Far out cosmology: dhw's imagined galaxy death (Introduction)

by David Turell , Saturday, December 24, 2022, 16:23 (698 days ago) @ David Turell

From yesterday's discussion:

"dhw: I can’t find the quote, but it makes no sense anyway...And why were the galaxies that had already disappeared during the 9 billion years that preceded our own all necessary for us to keep our feet on the ground? Perhaps you will now answer my bolded question.

"From the bold, how do you know galaxies disappear? The Milk Way is estimated as appearing in less than a billion years after the Big Bang, still here and active. The universe is in the business of creating stars which coalesce into galaxies.

Now:

https://www.universetoday.com/159329/webb-stares-deeply-into-the-universe-showing-how-g...

"True to its main science objectives, the JWST has peered back in time to the Universe’s earliest galaxies looking for clues to how they assemble and evolve.

"There’s only one way to understand the Universe and what led up to us, and everything else we can observe in the Universe. We have to somehow wind the clock back to long before the Earth, the Sun, our Solar System, or even the Milky Way existed in its present form. Fortunately, the Universe hasn’t expanded so much yet that all the other galaxies have disappeared over the observational horizon.

***

"The images show how the gravitational lensing from galaxy clusters in the foreground brings more distant objects into view. Some of the distant objects are ancient galaxies interacting with each other. Some of them are Active Galactic Nuclei, extremely luminous regions at the center of galaxies, where black holes superheat material that falls toward them. The AGN images should provide clues to how supermassive black holes (SMBHs) grow so large, an extremely active area of research.

***

"Research Scientist Rolf Jansen is one of the paper’s co-authors. He studies how the earliest galaxies formed and how they evolved into the forms they take today. “I was blown away by the first PEARLS images,” Jansen said. “Little did I know, when I selected this field near the North Ecliptic Pole, that it would yield such a treasure trove of distant galaxies and that we would get direct clues about the processes by which galaxies assemble and grow — I can see streams, tails, shells and halos of stars in their outskirts, the leftovers of their building blocks.”

***

“'With the enormous new range in both flux and wavelength that the JWST images provide, the community will now have the resources to expand and deepen the study of the morphology, SED (spectral energy distribution), star formation rates, masses, dust content, and extinction at redshifts extending to the epoch of first light, as well as better constrain how much diffuse light may be present in the infrared.”

"Young scientists just beginning their careers as the JWST begins its mission aren’t the only fortunate ones. For those of us who grew up on Hubble images, the James Webb is also a source of excitement and discovery. It’ll be fun watching as researchers working with Webb continue to make progress on some long-standing questions."

Comment: I've presented the true universe. After the Big Bang, it was about 300 million years until the first galaxies formed. It has been formation ever since. Galaxies don't just die. They can bump into each other and become absorbed. Yes, stars die, not galaxies. I have never found a description of a dying galaxy. The universe is alive in its own way, but gala xy death is not required. Look at the website, the images are mind-blowing.