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posted by janrinok on Tuesday September 28, @03:15PM   Printer-friendly [Skip to comment(s)]
from the it's-not-dead-it's-just-resting dept.

Hubble telescope helps find six 'dead' galaxies from the early universe:

You'd think large galaxies in the early universe would have had plenty of 'fuel' left for new stars, but a recent discovery suggests that wasn't always the case. Astronomers using the Hubble Space Telescope and the Atacama Large Millimeter/Submillimeter Array (ALMA) have found six early galaxies (about 3 billion years after the Big Bang) that were unusually "dead" — that is, they'd run out of the cold hydrogen necessary for star formation. This was the peak period for star births, according to lead researcher Kate Whitaker, so the disappearance of that hydrogen is a mystery.

The team found the galaxies thanks to strong gravitational lensing, using galaxy clusters to bend and magnify light from the early universe. Hubble identified where stars had formed in the past, while ALMA detected cold dust (a stand-in for the hydrogen) to show where stars would have formed if the necessary ingredients had been present.

The galaxies are believed to have expanded since, but not through star creation. Rather, they grew through mergers with other small galaxies and gas. Any formation after that would have been limited at most.

From CNET we read:

"The most massive galaxies in our universe formed incredibly early, just after the Big Bang happened," Kate Whitaker, a professor of astronomy at University of Massachusetts-Amherst and lead author of a new study, said in a statement. "But for some reason, they have shut down. They're no longer forming new stars."

It turns out, some old galaxies merely ran low on star fuel, or cold gas, early on in their lifetimes. The results of the group's study were published Wednesday in the journal Nature and could rewrite our knowledge of how the universe evolved.

Journal Reference:
Katherine E. Whitaker, Christina C. Williams, Lamiya Mowla, et al. Quenching of star formation from a lack of inflowing gas to galaxies, Nature (DOI: 10.1038/s41586-021-03806-7)


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  • (Score: 4, Funny) by Snort on Tuesday September 28, @03:35PM

    by Snort (5141) on Tuesday September 28, @03:35PM (#1182248)

    They are pining for the fjords.

  • (Score: 5, Informative) by ikanreed on Tuesday September 28, @03:35PM (2 children)

    by ikanreed (3164) on Tuesday September 28, @03:35PM (#1182249) Journal

    They're using "cold dust" as a proxy for star forming hydrogen, but it's possible that the dust we're used to seeing in modern galaxies may have different spectral properties than those in what I'll call "really quite early" galaxies, different elemental mixes perhaps. And it may be that the dust itself isn't as good a proxy for potential stellar hydrogen as we assume, because, spitballing, there could be some kind of dark matter bullshit arranging the dust into narrower shapes than we're used to.

    When we get to the actual paper [nature.com] we find a little more reason to accept the author's interpretation, though. The main thing they identify is a correlation across various redshift "time zones" between their proxy dust measure and the log of the rate of star formation. But with N=6 it's way less certainty than astronomy normally has. They'll need to find several more gravitationally lensed regions of space to observe before this can be taken as confirmed, tbh.

    • (Score: 2) by Runaway1956 on Tuesday September 28, @05:47PM (1 child)

      by Runaway1956 (2926) Subscriber Badge on Tuesday September 28, @05:47PM (#1182323) Homepage Journal

      Dark matter? Wiggle room? Dark matter is wiggle room, in and of itself. Dark matter tries to explain matter that we are unable to observe, right? Roughly 80% of the matter in the universe is unobservable, according to one estimate. But, is dark matter necessary to explain that? I don't think so. TFA explains that we have previously failed to observe entire galaxies that are observable, once we learn the trick to finding them.

      Then, we have other new discoveries, such as https://news.ucsc.edu/2020/05/missing-matter.html [ucsc.edu]

      Universe’s ‘missing matter’ finally found in the space between galaxies

      An international team of astronomers has solved the decades-old mystery of the ‘missing matter’ long predicted to exist in the universe but never before detected. The researchers have now found all of the missing ‘normal’ matter in the vast space between galaxies.

      The discovery, published May 27 in Nature, was made by studying massive flashes of energy from deep space, called fast radio bursts.

      “For decades, we have unsuccessfully searched for this missing matter with our largest telescopes. The discovery and localization of fast radio bursts was the key breakthrough needed to solve this mystery,” said corresponding author J. Xavier Prochaska, professor of astronomy and astrophysics at UC Santa Cruz.

      Maybe there really is "dark matter", with some strange attributes that we don't understand. On the other hand, maybe not. Maybe all that missing matter is simply too far away to detect with today's instruments. Or maybe a lot of it is simply obscured by closer matter. Or, maybe the aliens stole it, and stored it inside of a Dyson sphere. Or, instead of aliens, there are more black holes than we have accounted for that are hiding all that matter.

      --
      The only reason for not believing in it (Marxism) is that it doesn't work. - Thomas Sowell
      • (Score: 2) by maxwell demon on Wednesday September 29, @06:35AM

        by maxwell demon (1608) Subscriber Badge on Wednesday September 29, @06:35AM (#1182639) Journal

        Dark matter tries to explain matter that we are unable to observe, right?

        Wrong. Dark matter is, by definition, matter that we are unable to observe.

        The favoured candidate for dark matter is WIMPS (weakly interacting massive particles), but that is by far not the only hypothesis. There's also the MACHOS (massive compact halo objects) hypothesis, that says the missing matter is, well, massive compact halo objects (such as the black holes you mentioned). So black holes would not be an alternative to dark matter, it would be one possible form of dark matter.

        The option of the matter being too far away for us to see is, however, not possible. Matter in galaxies close enough to be seen quite obviously is not too far away to be seen (or else we wouldn't see those galaxies to begin with).

        --
        The Tao of math: The numbers you can count are not the real numbers.
  • (Score: 1, Funny) by Anonymous Coward on Tuesday September 28, @04:04PM

    by Anonymous Coward on Tuesday September 28, @04:04PM (#1182263)

    "The Sheriffs office did not return our calls for comment."

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