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Webb Discovers One of the Universe's First Galaxies (phys.org) 37

Posted by BeauHD from the blast-from-the-past dept.
Astronomers using the James Webb Space Telescope have identified an ultra-faint galaxy seen just 800 million years after the Big Bang. The galaxy contains almost no heavy elements, shows signs of intense early stellar radiation, and could offer a rare glimpse into the first stages of galaxy formation. Phys.org reports: In a paper published in the journal Nature, a team of scientists led by Kimihiko Nakajima, an astronomer at Kanazawa University, Japan, describes how they used the telescope to study a part of the deep universe and discovered a faint galaxy called LAP1-B. "LAP1-B establishes a 'fossil in the making,' a direct high-redshift progenitor of the ancient ultra-faint dwarf galaxies observed in the local universe," they wrote. Because the galaxy is so small and distant, it would normally be impossible to see. However, it was spotted due to a phenomenon known as gravitational lensing, in which a massive cluster of closer galaxies acts like a giant magnifying glass, boosting the light from LAP1-B by 100 times.

The scientists realized that most of the light from the galaxy wasn't coming from the stars, but from glowing clouds of gas. They analyzed this light by splitting it into a spectrum and studying the emission lines, which revealed the chemical composition of the gas. They found that the galaxy contains almost no heavy elements, and its oxygen abundance is about 240 times lower than the sun's, making it one of the most primitive star-forming galaxies ever observed. The emission lines also revealed intense ionizing radiation, which is what scientists expect to see from the first generation of stars.

The team also measured an elevated carbon-to-oxygen ratio. This matches the predicted chemical signature for the first star explosions in history from Population III stars, the first stars to exist in the universe. The stars we see today are Population I stars, which formed later and contain more heavy elements. Another fascinating finding is that, after measuring the gas's motion and speed, the researchers concluded that the galaxy is held together by a massive cloud of invisible dark matter.

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Webb Discovers One of the Universe's First Galaxies

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  • if they see a galaxy 800 million years before the Big Bang.
  • "the researchers concluded that the galaxy is held together by a massive cloud of invisible dark matter."

    IOW, the researchers don't know what holds the galaxy together.

    • Correct. That is why they call it "dark matter".

      Perhaps they should have called it "mysterious matter"?

      Fact is there is either "more gravity" the there should be (or can be explained by looking at the visible atter), hence the term "dark matter" (as the matter is - seems to be - invisible) -or- there is an entire unknown force working ... with similar properties like gravity.

      Which it is, we don't know.

      • Hmm. "We don't know" is hardly science we can "Unite Behind".

        But the social sciences get funding just the same.

        • Re: (Score:1)

          by Tablizer ( 95088 )

          Unite behind figuring out scientific mysteries.

          • True.
            I just wish the non-scientific "sciences" would admit that they don't actually know as fast as the scientific sciences do. It's often quite important.
            It would save many lives:

            Society: "Will this murderer commit murder again if we let him out of prison ?"
            Psychologists: No, let him out.
            Actual answer: We don't know but there's a good chance he will, keep him in.

            Oh, and sig fits.
            • The soft sciences were created by lots of cocaine. Soft Cheesus may also have been involved.

            • Knowledge is hard won in science. And it takes quite a bit of intellectual honesty to admin we don't know what something is. Dark matter is the label for phenomenon we can measure but we don't understand. It will be renamed when we do understand its nature.

            • Re: (Score:1)

              by Tablizer ( 95088 )

              There is a need for educated guessers, regardless of what we call them. The alternative is clueless guessers, who give us tariff inflation and stupid wars.

        • Re: (Score:2)

          by ceoyoyo ( 59147 )

          "We don't know" is the most important statement in science. As opposed to "absolutely, this is true and if you don't believe it you're a bad person."

        • That is why we unite behind: we don't know.
          But if you do know: why are you not telling us and farm in your Nobel Prize?

      • "Dark matter" always seemed like it would be indistinguishable from swarms of primordial black holes to me, but then, I'm not a physicist or a cosmologist.

        • You are talking about MACHOs massive, compact halo objects, one of the candidates for dark matter. However, given the apparent amount of missing mass, from what I gather if it was all small black holes then we'd expect to see a certain amount of direct interactions with light, and those don't show up. That rules out the hypothesis of it all being explained by those.

        • Re: (Score:3)

          by ceoyoyo ( 59147 )

          It did to cosmologists as well, so they studied that possibility. Evidence has mostly ruled it out, but there's still a window where it could be true.

          https://www.frontiersin.org/jo... [frontiersin.org]

    • Re: (Score:2)

      by evanh ( 627108 )

      That probably implies a shit-ton of earlier extra large blue giants had quickly, in a few million years, gone supernova to become a shit-ton of large black-holes.

      • Re: (Score:2)

        by HiThere ( 15173 )

        IIUC (I'm no specialist in the field!!):

        No, but one of the possible meanings of "dark matter" is "black holes created during the big bang". It's tricky to make it work, and it requires some adjustment in how stable black holes are, but it's possible. The problem is that it would require that they evaporate more quickly and quietly than theory says that they should.

        Note that these would be relatively small black holes. Possibly the larger ones became the nuclei around which the first generation of stars c

      • Which could've coalesced into TON 618 or Pheonix A, perhaps?
    • "Dark matter" sounds better than "who the fuck knows?".

  • Eventually weâ(TM)ll figure out itâ(TM)s just electromagnetic forces running through plasmas.

    Ugh, scientific orthodoxy is harder to crack than religion

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