Why do some galactic unions lead to doom?

Why do some galactic unions lead to doom?
This image shows the merger of two galaxies, known as NGC 7752 (larger) and NGC 7753 (smaller), also collectively called Arp86. In these images, different colors correspond to different wavelengths of infrared light. Blue and green are wavelengths both strongly emitted by stars. Red is a wavelength mostly emitted by dust. Credit: NASA/JPL-Caltech

Three images from NASA's Spitzer Space Telescope show pairs of galaxies on the cusp of cosmic consolidations. Though the galaxies appear separate now, gravity is pulling them together, and soon they will combine to form new, merged galaxies. Some merged galaxies will experience billions of years of growth. For others, however, the merger will kick off processes that eventually halt star formation, dooming the galaxies to wither prematurely.

Only a few percent of galaxies in the nearby universe are merging, but were more common between 6 billion and 10 billion years ago, and these processes profoundly shaped our modern galactic landscape. For more than 10 years, scientists working on the Great Observatories All-sky LIRG Survey, or GOALS, have been using nearby galaxies to study the details of galaxy mergers and to use them as local laboratories for that earlier period in the universe's history. The survey has focused on 200 nearby objects, including many galaxies in various stages of merging. The images above show three of those targets, imaged by Spitzer.

In these images, different colors correspond to different wavelengths of infrared light, which are not visible to the human eye. Blue corresponds to 3.6 microns, and green corresponds to 4.5 microns—both strongly emitted by stars. Red corresponds to 8.0 microns, a wavelength mostly emitted by dust.

One of the primary processes thought to be responsible for a sudden halt in star formation inside a merged galaxy is an overfed black hole. At the center of most galaxies lies a —a powerful beast millions to billions of times more massive than the Sun. During a galactic , gas and dust are driven into the center of the galaxy, where they help make young stars and also feed the central black hole.

Why do some galactic unions lead to doom?
This image shows the merger of two galaxies, known as NGC 6786 (right) and UGC 11415 (left), also collectively called VII Zw 96. It is composed of images from three Spitzer Infrared Array Camera (IRAC) channels: IRAC channel 1 in blue, IRAC channel 2 in green and IRAC channel 3 in red. Credit: NASA/JPL-Caltech

But this sudden burst of activity can create an unstable environment. Shockwaves or powerful winds produced by the growing black hole can sweep through the galaxy, ejecting large quantities of gas and shutting down star formation. Sufficiently powerful or repetitive outflows can hinder the galaxy's ability to make new .

The relationship between mergers, bursts of star formation, and black hole activity is complex, and scientists are still working to understand it fully. One of the newly merged galaxies is the subject of a detailed study with the W.M. Keck Observatory in Hawaii, in which GOALS scientists searched for galactic shockwaves driven by the central active galactic nucleus, an extremely bright object powered by a supermassive black hole feeding on material around it. The lack of shock signatures suggests that the role of active galactic nuclei in shaping galaxy growth during a merger may not be straightforward.

Why do some galactic unions lead to doom?
This image shows two merging galaxies known as Arp 302, also called VV 340. In these images, different colors correspond to different wavelengths of infrared light. Blue and green are wavelengths both strongly emitted by stars. Red is a wavelength mostly emitted by dust. Credit: NASA/JPL-Caltech

Merging galaxies in the appear especially bright to infrared observatories like Spitzer. GOALS studies have also relied on observations of the target by other space-based observatories, including NASA's Hubble and Chandra space telescopes, the European Space Agency's Herschel satellite, as well as facilities on the ground, including the Keck Observatory, the National Science Foundation's Very Large Array and the Atacama Large Millimeter Array.


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Feb 27, 2019
These are very nice images. But the assumptions by astronomers that all or most galaxies have a Black Hole in their centres don't hold water since there are no "direct" images of the Black Hole that is said to exist in our very own galaxy - the MilkyWay. The passage of Stars in orbit near the projected BH may be due to other causes. Until DIRECT IMAGES of the alleged Black Hole at Sgr A are available, it is premature to say that all or most other galaxies also have an SMBH in their midst. As Carl Sagan was known to have said: "Extraordinary claims require extraordinary evidence".
With bigger and better telescopic instruments, we may someday be able to prove or disprove the prevailing hypothesis of Black Holes.

Feb 27, 2019
There are some very complicated issues of galaxy formation. Unfortunately, here is the same problem as with the stars. The origin of galaxies remains unclear, in spite of huge activity in the field. What the "formation" means? It means that we have the material that is assembling into galaxies.
https://www.acade...ome_From

Feb 28, 2019
There is no way for stars to "form" all by themselves naturalistically. The cumulative gas gravity creates pressure heating which eventually balances out the gravitational force and you reach a stalemate/equilibrium condition between the two, a.k.a the Jeans Mass Limit. So far, there is no known method that allows the state of affairs to proceed naturalistically to ignition.
Various mechanisms have been proposed but they all require already existing stars. So how did the first stars form? Nobody knows.
So of course along comes dark matter and people jump on the bandwagon to solve their naturalistic conundrum. Except that dark matter is a total unknown with no confirmed characteristics that can be borrowed to support any star formation theory. Except of course that people do not let such little practical matters stop them and they go ahead and assign their own desired characteristics to suit their requirements. Take one unknown to solve another. Great non-science.

Feb 28, 2019
Take one unknown to solve another. Great non-science.


you just described the Bible!

Feb 28, 2019
There are no direct images of any variety of a deity.
No, pointing at a mirror doesn't make your case. It just means that your daily medicines are overdue.

There is no direct image of Gravity. freddy & sillyegghead could show their lack of belief in Gravity, amusing us by leaping off a tall building?
"Look up in the sky!"
"t's a bird!"
"It's plane!"
"It's? Ohh!!"
"That is going to be a pisser to clean up!"

There is no direct image for the Earth's atmosphere. N2, Ox & CO2 are all colorless, odorless gases.
The sky & images of the Earth's sky consist mainly of water vapor reflecting & refracting light.
Also Space dust pulled in by the planetary gravitational attraction.
Earth dust vacuumed into the sky by low-pressure weather fronts.
Volcanic flatulence.
What? No they don't really care what you are expecting. They damn well are going to blow-out whatever the hell it is that they damn well want to.
Suck it up. monkey boy!

& of course, bird crap.

Feb 28, 2019
assumptions by astronomers that all or most galaxies have a Black Hole in their centres don't hold water

1. It's not an assumption. It's a very strongly supported hypothesis.
2. The evidence has been given to you. You are using language that is inappropriate because it's prejudicial, particularly considering you don't have any opposing evidence, at least that you've chosen to post here. "Don't hold water" under these conditions is hyperbole, and rather ridiculous under the real circumstances.
3. Your trolling-type tactics and your repeated assertions that you're a space alien aren't helping anyone see you as anything but another nutjob.

Feb 28, 2019
there are no "direct" images of the Black Hole that is said to exist in our very own galaxy - the MilkyWay.
There are excellent reasons for this, which you have also been given. Your lack of mathematics training is betrayed here; the main issues are
1. Not enough resolution, which can only be addressed by getting a bigger telescope.
2. This is because the Galactic Center is 25,000 light years away, which is far enough that it's at the very edge of our ability technically to see something the size of our Solar System even with the resolving power of a telescope with an effective aperture the size of the Earth.
3. Black holes do not, of themselves, radiate much of anything. All the effects we see are due to the black hole's gravitational effects; these are observed unequivocally in the orbits of stars surrounding the black hole, and in the accretion disk.
[contd]

Feb 28, 2019
[contd]
3. Continued. These have included flashes as the black hole accretes boluses of mass, mostly gas and dust, and at least one observation of such a bolus actually being consumed while rotating around the black hole which gives yet more data that agrees with the stellar orbits and clearly defines an extremely high mass in a very small radius.
4. The Galactic Center is shrouded by clouds of dust and gas farther out, and toward our line of sight, obscuring it and making observations more difficult.

The EHT is right on the edge of what we can do technically. Let me say that another way: this is an *experiment*.

Now, you've asked that you get reasonable responses. There they are. Let's see how you deal with them.

Feb 28, 2019
As Carl Sagan was known to have said: "Extraordinary claims require extraordinary evidence".

1. If relativity predicts black holes, and predicts their accretion disks and the stellar orbits surrounding them, I'm not sure why you view black holes as an "extraordinary claim."
2. As for evidence, we find the stellar orbits, gas-and-dust cloud orbits, and accretion disk we expect. Theory predicts, evidence confirms. The evidence is good enough that nearly the entire astrophysics community accepts it.
3. No contrary evidence has been found.
4. No other theory has been presented that explains the evidence we see.

So at this point, the "extraordinary claim" seems to be that there are no black holes. Got any evidence for it? We haven't seen any so far.

Feb 28, 2019
Me Sad.
Da Schneib hates the gravity of my humoresque.
Me very Sad.

Next to mess with the loomeytoons who insist that BHs cannot exist.

As long as they keep their eyes tightly scrunched shut.

They can deny the invisible phenomena of Gravity as the cause of waves moving through the junkyards encircling .the Stygian Oubliettes.

Which is the same invisible gravity as tidal effect that combines with invisible winds & invisible low-pressure fronts to produce waves visible in large bodies of water.

Please let me know if aby of you crappy clown posse, go down to the docks.

& start preaching to the sailors & seamen how waves in the water are impossible.
Because all the causes are invisible!
The holey babble told you so.

Man, that'd be a laughriot watching you loons flying through the invisible air into the all too visible harbor. With the enthusiastic assistance of the mariners.

Mar 01, 2019
Me Sad.
Da Schneib hates the gravity of my humoresque.
Me very Sad.

Next to mess with the loomeytoons who insist that BHs cannot exist.

As long as they keep their eyes tightly scrunched shut.

They can deny... Gravity as the cause of waves moving through the junkyards encircling .the Stygian Oubliettes.

...the same invisible gravity as tidal effect that combines with invisible winds & invisible low-pressure fronts to produce waves visible in large bodies of water.
...let me know if aby of you crappy clown posse, go down to the docks.
& start preaching to the sailors & seamen how waves in the water are impossible.
Because all the causes are invisible!
The holey babble told you so.
Man, that'd be a laughriot watching you loons flying through the invisible air into the all too visible harbor. With the enthusiastic assistance of the mariners.
says rrwilliejoe

You talk funny and no one understands why. Were you dropped on your head when you were a baby?

Mar 01, 2019
Every time you troll like this, your cred is reduced again.

Mar 01, 2019
Take one unknown to solve another. Great non-science.


you just described the Bible!
says SCVgood2go

Actually, the Bible has omitted much in the first book - Genesis. After the list of generations after Noah and his sons, up to the times of Terah and then Abraham, the Bible then becomes a history of the Jews and far less of the rest of humanity. I call it a "Hebrewcentric chronology" which basically leaves out all others, including the Sumerians, Akkadians and Babylonians and others of the regions of Mesopotamia.
So the Bible is very inaccurate as to mentioning of those such as Gilgamesh, of whom it is alleged that events and characters in the Bible supposedly had been plagiarised by Jewish scribes to fit their own perceived history. The rest of humanity would also have stemmed from Noah and his 3 sons and their wives, but unfortunately, there was no inclusion of them.
Science is just a natural offshoot of Philosophy and the thinking mind.

Mar 01, 2019
THE GEORGES LEMAITRE EFFECT
FredJose> There is no way stars form by themselves naturalistically cumulative gravity balances out gravitational force you reach a equilibrium between the two the Jeans Mass Limit there is no known method that allows the state of affairs to proceed naturalistically to ignition
Mechanisms have been proposed require existing stars how did the first stars form Nobody knows

SCVGoodToGo> you just described the Bible

Exactly what any ordained priest would do for his Lord
Conjure out the vacuous vacuum that is space
Georges Lemaitre for his Lord
from nothingness that is vacuum conjured a singularity
from that singularity
Georges Lemaitre conjured the first COSMIC EGG
creating all the atoms
which all the stars in the galaxies contain
On the first Day of our Lord

p.s. beware priests bearing gifts

Mar 01, 2019
well. that COMIC EGG explains the weird-shaped dinosaurs! Here yesterday, gone today.
c'est la vie!

Mar 01, 2019
The Babble is propaganda from thousands of years ago written by drunken stone age sheep herders about an imaginary super magic daddy in the sky.

Anyone who thinks it's even slightly accurate is psychotic.

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