the Force of Gravity does not consider the speed of light or the quantum of action, known as Planck’s Constant (h).  But he did add the first dimension of gravity,
-
--------------------------- G = 6.7*10^-11,        1/c = 0,         h = 0.
-
- In 1905 Einstein came up with a refinement to Newton’s law of gravity and described it in terms of curved space and time relative to the speed of light being a constant, not to be exceeded, and the same for all observers, regardless of their velocity.  The speed of light is a constant everywhere in the Universe, always, 
-
--------------------------   C = 299,792,458 meters per second.
-
---------------------------  In order to make this constant a small number, like gravity, the reciprocal =                         1/c  =  3.335640952 * 10^-9 m/sec
-
- His 1905 “Special” Theory of Relativity considered bodies in constant motion and did not consider gravity.
-
----------------------------------  G = 0,              1/c = 3.3*10^-9,                h = 0.
-
-  In 1915 Einstein improved on his equations with the “General” Theory of Relativity which considered bodies in constant acceleration and added the dimension of gravity.
-
- Now we have two dimensions in our Constants of Nature,
-
 ----------------------------  G =6 .7*10^-11,      1/c = 3.3*10^-9,         h = 0.
-
-  In 1915 Max Planck added the quantum as the smallest element of energy that can be observed in Nature.  He did not consider the effect of gravity or the speed of light.
-
-   The smallest unit of energy, or unit of action,        h  = 6.63 * 10^-34 kg*m^2 /sec^2. 
-
-  It is essentially the unit of energy of a single wavelength of the photon.  The energy of the radiation is this constant unit times the frequency of the radiation (E = h*f).
-
-----------------------------  G = 0,         1/c = 0,           h = 6.6 * 10^-34
-
-  In 2006 we are still missing equations that tie all three of these Natural Constants together.  If we can tie Newton’s Gravity laws and Einstein’s Relativity laws and Planck’s Quantum Mechanics together we will have the Theory of Everything.  Who can come up with the equation that has all three of these Natural Constants in it?
-
-----------------------  G =6.7*10^-11,          1/c = 3.3*10^-9,           h = 6.6 * 10^-34 .
-
-  Note that these are all very small numbers:
-
-------------------------- G = .000000000067 meters cubed / kilogram * second squared
-
-------------------------- 1/c  = .0000000033 second squared / meter squared
-
-------------------------- H  =  .00000000000000000000000000000000066 kilogram 8 meter squared / second squared.
-
-  It is possible to arrange these three constants in equations that define the boundary of applications of our current theories in Physics.
-
-------------------------- Planck mass = (h*c/G)^.5  =  5.56 * 10^-8 kilograms
-
-------------------------- Planck length = (G*h/c^3)^.5  =  4.13 * 10^-35 meters
-
-------------------------- Planck time  =  (G*h/c^5)^.5  =  1.38 * 10^-43 seconds
-
-------------------------- Planck temperature  =  (h*c^5/G) = 3.5*10^32 Kelvin
-
-------------------------- Boltzmann’s constant is used to convert energy into temperature. 
-
-------------------------  Boltzmann’s constant = 1.38 * 10^-23 kg8m^2/sec^2 * Kelvin.
-
-  (See Review #377 for math calculations for these above Planck parameters.)
-
-  Planck Time is the smallest unit of time.  This is the first tick when time and space began with the Big Bang.  A Planck unit of time is the time it would take a photon traveling at the speed of light to cross the distance of a Planck length.
-
------------    t = d / v, 4.13*10^35 meters * 2.998*10^8 meters/second = 1.38 *10^43 seconds.
-
-  The Universe is 10^60 Planck seconds old.  Life on Earth did not appear until 10^59 Planck seconds.
-
-  Planck Temperature is the hottest temperature attained at the start of the Big Bang.  From that first moment the Universe has been cooling down.  Today we see it as 2.735 Kelvin (- 270 Centigrade), or Cosmic Microwave Background Radiation at 400 Gigahertz.
-
-   In the old days you could tune your analog television in between stations and you would see this microwave radiation as random “snow” on the screen.
-
-    There are 10^79 electrons in the Universe and 10^88 photons.  There are a billion photons for every electron.
-
-  Other Reviews available:
-
-  (1)  See Review #619 - Are our Natural Constants Changing?
-
-  (2)  See Review #599 - Fine Structure Constant.
-
-  (3)  See Review #377 - The Constants of Nature are Changing.
-
-  August 21, 2019                                                                                 643                                                                                                                                                             
----------------------------------------------------------------------------------------
-----  Comments appreciated and Pass it on to whomever is interested. ----
---   Some reviews are at:  --------------     http://jdetrick.blogspot.com ----- 
--  email feedback, corrections, request for copies or Index of all reviews
---  to:  ------    jamesdetrick@comcast.net  ------  “Jim Detrick”  -----------
-  https://plus.google.com/u/0/  -- www.facebook.com  -- www.twitter.com
 ---------------------               Wednesday, August 21, 2019         --------------------
-----------------------------------------------------------------------------------------

NUCLEAR ENERGY

-   2434  -  NUCLEAR ENERGY  -  Nuclear Energy is ready for a comeback in the US after 30 years in dormancy.  The US does not have the money, not the expertise, not the engineers, not the teachers but other nations do and we are teaming up to make a nuclear comeback
-
-

-
---------------------  2434  -  NUCLEAR ENERGY
-
-  Nuclear Energy is ready for a comeback in the US after 30 years in dormancy.  The US does not have the money, not the expertise, not the engineers, not the teachers but other nations do and we are teaming up to make a nuclear comeback.  26 requests to build nuclear power plants have been submitted to the US government from General Electric, Westinghouse and France.  And, they are likely to be approved.  Here is why:
-
-  Nuclear power is producing electricity at 1.6 cents per kilowatt-hour.  PG&E is charging me 11.4 cents per kilowatt-hour today.   We have 8 nuclear power plants in California.  We require 259,365 billion kilowatt-hours per year to run our state.
-
----------------  16 to 20% comes from nuclear
-
----------------  31% comes from natural gas
-
----------------  20% comes from hydro
-
----------------  20% comes from coal
-
----------------  4.9% comes from geothermal
-
----------------  0.4% comes from solar
-
----------------  1.5% comes from wind
-
-  The US has 103 nuclear power plants, over 20 years old,  that produce 20% of our nations electricity.  There are 400 nuclear power plants in the World.  France gets 80% of its electricity form nuclear.  Japan gets 50%.  The US is operating at 92% capacity to produce the 20% of our electrical needs.
-
-  We have not built a nuclear facility in the past 20 years.  Every one of our nuclear plants is different, requiring different engineering expertise to run them.  These plants were built during evolving technologies and changing government regulations.  Every one of France’s nuclear plants are exactly the same.  So, the same operators can move from one to another.
-
-  The biggest improvement in modern nuclear power plants is the recycling of spent fuel.  Recycling extracts more uranium and plutonium from the spent fuel rods.  The extracted plutonium is mixed with U235 and reused as new fuel rods.  This means that spent fuel does not need to stored underground where it remains radioactive for thousands, or millions, of years. 
-
-  By using recycled fuel rods Yucca Mountain, Nevada, the only site in the US where radioactive rods can be stored underground, will be the only nuclear storage we will need.  If we did not have recycling we would eventually need a dozen Yucca Mountains.  With recycling we will only need one Yucca Mountain and the fuel rods will only be radioactive for 700 to 1000 years, not millions of years.
-
-  Compared to coal there is very little waste even before recycling.  When U235 uranium atoms split in fission reactors, each releases 200 million electron-volts.  A fission reactor gets 82,000,000 million joules of energy per kilogram of fuel.  A 1000 megawatt power plant will only require 3.2 kilograms / day of fuel.
-
-  A fusion reactor gets 340,000,000  million joules of energy per kilogram of fuel.  Each fusion reaction combining 2 atoms releases 17.6 million electron-volts.  A 1000 megawatt power plant will only require 0.6 kilograms of fuel per day.  However, we do not expect to have practical fusion reactors operational for another 30 to 50 years.  Fusion is a hard technology to make work.
-
-  A coal power plant only gets 29 million joules of energy per kilogram of coal.  (Note the massive difference in energy density) .  A 1000 megawatt power plant would need 7,300.000 kilograms of fuel per day ( That’s 8,047 tons per day showing up in railroad cars.)  52% of California’s greenhouse gases come from coal burning.
-
-  The next big reason for nuclear is that it is needed in order to usher in the hydrogen economy.  A nuclear power plant produces electricity and heat.  That is exactly what is needed in a hydrogen production plant. 
-
-  Instead of those giant cooling towers reaching into the sky we should operate a hydrogen production plant nearby.  The hydrogen thermal chemical reaction requires 1000 C and nuclear power plants produce that as excess heat.  Nuclear is not portable and will not work to run automobiles.  But, the hydrogen plant next door is ideal to fuel automobiles creating an exhaust of H2O, not CO2.
-
-  Another important reason to go nuclear is it is ideal to meet growing electricity needs of developing countries.  The GNEP, Global Nuclear Energy Program,  a cold war result that is a treaty designed to prevent the proliferation of nuclear technology for weapons of mass destruction. 
-
-  The nuclear countries have agreed to give the developing countries nuclear enclosed power plants and sell them the electricity they want without their acquiring nuclear technology themselves.  These 300 megawatt modern power plants use safe 3 to 5% enriched U235 fuel and only need to be refueled every 20 years.  ( A crude bomb requires 20% enriched U235, a modern bomb requires 90% enrichment).
-
-  Modern nuclear power plants are smaller and need only be refueled every 20 years compared to our current plants that must be refueled every 2 years.  The modern plants are safe with automatic shut downs requiring no human intervention.
-
-   Pebble reactors in Japan and South Africa have fuel encased in ceramic pebbles that are impossible to melt even if the core goes out of control and tries a melt down. The pebbles just safely roll out on the floor.
-
-  The smaller modern power plants can be built on existing nuclear sites.  No new nuclear sites need to be commissioned.  The US will start building 20 plants by 2020.  GE, Westinghouse, and France have already submitted 26 separate proposals for licenses to build plants.  By recycling the spent fuel Yucca Mountain that has already been commissioned need be the only underground nuclear spent fuel rod storage we will need in the US.
-
-  Jasmina Vujic was the professor from UC Berkeley who gave this lecture.   She is originally from Serbia (Yugoslavia) , graduated from Budapest, got her masters and PhD from Michigan State and now is department head of Berkeley’s nuclear engineering.  Her nuclear engineering students in Berkeley already have jobs before they graduate.
-
-   Westinghouse is hiring 400 and France is hiring 300 engineers.  Nuclear engineer salaries are among the highest in industry.  The only need to get these investments off the ground is government guarantees for stability in regulations that will allow a predictable business plan to turn a profit building nuclear power plants.
-
-  The 400 nuclear plants in the World will grow by 168 by 2020:
-
--------------  China -------------------------- 35
--------------  India --------------------------- 24
--------------  Russia--------- -----------------23
--------------  US  --------- --------------------20
--------------  Japan, Korea, Taiwan-------- 19
--------------  Europe------------------------- 12
--------------  S. Africa--------- ---------------9
--------------  Latin America----------------- 4
--------------  Canada --------- ----------------4
-
-  Nuclear is back.  It can be safe and clean.  It can be an investment that ushers in the hydrogen economy that will totally change the infrastructure of US transportation.  Politically it will free us from foreign oil and the global warming greenhouse gases it produces.
-
-    What we need most is smart people.  We need smart politicians that have the ethics to do what is right for the nation.  We need teachers, we need students in engineering.  Not just nuclear engineers, materials engineers, chemical engineers, automobile engineers, civil engineers, environmental engineers. 
-
-  Nuclear can be a new era for many, if educated, good people have it and not the extremists who want to blackmail the world with the power of nuclear bombs.  That is the reason we are still boycotting Iran.
-
-  August 19, 2019.                                                                              701                                                                         
----------------------------------------------------------------------------------------
-----  Comments appreciated and Pass it on to whomever is interested. ----
---   Some reviews are at:  --------------     http://jdetrick.blogspot.com ----- 
--  email feedback, corrections, request for copies or Index of all reviews
---  to:  ------    jamesdetrick@comcast.net  ------  “Jim Detrick”  -----------
-  https://plus.google.com/u/0/  -- www.facebook.com  -- www.twitter.com
 ---------------------   Monday, August 19, 2019  -------------------------
-----------------------------------------------------------------------------------------

DARK MATTER and Black Holes

-   2433  -  DARK  MATTER  and Black Holes.  Astronomy is moving so fast it is hard to keep up.  Satellites and space probes are numerous and going out in space exploration in all directions.  They are making cutting-edge astronomical observations all the time.  At the same time, we are pushing the frontier of atomic physics.
-
-

-
-  --------------------------  2433 - DARK  MATTER  and Black Holes
-
-   We are incorporating Einstein’s theory of relativity and we are using the world’s fastest computers to do the calculations.  These new tools came together recently when astronomers witnessed the collision of two galaxies that occurred 100 million years ago, about the time dinosaurs ruled the Earth.  When matter and dark matter in these two galaxies collided different things happen to each. 
-
-  For matter the intergalactic gas and dust acts as a wind resistance that slows its movement.  However, Dark Matter does not experience the same type of drag due to the gas clouds.  Dark Matter does not seem to interact with any force other than gravity.   So, the collision separates matter and Dark Matter.
-
-  When matter and Dark Matter are close together the invisible substance can not be distinguished.  But, we know more mass is there because the laws of gravity say that the outskirts of the galaxies should rotate more slowly than those towards the center.  The only way for the laws of gravity to give us the answer we observe is to add 90% more matter to the equation.  We can not see what is causing this gravity, so, we call it Dark Matter.
-
-  With this galaxy collision the astronomers now have matter and Dark Matter separated.  The astronomers used gravitational lensing to map the matter and found that most of the mass was in clumps that appeared to have whizzed past the hot gas clouds with no resistance.  These astronomers believe that this is “direct evidence” that Dark Matter exists.  This invisible material represents 90% of the gravity that is in the Universe.
-
-  These astronomers are putting this new data into their computer simulations that model the birth of the Universe.  This supercomputer contains 25 million megabytes of data.  It solves 12,000 equations over and over again starting with the birth of the Universe as random, subatomic ripples in density.  Their model gives evidence suggesting that over billions of years gravity amplified these ripples to produce the clusters of galaxies seen today.
-
-  In addition to Dark Matter astronomers have collected evidence that 70% of the Universe contains a Dark Energy that is accelerating the expansion of the Universe as a form of anti-gravity. 
-
-  The computer model simulations confirm this view of the Universe leaving Dark Matter and ordinary matter to account for 25% and 5% of the Universe.  The 5% is what we see.  That leaves 95% of the Universe “dark” to us using our eyes and the technology currently available.
-
-  Using this publicly available computer model astronomers can experiment with many different Big Bang scenarios to see if the Universe we observe comes out of their data and the equations.  The new observed data is always being inputted as well as the equations using Einstein’s theory of relativity to modify Newton’s laws of gravity.
-
-  The model suggests that each core of massive galaxies contains a super massive black hole.  And, that is what current observations are also seeing.  The universe evolves so slowly from the point of view of us humans that what we see appear as still images.
-
-  But, something happened over the last 13,700,000,000 years to get us to this point we are observing.  Just as the blowing wind that we cannot see moves the leaves to tell us it is there, the motions of ordinary matter in the cosmos betray the gravitational pull of Dark Matter and the expansion push of Dark Energy.
-
-   Another method measures the bending of light passing by the galaxy, then measures how much ordinary matter is there that we can see, then the astronomers infer how much Dark Matter is also there.
-
-  What Dark Matter is actually made of is anyone’s guess.  But, the most popular guess by the experts is that it is composed of unknown subatomic particles with exotic properties.  Particle physicists are busy trying to find such particles in their particle accelerators that create the highest energies here on Earth.
-
- The galaxies create particle accelerators many times greater than we can create. Around Blackholes at the center of galaxies are super-hot atoms in plasma form.  Plasma is the forth form of matter: solid, liquid, gas, then plasma.
-
-   The plasma is so hot it emits X-rays that astronomers can detect.  This gets astronomers into the frontiers of atomic physics.  They are using super computers to calculate the temperature levels of high-temperature atoms ranging from carbon to iron. 
-
-  The astronomers measure the light spectrum of each element.  With the element iron they find the Iron-K-alpha line that appears to broaden for X-rays emanating from the center of active galaxies.  They are using Einstein’s theory of relativity to try and understand why the K-alpha line is broadening. 
-
-  Astronomers believe the explanation will represent the fact that a super massive Blackhole exists at the center of the galaxy.  This is another evidence for the existence of Blackholes that we also can not see.
-
-  Seeing is believing, or, is it that believing is seeing?
-
-  August 19, 2019.                                                                                   692                                                                           
----------------------------------------------------------------------------------------
-----  Comments appreciated and Pass it on to whomever is interested. ----
---   Some reviews are at:  --------------     http://jdetrick.blogspot.com ----- 
--  email feedback, corrections, request for copies or Index of all reviews
---  to:  ------    jamesdetrick@comcast.net  ------  “Jim Detrick”  -----------
-  https://plus.google.com/u/0/  -- www.facebook.com  -- www.twitter.com
 ---------------------   Monday, August 19, 2019  -------------------------
-----------------------------------------------------------------------------------------

EARTH - How the Earth was Formed?

-   1295  -  EARTH  -  How the Earth was Formed?   Nostalgia ain’t what it used to be and the night sky is not what you see.  What you see is a lot younger that what is.  The light you see left years ago, thousands, millions, even billions of years ago depending on what you are looking at.  What it is today is totally different but you are prevented from seeing it because the light has not reached us yet.
- 
-

-
--------------------------   1295  -  EARTH  -  How the Earth was Formed?
 -
-  Supernovae occur all the time and many of the stars you see in the sky have long since died and exploded into the interstellar medium.  When a supernova explodes it is like 1,000,000,000,000 hydrogen bombs going off all at once.  If a supernova exploded within 500 lightyears of us, we’d be goners.
-
-  On a good night it might be possible for you to count 6,000 stars.  If you are looking at one area of the sky you could maybe count 2,000.  Put on binoculars and you could see maybe 50,000 stars, 25 times as many stars come into view.
-
-   Substitute a 2-inch telescope and you could see 300,000 stars in that same area, 150 times as many stars as the naked eye can see.  Upgrade to a 16 inch telescope and you could see 50,000 to 100,000 galaxies each with billions of stars.  However, the individual stars in the galaxies would be too small to pick out individually.
-
-  A typical galaxy with 100,000,000,000 stars will have one supernova explosion every 200 to 300 years.  The Crab Nebula that we see today was a supernova witnessed with the naked eye in 1054.  In 1604 Johan Kepler witnessed a supernova that lasted in the sky for 3 weeks.  In 1987 a supernova was seen that occurred in a neighborhood galaxy, the Large Magellanic Cloud.  It was 169,000 lightyears away from us.
-
-  4,600,000,000 years ago gas and dust that was spread across 15,000,000,000 miles of space began to condense due to a steady accumulation of gravity as the cloud got denser and denser.  99.9% of all this space dust was used to create the Sun. 
-
-  The rest was debris that was used to create the rest of the Solar System.  The mass collected at the core of the Sun was squeezed to temperatures of 100 million degrees.  The core ignited with nuclear fusion converting hydrogen into helium.
-
-  The 0.1% of the interstellar dust that was still orbiting the Sun spread out in a rotating accretion disk.  The electrostatic force amongst the dust particles began to cause clumps.  As these clumps grew gravity began to create mergers and collisions and larger clumps.  The multiple collisions created asteroids, comets, and planets that swept through their orbits collecting more debris in a rain of meteorites.
-
-  All the material that collected on our planet and these other orbiting objects came from the elements created in the earlier supernovae explosions.  In 200,000,000 years the whole process was completed to create the Earth and the seven other planets.  All the asteroids and comets were never large enough for their gravity to create larger objects.
-
-   However, the collisions and mergers are still occurring to this day.  In fact, a large collision just 65,000,000 years ago in the Yucatan, Mexico, peninsula was so massive it killed all of the dinosaurs that roamed the Earth at that time.  One of the earlier collisions between the Earth and a Mars-sized object created the Moon.
-
-    In fact, the massive splash put into orbit 2 moons.  See Review 1291 “Two Moons” to learn more about this event.
-
-  August 13, 2019                                                                                 1295                                                                                                                                                             
----------------------------------------------------------------------------------------
-----  Comments appreciated and Pass it on to whomever is interested. ----
---   Some reviews are at:  --------------     http://jdetrick.blogspot.com ----- 
--  email feedback, corrections, request for copies or Index of all reviews
---  to:  ------    jamesdetrick@comcast.net  ------  “Jim Detrick”  -----------
-  https://plus.google.com/u/0/  -- www.facebook.com  -- www.twitter.com
 ---------------------               Tuesday, August 13, 2019         --------------------
-----------------------------------------------------------------------------------------

UNIVERSE - expanding space

-   2432  -  UNIVERSE  -  expanding space.  If you were born when the Universe was ten times its current age, our local group of galaxies would merge into one and would be the only galaxy you could see in the Universe for trillions of light years.
- 
-

-
-------------------------- 2432  -  UNIVERSE  -  expanding space
-
-  See Review 2413 about the COSMIC  LADDER, how astronomers measure the distances to the stars.   This Review explores further about our expanding Universe.  We can not see it or feel it but it is out there and in control of our destiny.  The appendix lists more reviews about the Universe. 
-
-  Our Universe is a vast, enormous place, full of stars, galaxies, clusters of galaxies, and vast cosmic voids in between them. As time goes on, gravitation will continue to pull these large concentrations of matter towards one another. At the same time the expansion of the vacuum of space throughout the Universe between the galaxy clusters works to drive them apart.
-
-   20 years ago, we discovered the ultimate fate to be controlled by dark energy that will defeat gravitation and continue this expansion.   Our Universe will never turn around and recollapse.
-
-  The current estimate for the diameter of the universe is 93 billion light years.
-
-  The Universe is full of galaxies that are clumped and clustered together. The farther away we look, distance-wise, the farther back in time we’re looking as well. Within our own galaxy, a star that’s 10 light years away is being seen as it was 10 years ago: it takes 10 years for light, moving at the speed of light, to traverse that distance.
-
-   At extremely large distances, the expansion of the Universe plays a bigger role. A galaxy whose light is arriving after a 10 billion year journey will be farther away than 10 billion light years today; it will be more like 16 billion light years distant.
-
-  Light gets emitted, travels through space, but the expanding space pushes all the unbound objects apart. This includes practically every distant galaxy outside of the local group of galaxies that are still controlled by their mutual gravitational attraction.
-
-  It isn’t simply that galaxies are moving away from us that causes a redshift, but rather that the space between ourselves and the galaxy redshifts the light on its journey from that distant point to our eyes. As the Universe continues to expand, objects that emitted the light wind up farther away than even the number of years the light traveled for when it arrives.
-
-  Under the framework of General Relativity and the laws of physics we can determine how the Universe expanded over its history and how it will expand infinitely far into the future. That part of the Universe that’s accessible to us today, 13.8 billion years after the Big Bang, is now 46 billion light years in radius.
-
-  The observable Universe might be 46 billion light years in all directions from our point of view, but there is more, unobservable Universe, perhaps even an infinite amount, just like ours beyond that.  There is likely much more Universe, in all directions. 
-
-  We can only observe the parts of the Universe where light has had enough time to reach us since the Big Bang. Based on the observed expansion rate, and the fact that we know our Universe is made of:
-
-------------------------  68% dark energy, which acts like a cosmological constant of expansion.
-
-------------------------  27% dark matter, which dilutes with volume as the Universe expands.
-
-------------------------  4.9% normal matter, which acts like dark matter but also collides with itself.
-
-------------------------  0.1% neutrinos, which acts like matter today but like radiation when it moves close to the speed of light.
-
-------------------------  0.01% photons, which dilute with volume and also have their wavelengths stretch-and-cool as the Universe expands.
-
-  Dark energy has come to dominate. As we move forward into the future, it will be the sole determining factor in the Universe’s expansion rate. As the Universe continues to expand, the matter density continues to drop, but the density of dark energy will remain constant.
-
-   Because the expansion rate (squared) is proportional to the energy density of the Universe,  the constant density that dark energy gives means the expansion rate remains  a constant.
-
-  Based on the current expansion rate as observed by the Planck satellite, 67 km/s/Mpc, that means two big things for the future:  the expansion rate will be 55 km/s/Mpc, when only dark energy is important, and  this expansion rate will cause distant objects to recede in an accelerating fashion, and the Universe will continually expand exponentially.
-
-  (Note that  km/s = kilometers per second velocity and an Mpc is a megaparsec, an astronomical unit of distance that equates to about 3.26 million light years.)
-
-  A constant expansion rate means that distant objects accelerate, and that the Universe expands exponentially.
-
-  Imagine a galaxy 10 Mpc away. If the expansion rate is 55 km/s/Mpc, then it appears to move away from us at 550 km/s due to the Universe’s expansion. Over time, it moves farther and farther away.
-
---------------------------  When it’s 10 Mpc away, it recedes at 550 km/s.
-
---------------------------  When it’s 20 Mpc away, it recedes at 1100 km/s.
-
---------------------------  When it’s 40 Mpc away, it recedes at 2200 km/s.
-
---------------------------  When it’s 80 Mpc away, it recedes at 4400 km/s.
-
-  The more time goes by and the farther away the galaxy is, the faster it recedes from view.  Our observable Universe, as we know it right now, is 92 billion light years in diameter. At 13.8 billion years of age that is how far the expansion has taken us.. Anyone living in our Universe, at any location, would see almost exactly the same thing from their vantage point.
-
-  When will the Universe reach 100 billion light years in diameter? When it’s 14.9 billion years old, just 1.1 billion years from now. At that point, the Universe will be 73% dark energy and the expansion rate will have dropped to 65 km/s/Mpc.
-
-  By time the Universe is 24.5 billion years old, a little more than 10 billion years in the future, it will be 94% dark energy, the expansion rate will be 57 km/s/Mpc, but the observable Universe will be 200 billion light years in diameter.
-
-  At an age of 37.6 billion years, the Universe will be 99.4% dark energy, the expansion rate will be 55.4 km/s/Mpc, and now the Universe will be 400 billion light years in diameter.
-
-  Every 12.2 billion years after that, the size of the Universe will double, with the expansion rate leveling off at 55.4 km/s/Mpc. This means the Universe will hit 1 trillion light years in diameter when it’s 54 billion years old; 10 trillion light years at 86 billion years; 100 trillion light years at 118 billion years; and a quadrillion light years in diameter at 149 billion years. By time the Universe is ten times its current age, it will be nearly ten thousand times its current size. That is the power of exponential expansion.
-
-  (The same thing happens in compound interest in your savings account.  That is the power of compound interest and exponential growth.) 
-
-  The observable Universe contains somewhere around 2 trillion galaxies. As we move ahead into the very distant future, all of that matter that isn’t a part of our local group of galaxies will recede from us towards these distant horizons of the Universe.
-
-   What is now contained within a sphere that’s 93 billion light years in diameter will be stretched out over larger and larger volumes, leading to a Universe where the average density eventually drops to zero.
-
-  If you were born when the Universe was ten times its current age, our local group of galaxies will merge into one and it would be the only galaxy you could see in the Universe for trillions of light years.
-
-   Enjoy our Universe the way it is while you are here, because it is expanding away from all of us at this exponential rate with every moment that passes.  May you live in interesting times.
-
-  Other Reviews available:
-
-  2419 - and  -  2393  - Age of the Universe
-
-  2412  -  Comprehending the expanding Universe.
-
-  2394  -  Wrap your mind around the Universe.
-
-  2348  -  The Universe from start to finish.  13 pages.
-
-  2347  -  The Island Universe
-
-  2335  -  The Universe almost did not happen.
-
-  2334  -  How is it expanding?
-
-  2262  -  How fast is it expanding?  List 21 more reviews about the Universe.
-
-  August 11, 2019                                                                                                                                                                                                                                             
----------------------------------------------------------------------------------------
-----  Comments appreciated and Pass it on to whomever is interested. ----
---   Some reviews are at:  --------------     http://jdetrick.blogspot.com ----- 
--  email feedback, corrections, request for copies or Index of all reviews
---  to:  ------    jamesdetrick@comcast.net  ------  “Jim Detrick”  -----------
-  https://plus.google.com/u/0/  -- www.facebook.com  -- www.twitter.com
 ---------------------               Sunday, August 11, 2019         --------------------
-----------------------------------------------------------------------------------------

COSMIC LADDER - the distance to the stars

-   2431  -  COSMIC  LADDER  -   the distance to the stars.  -   How can we possibly measure distances to faraway galaxies?  One technique is to use the redshift of light.  Measuring distances is the most difficult and challenging things that astronomers do.  Astronomers measure distances using stepping stones to reach farther and farther into the Cosmos.   Each step is a step on the distance ladder.
- 
-

-
-------------------------- 2431  -  COSMIC  LADDER  -   the distance to the stars
-
-   The farthest astronomers  can reach is the “ Observable Universe”. That is a distance of 13.7 billion lightyears in any direction.  Which is as far as light has traveled since the beginning of the Universe.  Since the beginning of time.  Beyond that distance the light has not had time to reach us yet.  And, if the expansion of the Universe is truly accelerating than that light at the edge never will reach us.
-
-  The stepping stones in measuring astronomical distances are these five:  (There are many, many more methods being tried, but, these are considered the most reliable today.)
-
--------------  (1)  Radar

--------------  (2)  Parallax
-
--------------  (3)  Main - Sequence Fitting
-
--------------  (4)  Cepheid Variables
-
--------------  (5)  White Dwarf Supernovae
-
-
--------------  (1)  Radar is no different than the radar gun the Highway Patrol officer is using except we bounce the radar beam off the planet instead of your car..  We measure the time for the radar beam to make the round trip and multiply by the speed of light to get the distance.
-
-  Once we know the exact orbits we can calculate the distance each planet is from the Sun.  The Earth to Sun distance is 93 million miles.  It is called one Astronomical Unit.
-
--------------  (2)  Parallax  -  Once we know the exact distance of the diameter of Earth’s orbit around the Sun we can use parallax to measure the distance to the stars.  Parallax is no different  than the Boy Scout measuring the distance across the river.
-
-    The Boy Scout sights a tree on the shore of the other side.  He measures the angle between the line of sight to the tree and along the river bank.  He then steps off a measured distance along the river bank, one step is one yard.  He measures the angle again between his new line of sight to the tree. 
-
-  Now, he has two angles and one side of a triangle and he can use simple trigonometry to calculate the perpendicular distance across the river.  Astronomers have to wait 6 months to make their same measurement to the star.  Astronomers measure the angle to the line of sight to the target star with reference to the background stationary stars that are much further away.  Then, 6 months later you measure the angle again.
-
-   The Earth has moved 2 times 93 million miles and the new line of sight shows the target star has shifted in the sky relative to the background stars.  The parallax angle is half the angle of the annual back and forth shift of the target star.  The distance is 3.26 lightyears * 1 / the angle in arc seconds. 
-
-  Again, it is simple trigonometry except in this case the sine of a very small angle is equal to the angle.  The hypotenuse of the right triangle is the distance to the star.
-
-  For example:  The parallax angle for the star, Sirius, is 0.379 arc seconds.  The distance is 1/.379  =  2.64 parsecs.  1 parsec = 3.26 lightyears.  So the distance to Sirius is 8.6 lightyears.
-
--------------  (3)  “Main - Sequence Fitting”  is the method of finding a star that is very similar to our Sun located in another galaxy.  Since we know the luminosity of our Sun, we measure it.  And, we measure the Apparent Luminosity of the far away star.  We calculate the distance based on the dimness resulting from the star being farther away.  Brightness falls off as the inverse square of the distance.
-
--------------------  Apparent Brightness  =  Actual Luminosity  /  4*pi* Distance^2
-
--------------------  Apparent Brightness  =  1.0 * 10^-12 watts / m^2
-
--------------------  Actual Luminosity  =  3.8*10^26 watts
-
--------------------  Distance^2  =  3.8*10^26  / 12.6 * 1.0*10^-12 meters^2
-
--------------------  Distance^2  =  .30*10^38 m^2
-
--------------------  Distance  =  .55*10^19 meters
-
--------------------  One lightyear = 9.5*10^16 meters
-
--------------------  Distance = 580 lightyears
-
-  So, taking the square root of the ratio of Actual to Apparent Brightness will give us the distance.
-
-  For example:    Main Sequence Stars are those ranging in mass to be bright , hot, blue stars to dimmer, cooler, red stars.  They plot on a temperature versus luminosity diagram in a straight line with a constant slope.  So, instead of measuring the dimness of just one star like our Sun we measure the dimness of the whole range of stars in a galaxy where we know the distance against a range of stars in a galaxy where we are trying to find the distance.
-
-    The Main Sequence stars in the Hyades Cluster is 7.5 times brighter than the Main Sequence of stars in the Pleiades Cluster.  So, Pleiades must be the square root of 7.5, or 2.75 times as far away.  Using the parallax method Hyades Cluster is 151 lightyears away.  The Pleiades Cluster must be 415 lightyears away.
-
--------------  (4)  Cepheid Variables stars are stars that pulsate in their brightness.  The longer the period of their pulsation the brighter the star.  We locate these Cepheid stars in a close in galaxy, like the Large Megellanic Cloud, where we have measured the distance using the above methods.
-
-   Then, we calculate the Actual Luminosity of the Cepheid star as a function of its period of pulsation.  Now, we locate similar Cepheid stars in far away galaxies that we want to know their distance.  We use the period of pulsation to calculate the Actual Luminosity, then, we the dimness of their Apparent Brightness to calculate the distance.  The same process as the Main-Sequence Fitting.
-
--------------  (5)  White Dwarf Supernovae are dying, exploding stars of a particular type whereby we know their mass before they explode and we can calculate what the brightness of the explosion should be.  After that we use the same ratio of Actual Luminosity to Apparent Brightness to calculate the distance.
-
-    The White Dwarf Supernovae are binary stars where one of the stars is a White Dwarf.  It is pulling mass, gas, from its companion star.  When the White Dwarf reaches 1.4 Solar Mass it explodes as a supernova.  Astronomers have calculated that when a star reaches the mass 1.4 times the mass of our Sun it’s core burns helium into carbon, into silicon, into iron and collapses into its core rebounding into a supernova explosion of known luminosity.
-
--------------  (1)  Radar, we can use radar to measure the distances out to 1/3of a lightyear which is inside our solar system.
-
--------------  (2)  Parallax, we can use parallax on Milky Way stars out to 1000 lightyears.
-
--------------  (3)  Main - Sequence Fitting , we can use Main-Sequence Fitting to measure nearby galaxies out to 1,000,000 lightyears.
-
--------------  (4)  Cepheid Variables, we can use Cepheid stars to measure distant galaxies out to 100,000,000 lightyears.
-
--------------  (5)  White Dwarf Supernovae are much brighter that Cepheids and we can use their standard luminosities to measure distances out to 10,000,000,000 lightyears, 10 billion lightyears, almost to the edge of the Observable Universe.
-
-  See Review 835 “ The Redshift Explained” to learn how we measure the receding velocities of these far away galaxies.  To calculate distances using Redshifts we need to use Hubble’s Constant for the rate of expansion of the Universe.  Edwin Hubble measured velocities for several galaxies where distances had been calculated using the above methods.
-
-------------  Galaxy A distance  =  10 million lightyears
-------------  Galaxy A velocity  =  492,000 miles per hour
-
-------------  Galaxy B distance  =  11 million lightyears
-------------  Galaxy B velocity  =  541,000 miles per hour
-
-------------  Galaxy C distance  =  700 million lightyears
-------------  Galaxy C velocity  =  34,400,000 miles per hour
-
-  So, next we have Galaxy D that is much farther away and we do not know its distance.  The Redshift tells us that its receding velocity is 49,000,000 miles per hour.  Well, if you take the ratios of the velocity to distance of the other galaxies you get 49,000 miles per hour per million lightyears.  If we assume this ratio is constant, Hubble’s Constant, then the Galaxy D must be 1,000 million lightyears away, 1 billion lightyears away.
-
---------------------  49,000,000 miles per hour  /  49,000 miles per hour / million lightyears  =  1000 million lightyears.
-
-  The whole accuracy of this distance measurement depends on if Hubble’s constant is truly constant and actually 49,000 miles per hour/ million lightyears.  If it really is constant and remained so over the life of the Universe then the reciprocal of Hubble’s Constant is the age of the Universe.
-
-   1 million lightyears / 49,000 miles per hour = 13.6 billion years old.  I will leave that calculation to the reader who has just climbed the Cosmic Distance Ladder to he farthest stars.
-
-  August 10, 2019                                                                               836                                                                                                                                                             
----------------------------------------------------------------------------------------
-----  Comments appreciated and Pass it on to whomever is interested. ----
---   Some reviews are at:  --------------     http://jdetrick.blogspot.com ----- 
--  email feedback, corrections, request for copies or Index of all reviews
---  to:  ------    jamesdetrick@comcast.net  ------  “Jim Detrick”  -----------
-  https://plus.google.com/u/0/  -- www.facebook.com  -- www.twitter.com
 ---------------------               Saturday, August 10, 2019         --------------------
-----------------------------------------------------------------------------------------