-
------------------------------ 4604 - EINSTEIN RING - could explain dark matter?
- The remarkably dense JWST-ER1 galaxy and
its Einstein ring, as captured by the James Webb Space Telescope last
year. A fresh analysis of a remarkably
massive yet compact galaxy from the early universe suggests that dark matter
interacts with itself.
-
- The galaxy formed just 3.4 billion years
after the Big Bang. It was first spotted
last October in images snapped by JWST.
At over 17 billion light-years from Earth, JWST-ER1g is the
farthest-ever example of a perfect "Einstein ring", an unbroken
circle of light around the galaxy, a result of light rays from a distant,
unseen galaxy being bent due to the space-warping mass of JWST-ER1.
-
- The cosmic mirage is not just a pretty
sight from a lucky alignment of galaxies; it also offers physicists a valuable
probe for model-independent measurements of the mass enclosed within the ring's
radius.
-
- By calculating just how much JWST-ER1g has
warped space-time around itself, the discovery team had estimated that the
galaxy weighs about 650 billion suns, which makes it a peculiarly dense galaxy
for its size. By subtracting the visible stellar mass from the total inferred
mass, physicists can measure how much of the galaxy is dark matter, an
invisible substance thought to make up over 80% of all matter in our universe.
-
- Despite decades of observations and heaps of
circumstantial evidence, the elusive substance is yet to be directly detected.
In JWST-ER1g, the discovery team determined that dark matter explains just
about half the mass gap, and that "additional mass appears to be needed to
explain the lensing results.
-
- JWST-ER1g's unusually high density could be
explained by a higher population of stars than currently thought. However, a
contraction mechanism by which ordinary matter "collapses and
condenses" into JWST-ER1g's dark matter halo could be packing "more
dark matter mass in the same volume, resulting in higher density.
-
- The halo of dark matter, densest at the
galaxy's center, is the gravitational glue that prevents spinning galaxies from
flying apart. Furthermore, models incorporating a certain type of dark matter,
in which its particles interact with themselves, provide "an excellent fit
to the measurement of JWST-ER1.
-
- We don't yet know what dark matter actually
is. Observational clues suggest it is a new kind of particle whose presence can
only be inferred from its gravitational interactions with ordinary matter. Dark
matter could be just one kind of particle or a complex variety of different
types, like in normal matter, that perhaps operates in the presence of
additional, unknown forces exclusive to
dark matter.
-
- Self-interactions could explain extremely
dense dark matter halos in certain galaxies, as well as puzzlingly low
densities in others, both of which are unexplained by the prevailing "cold
dark matter" theory.
-
- Physicists hope JWST can shed more light on
dark matter, so to speak. The telescope's unprecedented infrared eyes peer
further back in time than any other telescope, and its upcoming investigations
of galaxies from the very early universe could reveal clues about dark matter
particles and their behavior.
-
- We expect to see more surprises from JWST
and learn more about dark matter soon.
-
- November 10, 2024 EINSTEIN RING
- could explain dark matter? 4604
------------------------------------------------------------------------------------------
-------- Comments appreciated and Pass it on to
whomever is interested. ---
--- Some reviews are at: -------------- http://jdetrick.blogspot.com -----
-- email feedback, corrections, request for
copies or Index of all reviews
--- to:
------
jamesdetrick@comcast.net
------ “Jim Detrick” -----------
--------------------- --- Monday, November 11,
2024
---------------------------------
No comments:
Post a Comment