Index of recent Reviews

-  Here is an index of recent Reviews.
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-  If interested I can send them txt or email?  Just specify number.
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-   2478  -     UNIVERSE  -   what is its shape?  Astronomers look at data from the cosmic microwave background (CMB), the faint echo of the Big Bang, and are convinced that the universe is curved. This slow bending is not important for moving around our lives, or solar system, or even our galaxy. But, travel beyond all of that, outside our galactic neighborhood, far into the deep blackness, and eventually moving in a straight line you will loop around and end up right back where you started.
-   2479  - EQUATIONS -  making sense without the math.   Mathematical equations  are quite beautiful.  They present scientific truths simply and unequivocally.  Until,  they are proven wrong or incomplete by a more elegant truth in science.  Here we try to describe them without using the math symbols.
-   2480  -  -  ENERGY  -  Conservation of Energy.  -  We Earthlings need to learn how to conserve Energy.  We have two main problems facing us in the next 50 years.  The first is overpopulation.  Mother Nature can not sustain this many people on this small planet without irrevocable harm.  The second is Energy.  Over consumption of Energy is far outstripping our supply.
 -   2481  -  MERCURY  -  our planet next to the Sun.   Mercury’s transits outlast any eclipse. Enduring for nearly 5.5 hours, even the longest lunar eclipses fall short at about 4 hours.  Enjoy these  fantastic facts now about the transit of the planet Mercury as the next transit won’t arrive for 13 years.
-   2482  -  MATH  -  interest rates and growth   Let’s say the population growth is increasing at 2% per year.  How soon will it double?  We have a world population today of 7 billion. In 35 years, in the year 2046 the population will be 14 billion unless we lower the growth rate.  This is the most important math you will ever learn. 
-  2483  - EINSTEIN  -   testing his theories?    Einstein’s principle of relativity simply says that any two observers no  matter where they are or how they are moving will see the laws of nature operating the same way.  The Universe is the same for everybody, everywhere.  Descriptions of events are relative to the observer ------- the laws of nature are not.
-   2484 -  BIG BANG  -  how do we know what happened? There are two things that people learn about the Universe and the Big Bang is that surprise them more than any thing else.  The Universe hasn't existed forever but only for a finite time since the Big Bang, and that it's been expanding ever since that event took place.   Today it is accelerating in that expansion.
-  2485  -    ENERGY  -  all forms add up to zero?  All the forms of energy include positive and negative, north and south, matter and anti-matter so when you add up all the energy in the universe it comes to zero.  Zero is how it started, zero is how it is today ,and zero is how it will end.
-   2486  -  EARTH  -  Third Rock from the Sun.  The Sun’s energy itself is changing in its light energy.  It has several cycles of its own , “Could Our Sun Be a Variable Star?”  .  Today we are considered to be in a normal warming trend.  Global warming is claimed to be exacerbating this warming trend with human burning of fossil fuels and putting greenhouse gases into the atmosphere.
-   2487  -   CONSTANTS  -  Are our Natural Constants Changing?  The constants in Nature are very interesting.  We depend on them being constant in all our mathematical calculations and scientific understandings of how nature works.  But, we do not know where the constants came from, how they are what they are, they just are.  Now, questions are being asked, have they always been constant and are they changing?
-   2488  -  SUN  -  how hot is it?   How do we know that? How can we possibly  measure the temperature of the Sun?  Well, we know that radiation energy decreases as the square of the distance from the source.  We calculate the total energy from the Sun.  Then, we calculate the energy from the surface of the Sun.  It is in the math.
-   2489  -   SUN  -  facts you won’t believe?  -   The Sun is HOT but not so HOT.  In fact, your body heat is hotter than the Sun.  What?  You’re kidding?  Right? What you will learn from this review is that the Sun is not so hot but it is so big. 
-   2490  - QUASARS  -   light from distant past?  -  Quasars are Black Holes with personalities.  A lot of different personalities.  Many of the different objects in the Universe that astronomers have identified are actually the same thing, Quasars that are different sizes, different ages, and viewed from different perspectives.
-   2491  -  ASTRONOMY  -  how the Greeks started it?    The Greeks were the ancient astronomers.  They were scientists.  The Babylonians were great observers and recorders.  The Egyptians were great technicians and technologists.  But, the Greeks were scientists.  Every student should learn how their powers of observation and thought changed the world.
-   2492  -  ELECTROMAGNETIC  SPECTRUM  -  how we see?  Light is electromagnetic radiation, interdependent, mutually perpendicular transverse oscillations of electric and magnetic fields.   The spectrum of light is defined by the wavelength of a single cycle of this oscillation.  The spectrum of light that our eyes can see stretches from violet light at 400 nanometers wavelength to red light at 700 nanometers wavelength.  But, there is much more that we don’t see.