Astronomy news

Star gas

William Thompson sent the following link, http://newsinfo.nd.edu/news/25691/, which is Notre Dame University. It seems that two of its astrophysicists, N Lehner and C Hawk, have published a paper in Science (August 26th) that is important in our understanding of how stars are made - continuously. The same story can be seen at www.sciencedaily.com/releases/2011/08/110825164931.htm and at www.physorg.com/print233510806.html.

Youthful Moon - or not so youthful

A paper in Nature August 17th - see www.physorg.com/print232805174.html - is suggesting the Moon is somewhat younger than previously alleged, created by a giant impact between two bodies one of which was proto-earth. The Moon then formed from melted material ejected into space. It is further alleged that analysis of lunar rocks, or sample so far retrieved, can only be dated as far back as 4.36 billion years ago. This may sound quite old but apparently it is younger than earlier estimates of the Moon's age - which were 4.5 billion years ago.

The zodiacal light, meteor streams, and dark matter - is it an illusion?

At www.physorg.com/print190569543.html (April 15th 2010) is a piece on the dust between planets that scatters sunlight. Its origins are in comets according to Nesvorny and Jennisken (April 20th, The Astrophysical Journal). The zodiacal dust cloud is regularly replenished.

Roaming planets ... again

At a variety of blogs, for example at www.dailymail.co.uk/sciencetech/article-2023778/Planets-survive-stars-su... , we have this story that is basically a paper that purports to explain the discovery of planets unattached to star systems, lots of them. A new theory has inevitably been devised by (experts, according to the Daily Mail reporter). They suggest such planets may have been ejected from solar systems by supernova events (the explosion of stars).

Water on Mars?

NASA News at www.jpl.nasa.gov/news/news.cfm?release=2011-242&cid=release_2011-242 claims they have discovered water on Mars - briny water that flows in spring but disappears in the winter. However, the images are in regions too cold for water yet some kind of volatile has been detected - hence the idea of salty water.

At www.physorg.com/print231669586.html we hear that NASA is reporting two active regions on the Sun, or in general terms, two sunspots have sprouted and a solar flare is being predicted.

The mirror in the universe

At www.dailygalaxy.com/my_weblog/2011/08/could-mirror-matter-be-the-hidden-... (Augusts 4th) ... begins with, if dark matter exists it may take the form of mirror planets, mirror stars, and mirror galaxies (a bit of a mirage it would seem). The failure of physicists to actually find tangible evidence of dark matter has led to the idea of 'mirror matter' (basically a spatial reflection of ordinary matter).

Comet Elenin

At http://wattsupwiththat.com/2011/07/31/roll-to-observe-elenin-stereo-behi... we learn that NASA has just rolled its STEREO solar satellite to have a look at Comet Elenin P/2010X1, a comet which has attracted a lot of hullabaloo. The comments to this story are therefore worth browsing. One link for a sober look at Elenin is www.skyandtelescope.com/community/skyblog/observingblog/119704774.html 

Alfven Waves

At www.physorg.com/print230986047.html ... a paper in Nature on the role of oscillation in the corona of the Sun, known as Alfven waves, points out that when first observed in 2007 their amplitude did not appear great enough to drive the solar wind. New satellite observations reveal Alfven waves a 100 times stronger - enough to heat the Sun's outer atmosphere to millions of degrees and drive the solar wind. The waves are seen in high resolution images and can be viewed at www.sciencedaily.com/releases/2011/07/110727131404.htm

Trojan Asteroid.

A Twisted Tale of our Galaxy

At www.jpl.nasa.gov/news/news.cfm?release=2011-216&cid+release2011-216 ... a press release from NASA on the discovery by the Herschel Space Observatory that the Milky Way is not quite like how it was thought to be - and neither is the centre of the galaxy quite where it is supposed to be. An abstract and pdf version of the Astrophysical Journal Letters study is online at http://arxiv.org/abs/1105.5486 and more information can be found at www.nasa.gov/herschel and www.esa.int/SPECIALS/Herschel/index.html 

Vesta

The NASA Dawn spacecraft has returned images after starting its orbit around the asteroid Vesta - and various blogs and web sites have a picture of a lump of rock with depressions in it caused by smaller objects hitting it (the commonest culprit) - see www.jpl.nasa.gov/news.cfm?release=2011-213&cid=release_2011-213. Vesta is 330 miles across, or 530km, one of the biggest objects in the Asteroid Belt. Vesta is thought to be a source of meteorites that hit the earth from time to time.