Distant Stellar Explosion Helps Map Universe's Dark Ages

sciencehabit (1205606) writes "Near the beginning, the universe was without form and void, and darkness was upon the face of the deep. That's because until about a billion years after the big bang, there were no galaxies or stars to illuminate the heavens, which were then filled primarily with neutral hydrogen gas. But a rare ultra–high-energy stellar explosion called a gamma ray burst has offered a new glimpse into this obscure period—the so-called cosmic dark ages—and may help nail down precisely when it ended. A new study of the explosion's afterglow suggests that such neutral hydrogen abounded a billion years after the big bang, so the dark ages weren't quite over then."

If you didn't ge the joke in TFS...

[MrLogic17]

Since not everyone went to Sunday School, TFS is referencing Genesis chapter 1 verse 1.

I'd read you the verse proper, but since verse 2 hasn't been quoted yet, it's too dark to read...

Re:

[gringer]

Since not everyone went to Sunday School, TFS is referencing Genesis chapter 1 verse 1.

I'd read you the verse proper, but since verse 2 hasn't been quoted yet, it's too dark to read...

You have an off-by-one error. Verses in the bible don't begin at zero.

Re:If you didn't ge the joke in TFS...

[HornWumpus]

They did; until a Basic programmer (Satan) screwed up a copy loop.

It's a central belief of 'The Church of Christ, Computer Programmer'. Can I get a Semicolon from the congregation?

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[MightyYar]

Satan was obviously a Perl programmer, and he just shot a $[ = 1; at the beginning.

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[Charliemopps]

I don't think it was lost on anyone. It's funny because it was an incredibly accurate description of the beginning of time from a document thats nearly 4000 years old, before they even know what stars, time or space were. The concept of "Formless and Void" are incredibly advanced topics for the time period it was written in. We had no concept of "Void" at the time.

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[DMUTPeregrine]

Of course we had a concept of "Void" at the time, it's written in at least one document from the time (Genesis). There wasn't a numeric symbol for zero, but that doesn't mean there was no concept of emptiness.

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[DerekLyons]

It's funny because it was an incredibly accurate description of the beginning of time from a document thats nearly 4000 years old, before they even know what stars, time or space were. The concept of "Formless and Void" are incredibly advanced topics for the time period it was written in. We had no concept of "Void" at the time.

Well, 4000 years ago they didn't say "formless and void" they said "(something in a language that wasn't English)". They only said "formless and void" when the Bible was translated

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[Cyberax]

That might sound insightful, but it's not. It's just funny. The first verse means that the Earth was created before the first stars, which is not true. And even the second verse is not correct, as the first moments of the Universe's existence were so bright that it took millions of years for it to cool down to mere 'just hot enough to melt steel' temperature.

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[rgbatduke]

...and one could go on and on. Line by line, Genesis is pretty much nonsense, and isn't even particularly good poetry in places where it is poetic. Heaven and Earth first. Darkness on the face of the deep, where from the next sentence it is clear that the "deep" is the waters, that is, the ocean. Then light, which divides light from darkness, with light called day and dark night. Note well that there is still no sun, but there is day and night. Then he creates a "firmament" -- that would be a solid bo

I don't understand something

[mark-t]

If the universe is 13.8 billion years old, and the universe went through a dark period that was supposedly a billion years long, then why can we detect objects that are as far as 13.3 billion light years away? Shouldn't everything past about 12.8 billion light years be.... well... dark?

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[mark-t]

Do you not see a contradiction there? If nothing older was producing any light, then where did the older light come from?

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[Bengie]

He said "nothing in that period" produced any light, or very little. There was a time before the dark ages, but it was crazy high energy and short lived.

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[Anonymous Coward]

You do know that in astronomy and most of the science loving world we refer to anything on the EM spectrum as light?
 
The summary is, at best, cumbersome to anyone who considers all forms of radiation as light. The CMB is happened roughly 380k years after the big bang and is considered to be the first and oldest light according to the generally excepted model of the universe today. Even prior to the CMB there was light but the universe was opaque and this light is lost.

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[Bengie]

There is a difference between producing new light and remitting old light. During the dark ages, there were no new light sources, only recycling of old light. That was the argument. Someone was saying there couldn't have been "the dark age" because CMB pre-dates it, which argued that there was light. Well, duh. We know there was light, be no new light was being created via stars.

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[rgbatduke]

he universe was opaque and this light is lost.

Not exactly lost, just thermalized. The mean free path of photons was simply short relative to cosmic distances, and gravity hadn't yet pulled enough hydrogen down into a gravitational well to ignite it, the distribution of matter was still fairly uniform except where it was gravitationally coalescing.

Once the stars lit up, radiation pressure quickly enough swept their immediate vicinity clear and created "shockwaves" of moving stellar wind that nucleated lots

Re:I don't understand something

[wonkey_monkey]

why can we detect objects that are as far as 13.3 billion light years away?

"...years ago", rather than "light years away," really. The light has taken 13.3 billion light years to get here, but the source was closer than 13.3 billion light years away when the light was emitted, and is further than 13.3 billion lights years now* (by about 3-4 times).

*for a certain value of "now"

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[mark-t]

If the source was closer when the light we are seeing now was emitted, then we should be seeing it now at the distance it was at the time. The objects are, as we see them now on earth, over 13 billion light years away, which means that the light was emitted from them over 13 billion years ago. That doesn't sound particularly dark to me.

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[wonkey_monkey]

The objects are, as we see them now on earth, over 13 billion light years away

I'm not sure you should infer that from the article. All it says is (roughly) when the light was emitted; not how far away the object was at the time.

The object could have been, say, 5 billion light years away at the time of emission, but the expansion of space means the light has taken 13 billion light years to get here.

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[mark-t]

If the object was 5 billion light years away at the time of emission, then it would take 5 billion light years for that light to reach us... not more... even though by the time the light reached us the object would be much further.

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[CheshireDragon]

Spacetime is expanding at a very high rate. In that expansion the light emitted had a larger space to cross in order to get here. Therefor it would take longer for it get here than just the 5bn yrs. I been reading your comments and some of the folks here have been giving you great examples and explaining things perfectly. It is hard to grasp some of this if you are not a Physics/science major. Take a few entry level Physics classes, shit watch the new Cosmos show(or How the Universe Works is a great on

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[mark-t]

If something appears 5 billion light years away, then the light that you are seeing from that thing was emitted 5 billion years ago. If something appears to be 13.3 billion light years away, then the light that we are seeing from it was emitted 13.3 billion years ago... which is considerably earlier than the alleged dark period... ended. if things weren't really emitting any light before the dark age came to an end, then why can we detect them?

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[wonkey_monkey]

Article is wrong, there were some stars around in the first billion years.

Mod parent up

[Intrepid imaginaut]

Quite interesting.

Cosmic Background Radiation

[blue trane]

Doesn't the CMB indicate that re-ionisation occured much earlier, with the latest redshift being 7 which is well before a billion years since the Big Bang?

The discrepancy between CMB measurements and quasar measurements of reionization is presented in Week 5 of Greatest Unsolved Mysteries of the Universe [edx.org].

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[SpaceIsBig]

At a redshift of 7 the universe is about 770 Myr old (with either Planck or WMAP 9 cosmology) which is close enough to 1 Gyr that you can say "about a billion years" (I guess it sounds better in a pop. science article).

I have more of a problem with the line "there were no galaxies or stars to illuminate the heavens". They existed, it's just that the universe was opaque during this period.

Re:

[HornWumpus]

Wouldn't you like to drive a million dollar car? I know I would.

Re:

[Anonymous Coward]

Entry level workers get a job at McDonald’s at 25 smackers an hour to start working.

Trade school trained mechanic, after a few years in the field, is earning that or not much more. Not only does his hamburger shoot up to about 10-12 dollars for a combo, all costs for everything slowly rise like boats in a harbor with the incoming tide. He asks his boss for a raise, because he deserves more pay than some entry level laborer, and the cost of his companies business goes up. And now, the 25 dollar an hour

Re:

[KingOfBLASH]

Economics isn't that simple.

For one, you might get some people who couldn't get a job as a McDonald's fry cook under normal circumstances who would be willing to work illegally for $10 an hour.

Or McDonalds might now be able to justify the cost of an expensive robotic system, and no longer needs to employ fry cooks anymore (and the only guy working is an engineer who can fix them when they break, and he definitely should earn more than a trade school mechanic).

Or, bosses won't give a rats ass about the fact

Distribution

[dougg76]

Your reply does not account for the potential redistribution of wealth. Even if the cheap goods increase with price, it does not mean that the entire brunt of the cost increase will fall to its direct consumers. It might reduce the amount of money available to the speculators instead. Why do people have to talk so rude to each other instead of just making their point?

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[KingOfBLASH]

As best I can tell, you didn't read my post and went on into a rant on a complete side issue.

dark for first 100 million years, not billion

[rubycodez]

first stars are 100 million years after big bang, by the time 1 billion years passed galaxies were everywhere

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[PPH]

In the beginning, there was nothing.
And God said, "Let there be Light."
And there was still nothing, but you could see it.