December 17 2014 Astronomy Newsletter
Here's the latest article from the Astronomy site at BellaOnline.com.
Cosmic White Christmas
If you're dreaming of a white Christmas, the cosmos may have something of interest. How about deep snow on one of Saturn's moons, a gigantic Christmas tree whose lights are baby stars, a snowman on an asteroid or an Einstein ring?
*Martian meteorite – evidence of life?
An international team of experts analyzed the organic carbon in the Tissant meteorite and concluded that it's probably of biological origin. The meteor was flung into space by a collision on Mars about 700,000 years ago. Interestingly, I mentioned this meteorite in last week's article about the Natural History Museum in London: http://www.bellaonline.com/articles/art300439.asp This is because the museum has a piece of the Tissant meteorite. In 2012 an international team examined the meteorite and were very excited that it shows clear evidence of water weathering. One of those involved was Dr. Caroline Smith, the museum's curator of meteors, who said that they hadn't found any evidence of life in the meteor.
*Birthday: E.E. Barnard (1857-1923)*
Edward Emerson Barnard, born on December 16, 1857, was one of the great observational astronomers of his day. Among other things, he discovered 15 comets. He also has a star named after him. He was born into poverty, as his father had died soon before his birth, leaving only his mother to support the family. Barnard had little formal education and was largely self-taught, including his knowledge of astronomy. But the brilliance of his work earned him honors and an appointment as a professor of astronomy at the University of Chicago.
The winter solstice is on December 21st. This will be the shortest day in the northern hemisphere, and we can look forward to noticing the difference in day length several weeks into January. You can find out more about the solstice and how it's celebrated: http://www.bellaonline.com/articles/art179016.asp
On the day of the winter solstice 1968, Apollo 8 was launched. Its crew were the first humans to leave Earth's gravitational field and journey into an orbit around another world. It's one of the stories in this article about astronomy-related Christmas events: http://www.bellaonline.com/articles/art179016.asp
*Christmas gamma ray burst (GRB)*
One story that didn't make it into the article above is the gamma ray burst that NASA's Swift observatory detected on Christmas Day 2010. Gamma rays are extremely energetic radiation and a burst of them signals a massive explosive event somewhere. Astronomers are still not too sure what caused this GRB. There were two main theories at the time – and since then a third has been proposed. I'll settle for being glad that whatever happened it was a long way, as a nearby GRB would definitely be Very Bad News for us. You can see how someone has depicted this event modelled on a famous Van Gogh painting: http://www.pinterest.com/pin/250090585533618039/
Please visit astronomy.bellaonline.com for even more great content about Astronomy.
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I wish you clear skies.
Mona Evans, Astronomy Editor
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