Tuesday, April 18, 2023

3965 - GALAXIES - how the first ones formed?

 

-   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.

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-    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.

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-    “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.

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-   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.

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-    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.

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-    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.

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-  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.

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-    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.

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-    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.

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-    “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.

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                   April 18, 2023          GALAXIES  -  how the first ones formed?       3965                                                                                                                          

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--------------------- ---  Tuesday, April 18, 2023  ---------------------------

 

 

 

 

         

 

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