- 4565 -
FIRST GALAXIES - at
dawn of time? - Astronomers using the James Webb Space
Telescope have spotted a rare galaxy at the dawn of time that may be a
"missing link" between the oldest generation of stars and the ones we
see near Earth.
-
------------------------------------- 4565
- FIRST GALAXIES
- at dawn of time?
-
- JWST has found a bizarre galaxy in the
early universe whose gas outshines its stars, marking it out as a possible missing link in galactic
evolution.
-
- The galaxy, “GS-NDG-9422 (9422)”, was
spotted just one billion years after the Big Bang and is filled with massive
stars burning nearly twice as hot as those typically found in the local
universe.
-
- These exotic stars are bombarding the gas
clouds that surround them with enormous quantities of light particles (photons)
, heating the clouds up and causing them to outshine the stars they enshroud.
This is a rare trait hypothesized to exist in galaxies that contain the oldest
generations of stars.
-
- Astronomers aren't certain when the very
first globules of stars began to clump into the galaxies we see today, but
cosmologists previously estimated that the process began slowly during the
first few hundred million years after the Big Bang.
-
- Astronomers also aren't certain of the
types of stars that formed in the early universe, or the time they took to
ignite. Yet, as the only material emitted by the Big Bang was hydrogen and
helium, the original, primordial stars (Population III stars) are thought to
have been extremely large, very bright and incredibly hot.
-
- But because the first and most massive
cosmic furnaces blazed so intensely, they also burned out quickly: exploding in
supernovae that scattered heavier elements forged through nuclear fusion in
their hearts, thus laying the foundations for planets and later generations of
stars.
-
- To search for evidence of the earliest
stars, the researchers pointed the JWST at an extremely distant region of the
sky. Light travels at a fixed speed through the vacuum of space; this means
that the deeper we look into the universe, the further back in time we see as
we detect light coming from ever more remote sources.
-
- This fact enabled the astronomers to spot
“galaxy 9422”. The galaxy's stars are burning at temperatures of 140,000
degrees Fahrenheit, almost twice as hot as the 70,000 to 90,000 degrees F found
in our local universe. Despite this, the ultra-hot stars are likely not part of
the oldest generation of stars in the universe, as the researchers spotted
elements beyond just hydrogen and helium.
-
- We know that this galaxy does not have
Population III stars, because the Webb data shows too much chemical
complexity. However, its stars are
different than what we are familiar with.
The exotic stars in this galaxy could be a guide for understanding how
galaxies transitioned from primordial stars to the types of galaxies we already
know.
-
- It's a very exciting time, to be able to
use the Webb telescope to explore this time in the universe that was once
inaccessible. We are just at the
beginning of new discoveries and understanding.
-
-
September 27, 2024 FIRST
GALAXIES - at dawn of time? 4565
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--------------------- --- Saturday, September 28,
2024
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