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Here's the latest article from the Astronomy site at BellaOnline.com.

Scale of the Universe 2 - website
How big is the Universe? And how small? This website takes you from yoctometers - unbelievably small - to yottameters – just as unbelievably big. Navigate up or down from the human scale, with drawings and diagrams that make sense of the numbers. A great tour for everyone.

http://www.bellaonline.com/articles/art182060.asp

*Birthday*

Edwin Hubble was born on November 20, 1889. To most people Hubble's name is best known because of the great space telescope that bears his name. However Hubble's work was worthy of this tribute to him.

Hubble was the first person to demonstrate that the Andromeda Nebula was not an object in the Milky Way, but a galaxy in its own right. He found a variable star in the “nebula” and using Leavitt's Law, calculated that it was far too far away to be part of our Galaxy. Here is a picture of the photographic plate and Hubble's marks: http://www.pinterest.com/pin/250090585531415562/ (To find out more about Henrietta Leavitt: http://www.bellaonline.com/articles/art29166.asp)

But Hubble's next revolutionary work was an investigation into the relationship between the distance of redshifted galaxies and their velocities. He showed that the more distant they were, the faster they were receding. This provided evidence for the cosmological idea that the Universe was expanding. Even Einstein, who had rejected the idea, was convinced by Hubble's work.

*What happened to Mars's water?*

Evidence tells us that Mars was warmer and wetter four billion years ago. Mars may well have looked more like this than the red desert we know today: http://www.pinterest.com/pin/250090585531408166/. But it lost its atmosphere starting around 3.5-3.7 billion years ago. As the atmosphere thinned, the surface water went. Where did the water go? What happened to the atmosphere? NASA is sending MAVEN (Mars Atmosphere and Volatile Evolution) to study the Martian atmosphere to try to find out. It was launched on November 18.

In this short video, LeVar Burton - space enthusiast and actor (Stark Trek) - explains, on behalf of NASA, what the MAVEN mission hopes to accomplish: http://www.pinterest.com/pin/250090585531408185/.

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I wish you clear skies.
Mona Evans, Astronomy Editor
http://astronomy.bellaonline.com

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