- 4575
- FARTHEST GALAXIES -
earliest galaxies? - James Webb Space Telescope found "tiny
red dots" in the early universe representing overgrown supermassive black
holes and stars that are impossibly old for the infant universe. These odd red bodies hide stars that models
suggest are "too old" to have lived during early cosmic times and
black holes that measure up to thousands of times larger than the supermassive
black hole at the heart of the Milky Way.
-
---------------------------------------------- 4575
- FARTHEST GALAXIES -
earliest galaxies?
-
- Scientists believe these “tiny red dots”
must have been born in a way unique to the early universe by a method that
seems to have ceased after around 1 billion years of its existence. The three little red dots are seen as they
were when the universe was between 600 million and 800 million years old.
-
- Though that may seem like a tremendously
long time after the Big Bang, the fact that the universe is 13.8 billion years
old means it was no more than 5% of its current age when these objects existed.
-
- Scientists from Penn State University saw
these mysterious crimson cosmic oddities when investigating the early universe
with the JWST's Near Infrared Spectrograph (NIRSpec) instrument as part of the
RUBIES survey.
-
- What's behind the dots? The researchers studied the intensity of
different wavelengths of light coming from the little red dots. This revealed
signs that the stars are hundreds of millions of years old. This is far older than is expected for stars
at this early stage of the universe.
-
- The researchers also saw traces of
supermassive black holes within the little red dots' regions with masses
equivalent to millions, sometimes even billions, of suns. These black holes are
between 100 and 1,000 times as massive as Sagittarius A* (Sgr A*), the
supermassive black hole at the heart of the Milky Way that sits just 26,000
light-years from Earth.
-
- Both of these discoveries are not expected
under current models of cosmic evolution, galaxy growth, or supermassive black
hole formation. All of these theories suggest galaxies and supermassive black
holes grow in lockstep, but, this growth
takes billions of years, not millions of years.
That's a difference of a 1000 times???
-
- These regions appear to be packed with
ancient stars, hundreds of millions of years old, in a universe that is only
600 million to 800 million years old. Remarkably, these objects hold the record
for the earliest signatures of old starlight.
It was totally unexpected to find old stars in a very young universe.
-
- They first spotted the little red dots
while using the JWST back in July. At the time, the researchers immediately
suspected the objects were actually galaxies that existed roughly 13.5 billion
years ago.
-
- Deeper investigation of these objects'
light spectra confirmed these as galaxies that lived during the very dawn of
time and also revealed that "overgrown" supermassive black holes and
impossibly "old" stars were powering the red dots' impressive light
output.
-
- These galaxies are either unexpectedly old
and more massive than the Milky Way, having formed far earlier than models
predict, or have normal amounts of mass yet overly massive black holes somehow.
-
- Distinguishing between light from material
falling into a black hole and light emitted from stars in these tiny, distant
objects is challenging. Of course, all
black holes have light-trapping boundaries called "event horizons,"
meaning that, however much light they contribute to the little red dots, it
must come from the material that surrounds them rather than from within.
-
- The tremendous gravitational influence of
the black holes generates turbulent conditions in this material, which also
feeds the black hole over time, heating it and causing it to glow brightly.
Regions powered by supermassive black holes in this way are called
"quasars," and the regions of their galaxies they sit in are known as
"active galactic nuclei (AGNs)."
-
- These newly found, "red dot" black
hole regions could be different from other quasars, even those the JWST has
already seen in the early universe. The
red dot black holes seem to produce far more ultraviolet light than expected.
Still, the most shocking thing about these supermassive black holes remains
just how massive they seem.
-
- The ultraviolet light has the highest
energy. By the time that light reasches
us it lost energy and is in the red end of the light spectrum.
-
- Normally, supermassive black holes are
paired with galaxies. They grow up
together and go through all their major life experiences together. But here,
are 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.
-
- Using both the Gemini North telescope and
the Subaru Telescope, a team of astronomers have discovered a pair of merging
quasars seen only 900 million years after the Big Bang. Not only is this the
most distant pair of merging quasars ever found, but also the first confirmed
pair found in the period of the universe known as “cosmic dawn”.
-
- The red dot galaxies themselves are also
surprising. They seem to be much smaller than other galaxies despite having
almost as many stars. That means the red dot galaxies seem to consist of
between 10 billion and 1 trillion stars crammed into a galaxy a few hundred
light-years across with a volume 1,000 times smaller than the Milky Way.
-
- To put that into context, if the Milky Way
were reduced to the size of one of these red dot galaxies, then the closest
star to the sun (Proxima Centauri, which is 4.2 light-years away) would be
within the solar system. Additionally, the distance between the Earth and the
Milky Way's supermassive black hole, Sgr A*, would be reduced from 26,000
light-years to just 26 light-years. That would see it and its surroundings
appearing in the night sky over Earth.
-
- These early galaxies would be dense with
stars. Stars 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.
And, the universe stopped making objects like these after just a couple
of billion years. They are unique to the early universe.
-
- The team intends to follow up on its
findings with more observations of these confusing little red dots to
understand the dots' mysteries better. This will include obtaining deeper
spectra by pointing the JWST at the red objects for prolonged periods of time
to obtain emission spectra of light associated with various elements. This
could help unravel the contributions of ancient stars and supermassive black
holes in the galaxies.
-
- There's another way that we could have a
breakthrough, and that's just having 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.
-
-
October 12, 2024 FARTHEST GALAXIES -
earliest galaxies? 4575
------------------------------------------------------------------------------------------
-------- Comments appreciated and Pass it on to
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--- Some reviews are at: -------------- http://jdetrick.blogspot.com -----
-- email feedback, corrections, request for
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--- to:
------
jamesdetrick@comcast.net
------ “Jim Detrick” -----------
--------------------- --- Sunday, October 13,
2024
---------------------------------
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