Tuesday, June 5, 2007

187)A young mother star(sun) and her baby planet:embryology of a forming planet.

The process that forms new planets today is the same process that formed our sun 4.8 billion years ago and our planet earth 4 billion years ago. One can take a front row seat today and observe the formation of new stars and planets, all at different stages of their development, in, for example, the Orion Nebula, not very far away from our own solar system in the Milky Way galaxy:

"The creation according to Islam is not a unique act in a given time but a perpetual and constant event; and God supports and sustains all existence at every moment by His will and His thought. Outside His will, outside His thought, all is nothing, even the things which seem to us absolutely self-evident such as space and time. Allah alone wishes: the Universe exists; and all manifestations are as a witness of the Divine will."(Aga Khan III, Memoirs, 1954)

Planet formation

When worlds collide

May 31st 2007
From The Economist print edition

Theories of how dust and ice become home

STELLAR and planetary nurseries are private places. Unfortunately for science, the nearest young stars that could be producing planets are so far away that conventional telescopes are unable to discern what is in the cradle. Moreover, such births are shrouded in swirling discs of dust that normally prevent the curious from taking a peek at the new-born. But one astronomer has just done precisely that.

Joshua Eisner of the University of California, Berkeley, trained his attention on a star a mere 6m years old. It goes by the name of MWC 480 and lies some 450 light years away in the constellation Taurus. By combining the light-gathering power of two telescopes on the summit of Mauna Kea, in Hawaii, Dr Eisner was able to create, in effect, a giant telescope.

The discs surrounding stars consist mostly of hydrogen, but they also contain small quantities of dust and ice. Hitherto, it was thought that dust, ice and gas were thoroughly mixed together in these discs.

As Dr Eisner reports in this week's Nature, however, by focusing his combined telescopes on the region of the disc close to MWC 480—in other words, the part corresponding to where the Earth formed round the sun—he was able to see distinct zones within the disc. He saw that the constituent parts were being separated, with hydrogen gas falling into the star while water vapour remained farther out and the dust was farther out still.

This discovery could help to explain how water comes to be incorporated into rocky planets such as the Earth. It could also help illuminate how giant, gaseous exoplanets often come to orbit their parent stars so closely.

The dominant theory of planetary formation argues that each system started out as a cloud of debris orbiting a star. Within the cloud, some parts are sufficiently dense to start collapsing under their own gravity. Specks form into clumps, these collide with other clumps, and the process continues until all the matter in any given orbit is concentrated into one object—a planet. Rocky planets would form nearest the parent star, with gas giants farther out.

The problem is that most of the exoplanets detected to date, being gas giants, are too close to their stars to have been born there. Astronomers think they must have migrated in from the outer reaches. But having started to spiral inwards, why have they then stopped?

Dr Eisner argues that the separation of material in the protoplanetary disc indicates that something—possibly the star's magnetic field—is holding some forms of matter away from the surface. He thinks exoplanets are pulled towards the star by the dust and that when the dust runs out, the exoplanets stop moving. Mother, it would appear, has ways of holding her offspring at arm's length.


Islam, eminently logical, placing the greatest emphasis on knowledge, purports to understand God's creation:Aga Khan 4(2006)
The God of the Quran is the One whose Ayats(Signs) are the Universe in which we live, move and have our being:Aga Khan 3(1952)
Our interpretation of Islam places enormous value on knowledge. Knowledge is the reflection of faith if it is used properly. Seek out that knowledge and use it properly:Aga Khan 4(2005)