- 4102 - DARK STARS - did Webb just discover them? Current theories about the Universe will need updating. Webb has revealed what our universe looked like 13.5 billion years ago, when the first stars and galaxies took shape after the Big Bang.
-------------- 4102 - DARK STARS - did Webb just discover them?
- These “first light” images came from
the “Near Infrared Camera”(NIRCam) which
is one of the most sensitive infrared cameras ever built. NIRCam will serve as the primary imager
aboard the Webb as it travels 1 million miles into space.
-
- NIRCam is an infrared imager measuring
wavelengths of light from 0.6 to 5 microns. It was created to detect the
earliest star clusters and galaxies, as well as stars in nearby galaxies and
young stars in the Milky Way and objects in the Kuiper Belt.
-
- Webb was launched on December 25, 2021, a
project nearly two decades in the making.
NIRCam is pushing the envelope of optical performance. In addition to NIRCam, Webb has the Solar
Ultra-Violet Imager and the Geostationary Lightning Mapper (GLM) for the
Geostationary Operational Environmental Satellite (GOES-R).
-
- NIRCam technology was developed to bond
cryogenic optics that allow NIRCam to remain stable while functioning in
ultracold temperatures: around 40 Kelvin, or about 150°F colder than the lowest
temperature ever recorded in Antarctica.
-
- The same camera mount design has flown
successfully on other missions, including NASA’s Interface Region Imaging
Spectrograph (IRIS), an instrument studying how energy and plasma move near the
sun’s surface.
-
- More projects are underway on different
scales of missions and science, from programs that look at the evolution of
massive stars to monitoring the Earth’s carbon cycle. Others would
revolutionize vibration isolation and precision pointing for future missions,
and more projects would focus on technologies designed to build smaller,
lighter-weight space telescopes.
-
- The SPIDER (Segmented Planar Imaging
Detector for Electro-optical Reconnaissance) prototype is one example. It uses
a thin array of tiny lenses in place of bulky mirrors or larger lenses,
potentially cutting size, weight and power needs 10 to 100 times.
-
- During the commissioning period, the
telescope’s 18 gold-plated hexagonal mirrors , together totaling more than 21
feet in diameter, will unfold origami-style and its tennis-court-sized
sunshield will unfurl. Then, the telescope and its elements will be cooled,
aligned and calibrated.
-
- With 18 segments, each with the ability to
move in various directions or even change curvature, there are a lot of ways
you can tune the mirror. Light enters
NIRCam, which uses wavefront sensing and control tools to align the
mirror.
-
- Commissioning the telescope in space took
six months. As Webb completes its five-
to 10-year mission science will be looking out for the science images NIRCam
will produce.
-
- A team of three astrophysicists analyzed
images from the James Webb Space Telescope (JWST) and found three bright
objects that might be “dark stars,” theoretical objects much bigger and
brighter than our sun, powered by particles of dark matter annihilating. If
confirmed, dark stars could reveal the nature of dark matter, one of the
deepest unsolved problems in all of physics.
-
- Although dark matter makes up about 25% of
the universe, its nature has eluded scientists. Scientists believe it consists
of a new type of elementary particle, and the hunt to detect such particles is
on.
-
- Among the leading candidates are “Weakly
Interacting Massive Particles”. When they collide, these particles annihilate
themselves, depositing heat into collapsing clouds of hydrogen and converting
them into brightly shining dark stars. The identification of supermassive dark
stars would open up the possibility of learning about the dark matter based on
these observed properties.
-
- The objects’ spectroscopic properties,
including dips or excess of light intensity in certain frequency bands, could
help confirm whether these candidate objects are indeed dark stars. Confirming the existence of dark stars might
also help solve a problem created by JWST that is there seems to be too many
large galaxies too early in the universe to fit the predictions of the standard
model of cosmology.
-
- The three candidate dark stars
(JADES-GS-z13-0, JADES-GS-z12-0, and JADES-GS-z11-0) were originally identified
as galaxies in December, 2022, by the
JWST Advanced Deep Extragalactic Survey (JADES). Using spectroscopic analysis,
the JADES team confirmed the objects were observed at times ranging from about
320 million to 400 million years after the Big Bang, making them some of the
earliest objects ever seen.
-
- “Dark stars” could theoretically grow to be
several million times the mass of our sun and up to 10 billion times as bright
as the sun. JWST has found three
supermassive dark star candidates.
-
- At the centers of early protogalaxies,
there would be very dense clumps of dark matter, along with clouds of hydrogen
and helium gas. As the gas cooled, it would collapse and pull in dark matter
along with it. As the density increased, the dark matter particles would
increasingly annihilate, adding more and more heat, which would prevent the gas
from collapsing all the way down to a dense enough core to support fusion as in
an ordinary star.
-
- Instead, it would continue to gather more
gas and dark matter, becoming big, puffy and much brighter than ordinary stars.
Unlike ordinary stars, the power source would be evenly spread out, rather than
concentrated in the core. With enough dark matter, dark stars could grow to be
several million times the mass of our sun and up to 10 billion times as bright
as the sun.
-
-
July 23, 2023 DARK
STARS - did Webb just discover them? 4102
------------------------------------------------------------------------------------------
-------- 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, July 24, 2023
---------------------------------
No comments:
Post a Comment