Ultra-Dense Galaxies In the Early Universe

Science Daily is reporting on the characterization of a population of ancient galaxies, formed less than 3 billion years after the Big Bang, that are as massive as some modern galaxies but are only 1/20 the size. Each of the 9 compact galaxies found is less than 5,000 light-years across, and could fit comfortably inside the Milky Way's central hub (if you moved the supermassive black hole out first). The stars in these galaxies were 1/2 to 1 billion years old when observed and at least one generation of massive stars had already exploded as supernovae.

A science fiction reference

[Anonymous Coward]

Poul Anderson's Tau Zero [amazon.com] makes the suggestion that interstellar contacts between races are more likely in the beginning of the universe than towards the end, simply because all matter will spread so far apart and there won't be enough fuel to move around.

Gene Wolfe's Book of the New Sun also conjectures a future where galaxies move so far apart that the steersmen of ships cannot locate their destinations by sight and must rely on old charts.

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[MightyMartian]

Poul Anderson's Tau Zero makes the suggestion that interstellar contacts between races are more likely in the beginning of the universe than towards the end, simply because all matter will spread so far apart and there won't be enough fuel to move around.

That's a little silly. Even though the galaxies and stars must have been much closer together again, I don't think that any period where the distance would have made any substantial distance to traversing interstellar or intergalactic distances that the u

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[amRadioHed]

Right, these dense galaxies are only 1/20th the size of the Milky Way, and that talking about volume I believe so actual differences in travel time will be less then an order of magnitude. Not going to make much of a difference when it comes to interstellar travel.

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[dryeo]

The radiation density is something most people never think about. Not only would there be more supernova but also areas rich in star formation also put out quite a bit of radiation.
Even now in our galaxy there is a large percentage of it that is inhabitable and not only that but I understand the majority of stars are in orbits around the core that are elliptical enough to pass close or through the core regularly.
Another problem with areas of space that are packed with stars is the odds that other stars will

Probably won't matter much

[Moraelin]

The thing is, the rate of new star formation is decreasing over time.

While technically there still is plenty of hydrogen left, the quantity of _free_ hydrogen (available for a new star) is becoming gradually more rare. More and more is locked inside old dead stars. Even a supernova doesn't eject all the matter in the star. A red giant only sheds the outer layer, or to put it other wise, does about as much to recycle the star as shedding does to recycle your dog ;)

So basically if we're talking 100 billion ye

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[Luyseyal]

Guess we'll just have to figure away to recycle all those old stars. Looks like we have some time to figure it out. :)

-l

No Parking

[Sta7ic]

'course, all those galaxies would still fit if you DIDN'T move the supermassive black hole first. You'd just have to remove "comfortably" from the statement.

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[kalirion]

Everything fits with a supermassive black hole. Or rather in a supermassive black hole.

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[repapetilto]

besides your mom, of course

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[account_deleted]

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[account_deleted]

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[hanover.fiste]

Oops - off by an order of magnitude

Three orders of magnitude, Shirley. (10^^6 vs 10^^9)

Interesting, but no big surprise....

[syousef]

...when the whole Universe was much denser at that stage. It's still good science, and another piece of information the human race possesses (especially in the detail) but I'm unsurprised.

Citation

[LightPhoenix7]

Science Daily isn't announcing anything, they just regurgitate press releases.

A team of astrophysicists at Yale have published a paper in The Astrophysical Journal Letters. They're the ones announcing it.

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[Anita Coney]

The blurb says "reporting" not "announcing." Maybe they've fixed it since I showed up.

Imprecision Annoys

[SWestrup]

Am I the only one annoyed by such an imprecise expression as "1/20th the size". One doesn't know from reading it if this is 1/20th the linear dimensions, or 1/20th the volume. (Turns out its the former, which makes it 1/8000th the volume, which is far more interesting.)