Most Distant Galaxy Gives Clues to Early Universe

NinjaT writes "From CNN, 'Scientists said on Wednesday that they have found the most distant galaxy yet, nearly 13 billion light-years away, in a discovery that could help explain how stars were formed at the dawn of time. The galaxy, named IOK-1, is so far away that the light waves that reached Earth depict it as the system of stars existed shortly after the Big Bang created the universe 13.66 billion years ago. That period, known to astronomers as the Dark Ages, saw the formation of the first stars and galaxies from elementary particles. Scientists had been unable to directly observe that time period until now.'"

Comments

Re:I know cosmology is an inexact science but

[HuguesT]

From very far away they are not so easy to tell apart. Essentially these are two objects that emit extremely red-shifted light.

Re:What I find difficult to understand

[FirienFirien]

Fusion reactions in stars will combine everything up to iron. Hydrogen - being the most abundant - will be the major fusion to form Helium; there's so much of it that that's pretty much all you'll see. However as the amount of He goes up, it'll become combined with H and other He to form Li and Be, and so on - all the way up to iron. Past that the energy of fusion required is simply too high, and with a normal star you'll never see anything with a higher atomic mass. Your iron star going supernova is a little misleading, as the supernova star won't be made of iron - at that mass it'll very likely have a good amount of iron compared to other stars, but in general the greatest part of its mass will still be H and He. Only from that supernova energy, (and the occasional cosmic ray collision, but I think those are negligible in comparison to the amount of matter in a supernova) do you get the energy required to fuse higher elements.

So - the elements above Helium come from normal fusion in a star; they don't have their own phases, everything just bumps into everything else at once. All your elements above iron have a greater fission energy than fusion energy, and with the amount of trigger radiation inside a star they don't generally last long. When they get ejected from a supernova, there's less to trigger them, so they stay stable for longer; that's why we have everything higher than iron, though even on earth they're in relatively minute quantities.

One last thing to point out is that your question about carbon seems odd - bear in mind that a carbon atom only has an atomic mass of 12, while iron has an atomic mass of 56. Carbon is relatively abundant compared to iron. To hazard a guess, if you laid the periodic table in a straight line you would probably see an approximately logarithmic amount of each element, up to iron and beyond; it'll be a little complicated since some elements are more likely to decay back to lighter elements faster than others, but that's the gist.

Disclaimer: this is all out of what I remember from courses; it may not be 100% accurate, though I believe it should clarify things enough.

Abundance of elements

[Roy Ward]

> To hazard a guess, if you laid the periodic table in a straight line you would probably see an approximately logarithmic amount of each element, up to iron and beyond; it'll be a little complicated since some elements are more likely to decay back to lighter elements faster than others, but that's the gist.

Not quite right:

http://www.seafriends.org.nz/oceano/abund.htm

Some elements (Oxygen, Carbon, Neon) seem to form more easily than Lithium, Beryllium etc.