- 3886 - EARLIEST GALAXIES - did JWST find them? The James Webb Space Telescope has discovered a group of galaxies from the dawn of the universe that are so massive they shouldn't exist. The six gargantuan galaxies contain almost as many stars as the Milky Way despite forming only 500 to 700 million years after the Big Bang.
------------ 3886 - EARLIEST GALAXIES - did JWST find them?
- If these
early galaxies are real, the discovery calls our entire understanding of galaxy
formation into question. You just don't
expect the early universe to be able to organize itself that quickly. These
galaxies should not have had time to form.
-
- Cosmologists
previously estimated that the process began slowly taking shape within the
first few hundred million years after the Big Bang. Currently accepted theories
suggest that 1 to 2 billion years into the universe's life, these early
protogalaxies reached adolescence forming into dwarf galaxies that began
devouring each other to grow into ones like our own Milky Way Galaxy.
-
- Because
light travels at a fixed speed through the vacuum of space, the deeper we look
into the universe, the more remote light we intercept and the further back in
time we see. By using the James Webb Space Telescope (JWST) to peer roughly
13.5 billion years into the past, the astronomers found that enormous galaxies
had already burst into life very quickly after the Big Bang, when the universe
was just 3% of its current age.
-
- The galaxies
are so massive that either the models need to be altered, or scientific
understanding of galaxy formation requires a fundamental rethink. The Milky Way
forms about one to two new stars every year.
Some of these galaxies would have to be forming hundreds of new stars a
year for the entire history of the universe.
-
- Right now,
all evidence points to these celestial objects being galaxies, but the
astronomers haven't ruled out that some of them could be enormous quasars or
supermassive black holes. This is our
first glimpse back this far, so it's important that we keep an open mind about
what we are seeing.
-
- While the
data indicates they are likely galaxies, I think there is a real possibility
that a few of these objects turn out to be obscured supermassive black holes.
Regardless, the amount of mass we discovered means that the known mass in stars
at this period of our universe is up to 100 times greater than we had
previously thought.
-
- The $10
billion JWST launched to a gravitationally stable location beyond the moon's
orbit, a Lagrange point, in December 2021. The space observatory was designed
to read the earliest chapters of the universe's history in its faintest
glimmers of light, which have been stretched to infrared frequencies from
billions of years of travel across the expanding fabric of space-time.
-
- Staring
off into the ancient past with a $10 billion space telescope, wqith hope to
find extraordinarily faint signals from the earliest galaxies. The James Webb Space Telescope was built to
peer back in time and identify the Universe’s very first galaxies.
-
- The
expansion of the Universe stretches the light emitted by ancient objects
billions of years ago. The stretching shifts the light toward the red end of
the visible light spectrum. The James Webb Space Telescope was built to see
this light and identify the ancient galaxies that emitted it.
-
- The
telescope’s GLASS Survey used the galaxy cluster called Pandora’s Cluster
(Abell 2744) as a gravitational lens to magnify distant galaxies behind it and
found 19 bright objects that appear to be early galaxies.
-
- But there’s
a problem: our theories and models of galaxy formation suggest there shouldn’t
be so many of these earliest galaxies. The JWST’s findings needed to be
confirmed. The ESO’s ALMA (Atacama Large
Millimetre/sub-millimetre Array) will examine a candidate galaxy from GLASS and
to try to confirm it. If all of these
ultra-distant galaxy candidates were real, we’d have too many of them too early,
forcing us to rethink how galaxies begin forming within the Universe.
-
- Galaxy named
“GHZ2/GLASS-z12”, one of the brightest and most robust candidates at z >
10. “ z > 10” means that the light
from the galaxy has been travelling for over 13.184 billion years and has
travelled a distance of at least 26.596 billion light-years.
-
-
Spectroscopy is needed to confirm the primeval nature of these
candidates. It’s possible that the
light from some of these galaxies is red due to dust rather than distance, and
spectroscopy could help differentiate between the two. Astronomers turned to
ALMA, the world’s most expensive ground-based telescope currently operating.
-
- They used
it to look for an oxygen line (O III) in the spectroscopy at the same frequency
found in the JWST observations. O III is doubly-ionized oxygen, and it’s key
because oxygen has a short formation time relative to other elements.
-
- Stars can
generate oxygen on a short 50 Myr time scale. Other elements, like carbon take
nearly 500 Myr to appear in a galaxy. This means that oxygen is generally the
best redshift indicator and is likely the brightest emission line in the early
Universe. Could ALMA find it?
-
February 23, 2023 EARLIEST GALAXIES
- did JWST find them? 3886
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