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Earth part of a galaxy which is being consumed by the Milky Way. Read On...
Rediff Features Bureau
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June 26, 2007 13:09 IST
Remember preening over all that stuff about how we earthlings were part of this magnificent galaxy called the Milky Way?

Brace yourself for a shock, bring out those handkerchiefs while wailing violins build to a crescendo around you: The earth is actually part of a formation called the Sagittarius Dwarf galaxy; an entity so small -- in the larger scheme of the cosmos -- that it got swallowed up by the Milky Way.

Media reports cite a major project headed by University of Massachusetts astronomers in the United States that prove the Milky Way is gobbling up a smaller, neighboring galaxy in what reports, tongue in cheek, refer to as ongoing galactic cannibalism.

The study, published in the Astrophysical Journal, demonstrates how the debris from the Sagittarius galaxy, which is 10,000 times smaller in total mass than the Milky Way, is getting consumed by the latter.

The Sagittarius galaxy had itself been discovered by a team of British astronomers in 1994; the latest study, relying heavily on infrared maps of the universe to strip away millions of foreground stars and home in on Sagittarius, demonstrates how the latter has been pulled into the Milky Way's area of cosmic influence.

'We sifted several thousand interesting stars from a catalog of half a billion,' co-author Michael Skrutskie, a University of Virginia and principal investigator for the 2MASS project. 'By tuning our maps of the sky to the 'right' kind of star, the Sagittarius system jumped into view.'

Astronomers have been puzzling over the fact that from our point of view, the Milky Way is seen at an angle. Had the sun been part of this galaxy, it would have been oriented to the Milky Way's own path, and the planets including Earth would have been oriented around the sun in the same way as the sun aligns with the Milky Way.

The fact that the Milky Way is at an odd angle in our sky first suggested, researchers say, that the Sun is influenced by some other system.

That system has now been identified.

Scientists now say that over a period of two billion years, the Sagittarius galaxy has been dying as an entity, with the Milky Way meticulously consuming its bulk.

'After slow, continuous gnawing by the Milky Way, Sagittarius has been whittled down to the point that it cannot hold itself together much longer,' team member study co-author Martin Weinberg of the University of Massachusetts is quoted as saying. 'We are seeing Sagittarius at the very end of its life as an intact system.'

So what does any of this have to do with us?

The simple answer, in two words, is: Global warming.

Scientists postulate that as the Sun and its attendant satellites, including Earth, get consumed by the Milky Way, the higher energy levels in this much larger galaxy will cause the Sun to burn hotter, and to emit higher energy.

This, scientists say, is one reason temperatures have been rising steadily in all plants in our solar system.

Things are going to get considerably hotter all round.

As the consumption of Sagittarius by the Milky Way continues, further changes are being spotted, and monitored, in our own planetary system: Dark spots appearing, and growing, on Pluto; auroras being reported on Saturn; the polar shifts in Uranus and Neptune; the doubling of the intensity of the magnetic field on Jupiter.

Change is constantly, continuously, happening on the Sun, and the planets, thanks to this forced galactic marriage of Sagittarius with the much larger Milky Way -- and scientists are, thanks to this discovery, only now beginning to quantify this change, and its implications for all of us.

Time, meanwhile, for us to get used to our status as adoptive children of the Milky Way, rather than its own natural scions.

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