Skip to comments.Cool gas answers riddle of galaxy growth (possibly solving the mystery of galactic proportions)
Posted on 10/13/2010 7:57:26 PM PDT by NormsRevenge
PARIS (AFP) European astrophysicists said on Wednesday they could settle a mystery about how galaxies crank up in size, developing from proto-structures in the early Universe to the billion-star behemoths of today.
Analysis of ancient light, known as redshift, indicates that the first galaxies were formed nearly 13 billion years ago, about a billion years after the "Big Bang" that created the Universe.
They then dramatically fattened up to become the giant systems we see today, and the question is why.
Until now, many experts believed that galaxies increased in size by colliding with others, in the same way that a company can grow by merging with a competitor.
But a rival theory argues that this is not the only way.
A gentler, incremental approach also works, under which a youthful galaxy sucks in cool interstellar gas as the raw material for making new stars, according to this argument.
A team of astronomers, reporting in the British journal Nature, put the idea to the test using a light-analysing spectrograph on Europe's Very Large Telescope (VLT) in Chile's Atacama desert.
The group chose three very distant galaxies -- smoothly rotating discs, similar to the Milky Way -- in order to ensure that any buildup was not the result of a collision with other galaxies.
What they were looking for was a chemical signature of so-called heavy elements, or elements that are formed from the primordial gases of hydrogen and helium.
In all three cases, the sky-gazers found a patch close to the galactic centre that was a breeding ground for stars and had markedly fewer heavy elements.
(Excerpt) Read more at news.yahoo.com ...
An artistic impression of gas accretion on a high redshift galaxy. European astrophysicists said on Wednesday they could settle a mystery about how galaxies crank up in size, developing from proto-structures in the early Universe to the billion-star behemoths of today. (AFP/ESO/L. Calcada)
A new image taken with the powerful HAWK-I camera on ESOs Very Large Telescope at Paranal Observatory
in Chile shows the beautiful barred spiral galaxy NGC 1365 in infrared light. NGC 1365
is a member of the Fornax cluster of galaxies, and lies about 60 million light-years from Earth.
Fire up the starship, lets go and check it out in person. lol.
only 60M LY
One must ponder whether these “geniuses” were educated at East Anglia University.
what the heck is a light-year, you ask..
How does this relate to the massive Black Holes that are at the center of many Galaxies?
I’ve always been under the impression that Galaxies appear to be stars, dust, and gases wrapped around a gravitational vortex of sorts, with everything being pulled toward the Black Hole at the center. Many of the Spiral Galaxies look just like hurricanes. This article seems to suggest that the formation of the Galaxies has nothing to do with Black Holes.
Recent theory indicates that black holes spit out radiation composed of the elements taken in. Black holes, in this view, are star factories.
I thought “red shift” indicated movement away from the observer, blue shift was movement towards the observer just like the Doppler effect. This article states it is ancient light.
>>> galaxies — smoothly rotating discs, similar to the Milky Way — in order to ensure that any buildup was not the result of a collision with other galaxies.
However there are two known globular clusters in collision with the Milky Way even now. I don’t think they can be secure in saying there were no prior larger collisions in the deep past.
>>>>I thought red shift indicated movement away from the observer, blue shift was movement towards the observer just like the Doppler effect. This article states it is ancient light.
AP and Yahoo both dumb things down. Most people don’t understand the Doppler effect—to them it has something to do with the weather....
Thought this might interest you. Science/Space ping
Red shifted light is the characteristic of both ancient and very distant sources simultaneously, due to the expanding universe. The further away the source, the faster it is receding from us. Gravitational effects also affect redshift, according to General Relativity.
So, they infer distance from, among other things, the amount of red shift. In fact the furthest known sources have red shifts of orders of magnitude, all the way into the microwave region. This is the explanation mooted for the so-called Cosmic Background radiation, which is believed to be left over from the “Big Bang,” and thus the oldest (and the most redshifted) radiation we can observe.
I think the article was just being brief, perhaps out of necessity.
Until now, many experts believed that galaxies increased in size by colliding with others, in the same way that a company can grow by merging with a competitor. But a rival theory argues... A gentler, incremental approach also works, under which a youthful galaxy sucks in cool interstellar gas as the raw material for making new stars, according to this argument.Yeah, and where did Cain's wife come from?
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Always being the guy who has to disillusion people is a dirty job, but somebody's gotta do it....
The big bang idea is basically bad science, bad philosophy, and bad theology rolled into a package and I don't care how many people think they have Nobel prizes for anything associated with it.
Having all the mass of the universe collapsed to a point would be the mother of all black holes and nothing would ever "bang" its way out of that. Likewise having a supposedly omniscient and omnipotent God suddenly decide it would be a cool thing to create a universe at some specific time while the idea had never occurred to him previously is basically nonsensical and it doesn't matter whether that's 7000 or 17B years ago.
But don't take my word for it...
University of California, San Diego ^ | 10 January 2005 | Kim McDonald
Posted on Mon 10 Jan 2005 01:30:09 PM PST by PatrickHenry
An international team of astronomers has discovered within the heart of a nearby spiral galaxy a quasar whose light spectrum indicates that it is billions of light years away. The finding poses a cosmic puzzle: How could a galaxy 300 million light years away contain a stellar object several billion light years away?
The teams findings, which were presented today in San Diego at the January meeting of the American Astronomical Society and which will appear in the February 10 issue of the Astrophysical Journal, raise a fundamental problem for astronomers who had long assumed that the high redshifts in the light spectra of quasars meant these objects were among the fastest receding objects in the universe and, therefore, billions of light years away.
Most people have wanted to argue that quasars are right at the edge of the universe, said Geoffrey Burbidge, a professor of physics and astronomer at the University of California at San Diegos Center for Astrophysics and Space Sciences and a member of the team. But too many of them are being found closely associated with nearby, active galaxies for this to be accidental. If this quasar is physically associated with this galaxy, it must be close by.
Astronomers generally estimate the distances to stellar objects by the speed with which they are receding from the earth. That recession velocity is calculated by measuring the amount the stars light spectra is shifted to the lower frequency, or red end, of the light spectrum. This physical phenomenon, known as the Doppler Effect, can be experienced by someone standing near train tracks when the whistle or engine sounds from a moving train becomes lower in pitch, or sound frequency, as the train travels past.
Astronomers have used redshifts and the known brightness of stars as fundamental yardsticks to measure the distances to stars and galaxies. However, Burbidge said they have been unable to account for the growing number of quasi-stellar objects, or quasarsintense concentrations of energy believed to be produced by the swirling gas and dust surrounding massive black holeswith high redshifts that have been closely associated with nearby galaxies.
If it werent for this redshift dilemma, astronomers would have thought quasars originated from these galaxies or were fired out from them like bullets or cannon balls, he added.
The discovery reported by the team of astronomers, which includes his spouse, E. Margaret Burbidge, another noted astronomer and professor of physics at UCSD, is especially significant because it is the most extreme example of a quasar with a very large redshift in a nearby galaxy.
No one has found a quasar with such a high redshift, with a redshift of 2.11, so close to the center of an active galaxy, said Geoffrey Burbidge.
Margaret Burbidge, who reported the teams finding at the meeting, said the quasar was first detected by the ROSAT X-ray satellite operated by the Max-Planck Institute for Astrophysics in Garching, Germany and found to be closely associated with the nucleus of the spiral galaxy NGC 7319. That galaxy is unusual because it lies in a group of interacting galaxies called Stephans Quintet.
Using a three-meter telescope operated by the University of California at Lick Observatory in the mountains above San Jose and the universitys 10-meter Keck I telescope on Mauna Kea in Hawaii, she and her team measured the redshifts of the spiral galaxy and quasar and found that the quasar appears to be interacting with the interstellar gas within the galaxy.
Because quasars and black holes are generally found within the most energetic parts of galaxies, their centers, the astronomers are further persuaded that this particular quasar resides within this spiral galaxy. Geoffrey Burbidge added that the fact that the quasar is so close to the center of this galaxy, only 8 arc seconds from the nucleus, and does not appear to be shrouded in any way by interstellar gas make it highly unlikely that the quasar lies far behind the galaxy, its light shining through the galaxy near its center by an accident of projection.
If this quasar is close by, its redshift cannot be due to the expansion of the universe, he adds. If this is the case, this discovery casts doubt on the whole idea that quasars are very far away and can be used to do cosmology.
There exists a gravitational component to red shift, and the article doesn’t specify whether this was being taken into account.
I don’t know whether the mass of a quasar would be large enough to produce significant redshift in the case cited. Is there any more recent news on this?
That is interesting. It throws one of their pet theories about the universe into doubt.
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