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

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.