Posted on 11/28/2001 11:39:15 AM PST by mdittmar
LONDON (Reuters) - Astronomers have calculated the mass of the heaviest stellar black hole in our galaxy in a discovery that turns the accepted theory of how such objects are formed and behave on its head. Scientists at the Astrophysical Institute in Potsdam, Germany, and the European Southern Observatory in Chile said the huge black hole has 14 times more mass than the Sun and is in a remote area of the Milky Way almost 40,000 light-years away.
A light year is about six trillion miles.
The black hole and the star that revolves around it and feeds it are in the stellar system called GRS1915+105.
Black holes suck in everything near them including light and can only be detected by the activity around their edges. Stellar black holes, the remnants of dead Sun-like stars, typically have the mass of three to seven Suns.
"The one that I found is 14," Jochen Greiner, of the Astrophysical Institute, said in a telephone interview.
Greiner and his colleagues identified the star that feeds the black hole by studying the steady flow of stellar material. In research reported in the science journal Nature, they estimated the mass of the black hole by analyzing the orbital motion of the star around it.
The distance between the star and the black hole is about half the distance between the Earth and the Sun.
The size of GRS1915+105, which astronomers have dubbed a microquasar, has cast doubt over the theories on how black holes are formed.
Scientists consider microquasars, binary systems consisting of a normal star and a black hole or neutron star, as natural laboratories for testing Einstein's general theory of relativity.
GRS1915+105 is one of a handful of microquasars in our galaxy. Scientists are puzzled by the size of the black hole because the interaction in a binary system increases the mass loss of the star and they don't know how it can retain enough mass to form such a massive black hole.
"The big mystery now is how can theory explain these 14 solar masses which I have measured," said Greiner.
"The present theory cannot explain how to produce such large masses," he added.
Correction: It's just that our telescope was pointed at Molly Ivins when she bent over to pick up a bar of soap.
First, take the case of a single star that formed billions of years ago from the gravitational accumulation of small particles of stuff, mostly hydrogen. (Creationists in the back of the room, please put your hands down and wait until I'm finished.) As gravity pulls the stuff together, it gets denser and hotter until thermonuclear reactions can take place. These reactions generate enough outward pressure to hold the core of the star stable against the force of gravity for billions of years.
As time goes on, the thermonuclear reactions create heavier nucleii out of the hydrogen. Eventually, the thermonuclear reactions use a lot of the hydrogen and the core gets denser and hotter still. Several things can happen at that point, depending on the mass of the star.
For really massive stars (20 times the mass of our sun or more), an explosion will occur that blows most of the mass away, leaving a dense core. If the core is less than about 1.4 solar masses, it becomes a dwarf star, gradually cooling off and getting dimmer. If the core is greater than 1.4 but less than about 3 solar masses, it becomes a neutron star. In a neutron star, the electrons and protons of atoms are squeezed together to become neutrons (releasing neutrinos). The resulting material, consisting only of crushed neutrons, is so dense that a matchbox full of it would have the same mass as a battleship. At that density, only quantum mechanical effects prevent further crushing by gravity.
Finally, if the remnant core has greater than 3 solar masses, even quantum mechanical forces can't overcome gravity and it becomes a black hole.
OK, now to the mystery here: In a binary system, there are two stars. The second star will suck a lot of the mass away from the first star during the long period of stellar evolution before the black hole forms. (Creationists, please keep still for a little while longer.) In order for the remnant to be 14 solar masses, the orginal star had to be maybe 100 solar masses or more before it blew up. But it's difficult for a star in a binary pair to be that large. Hence the mystery.
Now the creationists can have the floor (if they want it) to explain how the objects observed in the heavens can have been created in 5,000 years consistently with the observed laws of physics. No fair postulating that God started the universe off 5,000 years ago with the correct initial conditions to make it look billions of years old; that's cheating.
I disagree. The simplest and most likely explanation is that the astronomer's data or calculations were flawed.
Happily, she was clothed at the time.
And the scientists have discovered a new element: Ol'Crustium.
Yep, the "Killer Canolli from Outer Space" - surely one of the best.
"There is no third planet.", said Kirk.
Sobbing, Matt Decker replies, "Don't you think I know that? There was, but not anymore! They called me. They begged me for help, 400 of them. I couldn't. I -- I couldn't ...".
I've read that Russian astronomers refuse to use the term "black hole" because it translates to their expression for anus. They say "collapsed stellar object" instead. Can someone in the field confirm this? Or is it just an urban legend?
The fact that the companion star is feeding the black hole suggests that it is filling its own Roche lobe. As the black hole grows, the Roche lobe of the companion star is going to shrink, which means that more of the star will be available to the black hole. Over time a significant fraction of the star migrates to the black hole.
Anything obviously wrong with that model?
(I still don't understand the peculiar sentence in the article, BTW.)
No, the Russians use the term "brown star", but American astronomers have in turn balked at that.
</kidding>
ROFLMAO...Excellent.
From now on, all Caring Persons shall take efforts to refer to them as "Holes of Color".
Those which are obscured by a large, crusty event horizon, shall be known as "Holes of Cover".
Then there is the theory that it swallowed another star in a short time billions of years ago, leaving no observable trace today. That would be improbable because it would require the star it collided with to be lined up almost perfectly, otherwise the best it could do would be to capture the other star into a decaying orbit and eat it more slowly.
I wish I were an astrophysicist with the training and computer models to play around with -- this is fascinating stuff. Getting someone to pay for this type of research is the hard part, maybe even harder than doing the research IMHO.
A few years ago, the MSU newspaper ran a story about race relations in South Africa. The article was peppered with references to "South African African Americans."
Political Correctness is so incredibly stupid, dense, obtuse, and humorless that it can only be imposed with the crush of a boot-heel.
Fortunately (for its adherents), that seems to be the way it's imposed on the rest of us.
I'm just suprised that nobody has complained about the term "Brown-Dwarf". I wonder if a lawyer could keep a straight face saying: "We represent the Lollipop-kids...the lollipop-kids...the lollipop-kids." Oh...never mind, they were midgets.
No, it's not cheating. To the contrary, it's completely consistent with the basic premise of Creation itself, i.e., God creates a "finished product", such as Adam, for example.
Adam's body, created instantly, had "the correct initial conditions to make it look [tens] of years old". Adam had the appearance of an embryo that grew to a fetus, that grew to an infant, that grew to a child, that grew to an adolescent, that grew to an adult -- but, none of those stages earlier than the final adult condition occurred.
Creation is inherently the act of producing something with the appearance of having undergone a lengthy process, without it actually undergoing that process. To argue otherwise would be to argue that at most, God created "raw materials". Once one acknowledges Divine Creation of any entitity (world, solar system, human being, etc.), one acknowledges that God has created a finished product that has the appearance of something that had been around for a while. (Take a snapshot of the Solar System one microsecond after it's created. Plot the trajectories of the planets, then take the known data, and "run it backwards", and see what you get. What you'll get are tables of where each planet would have been at various points in time before they existed!)
"Cheating"? Harumph!
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