Astronomy news

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.

Ceres and Vesta - a foretaste to a visit by the Dawn spacecraft

Astronomy and Astrophysics journal is publishing a study of the orbital evolution of minor planets, including asteroids such as Ceres and Vesta, in the lead-up to the visit by the Dawn spacecraft. It seems that the earth's past orbit cannot be reconstructed beyond 60 million years ago, it is claimed. In other words, the past orbit of the earth is open to conjecture and it is not as cut and dried as uniformitarianism would have us believe.

Black Holes

At www.physorg.com/print229767192.html there is some speculation about the origin of black holes. They were not formed by mergers between galaxies as hypothesised elsewhere, it says. They are mostly found in massive galaxies with lots of dark matter, it is alleged, and continues by saying they are absent in galaxies of moderate mass. The information is derived from space telescopes and cameras and is published in the Astrophysical Journal and represents an attempt to explain why some galaxies have extremely bright features, evidence of activity, and others are less bright.

The Sun ... dark fireworks

This story is at a variety of sites but www.physorg.com/print229686172.html is as good as most. On June 7th this year, 2011, a flash of X-rays was registered with an origin in the Sun - but was fairly moderate as these things go. However, when astronomers looked at the images taken by cameras on satellites circling the earth they were astonished at the intensity of the solar storm. A video and a smaller You Tube version is available online to view.

Dwarf Galaxies ... again

At www.dailygalaxy.com/my_weblog/2011/07/is-there-a-fundamental-flaw-in-our... is an interesting question - and it is all up for grabs. The bigger galaxies are supposed to form from a merger of smaller galaxies but the properties of dwarf galaxies do not seem to match this scenario. Eline Tolstoy from the University of Groningen in the Netherlands draws attention to this anomaly. Dwarf galaxies are the most straight forward objects astronomers can study as far as star formation is concerned.

Dwarf Galaxies

Pavel Kroupa of the University of Bonn, and colleagues, analysed the notion of dwarf galaxies, thousands of stars that orbit the Milky Way. These are apparently orbiting in a plane rather than being evenly distributed - which is a problem for calculations. These seem to show such small galaxies do not contain dark matter yet, observations of their orbital speed implies they should contain dark matter as the extent material is not enough to explain the velocities inferred.