Hubble Delivers Indications Of Black Holes

tomorama writes: "Working with the Hubble Space telescope, Ohio State University astronomers studied the most central 1000 light years -- or 6 quadrillion miles -- of 24 spiral galaxies. Associate Professor Richard Pogge and graduate student Paul Martini discovered a distinct swirling pattern in 20 of the 24 galaxies, indicating that huge masses of dust were being sucked into gigantic black holes." The link is worth visiting for the enhanced photo of a black hole at feeding time alone.

Comments

Re:Implications of black holes in an open ended un

[drudd]

Its a common misconception that black holes some how "suck" in matter. In fact black holes have exactly the same amount of gravitational attraction as a different object with the same mass. If we replaced our sun with a black hole of the sun's mass, the earth would continue to orbit.

Since black holes form and grow from matter which was already in the general vicinity, objects which were far away feel the exact same gravitational force, regardless of whether the mass is in star or black hole form.

Doug

What happens once it all goes in?

[ca1v1n]

I have seen a lot of questions here about white holes and black hole decay. I thin kI should clarify some of the misconceptions.

Many people have difficulty with the idea of a black hole sucking up matter for all eternity, and have thus looked for a way out, something which allows that matter to be reclaimed by the universe. This has led to some rather interesting theories regarding things like white holes. These theories have never been supported by any astronomical evidence, nor do they even make much logical or mathematical sense, at least not in a typical Einsteinian view of the universe. Fortunately, someone has found a "way out". This person is Stephen Hawking. He devised a mechanism by which a black hole could leak out matter and energy slowly over time. This so-called "Hawking radiation" is emitted proportionally to the size of the black hole at the event horizon. Thus, a large black hole would emit energy and matter much faster than a small one, but a small one could eventually decay to the point where it no longer had the mass to generate the gravity well required to contain light. Of course, this is a VERY slow process, and most black holes are gaining mass many orders of magnitude faster than they are losing them.

So, yes, if you went into a black hole, you would be able to get out...

...In trillions of pieces over trillions of years.

Implications of black holes in an open ended univ.

[RNG]

Hmm,

the more we look out into space, the more it seems that objects which were once considered extraordinary/rare, are acutally pretty common (quasars, black holes, neutron stars, etc.).

What are the implications of supermassive black holes in an open ended universe? Does that not suggest that eventually (in 10s of billions of years), everything will eventually be sucked into one of these black holes. Will we eventually have a universe populated by a few (or one) supermassive black hole(s) or am I being overly dramatic here? Are there any models on what the eventual state of such a universe would be? Inquiring minds want to know ...

More and better pictures.

[Raymond Luxury Yacht]

Drop by NASA's gallery for better shots from space.

Re:Implications of black holes in an open ended un

[roman_mir]

The distance between two stars in any given galaxy is thousands, millions and billions times smaller that the distance between any two galaxies. Even in an unlikely case that some black hole somewhere would consume the remnants of its galaxy by gravitating them toward itself, the reality is that this black hole, no matter how massive it is will not be affected by gravitational pull of other galaxies nor will it affect any other galaxy by its own gravitational pull. (Use Newton's 3'rd law to calculate the gravitational pull exerted by a black hole onto a galaxy) If you assume a homogenious and an isotropic universe then there will be no preference for a direction a black hole may choose on. However, by the law of Hubble the universe is expanding and so the distances between objects become larger (50 to 100 KM each second for each MGParsec.) What happens is that the Expansion of the Universe is actually greater than the velocity of any type of movement by a black hole created due to gravitational attraction between a black hole and another galaxy.

In short - this universe will never become one huge black hole, unlike New York or Toronto, which already are.

Not really "being sucked into a black hole"

[StupendousMan]

The images produced by Pogge and Martini show material in the inner spiral arms of the galaxies. It's a stretch to refer to this as material "being sucked into gigantic black holes." Note the scale of the images: the resolution is a few hundred light years. The accretion disk around the black hole is less than one light year in radius; it is completely unresolved in thes pictures.

The material shown in these images MAY be spiralling gradually in towards the center of the galaxies, but it may also be in relatively stable orbits around the center. Suppose that a small component of the total velocity -- which is several hundred km/sec -- is radially inwards. It would take tens of millions of years for the material to reach the black hole.

Writing that these pictures show gas which is
"being sucked into a gigantic black hole" is about as accurate as writing "and here's a picture of Angeline Jolie growing old and wrinkled at the Academy Awards ceremony." Sure, technically, she is growing oldER and adding a micro-wrinkle or two as she sits in the audience ... but it's not really relevant under the circumstances.

By a curious coincidence, I just wrote up a lecture on black holes at the centers of galaxies
for the introductor astro course I'm teaching. Check out

http://spiff.rit.edu/richmond/classes/phys240/le ctures/blackholes/blackholes.html.