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Where Exactly Do You Think You Are You Right Now?

You are a tiny speck on a rock that is speeding along 
traveling over a million miles a month as it whirls around the Sun.
Light travels 9,500,000,000,000,000 meters in a year.
The nearest star is about 4 light years (ly) away.
The solar system is a part of the Milky Way galaxy comprised of 1,000,000,000,000 stars
(The Milky Way is 10,000 light years in diameter).
The neighborhood of galaxies near us has a diameter of 3,000,000 light years.
The Universe has many clusters of galaxies tens of millions of light years in diameter.
Clusters of galaxies are spaced out, on the average, by hundreds of millions of light years.
We see those galaxies in all directions, and with our biggest telescopes we can detect them 
at a distance of several billion (1,000,000,000) light years. When we look out into space 
we are looking back in time.
These clusters of galaxies are all moving 
away from each other. This motion tells us that the universe is expanding. 
From Michael Zeilik, Astronomy: The Evolving Universe,6th Ed., 1991

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Do you use your mind to do experiments? What is a thought experiment?
"Here is Einstein's own example of the principle of equivalence. 
Imagine that you are on the earth in a spacecraft with no windows. 
If you drop objects in the spacecraft and measure their accelerations,you would 
find that they fall with the same acceleration 9.8 m/s/s. Now suppose that 
without your knowledge, you and the spacecraft were placed out in space and 
constantly accelerated at 9.8 m/s/s. Repeat your experiments dropping other objects.
They will accelerate at 9.8 m/s/s. Where are you? You'd probably conclude that you 
were still on earth-unless you could look out of the spacecraft.You cannot, by your 
experiments, distinguish between the effects due to a gravitational force and those 
due to the force of a rocket engine" (Zeilik 1991).

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Evolution is the change in allele frequencies in a population over time, 
but the Earth is not impermeable. The original chemical building blocks for life 
may have been seeded around the galaxy by comets. 

Comets are probably also the cause of periodic mass extinction events such as the
the one that wiped out the dinosaurs and led to the rise of the mammals from an
ancestral mole-like mammal that probably survived underground.
Scientists are currently examining meteorites from Antarctica 
and believe that they have found evidence suggesting evolution and life on Mars.

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