Sunday, November 24, 2024

4617 - 2023 DISCOVERIES - in astronomy -

 

-  4617 -   2023 DISCOVERIES  -   in astronomy.  -    For the James Webb Space Telescope in outer space December 25 is a pretty special birthday.  Fans will be celebrating the second anniversary of the launch of NASA's James Webb Space Telescope (JWST). Since coming online in mid-2022 it is the most powerful telescope ever built.


----------------------------------   4617  -  2023 DISCOVERIES  -   in astronomy

-    Not long after coming online, the JWST immediately discovered six enormous "universe breaker" galaxies, containing what seemed to be almost as many stars as the Milky Way, dating to just 500 million years after the Big Bang.

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-    The finding caused a stir in the astronomical world, with some scientists suggesting that it had put our current view of galaxy evolution, or even our understanding of the universe, into doubt.   The strange discovery pointed to a deepening mystery around how large galaxies first bloomed in our universe.

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-    After running simulations, other astronomers suggested that the galaxies might not contain as many stars as first seemed, and could instead just be glowing unusually brightly. Whatever the answer, follow-up observations of the mysterious galaxies are needed before scientists can be certain.

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-   The universe is expanding, but depending on where cosmologists look, it's doing so at different rates. In the past, the two best experiments to measure the expansion rate were the European Space Agency's Planck satellite (which gave a most likely expansion rate of 67 kilometers per second per megaparsec) and the Hubble Space telescope, which studied pulsating stars called Cepheids and found a higher value of 73 km/s/Mpc. (kilometer/second/megaparsec)

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-   Cosmologists thought this tension might be down to uncertainty caused by Hubble not distinguishing between Cepheids and background stars, but the JWST had a result of  74 km/s/Mpc.

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-   The large ancient galaxies on the JWST's list of discoveries and black holes like CEERS 1019, which had a mass 10 million times that of our sun and was found by the JWST just 570 million years after the Big Bang, making it the oldest black hole spotted.  Earlier this month, the telescope discovered an even older massive black hole 440 million years after the universe began.

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-    How these swelled to such staggering scales so early on is an ongoing mystery.    The telescope's ultrapowerful eye has also revealed glimpses of completely new, unexplainable objects. After being trained on the Orion Nebula, the JWST found 42 pairs of Jupiter-mass binary objects, or "JuMBOs", Jupiter-sized planets drifting through space in pairs, some as far apart from each other as 390 times the distance between Earth and the sun.

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-    The JuMBOs are too small to be stars, but as they exist in pairs, they are unlikely to be rogue planets ejected from solar systems. Their discovery has alerted astronomers to a brand-new formation mechanism for planets or even for failed stars.

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-    Another feature of the JWST is its ability to measure a spectrum of the atmospheres of distant exoplanets, a toolkit which enabled it to spot the potential signs of life in on a Goldilocks water world 120 light-years away.   The exoplanet it found, “K2-18 b”, is a sub-Neptune planet (weighing in somewhere between the mass of Earth and Neptune) orbiting the habitable zone of a red dwarf star.

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-    After taking an atmospheric spectrum, the JWST found it rich with hydrogen, methane and carbon dioxide which are all chemical markers of a hydrogen-rich world that is a prime contender for extraterrestrial life.

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-    More tantalizing still was the detection of dimethyl sulfide (DMS), a cabbage-smelling compound only known to be produced by microscopic algae in Earth's oceans.

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-    Stars and galaxies aren't evenly spread throughout our universe. Instead, they're connected by an enormous cosmic web which is a gigantic network of crisscrossing celestial super-highways paved with hydrogen gas and dark matter.

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-     Taking shape in the chaotic aftermath of the Big Bang, the web's tendrils formed as clumps from the roiling broth of the young universe; where multiple strands of the web intersected, galaxies eventually formed.

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-     Insights into the structure of this web not only give us a glimpse of the chaotic particle interactions that led to a universe existing in the first place.  Astronomers using the JWST were stunned when they spotted the earliest strand of this web ever seen.  It was a gassy tendril made of of 10 closely packed galaxies spanning more than 3 million light-years in length.

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-   The filament formed when the universe was just 830 million years old, and is partially wrapped around a bright black hole. Researchers hope to find answers as to how these very first galaxies formed.

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-   Another addition to the JWST's long list of cosmic distance records this year was its discovery of the most distant gravitationally lensed object ever seen — an "Einstein ring" produced by the warping of light from a distant galaxy.   How distant? A mind-bending 21 billion light years away, which, given the universe's 13.8 billion years of age, means that the light from the galaxy traveled almost twice that distance due to the universe expansion.

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-   Dark matter is the unseen substance believed to make up 70% of the universe's matter.

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November 24, 2024            2023 DISCOVERIES  -   in astronomy             4618

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--------------------- ---  Sunday, November 24, 2024  ---------------------------------

 

 

 

 

 

           

 

 

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