Posted on 01/10/2005 1:30:09 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 team’s 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 Diego’s 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 star’s 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 quasars—intense concentrations of energy believed to be produced by the swirling gas and dust surrounding massive black holes—with high redshifts that have been closely associated with nearby galaxies.
“If it weren’t 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 team’s 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 Stephan’s Quintet.
Using a three-meter telescope operated by the University of California at Lick Observatory in the mountains above San Jose and the university’s 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.”
Other members of the team, besides Geoffrey and Margaret Burbidge, included Vesa Junkkarinen, a research physicist at UCSD; Pasquale Galianni of the University of Lecce in Italy; and Halton Arp and Stefano Zibetti of the Max-Planck Institute for Astrophysics in Garching, Germany.
Not to mention satellite TV (and radio) broadcasting so we can have 20 movie channels 17 channels showing large reptiles and 200 channels showing ugly rotating jewelry.
You can find it in good libraries, and browsing through it is well worth a few hours of pleasurable time. I only hope he lives long enough to see his life efforts vindicated.
Hey. Thank you for the mental picture. Info like that helps everyone understand the theory.
So, in this concept, there are galaxies or other objects, out there, that have exceeded the speed of light. Those which have gone the farthest since the big bang, and are therefore DARK MATTER because you can't see an object traveling away from you faster than the speed of light.
They are now going the speed of dark.
Not when compared to the size of the universe.
\ : l)
And all of these building blocks (redshift, doppler,rate of expansion, temperature, limitation on temperature and visible light increase due to expansion, all of these things theories cite the other ones as proof.
What I am saying is that since there are objects that do not conform to one of the most basic theories, then how can any of them be right. It seems there is a lot of circular reasoning going on. Even Einstein's theory of relativity was defect and had to be corrected by the 'cosmological constant', which Einstein later admitted was the biggest mistake of his life.
Why is the cosmological constant still used?
What is the true density of the universe?
The big bang and then either infinite expansion or eventual collapse theory is based on the density of the universe.
So how can we be sure of the density of the universe if we do not know it's size?
Yes, but the article certainly downplays his contribution.
Isn't this the basic thing that got Arp thrown out of America before he ended up at the Max Planck Institute? Some parts of the American scientific establishment still behave like the Inquisition it seems...
"A little more slowly Simplicio."
Until the 1920's the extent of the universe was thought to be encompassed by the Milky Way. I have an 1898 astronomy text which says of the Andromeda Nebula, "The question may be asked, What is the probable size and distance of this wonderful nebula? and could it be an external universe?"
The observance of a "temporary star" within the nebula is mentioned, and it's noted how bright it would have to be to appear as it did across such a vast distance ... "This seems improbable, and tends to the conclusion that the nebula is NOT an external galaxy, but a member of our own sidereal system, a system which probably includes all the stars and nebulae visible in our largest telescopes."
Note that Andromeda looms larger than the moon in the sky, at a distance of 2 million light years - a vast distance, but right next door. With greater magnification, you can qualitatively track the distance of galaxies out to billions of light years, the scale of the cosmos, and their red shift at these distances is a simple, gross feature, like the roundness of the earth. It will not be overthrown by refinements and anomalies.
So, how reactionary are you? I'm supposing you accept the fact of "external galaxies", but if you do, you are in for the whole ride, I should think.
Maybe the backside of a jet release that is headed the opposite direction.
Actually, it's not highly unlikely that you'd be travelling at the speed of light already, it's impossible. Let's assume that you're actually travelling at something like 99.9999% of the speed of light, though, so that if velocities followed the Gallilean additive law, you'd end up with speeds greater than c. If you were travelling at such a speed and then threw a baseball at 90 mph, an observer on the ship would see the baseball speeding away at 90 mph, while a ground-based observer would see the baseball move just a slight bit faster than the ship, but slower than c. If, instead of a projectile, the astronaut on the ship turned on a laser beam, an observer on the ship would see the light from that beam travelling at c, as would a ground-based observer. This means that the observer on the ship would see the light speeding away from the ship as normal, but the observer on the ground would see the ship almost keeping pace with the light beam. The implication of that fact is that time ticks at a different rate for an observer on the ship than it does for a ground-based observer, and that length measurements made by the two observers also would be different. The distance travelled by the light would look enormous to the ship-based observer and tiny to the ground-based observer. The time measured for the travel of that distance would be smaller for the ship-based observer and larger for the ground-based observer. The ratio of that distance travelled to the time that it required to do so would be the same for both observers, namely c.
Einstein's theory of general relativity was actually perfectly fine without the cosmological constant. The equations of general relativity without this constant showed that the universe must either be expanding or contracting. Einstein, however, believed that this was a nonsensical result. He believed that the universe was eternal and unchanging, so he added a "fudge factor" to his equations that made the equations allow a static universe. The cosmological constant was the fudge factor. Once Hubble's observations made it clear that the universe was indeed expanding, Einstein realized that the cosmological constant was a mistake. This idea has been resurrected more recently due to observations about the rate of expansion of the universe. If you throw a ball up into the air, gravity causes the speed of the ball to decrease as it gets higher. Similarly, gravity should cause the speed of expansion of the universe to decrease over time (whether it will slow to a stop and start to contract, like the ball slowing to a stop and then falling, is an open question. Inflationary theory says that it should slow down but only come to a stop at infinite time, similar to throwing the ball at exactly the escape velocity). Recent observations have suggested that the speed of expansion is actually increasing, however. Therefore, the idea of dark energy, which exerts a negative pressure was formulated. This would cause a repulsive force that explains the acceleration of the expansion. Mathematically, this dark energy fits into the equations of relativity in exactly the same way as Einstein's original "fudge factor," hence the idea that the cosmological constant is back in the theory.
It would be interesting to look at repeated observations of this quasar. Now that 300-million-sun size black holes have been found orbiting each other in the centers of galaxies, it might be that this one was simply moving away from us in a rapid orbit.
It also makes me wonder if a large part of the universe's missing mass won't turn up in dormant super-massive black holes in galactic cores now that theorists are looking at galaxies forming around black holes rather than the reverse.
Neat idea. Light is captured by the inconceivable gravity near the event horizon of the black hole, spins around the black hole, and escapes with an altered red shift, giving the illusion it came from much farther away..
I've thought about this, but there are arguments against it.
Physically, it would go like this. Suppose there were some form of matter that interacts gravitationally with normal matter, but in no other way. Suppose further that this dark matter were able to form clumps.
If there were a dark matter clump massive enough to be near the black hole limit, it would be an interesting object, indeed. It would be totally invisible, but it would bend light in odd ways, but be otherwise invisible, and it would suck matter right into its center.
The matter so sucked would be perfectly happy to pass through it, to oscillate through it with perfectly harmonic motion, and even to come to rest in its center, because it would be in free-fall the whole time.
[OK, it wouldn't be happy. In fact, it would be downright unhappy. In fact, it would in all likelihood be torn apart by the extreme tidal forces, unless it were small enough and tough enough to handle the tides. Nano-robots would be happy.]
If matter came to rest inside such a dark star, the light from the matter would be gravitationally redshifted. It's impossible to calculate by how much, because we don't know the density of the condensed dark matter, so we don't know what its black hole limit is. If the density were low enough, it might be possible to make an extremely massive object that is nevertheless below the black hole limit. [The ~5 solar-mass limit for nuclear matter is so low because nuclear matter is so dense.]
So what makes this an unlikely explanation?
Not catching Arp's name among the researchers for this study, I initially thought Arp's longstanding claims were getting some independent corroboration. I guess that's still true, but not as much as I first thought.
Sounds reasonable to me.
Except that energy is conserved. If light falls in towards a black hole, it gets blueshifted. If it makes it out again, it gets redshifted by an equivalent amount. The final frequency is the same as the starting frequency. All that matters is your relative velocity and gravitational acceleration with respect to the original source.
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