New Views Of The Early Universe Shed Light On Mysteries of Star Birth

Astronomers have recently gotten the clearest views of some of the most mysterious phenomena in the early universe: The "star factories" where new stars switch on. How exactly do you ignite a star? We are closer to knowing than ever.

The new star factories the astronomers discovered are in the galaxy dubbed SMM J2135-0102. And much to the astronomers surprise, they found that it was producing stars 250 times faster than our own galaxy!

How are stars "born" in the first place? For stars like our Sun, life begins in a molecular cloud (the Orion Nebula at the top of this post is a prime example), which are typically located in the "arms" of spiral galaxies. These molecular clouds contain the building blocks of stars, mostly molecular Hydrogen as well as (although far less abundant) Carbon Dioxide and Water. As these clouds are bombarded by interstellar radiation from nearby stars (so called
galactic winds, small turbulent eddies of gas and dust begin to form, eventually coalescing into enough mass to begin collapsing under its own gravity.

New Views Of The Early Universe Shed Light On Mysteries of Star Birth

As these clumps begin to further collapse (for roughly 10 billion years), they begin to spin thanks to angular momentum . A disk of in-falling material begins to form around the clump and it is at this point that we have a "protostar." This in-falling gas causes the pressure and temperature of the protostar to increase, allowing it to be seen in the infrared spectrum . Up until this point, thermonuclear fusion (a star's main power source) has yet to begin inside of the protostar. It is not until enough matter has accreted onto the protostar (typically this takes a few million years), that the critical pressure is reached to begin bonding hydrogen into helium . And with that first fusion of atoms, we have a star!

Now while this process may seem quite simple, this is only for fairly recent star formation. What about for stars forming in the early Universe (which was a much more disorganized place than the Milky Way galaxy)? Thanks to a gravitational lens, scientists at the Harvard-Smithsonian Center for Astrophysics (CfA) have gotten a peek at the star forming regions of the early Universe. Of the 4 star forming regions discovered in SMM J2135-0102, astronomers found that they were 100 times brighter than similar regions in nearby galaxies. According to astronomer Mark Swinbank of Durham University, "We don't fully understand why the stars are forming so rapidly, but our result suggests that stars formed much more efficiently in the early universe than they do today."

These new results shed light on an era in the universe when many stars were first forming and galaxies were first developing. Astronomers hope that this new data provides insight into how galaxies like the Milky Way formed. According to Steven Longmore of the CFA:

That will allow us to test exactly how generic our results are: Is the star formation occurring within galaxies in the early Universe always so vigorous? Or are we catching this particular galaxy at a very special time?

Via Nature