- 3965 - GALAXIES - how the first ones formed? On Earth, we often take our planet’s magnetic field for granted. It protects living creatures from the sun’s rays, draws compass needles north and even creates beautiful auroras. Other worlds in our solar system have magnetic fields too, but , what about Earth-like planets around other stars?
------------ 3965 - GALAXIES - how the first ones formed
-
Observations from the “Very Large Array” (VLA) radio telescopes in New
Mexico revealed evidence of a magnetic field on the rocky exoplanet “YZ Ceti
b”, which orbits a star about 12 light-years away from Earth. This is the first
possible detection of a magnetic field on a planet beyond our solar system.
-
- Magnetic
fields are particularly interesting because they’re an important part of making
a planet habitable. Without a magnetic field, energetic particles from a star
can erode a planet’s atmosphere, stripping away the blanket of gas that can
support life.
-
- “YZ Ceti
b”, isn’t a habitable planet. To detect
the radio waves from a small, far-away exoplanet’s magnetic field, astronomers
had to look towards a particularly extreme example. YZ Ceti b is quite close to
its star. Far too close to be a pleasant
temperature for life. It’s also
orbiting at such a pace that one of its
years is only two Earth days long.
-
- This is so
close in that the planet “plows” through material sloughing off of the star.
The planet’s magnetic field pushes electrically charged plasma back toward the
star, which then interacts with the star’s own magnetic field, emitting bright
flashes of energy.
-
- The radio
waves observed were an aurora on the star, likely created by the interactions
with the planet. Is the stellar aurora
entirely caused by YZ Ceti b? Further observations are needed to confirm this
is actually due to a rocky planet’s magnetic field, and not just a feature of
the star itself.
-
- This could
be the first detection of a magnetic field on a rocky exoplanet. But , it's
going to be a lot of follow-up work before a really strong confirmation of
radio waves caused by a planet comes out. -
-
“XRayGalaxiesA” new investigation measured X-ray emissions from clusters
of galaxies. This helped to reveal the structure of these clusters and the
distribution of matter throughout them.
-
- The data they
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.
-
- 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.
-
- “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.
-
April 18, 2023 GALAXIES - how
the first ones formed?
3965
----------------------------------------------------------------------------------------
----- 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” -----------
---------------------
--- Tuesday, April 18, 2023 ---------------------------
-
No comments:
Post a Comment