- 3967 - UNIVERSE - earliest structure defined? SLAC cosmologists are currently attempting to expand the size of computer simulations of the cosmos while improving accuracy. They will also look at how these observations conform to other cosmological models.
------------ 3967
- UNIVERSE -
earliest structure defined?
-
- A new
investigation of the structure of galaxy clusters has found it agrees with
predictions made by the standard model of cosmology, the best explanation
scientists have of the evolution of the universe over its 13.8 billion-year
existence.
-
- Astronomers
measured X-ray emissions from clusters of galaxies to reveal the structure of
these clusters and the distribution of matter throughout them.
-
- The data
collected conform to a model of universal evolution and structure called the
lambda cold dark matter (ΛCDM) model, which suggests that the infant universe
was an extremely hot, dense sea of photons and matter tightly coupled as
plasma.
-
- As the
infant universe underwent a period of rapid expansion called inflation, small
perturbations spread through the plasma as a sound wave, producing under- and
over-densities of both matter and radiation, but not affecting dark matter.
-
- According
to the ΛCDM model, the plasma expanded and cooled, and electrons and protons
soon combined to form the first atoms, with free electrons no longer infinitely
scattering photons. This allowed the universe to become transparent to light.
-
- Overdense
regions collapsed to birth the first stars, and the universe eventually reached
its current state, with clusters of galaxies as the largest bound objects
linked by a vast cosmic web of dark matter.
-
- It's easier
to use X-ray emissions as a measurement of mass distribution when the energy of
the gas in clusters is balanced by the pull of gravity as it binds the entire
system.
-
- This balance
is achieved when galaxy clusters have settled down into a "relaxed"
state, so mass distribution studies typically focus on these galaxies. when researchers compare real observations
with the theoretical predictions of the ΛCDM model, they must take into account
that there has been a bias toward selecting these "relaxed" galaxies.
-
- Redshift is
the stretching of the wavelength of light that occurs as a result of the
expansion of the universe. The farther light has traveled, the more it is
shifted toward the red end of the electromagnetic spectrum. That means the
earlier and more distant the galaxy, the more extreme the redshift, thus making
this a great measure of both distance and age.
-
- When the
Vera C. Rubin Observatory opens its eye on the universe, it will begin the
Legacy Survey of Space and Time, which should spot far more galaxy clusters.
Joining this quest will be the fourth-generation cosmic microwave background
experiment, while the European Space Agency's Athena satellite mission will
follow up with more X-ray measurements.
-
April 20, 2023 UNIVERSE -
earliest structure defined? 3967
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