NASA/Chandra X-Ray Observatory
The galaxy M87, which is about 50 million light-years from Earth.
Posted on 08/03/2004 6:41:24 PM PDT by neverdem
Another black hole is singing, although it seems a little tone-deaf.
Last year, astronomers discovered that outbursts from a giant black hole were spreading pressure waves through the thin hot gas of the distant Perseus cluster of galaxies. The frequency of these waves was equivalent to a B flat, 57 octaves below middle C, the astronomers calculated.
Now another group of astronomers has discovered waves from another massive black hole spreading outward from the center of a galaxy known as M87 at the heart of the Virgo cluster, about 50 million light-years from Earth. They appear as rings and arcs of brightness in images of the galaxy obtained by NASA's Chandra X-Ray Observatory.
The sound waves in M87, spaced about four million years apart, are a little more than an octave higher than the Perseus black hole, they said, and a little rougher and less pure.
"If one could hear the sound, it would be more like the cannons in the '1812 Overture' than the pure tone of a musical instrument," said Dr. William Forman of the Harvard-Smithsonian Center for Astrophysics.
Frivolous as it may sound, the phenomenon is part of a changing picture of the relation between galaxies (and the other luminous structures that web the sky) and black holes, the Einsteinian monsters that seem to dwell in the heart of almost every galaxy.
In this view, black holes may regulate both their own growth and the growth of their galaxies by explosive outbursts, orchestrating the flow of gas that is essential to the formation of stars, the lifeblood of the luminous universe.
Dr. Abraham Loeb, a theorist at the Harvard-Smithsonian Center, said, "People have only recently come to realize that the central black holes affect the formation of galaxies in a profound way."
Because it is nearly next door in cosmic terms, M87 is a natural laboratory for examining how black holes relate to the galaxies around them.
"Now we see how the black hole grows, how it affects the gas from which it grows," Dr. Forman said. "It all seems to connect."
Dr. Forman is part of a multinational team of astronomers that has used Chandra and other X-ray satellites to study what is going on in M87, and the lead author of a paper submitted to The Astrophysical Journal.
Speaking of the Virgo and Perseus results, Dr. Christine Jones of the Harvard-Smithsonian Center, also on the team, said, "We are seeing evidence of recurrent outbursts of the black holes in these galaxies."
It may seem contradictory to talk about a black hole releasing energy. According to Einstein's general theory of relativity, black holes are so dense that neither matter nor energy nor light nor anything else, including sound, can escape from them. They are sheer gravitational death. Nothing but inexorable doom, crushing and stretching, awaits anything that enters. A famous calculation by the Cambridge University theorist Dr. Stephen Hawking 30 years ago showed that when quantum effects are taken into account, black holes would leak and eventually explode, but the process would take much longer than the age of the universe, and so is little comfort.
But black holes can produce energy in the space around them by virtue of their enormous gravitational fields. Long before any infalling material, whether astronaut or gas cloud, reached the point of no return, it would be accelerated to nearly the speed of light and heated to millions of degrees, sparking X-rays and high-energy particles, as it swirled in a thick dense disk around the cosmic drain.
As a result of enormous pressure and magnetic fields, some of that stuff would never make it into the hole but would be squeezed like toothpaste and shot across space, away from the black hole in two oppositely directed jets.
The more black holes eat, the more they spill, and it is widely thought that their feeding frenzies power the violence seen in the nuclei of many galaxies, including the powerful quasars that are so bright they outshine their parent galaxies. Although the most massive black holes amount to only a tiny fraction of the mass of their galaxies, a tenth of a percent at most, they release huge quantities of energy, Dr. Loeb pointed out.
A wealth of observations of M87 over the years have illuminated, in messy, chaotic detail, the feeding habits of its central black hole, estimated to weigh in at two billion to three billion times the mass of the Sun. Dr. Forman said evidence of the messiness includes a sharp knotted spike, or jet, of energetic particles shooting from the galaxy's core; giant lobes of radio energy extending far out into intergalactic space; other bubbles and cavities, apparently inflated by the jet, in the inner regions of the galaxy; and a pair of arms of X-ray emission, one of which resembles the column of a rising mushroom cloud from a nuclear explosion.
The jet and an invisible counterpart going in the opposite direction, crashing into interstellar gas, seem to create the galaxy's discordant drum roll. In the new work, Dr. Forman and his collaborators combined two different Chandra pictures and data from the German Rosat and the European Space Agency's XMM-Newton satellites. The sound waves appear as bright arcs in the X-ray glow of hot gas that suffuses the M87 galaxy and the Virgo cluster in which it sits
One of them makes an entire circle around the nucleus, at a radius of about 45,000 light-years. Another arc sits at a radius of about 57,000 light-years from the center. The most recent outburst, they estimated, was about 11 million years ago and was the equivalent of about 10 million supernova explosions.
The results echo the earlier ones from the Perseus cluster and strengthen the conclusion that through their outbursts black holes may be reaching across intergalactic space and controlling the fates of billions of stars not yet born.
Clusters of galaxies are the largest assemblages of matter in the universe, with masses up to a trillion Suns.
Most of the ordinary matter in them, however, is not in the form of stars but in a dilute gas that has been heated to millions of degrees by falling into the cluster. It has long been a puzzle why this gas does not cool off, fall into the center of the cluster and make new stars.
Now it seems that singing black holes are heating the gas and keeping it from falling.
"This certainly shows that Perseus isn't an isolated case and shows that considerable energy is propagating out from the central engine into the intracluster gas," said Dr. Andrew Fabian of Cambridge University, who led the team that worked on Perseus.
As a result, the birth of new stars in those clusters has virtually halted. Dr. Peter Edmonds, another Harvard-Smithsonian astronomer who was not a member of either team, said in an e-mail message, "Billions or trillions of stars might be prevented from forming in M87 because of this black hole activity."
Such feedback activity from black holes, said Dr. Fabian and other astronomers, may be responsible for limiting the growth of galaxies. As the galaxy grows, the central black hole feeds and feeds from the accretion of gas, dust and smaller galaxies until its outbursts are strong enough to keep more material from falling into either the hole or the galaxy.
That kind of self-regulation, Dr. Loeb said, may explain a puzzle noted a few years ago. In 2000, work by two groups of astronomers, one led by Dr. Karl Gebhardt of the University of Texas, and another by Dr. Laura Ferrarese of Rutgers, found a mysterious correlation between the masses of the black holes and the masses of the galaxies in which they lived.
Bigger galaxies have larger gravitational fields and thus attract more material into their centers where the black holes feed, Dr. Loeb explained, and therefore black holes have to grow larger before their outbursts have enough oomph to hold off the gas falling into them.
But that view may be too simplistic, according to Dr. Anton Koekemoer of the Space Telescope Science Institute in Baltimore, who notes that the jets and outbursts from black holes actually seem to touch off the formation of stars by compressing interstellar gas along their boundaries, and to keep other gas from falling and condensing. "Both effects are going on at the same time," he said.
Just where these black holes came from is another problem.
Using Hubble as well as other telescopes, astronomers have inferred the presence of black holes, weighing up to a billion times the mass of the Sun, at the centers of most galaxies, including ones that existed only a billion years after the Big Bang itself. Earlier this year Stanford astronomers announced that they had found one with a mass of 10 billion times the mass of the Sun.
One theory is that these black holes are the remains of an early generation of very massive stars that condensed out of the primordial soup of hydrogen, 100 million to 200 million years after the Big Bang. They would rapidly burn out and explode, leaving behind a generation of "baby black holes," in Dr. Koekemoer's words, 100 or 200 times as massive as the Sun. These then grow by swallowing more gas or even each other. Dr. Loeb outlined an alternative scheme. Under certain circumstances, he explained, supermassive stars could be formed at the beginning. When they burned out and exploded these stars would leave behind black holes as much as 1,000 times as massive as the Sun.
"This would give you a jump-start," Dr. Loeb said.
Dr. Fabian said that how massive black holes could grow to large sizes without stifling their own growth was still an unsolved problem. Most of the growth of these black holes happened in the first few billion years of time, astronomers say, when the universe was dense with gas and the baby fragments of galaxies were furiously merging. The heyday of the quasars was about 10 billion years ago, when the universe was only four billion years old.
Since then the black holes of the universe have been relatively quiescent, including the one in our own Milky Way galaxy, only occasionally kicking up their heels in outbursts like the ones in M87 that are nonetheless and perhaps fortunately only a shadow of the energies of the quasars.
"A big black hole is kind of like a spider," Dr. Koekemoer said. "Most of the time it sits at the center of the galaxy doing nothing. Then a bug comes by. When it eats a bug, there is a burst of activity."
In the case of black holes, the bugs could be little galaxies, like the Milky Way's satellite, the Large Magellanic Cloud. And the result perhaps could be a chirp from our own resident black hole.
"If the Milky Way galaxy swallows the Large Magellanic Cloud, the black hole will light up," Dr. Koekemoer explained, adding, "It's been hungry a long time."
NASA/Chandra X-Ray Observatory
The galaxy M87, which is about 50 million light-years from Earth.
ping
hard science ping
(even if it is from the NYSlimes)
Gabriel's...... B-flat horn........I knew that.......
:-)
A 'Band' of angels?
:-)
Yeah except that Hawiking has now said he was incorrect about black holes...so thqat needs to be rethought...Look astronomers by their own admissions are studying informatin that is probably billions of years old ( as in already done and finished) . The universe merely reminds us how small and really vainglorious man really us. Imagine being arogant enough to think that you actually have an answer to cosmology...
After all, it is a Messier object...
Bb. Our power grid at 60 Hz is close to B. B natural. In fact, in 'Singin' in the Rain' I was required to produce a B natural on my stringbass in the scene where they turn on the broadway lights so the character can say something to the girl. I think that's what they were doing, I couldn't actually see the show from the pit. It's very dark in the pit--like a black hole--but information emits from the pit just like Hawking's new black hole model. In this case we sounded like a neon sign, which contains a plasma--another link, to the gases surrounding a black hole.
Boy, don't you wish you knew the answers to all this? Mind boggling, mysterious, and wonderful. 'The stuff that dreams are made of.'
It was a good show. Technically complex, but it came off well. Now there are a bunch of people that think I can actually play the bass.
There is very hard scientific evidence to support that *ALL* Black Holes will "sing" at the same frequency:
After all, anything too close to a Black Hole is going to BE FLAT.
Is that what the South Park gang calls the "brown noise"?
Okay: middle-C = 261.63 Hz. 2^57 = a honkin' biiig number (1.441151880758559e+17)
One cycle would be: 2^57/60(seconds/minute)/60(minutes/hour)/24(hours/day)/365.2442(days/year) /261.63(hertz)= 17.45530811017224 MILLION years.
And B-flat is just a tad below middle-C, so, they 'measured' this 'frequency' exactly...HOW?
I thought "In space, no one can hear you sing"?
Gore couldn't have been modeled on Maximilian - Maximilian had a sunnier personality and was a much better actor.
You've finally vindicated one of my long-held beliefs, namely that Air Supply COULDN'T have come from this galaxy (not to mention this planet).
See my post up above. It's always amusing to me that scientists would be so much smarter and save a lot of wasted research time if they'd only take the Bible seriously.
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