- 4519 - EARLIEST UNIVERSE - is not what we expected? - James Webb Space Telescope (JWST) confirmed that luminous, very red objects previously detected in the early universe upend conventional thinking about the origins and evolution of galaxies and their supermassive black holes. They identified three mysterious objects in the early universe, about 600–800 million years after the Big Bang, when the universe was only 5% of its current age.
--------------------------------- 4519 - EARLIEST UNIVERSE - is not what we expected?
- The team studied spectral measurements, or
intensity of different wavelengths of light emitted from the objects. Their
analysis found signatures of "old" stars, hundreds of millions of
years old, far older than expected in a young universe.
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- They were also surprised to discover
signatures of huge supermassive black holes in the same objects, estimating
that they are 100 to 1,000 times more massive than the supermassive black hole
in our own Milky Way. Neither of these are expected in current models of galaxy
growth and supermassive black hole formation, which expect galaxies and their
black holes to grow together over billions of years of cosmic history.
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- The galaxies appear to be packed with
ancient stars—hundreds of millions of years old—in a universe that is only
600–800 million years old. Remarkably, these objects hold the record for the
earliest signatures of old starlight.
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- It was totally unexpected to find old stars
in a very young universe. The standard models of cosmology and galaxy formation
have been incredibly successful, yet, these luminous objects do not quite fit
comfortably into those theories.
-
- At the time, the researchers suspected the
objects were galaxies, but followed up their analysis by taking spectra to
better understand the true distances of the objects, as well as the sources
powering their immense light.
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- The researchers then used the new data to
draw a clearer picture of what the galaxies looked like and what was inside of
them. Not only did the team confirm that the objects were indeed galaxies near
the beginning of time, but they also found evidence of surprisingly large
supermassive black holes and a surprisingly old population of stars.
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- It's very confusing. You can make this uncomfortably fit in our
current model of the universe, but only if we evoke some exotic, insanely rapid
formation at the beginning of time.
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- The JWST is equipped with infrared-sensing
instruments capable of detecting light that was emitted by the most ancient
stars and galaxies. The telescope
allows scientists to see back in time roughly 13.5 billion years, near the
beginning of the universe as we know it.
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- One challenge to analyzing ancient light is
that it can be hard to differentiate between the types of objects that could
have emitted the light. In the case of these early objects, they have clear
characteristics of both supermassive black holes and old stars.
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- However, it's not yet clear how much of the
observed light comes from each—meaning these could be early galaxies that are
unexpectedly old and more massive even than our own Milky Way, forming far
earlier than models predict, or they could be more normal-mass galaxies with
"overmassive" black holes, roughly 100 to 1,000 times more massive
than such a galaxy would have today.
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- Aside from their unexplainable mass and
age, if part of the light is indeed from supermassive black holes, then they
also aren't normal supermassive black holes. They produce far more ultraviolet
photons than expected, and similar objects studied with other instruments lack
the characteristic signatures of supermassive black holes, such as hot dust and
bright X-ray emission. The most
surprising thing is how massive they seem to be.
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- Normally supermassive black holes are paired
with galaxies. They grow up together and
go through all their major life experiences together. But here, we have a fully
formed adult black hole living inside of what should be a baby galaxy. That
doesn't really make sense, because these things should grow together, or at
least that's what we thought.
-
- The researchers were also perplexed by the
incredibly small sizes of these systems, only a few hundred light years across,
roughly 1,000 times smaller than our own Milky Way. The stars are approximately
as numerous as in our own Milky Way galaxy—with somewhere between 10 billion
and 1 trillion stars—but contained within a volume 1,000 times smaller than the
Milky Way.
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- If you took the Milky Way and compressed it
to the size of the galaxies they found, the nearest star would almost be in our
solar system. The supermassive black hole in the center of the Milky Way, about
26,000 light years away, would only be about 26 light years away from Earth and
visible in the sky as a giant pillar of light.
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- These early galaxies would be so dense with
stars—stars that must have formed in a way we've never seen, under conditions
we would never expect during a period in which we'd never expect to see them. For whatever reason, the universe stopped
making objects like these after just a couple of billion years. They are unique
to the early universe.
-
- There's another way that we could have a
breakthrough, and that's just the right idea.
We have all these puzzle pieces and they only fit if we ignore the fact
that some of them are breaking. This problem is amenable to a stroke of genius
that has so far eluded us, all of our collaborators and the entire scientific
community.
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-
July 3, 2024 EARLIEST
UNIVERSE - is not what we expected? 4519
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--------------------- --- Thursday, July 4, 2024
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