Star 13.7 billion years old

Star SMSS J0313000.36-670839.3 observed by australian astronomer Stefan
Keller should be that old according to its iron content that is almost zero.

See
http://www.nature.com/nature/journal...ture12990.html

and pay 43 euros (around 58 dollars) if you haven't access to nature.
Note that arxiv does NOT have this article, at least it doen't appear in
the list of articles on arxiv by Stefan Keller.

Now, where did the "dark ages" go?

Remember, we were told that "at the beginning" the universe passed
through a time (400-500 million years, its length varied) where there
weren't any stars, the "dark ages" period. For instance Wikipedia says:

"The Dark Ages are currently thought to have lasted between 150 million
to 800 million years after the Big Bang. "

This period has been shrinking and shrinking and now it has completely
disappeared. There are 4 stars of this type discovered so far, stars
that aren't THAT far away from us (this one is 6 000 light years away),
so they must be fairly common in our galaxy.

So, right after the suposed bang, at z=30 the universe was full of
normal stars that didn't had any trouble forming when the CMB
temperature was a balmy 85 Kelvin!

In article , jacob navia
writes:

Now, where did the "dark ages" go?

Remember, we were told that "at the beginning" the universe passed
through a time (400-500 million years, its length varied) where there
weren't any stars, the "dark ages" period. For instance Wikipedia says:

"The Dark Ages are currently thought to have lasted between 150 million
to 800 million years after the Big Bang. "

This period has been shrinking and shrinking and now it has completely
disappeared. There are 4 stars of this type discovered so far, stars
that aren't THAT far away from us (this one is 6 000 light years away),
so they must be fairly common in our galaxy.

So, right after the suposed bang, at z=30

Please calculate how much time elapsed between z=infinity and z=30. It
is not "right after".

What is the age of the universe, with error bars? What is the age of
this star, with error bars? If there is a discrepancy, how significant
is it?

the universe was full of
normal stars that didn't had any trouble forming when the CMB
temperature was a balmy 85 Kelvin!

Star formation will not suddenly switch on at a certain redshift. There
will be a time when it is much more difficult, but still maybe a few (4,
say) stars will form.

On Thursday, February 13, 2014 6:42:58 AM UTC-5, jacob navia wrote:
Star SMSS J0313000.36-670839.3 observed by australian astronomer Stefan
Keller should be that old according to its iron content that is almost zero.

The preprint article is here...
http://arxiv.org/abs/1402.1517

Now, where did the "dark ages" go?

To be fair, the scientific journal article never mentions an age of
13.7 billion years, or any age for that matter. The age number you
mention appears to be part of the press package, which gives a nice
handle on the star, but is not the actual science at issue.

What is the measurement range on the 13.7B age number? We need to know
that to decide whether current cosmological models are in jeopardy or
not.

But to some extent you are right, the ages of the oldest stars - and
star clusters - are an independent constraint on the age of the
universe.

CM

To be clear, the authors did not measure the age of SMSS
J0313000.36-670839.3. They simply said that because of its very low
iron abundance that it must be one of the first stars formed. For
example,

http://www.sci-news.com/astronomy/sc...tar-01752.html

"Truthfully, we don't actually know how old SM0313 is. This is
because, sadly, we can't determine a specific age of these kinds of
objects. However, the chemical composition of SM0313 tells us that it
is a second-generation star in the Universe which naturally makes this
star nearly as old as the Universe itself," said co-author Dr Anna
Frebel from Massachusetts Institute of Technology and Kavli Institute
for Astrophysics and Space Research.

--Wayne

On Thursday, February 13, 2014 6:42:58 AM UTC-5, jacob navia wrote:
Star SMSS J0313000.36-670839.3 observed by australian astronomer Stefan

Keller should be that old according to its iron content that is almost zero.



See

http://www.nature.com/nature/journal...ture12990.html

Le 15/02/2014 09:08, Phillip Helbig---undress to reply a écrit :
In article , jacob navia
writes:

Now, where did the "dark ages" go?

Remember, we were told that "at the beginning" the universe passed
through a time (400-500 million years, its length varied) where there
weren't any stars, the "dark ages" period. For instance Wikipedia says:

"The Dark Ages are currently thought to have lasted between 150 million
to 800 million years after the Big Bang. "

This period has been shrinking and shrinking and now it has completely
disappeared. There are 4 stars of this type discovered so far, stars
that aren't THAT far away from us (this one is 6 000 light years away),
so they must be fairly common in our galaxy.

So, right after the suposed bang, at z=30

Please calculate how much time elapsed between z=infinity and z=30. It
is not "right after".


Of course not. It is 101 million years after the big bang. You will
agree that 100 million years is absolutely nothing in cosmological terms...


What is the age of the universe, with error bars? What is the age of
this star, with error bars? If there is a discrepancy, how significant
is it?



This star should be around the same age of the universe. The error bars
are significant as with all these extreme measurements but it means that
the "dark" ages did not actually exist...

the universe was full of
normal stars that didn't had any trouble forming when the CMB
temperature was a balmy 85 Kelvin!

Star formation will not suddenly switch on at a certain redshift. There
will be a time when it is much more difficult, but still maybe a few (4,
say) stars will form.


But the problem is that from a small sample in a single small portion of
a single galaxy we have a significant sample size!

I remember the discussion with Mr Oldershaw about biased or non biased
sample size. I think you will agree that this sample is not biased, i.e.
if there were only 4 stars at that epoch of the universe it would REALLY
be a big coincidence that all four would be found in this galaxy and so
near our home planet isn't it?

On 2/13/2014 12:42 PM, jacob navia wrote:
Star SMSS J0313000.36-670839.3 observed by australian astronomer Stefan
Keller should be that old according to its iron content that is almost zero.

See
http://www.nature.com/nature/journal...ture12990.html

and pay 43 euros (around 58 dollars) if you haven't access to nature.
...
So, right after the suposed bang, at z=30 the universe was full of
normal stars

Not entirely normal, it had an extremely low iron content,
someone just wrote.

If you want to argue that the big bang did not take place
13.8 Gy ago, then you have to replace it with a special
point in time, 13.8 Gy ago, where the metallicity of
formed stars completely drops to zero..

--
Jos

In article ,
" writes:

But to some extent you are right, the ages of the oldest stars - and
star clusters - are an independent constraint on the age of the
universe.

It cuts both ways, of course; if one is sure of the age of the universe
from other arguments, this can be a hint that the ages of stars are
wrong. It wasn't this way in the 1930s, but it was this way in the
early 1990s, when globular-cluster ages were much too large. (To be
fair, some people tried to "correct" them to be low enough to be
compatible with an Einstein-de Sitter universe and/or a high value of
the Hubble constant.)

In particular, if there is a conflict between the estimated age of ONE
star and several other lines of evidence for a younger age of the
universe, my money would be on the latter.

Yes, one can estimate the age of a star, but it is not a direct
measurement, but rather the end of a sequence of inferences.

In article , jacob navia
writes:

Of course not. It is 101 million years after the big bang. You will
agree that 100 million years is absolutely nothing in cosmological terms...

It isn't much. However, it is a long time for a massive star.

This star should be around the same age of the universe. The error bars
are significant as with all these extreme measurements but it means that
the "dark" ages did not actually exist...

A rash conclusion with no numbers. :-(

University of California - Santa Cruz. "Distant quasar illuminates a
filament of the cosmic web." ScienceDaily. ScienceDaily, 19 January
2014. www.sciencedaily.com/releases/2014/01/140119142452.htm.

A star formed from this filament and then captured by a nearby galaxy
could have low metallicity and appear to be a 2nd gen star but would
not be as old as the Universe. It would not surprise me if that is the
case with the star in question in this post.

Brad

[Mod. note: reformatted -- mjh]