----------------------- # 1585 - Andromeda, Milky Way Galaxy Collisions.
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-1585 - Andromeda, Milky Way Galaxies are on a collision course. What is the tug of war between gravity and Dark Energy? When will the collision happen?
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- The Universe is expanding and galaxies are flying away from each other. A better description would be that the space between galaxies is expanding and pushing galaxies apart from each other. However, this is only on the grander scale. On large scales Dark Energy is dominate. It is the mysterious force that is expanding the vacuum of empty space. This expanding force is in a constant tug of war that is against the attractive force of gravity trying to pull the masses of galaxies back together.
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- So, galaxies flying apart is only true if there is enough space between them where gravity becomes the weaker force. The force of gravity is equal to the product of the masses and inversely equal to the square of the distance between them. The size of the mass and the space between them is what determines what is happening, expansion or collapse.
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- When gravity wins galaxies form into clusters and some galaxies collide with each other forming larger galaxies. The Milky Way Galaxy and the Andromeda Galaxy are part of a Group of 25 galaxies, but, these two are on a collision course. The Andromeda Galaxy , M31, is heading directly towards us at 270,000 miles per hour. Of course, we could just as easily say that the Milky Way is heading directly towards Andromeda. That is the closing speed between us, and, it depends on your point of view which direction it is heading.
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- The force of gravity = Gravitational Constant * Mass * mass / separation distance squared.
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-------------------- F = G * M*m / r^2
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- The mass of the Milky Way Galaxy is 5.68^10^11 Solar Mass.
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- A Solar Mass is the mass of our Sun, which is 2*10^30 kilograms.
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- The mass of the Milky Way Galaxy is 1.14*10^42 kilograms.
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- The mass of the Andromeda Galaxy is 20% larger, 7.1^10^11 Solar Mass, or 1.42*10^42 kilograms.
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- The distance between the galaxies is 2,540,000 lightyears.
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- One lightyear is 9.46*10^15 meters, so , the distance to Andromeda is 24.1*10^21 meters.
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- Solving for the force of gravity, F = (6.67*10^-11) * (1.42*10^42) * (1.14*10^42 ) / (24*10^21)^2
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---------------------------------------- F = 1.87*10^29 kilogram * meters / seconds^2
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- Notice that the units of Force are in F= m*a, mass times acceleration. The unit is called “ Newtons”.
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- At a distance of 2.54 million lightyears closing at a constant speed of 270,000 miles per hour, how long before the galaxies collide?
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--------- time = distance / rate = 2.54*10^6 LY * 9.46*10^15 m / LY / 2.7*10^5 mph *0.447 m/sec / mph / 3.16*10^7 seconds / year.
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--------- time = 6.3*10^9 years.
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- The collision occurs in 6.3 billion years if the closing speed is constant.
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- A more sophisticated calculation has the collision beginning in 4 billion years, but, the whole merger will take another 1 billion years. After 7 billion years the collision is somewhat complete and the new larger galaxy is elliptical, no longer two spiral galaxies.
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- We will have to view from some place else because our Solar System will be cooked by our Sun turning into a Red Giant Star in just 1 billion years.
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- It is surprising to learn that the galaxy collisions present little chance for star collisions. The space between stars is so great that a star to star collision will rarely happen.
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- Today the Andromeda Galaxy appears as a faint white fuzzy cloud about the size of a Full Moon. The galaxy has its own Constellation, Andromeda the Princess, in the north east sky next to the Constellation the Great Square of Pegasus.
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- Precise measurements have been made on the direction and closing speed of the two Galaxies over the past 7 years. The actual intersection will begin in 3.75 billion years. At that point the tidal forces between the two massive galaxies will warp their spiral disks. In 3.85 billion years the shockwaves of gravitational collisions will trigger a burst of new star formations. There will be twice as many stars in the night sky.
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- In 4 billion years the galaxies will pass through each other being tidally stretched and warped beyond recognition.
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- In 5 billion years the stars that pass each other will begin making U-turns being pulled back to the center of gravity.
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- In 7 billion years the stars will be orbiting a common center of gravity and a giant elliptical galaxy will form with a 10 million Solar Mass Blackhole at the center. The Sun may have survived all this chaos but by then it would have burned all its nuclear fuel and be orbiting as a White Dwarf Star. It would be about the size of the Earth but have an extreme density of carbon and oxygen so dense that a teaspoon on Earth would weigh as much as a small truck.
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- We made the 2 body math look pretty simple. In reality the war between gravity and Dark Energy gets very, very complicated. To start with we have the Dark Matter that is surrounding the galaxies in a giant halo. We know the Dark Matter is there because measuring the speed of the stars at the edges of the spiral disks shows they are orbiting too fast to keep from flying out into outer space unless these was 5 times as much mass holding them in place.
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- Besides Dark Matter the Cosmic Web structure of galaxies is very complicated. Starting with these two galaxies being part of a Local Group of 25 galaxies, then this group of galaxies is part of a larger cluster of galaxies which is part of a super cluster of galaxies all connected by filaments of strings of galaxies separated by voids, bubbles of empty space. The filament defines a wall around a void. The space in the void is expanding.
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- Our Galaxy is on a filament moving away from the center of a void toward a Super cluster. The Virgo Cluster is 55 million lightyears away. This Cluster is part of a larger Virgo Supercluster all being pulled toward an even larger super cluster called the Norma-Hydra-Centaurus Supercluster. This Supercluster is being pulled toward a 4 times more massive cluster of galaxies called the Shapley Concentration of galaxy clusters. It is 100 million lightyears away.
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- Meanwhile the voids between those clusters are expanding at an acceleration rate of 47,000 miles per hour per 1 million lightyears of space. Is this not complicated? An announcement will be made shortly, stay tuned.
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RSVP, please reply with a number to rate this review: #1- learned something new. #2 - Didn’t read it. #3- very interesting. #4- Send another review #___ from the index. #5- Keep em coming. #6- I forwarded copies to some friends. #7- Don‘t send me these anymore! #8- I am forwarding you some questions? Index is available with email upon request. Some reviews are at http://jdetrick.blogspot.com Please send feedback, corrections, or recommended improvements to: jamesdetrick@comcast.net. ---- “Jim Detrick” -- www.facebook.com, -- www.twitter.com, -- 707-536-3272 Tuesday, April 2, 2013
----------------------- # 1584 - Universe Lifetimes.
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-1584 - Universe lifetimes. The stars, the galaxies, and the Universe itself as a life cycle we are trying to understand. X-rays are giving us a new vision on the scene.
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- Lifetimes are changing. Stone age man had an average lifetime of 20 years. Today the average lifespan is 67 years and still climbing. At the age of the dinosaurs the year lasted 370 days. Today it is only 365.256366 days long. The Earth wobbles through the plane of the Solar System every 100,000 years. Last year the Universe was 13.7 billion years old.
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- This year the age of the Universe is 13.8 billion years. More Cosmic Microwave Background data now available from new spacecraft has brought us new data. The recalculation is a 7% increase in the age of the Universe ,but, it is 100,000,000 years older. Our planets were thought to have formed in the Solar System in less than 200,000,000 years. That happened 4.5 billion years ago.
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- We believe the Universe is expanding to try to achieve a lower state of entropy. Entropy is randomness, or a high state of disorder. The Big Bang started with the lowest state of entropy in uniform order. The disorder and entropy has been increasing ever sense. Energy always seeks to reach its lowest level. Entropy always seeks to reach its highest level.
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- Gravity opposes the expansion and where pockets of gas were higher density stars would form. As gravity crushes matter fusion creates radiation that opposes gravity. The balance of forces determines the lifetimes of stars. Dark Matter’s gravity collects stars into galaxies. In between Dark Matter galaxies and cluster of galaxies is Dark Energy. Dark Energy is like the radiation in space that is expanding space moving the galaxies away from each other. The voids between them are expanding bubbles of space.
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- Eventually we will be in a single bubble that will be our Observable Universe. Everything else will have expanded so far their light will never reach us.
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- The stars have a lifetime determined by their mass. The largest stars burn their nuclear fuel quickly and die as supernovae in only a few million years. Smaller stars like our Sun have lifetimes of 10 billion years. Our Sun will die as a White Dwarf star. It is not big enough to go supernova. Red Dwarf stars and Brown Dwarf stars that are smaller still will live for 100 trillion years as they slowly cool down.
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- Galaxies eventually evaporate. Protons eventually decay into photons. That will take another 10^40 years. Blackholes will also eventually evaporate and decay. For that you will have to wait 10^100 years. That is really a long time.
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- Is the Universe really flying apart? Or, is Mother Nature fooling us? Astronomers see the Universe as expanding because the light from distant galaxies is redshifted by the time it reaches. the light’s wavelength is stretched due to traveling through expanding space over its entire journey.
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- The light that astronomers can gather from the edge of the Observable Universe is only 1 photon per second. Could there be large scale factors that have unknown properties? Maybe the Cosmos is not uniform? Maybe expanding space is an illusion? In many ways we are flooded with data and starving for knowledge.
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- Chandra is a large space telescope built to purposely collect fewer photons and build up an image over a long focusing time. The images are recreated by computer software that uses the photon brightness differences and the grazing angles to “ see” with fewer photons. The detectors collect a few hundred photons, each having very high energy in the X-ray frequency range. X-rays range from 10 nanometers wavelength to as short as 0.01 nanometers wavelength.
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- The entire sky is diffused in X-ray energy. Where does this energy come from? In may have started out as Gamma Rays and been redshifted into lower energy X-rays?
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- The moon reflects X-rays and the minerals on its surface fluoresce. The X-rays get absorbed and visible light get re-emitted from the surface.
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- The Sun creates X-rays in its magnetic fields at its surface. The magnetic field lines break and reconnect creating high temperature X-rays.
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- The Blackhole at the center of our Galaxy is the brightest X-ray source. Binary Stars where one star steals mass from the other creates another source of bright X-rays. Gravity and magnetic fields accelerate ionized particles into jets and shockwaves. When ionized particles slam into gas and dust their deceleration emits radiation heating the gas clouds to millions of degrees. Thermal radiation emits in all directions along with X-rays.
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- These studies are telling astronomers how galaxies go through their lifecycles. Astronomers want to learn how did we get form the Big Bang to spiral galaxies orbiting Blackholes separated by voids of empty space? The more astronomers can “ see “ the better we can understand the life cycles of the Universe. An announcement will be made shortly, stay tuned.
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RSVP, please reply with a number to rate this review: #1- learned something new. #2 - Didn’t read it. #3- very interesting. #4- Send another review #___ from the index. #5- Keep em coming. #6- I forwarded copies to some friends. #7- Don‘t send me these anymore! #8- I am forwarding you some questions? Index is available with email upon request. Some reviews are at http://jdetrick.blogspot.com Please send feedback, corrections, or recommended improvements to: jamesdetrick@comcast.net. ---- “Jim Detrick” -- www.facebook.com, -- www.twitter.com, -- 707-536-3272 Friday, March 29, 2013
----------------------- # 1583 - Simulating the Expanding Universe
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- The Universe is expanding but in an astronomer’s lifetime she would hardly notice. 100 years ago the astronomers were certain the Universe was “ static” neither expanding or contracting. The Milky Way Galaxy was our Universe. Then, 1920’s Hubble’s discoveries changed all that. Other galaxies were discovered that were moving away from us. The further away the galaxy was the faster it was receding away.
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- Today astronomers are studying galaxies that are billions of lightyears away. Today astronomers can model the Observable Universe, put the model on a computer. They can start the simulation after the Big Bang and use the algorithms in physics to run the expansion of time. Then see how the results compares with what we see today. If there is not a good match astronomers can change initial conditions, or change assumptions, and run it again.
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- Cosmology has entered the world of experimentation. Google the Bolshoi to learn more. http:hipacc.ucsc.edu/Bolshoi.
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- The observations are the inputs. The laws of physics run the software. Einstein’s Theory of General Relativity are the equations in the software.
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- The simulation assumes Cosmic Inflation occurred shortly after the Big Bang. The Inflation grew the Universe 1,000 times faster than the speed of light. The quantum fluctuations at the sub-atomic level when the expansion began grew into the lumps of matter and energy we see in the Universe today.
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- Gravity coalesced Cold Dark Matter into halos around ordinary matter . These structures eventually evolved into galaxies and clusters of galaxies interconnected by filaments of matter and separated by giant voids of space.
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- The simulation also assumes Einstein’s Cosmological Constant that opposes gravity . This is the Dark Energy that is expanding space and growing the size of the Universe.
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- The model’s assumptions best fit is when 73% of the Universe is Dark Energy and 22% is Dark Matter. 5% is ordinary matter ( Baryonic matter which is made up of protons and neutrons.). Only 0.5% is the matter visible as stars and gas/dust that we call “ our world”.
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- The simulations created take a lot of computer time, about 6 million CPU hours. the resolution in the software is down to 5,000 lightyears. ( The Milky Way Galaxy is 100,000 lightyears with a Dark Matter halo extending out to 2,000,000 lightyears.)
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- Using the simulations astronomers can observe the Dark Matter directly. We know the Dark Matter exists by measuring the speeds f stars and gas in galaxies and the speeds of galaxies orbiting in clusters of galaxies. Another measure is the bending of light from background galaxies passing by foreground clusters of galaxies.
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- The computer simulations are agreeing accurately with the observations we see today. The calculations and assumptions must be close to reality. Now astronomers can start experimenting with “ what if’s” in the laboratory. Astronomers can change the assumptions and quickly see the results. They can run the software forward in time and see what the Universe will look like in the future.
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- It all boils down to simple multiplication. The Earth is 10^7 meters, the Galaxy 10^22 meters, the Observable Universe 10^27 meters, the Whole Universe 10^58 meters. An announcement will be made shortly, stay tuned.
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RSVP, please reply with a number to rate this review: #1- learned something new. #2 - Didn’t read it. #3- very interesting. #4- Send another review #___ from the index. #5- Keep em coming. #6- I forwarded copies to some friends. #7- Don‘t send me these anymore! #8- I am forwarding you some questions? Index is available with email upon request. Some reviews are at http://jdetrick.blogspot.com Please send feedback, corrections, or recommended improvements to: jamesdetrick@comcast.net. ---- “Jim Detrick” -- www.facebook.com, -- www.twitter.com, -- 707-536-3272 Thursday, March 28, 2013
----------------------- # 1582 - Pythagorean Theory of Relativity
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- If Pythagoras had discovered the Theory of Relativity it would have been a lot easier to understand.
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-------------------------- E = mc^2
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- This formula only applies to a mass that is at rest. If a mass is in motion you must consider its Total Energy to include Kinetic Energy and Momentum. Momentum is mass * velocity. So, if the mass is in motion the Energy equation expands to:
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------------------- E^2 = ( mc^2)2 + (mv* c ) ^2
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- This can be recognized as the Pythagorean Theorem for Relativity. “E” is the hypotenuse, “(mc^2)” is the opposite side of a right triangle and (mv*c) is the adjacent side of the right triangle. The Theorem says that the hypotenuse squared is equal to the sum of the squares of the other two sides of a right triangle. So:
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---------------- E^2 = ( mc^2)2 + (mv* c ) ^2
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- “(mc^2) is the opposite vertical side. When the velocity is zero the horizontal line collapses into the vertical line. The hypotenuse E becomes the same as the vertical line mc^2 and E = mc^2 when the velocity is zero.
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- Likewise, if the mass is zero the vertical line collapses into the horizontal line and the hypotenuse E = mv^2 * c. The energy of the massless object is a photon. But, its momentum is not zero even though the mass is zero there is always a quantum of energy in each cycle of oscillation. The Energy of photons is Planck’s Constant * Frequency of oscillation. E = h* f. However, if there is just the slightest bit of mass of another particle the hypotenuse will always be greater than the adjacent side. What we can say is the smaller the mass becomes the closer E = mv*c, Energy = the momentum times the speed of light.
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- Reformatting the equation to solve for the velocity of the mass
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------------------------------- v = mv*c / E * c
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- As mv *c / E approaches “one” the velocity approaches the speed of light
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------------------------------ v = c
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- Light can be thought of as particles, photons, with zero mass but still momentum. Their motion can only be one speed, 186,000 miles per second.
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- All light, electromagnetic radiation, travels at this single speed. It has been traveling at this speed ever since the Big Bang. We say the size of the Universe is its age in lightyears. That is how far light travels in one year = 5,880,000 million miles. So the age of the Universe is 13.8 billion years and the distance the light has traveled is 13.8 billion lightyears distance.
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- If you point your telescope due east and see to the edge of the Observable Universe you can only see 13.8 billion lightyears distance. But, if you point your telescope to the west you could see another 13,8 billion lightyears in that direction. In that sense we the observer are in the center of the Universe. Of course , every observer can say that.
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- The Observable Universe is therefore 27.5 billion lightyears in diameter.
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- But, during the 13,8 billion years of time that it takes the light to reach us the Universe has been expanding. So, the Universe we can not see, because the light has not reached us yet , is out 46 billion lightyears in both directions. The diameter of the Universe today is 93 billion lightyears across.
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- Comparing the size of Earth ( 10^7 meters) to the size of the Universe (10^27 meters) is like comparing the size of a virus (10^-6 meters) to the size of the Solar System (10^14 meters).
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- And, we know that the Whole Universe is much, much larger than the 93 billion lightyears. Because the Universe is homogeneous in all directions and the geometry is flat, meaning parallel lines neither diverge or converge then the Universe must be infinitely bigger. The Cosmic Inflation that occurred during the first seconds of the Big Bang expanded the Universe faster than the speed of light.
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- When we conceive the Whole Universe we are no longer in the center. There is no center. Space and time are expanding in all directions, everywhere. Today we measure this expansion of space to be traveling at 47,000 miles per hour per each million lightyears distance. Once we see out a billion light years distance of expanding space we see galaxies receding at 47,000,000 miles per hour.
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- When we get to the edges of the Observable Universe over 46 billion lightyears the galaxies are moving away from us at 2,162,000,000 miles per hour. That is over 3 times faster than the speed of light. The speed of light is 670,633,500 miles per hour. That light will never reach us. Never.
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- Nothing can exceed the speed of light. So, how can a galaxy be moving that fast? It must be impossible, and , violating the Theory of Relativity. True, no “ thing” can travel faster than the speed of light. But, nothing says that space can not expand faster than the speed of light. The more space there is the faster things are expanding away from each other.
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- We have not violated the Pythagorean Theorem: E^2 = (mc^2)^2 + (mv*c)^2
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RSVP, please reply with a number to rate this review: #1- learned something new. #2 - Didn’t read it. #3- very interesting. #4- Send another review #___ from the index. #5- Keep em coming. #6- I forwarded copies to some friends. #7- Don‘t send me these anymore! #8- I am forwarding you some questions? Index is available with email upon request. Some reviews are at http://jdetrick.blogspot.com Please send feedback, corrections, or recommended improvements to: jamesdetrick@comcast.net. ---- “Jim Detrick” -- www.facebook.com, -- www.twitter.com, -- 707-536-3272 Tuesday, March 26, 2013
----------------------- # 1581 - Species - The Diversity of Life
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- There is an enormous diversity and complexity among the species that live on Earth. How many species of life are there? Estimated to be at least 9,000,000 different species with only 4,500,000 of them discovered and named. That count is not counting the variety of bacteria and microbe life. Life of any sort has not been discovered outside Earth. And, only half of life has been discovered on Earth.
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- Defining a unique species is not easy. And, there is much debate and disagreement of how the classifications are made. Therefore, these numbers are rounded off as today’s best estimates.
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- To define a species we start with “ the beginning of life” >>>>>> Domains >>>>> Kingdoms >>>>>> Phylum’s >>>>> Classes >>>>>> Families >>>>> Genus >>>>> Species. Species are defined as life that is capable of interbreeding. If you collect enough of interbreeding species believed to have the same ancestors you have a “ Genus”.
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- Here are the species categories you are familiar with:
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------------------------ DISCOVERED ----------------- ESTIMATED UNDISCOVERED
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------- Insects --------------- 950,000 -------------------------- 8,950,000
------- Plants ----------------- 270,000 -------------------------- 380,000
------- Arachnids ----------- 75,000 --------------------------- 740,000
------- Mushrooms --------- 72,000 --------------------------- 470,000
------ Mollusks ------------- 80,000 --------------------------- 250,000
------- Vertebrates --------- 56,000 ----------------------------- 61,000
------- Algae ---------------- 40,000 --------------------------- 400,000
------- Protozoa ------------ 30,000 --------------------------- 210,000
------- Crustaceans -------- 75,000 --------------------------- 180,000
------- Other --------------- 120,000 -------------------------- - 400,000
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--------- TOTAL --------- 4,500,000 ----------------------- 7,841,000
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- These numbers are rough estimates. For example there are other estimates that the total number of insects is 30,000,000 not the 9,900,000 that I have listed above. Finding and identifying species on Earth is still work in process.
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- If you are reading this you are one of the vertebrates classified among the 5,490 mammals. The rest in your family of the species are fish, amphibians, reptiles and birds.
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- Now to really stretch your thinking ponder this: all of this diversity started from a single gene pool.
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- Mice and humans share 80% the exact same protein coded genes. 80% of us comes from the same gene pool. We are just learning this stuff as we can study DNA at the microscope level. To understand the DNA substructures your vision must get down to 100 angstroms, or 10 nanometers. A hydrogen atom is 1 angstrom or 0.1 nanometer in diameter.
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- When science can witness this level of substructure they can learn how the genetic message of DNA is copied to RNA for the production of proteins. Understanding this process is critical for the growth , development, health, and survival of the species.
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- Counter- intuitively the total number of genes is not evidence of the complexities of the species. A Fruit Fly is far more complex than the nematode worm yet the worm has 20,000 genes and the Fruit Fly has 14,000 genes. We humans have between 30,000 and 40,000 genes. These numbers are still in the process of discovery. Genomes are still being sequenced in plants and animals.
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- What science has already learned is that the number of genes do not create complexity but, the various combinations and multiple transcription factors are what create evolutionary complexity. The species with the highest known number of genes is the protozoan with 60,000 genes, 3 times as many as the human sub-species.
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- The recent discoveries are being made using a single-particle cryo-electron microscope recording a series of 2D images, then, using a computer to create a high-resolution 3D reconstructions.
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- The genome is the entirety of a species hereditary information. With it science can trace the ancestors of species and clearly tell which species are related. Genomes include both the genes and other non-coding sequences of DNA/RNA. An announcement will be made shortly, stay tuned.
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RSVP, please reply with a number to rate this review: #1- learned something new. #2 - Didn’t read it. #3- very interesting. #4- Send another review #___ from the index. #5- Keep em coming. #6- I forwarded copies to some friends. #7- Don‘t send me these anymore! #8- I am forwarding you some questions? Index is available with email upon request. Some reviews are at http://jdetrick.blogspot.com Please send feedback, corrections, or recommended improvements to: jamesdetrick@comcast.net. ---- “Jim Detrick” -- www.facebook.com, -- www.twitter.com, -- 707-536-3272 Sunday, March 24, 2013
----------------------- # 1580 - Asteroids the bricks that build Solar Systems
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- Asteroids have been in the news lately. Some are called comets. There is really little difference. Asteroids are rocks and Comets are loose rocks with water ice that makes for a great tail when they orbit near the Sun. Asteroids too may be loose rocks and not always solid rocks. This is important because loose rock asteroids would form planets more quickly. Knowing the density of asteroids would help us understand how our Solar System first formed.
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- Knowing how our Solar System formed would help us understand the more than 1,500 planets we have now discovered orbiting other suns. What are the differences between our solar system and their solar system? Our Solar System formed in 200,000,000 years 4.5 billion years ago, just a billion years after the Sun formed. If we can understand solar system formation we may be able to predict the chances of life evolving on other planets.
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- Density is mass / volume. The density of water is 1 gram / cubic centimeter. A density of 3 to 5 grams/ cm^3 would be a rocky asteroid. Density of 1 to 2 gm/cm^3 would be a rocky rubble, a comet, a dirty snowball.
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- There are 551,621 registered asteroids. Registered means their size has been estimated and their orbits have been calculated. However, we do not know the mass or the volume of most asteroids. Most asteroids lie between the orbits of Mars and Jupiter. Some “Trojan” asteroids are in the same orbit of Jupiter, either ahead or trailing. The belt of asteroids would have formed another planet except for the fact the that Jupiter’s gravity created tidal forces that kept pulling them apart.
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- The biggest asteroid in the belt is Ceres, 1,000 kilometers in diameter. Vesta is the second biggest. See Review # 1572 to learn about a spacecraft that visited Vesta in 2012. Now the same spacecraft , “ Dawn” has left Vesta and is on its way to Ceres.
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- There are millions of asteroids that have not been registered. Some are greater than 150 meters in diameter and are in Near Earth orbits. There are 6,000 of these Near Earth asteroids that are known. 15 of them have been visited by spacecraft. “Lutetia” had a recent visit. It is a dumbbell shaped asteroid that is 100 kilometers long. “ Mathilde is 53 kilometers and has a 30 kilometer crater.
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- See the pictures of these asteroids by google” “ Cosmic Diary Network” a blog by Franck Marchis.
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- We know the Sun formed with an accretion disk of dust and rocks and water and gas. And, gravity within the disk caused a chaos of collisions between all this material. As collisions grew bigger and gravity became stronger more collisions created big enough asteroids to be called planets. When asteroids get a certain size gravity pulls them into a perfect sphere and creates a core at the center. We believe this planet formation took only 200,000,000 years. Back to the density problem:
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- Most asteroids are not spherical because they are not massive enough. If their density is solid rock it is hard to calculate how solid rock collisions could have formed planets in 200,000,000 years. However, if asteroids are low density “ rubble piles” then collisions could collect into larger planet sized rocks more readily. That is where the four Terrestrial Planets came from, asteroid collisions.
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- In 1994 spacecraft visited asteroid “ Ida” and it was found to have a moon. To date 205 asteroids have been found to be binaries, or have moons. “87 Sylvia” has 2 moons. Its mass is 1.48*10^19 kilograms, its size is 192 km by 132 km by 116 km. It is 25 to 60 % porous and has a density of 1.2 gm/cm^3. This information could all be calculated because the asteroid had a moon. The orbit velocity and distance of orbit allowed calculations of mass. Dimensions gave us volume. The conclusion came from the density being not much more than pure water. This can not be a solid rock asteroid.
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- Adaptive optics are now being used on telescopes to see the moons orbiting asteroids. Many more density calculations will tell astronomers better how our Solar System formed. They can then compare this knowledge with what they learn about the exoplanets in other solar systems.
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- Nano-telescope satellites have been funded to do the job like Hubble but using much smaller ad cheaper telescopes just for studying asteroids. Light curves of these asteroids can be studied to determine orbits and their spectrum to determine mineral composition.
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- Protecting us from and Earth- asteroid collision is not the only motivation for studying asteroids. Having time to send a spacecraft to deflect its trajectory is certainly a worthy goal. But, learning how our Solar System formed and the potential for life on other planets is too. An announcement will be made shortly, stay tuned.
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RSVP, please reply with a number to rate this review: #1- learned something new. #2 - Didn’t read it. #3- very interesting. #4- Send another review #___ from the index. #5- Keep em coming. #6- I forwarded copies to some friends. #7- Don‘t send me these anymore! #8- I am forwarding you some questions? Index is available with email upon request. Some reviews are at http://jdetrick.blogspot.com Please send feedback, corrections, or recommended improvements to: jamesdetrick@comcast.net. ---- “Jim Detrick” -- www.facebook.com, -- www.twitter.com, -- 707-536-3272 Saturday, March 23, 2013
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1580 - Asteroids the bricks that build Solar Systems. Knowing the density of asteroids would help us understand how our Solar System first formed.
----------------------- # 1579 - Socrates, a great teacher
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- Socrates was a great teacher. His method of teaching was not to lecture, not to answer questions. But, more simply to return a more thoughtful question for every question asked. This would allow self-discovery in the pursuit of knowledge. Teaching how to learn.
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- To illustrate Socrates teachings. Get a pencil and paper and follow along as Socrates teaches a slave some geometry. He begins by drawing a large square in the sand. He then extends 2 lines through the center to divide the larger square into 4 smaller squares. Now each square is 1 square foot and each side is 2 feet.
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- Socrates: What is the area of the square? How many square feet are there?
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- The slave easily sees that the larger square is 4 square feet, the sum of the 4 smaller squares.
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- Socrates: What would be the length of one side needed to double the area of this square? Double the area is 8 square feet.
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- The slave instinctively says that each side must be 4 feet long.
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- Socrates: Instead of telling the slave his answer is wrong. Socrates simply takes his answer and draws a larger square 4 feet on a side. He then shows that inside the larger square are 3 more squares like the previous one. Again dividing each of the squares into smaller 1 foot squares the slave is quick to see that the area is 16 square feet, not the 8 square feet desired.
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- The slave realizes that sides of 2 feet is too small and sides of 4 feet is too large he says that the answer must be 3 feet sides.
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- Socrates: Again Socrates takes his answer and draws another square 3 feet on a side. When divided up the count is an area of 9 square feet. The area is too large. How are we going to find the length of the side that will be the correct answer of 8 square feet?
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- The slave says “ I do not know”
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- Socrates says this is important knowledge. Before you thought you knew but you were mistaken. Now, you know you don’t know. Now, your mind is open to inquiry for new knowledge.
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- To help the slave see the solution Socrates asks the slave to go back to the original square that is 4 square feet. Then to the larger square that is 16 square feet. How much bigger is the larger square than the smaller square?
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- 4 times bigger.
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- Socrates: We want our answer to be 2 times bigger. Take the smaller square and draw a line from corner across the center to the other corner. You have divided that square in half. Do the same to the other 3 squares. Do the 4 equal lines you drew contain a square inside the larger square?
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- Yes!
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- What is the area of one triangle that you have created when you divided the square in half?
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- ½ for the 4 square feet is 2 square feet. Each triangle is 2 square feet.
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- Socrates: How many triangles are there?
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- 4 triangles, each 2 square feet, the total area of the new square is 8 square feet. That is the answer we wanted.
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- The line stretching from corner to corner of the new square is the proper length to have a square that is 8 square feet.-
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- If the teacher were Pythagorean, instead of Socrates:
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---------------------- 2 feet^2 + 2 feet^2 + 2 feet^2 + 2 feet^2 = 8 feet^2
---------------------- Square root of ( 2^2 + 2^2 ) * Square root of ( 2^2 + 2^2) = ?
---------------------- Square root of ( 8 ) * Square root of ( 8) = 8
---------------------- ( 2.83 ) * (2.83) = 8
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- Each side is 2.83 feet long and the hypotenuse of the right triangle is equal to the square root of the sum of the squares of the other 2 sides.
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- Teacher: What do you call a person who keeps talking when people are no longer listening?
- Student: A teacher.
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- Teacher: Noah, your composition on “ My Dog” is exactly the same as your sisters. Did you copy Ava’s paper.
- Noah: No sir, it’s the same dog.
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- Teacher, Nathan, name one important thing we have today that we did not have 10 years ago?
- Nathan: Me
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- Teacher: Why are you late?
- Noah: Class started before I got here.
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- Teacher: Why are you doing your math multiplications on the floor?
- Noah: You said to do it without using the tables.
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- Maybe it “is” wrong, but you asked me how “ I “ spell it.
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RSVP, please reply with a number to rate this review: #1- learned something new. #2 - Didn’t read it. #3- very interesting. #4- Send another review #___ from the index. #5- Keep em coming. #6- I forwarded copies to some friends. #7- Don‘t send me these anymore! #8- I am forwarding you some questions? Index is available with email upon request. Some reviews are at http://jdetrick.blogspot.com Please send feedback, corrections, or recommended improvements to: jamesdetrick@comcast.net. ---- “Jim Detrick” -- www.facebook.com, -- www.twitter.com, -- 707-536-3272 Friday, March 22, 2013
