Comments on: Unusual Galaxies Eat Their Neighbors http://www.universetoday.com/2008/06/23/unusual-galaxies-eat-their-neighbors/ Space and astronomy news Sun, 8 Nov 2009 10:14:11 -0600 http://wordpress.org/?v=2.8.5 hourly 1 By: Anne http://www.universetoday.com/2008/06/23/unusual-galaxies-eat-their-neighbors/comment-page-1/#comment-25702 Anne Thu, 10 Jul 2008 12:29:37 +0000 http://www.universetoday.com/?p=15247#comment-25702 Thanks for the reply. It does make more sense now. Thanks for the reply. It does make more sense now.

]]> By: al http://www.universetoday.com/2008/06/23/unusual-galaxies-eat-their-neighbors/comment-page-1/#comment-24495 al Wed, 25 Jun 2008 05:12:00 +0000 http://www.universetoday.com/?p=15247#comment-24495 erm .. wow ! The more I learn the more I get confused ! erm .. wow !
The more I learn the more I get confused !

]]> By: Astrofiend http://www.universetoday.com/2008/06/23/unusual-galaxies-eat-their-neighbors/comment-page-1/#comment-24480 Astrofiend Tue, 24 Jun 2008 23:43:44 +0000 http://www.universetoday.com/?p=15247#comment-24480 "joe Says: June 23rd, 2008 at 11:28 pm " @Joe, @ anne It should be emphasized that these black holes are not actually taking material from the other galaxy. Rather, the gravitational interactions of the two galaxies disturb the equilibrium 'orbits' of material already encircling the black hole, which causes it to begin spiraling in and getting consumed. "Chuck Lam Says: June 24th, 2008 at 5:47 am " @Chuck Lam This is a great point - in fact, it is this very line of evidence that provided the original strong evidence that these object are powered by black holes, and not some other mysterious phenomenon. If you think about it, no information can travel faster than the speed of light. Hence, if we see variability on timescales of say, a day, we just use the very simple relation distance = velocity_of_light*time to give us and estimate of the maximum expanse of the light emitting region, in this case, one light-day. There is only one known object that can power such luminous variability that we know of, and that object is a supermassive black hole at the centre of the galaxy! "joe Says:
June 23rd, 2008 at 11:28 pm "

@Joe, @ anne

It should be emphasized that these black holes are not actually taking material from the other galaxy. Rather, the gravitational interactions of the two galaxies disturb the equilibrium 'orbits' of material already encircling the black hole, which causes it to begin spiraling in and getting consumed.

"Chuck Lam Says:
June 24th, 2008 at 5:47 am "

@Chuck Lam

This is a great point – in fact, it is this very line of evidence that provided the original strong evidence that these object are powered by black holes, and not some other mysterious phenomenon.

If you think about it, no information can travel faster than the speed of light. Hence, if we see variability on timescales of say, a day, we just use the very simple relation distance = velocity_of_light*time to give us and estimate of the maximum expanse of the light emitting region, in this case, one light-day. There is only one known object that can power such luminous variability that we know of, and that object is a supermassive black hole at the centre of the galaxy!

]]> By: Chuck Lam http://www.universetoday.com/2008/06/23/unusual-galaxies-eat-their-neighbors/comment-page-1/#comment-24470 Chuck Lam Tue, 24 Jun 2008 21:10:52 +0000 http://www.universetoday.com/?p=15247#comment-24470 The smaller of the two galaxies in the photo may be the larger and more than a few light years apart. Is Tang sure one galaxie is feeding off the other? The smaller of the two galaxies in the photo may be the larger and more than a few light years apart. Is Tang sure one galaxie is feeding off the other?

]]> By: greg c http://www.universetoday.com/2008/06/23/unusual-galaxies-eat-their-neighbors/comment-page-1/#comment-24461 greg c Tue, 24 Jun 2008 18:36:55 +0000 http://www.universetoday.com/?p=15247#comment-24461 great LOL! great LOL!

]]> By: themadlolscientist http://www.universetoday.com/2008/06/23/unusual-galaxies-eat-their-neighbors/comment-page-1/#comment-24458 themadlolscientist Tue, 24 Jun 2008 17:47:13 +0000 http://www.universetoday.com/?p=15247#comment-24458 AstroNOMNOMNOMy! Sorry, just couldn't resist. :-) AstroNOMNOMNOMy!

Sorry, just couldn't resist. :-)

]]> By: Howard http://www.universetoday.com/2008/06/23/unusual-galaxies-eat-their-neighbors/comment-page-1/#comment-24457 Howard Tue, 24 Jun 2008 17:36:22 +0000 http://www.universetoday.com/?p=15247#comment-24457 Maybe the motion of the "local" stars around the black hole is sufficient to generate enough centripetal force to keep them from being sucked in. Maybe the motion of the "local" stars around the black hole is sufficient to generate enough centripetal force to keep them from being sucked in.

]]> By: Bill http://www.universetoday.com/2008/06/23/unusual-galaxies-eat-their-neighbors/comment-page-1/#comment-24438 Bill Tue, 24 Jun 2008 14:38:14 +0000 http://www.universetoday.com/?p=15247#comment-24438 If this is a gravitational interaction, why does the material make a huge half circle in extending from one galaxy to another? If this is a gravitational interaction, why does the material make a huge half circle in extending from one galaxy to another?

]]> By: Chuck Lam http://www.universetoday.com/2008/06/23/unusual-galaxies-eat-their-neighbors/comment-page-1/#comment-24428 Chuck Lam Tue, 24 Jun 2008 12:47:18 +0000 http://www.universetoday.com/?p=15247#comment-24428 Hmm . . . how can a galaxie perhaps as little as a couple hundred thousand light years in diameter have a center that fluctuates in brightness on a time scale that we can detect? It defies logic. Hmm . . . how can a galaxie perhaps as little as a couple hundred thousand light years in diameter have a center that fluctuates in brightness on a time scale that we can detect? It defies logic.

]]> By: Anne http://www.universetoday.com/2008/06/23/unusual-galaxies-eat-their-neighbors/comment-page-1/#comment-24412 Anne Tue, 24 Jun 2008 07:26:55 +0000 http://www.universetoday.com/?p=15247#comment-24412 Yeah, it does make no logical sens. I thought the galaxy itself moved not that material from the neighbouring galaxy moved towards the black hole, what about the material close to the blackhole, isn't it 'consumed' as well? Yeah, it does make no logical sens. I thought the galaxy itself moved not that material from the neighbouring galaxy moved towards the black hole, what about the material close to the blackhole, isn't it 'consumed' as well?

]]> By: joe http://www.universetoday.com/2008/06/23/unusual-galaxies-eat-their-neighbors/comment-page-1/#comment-24407 joe Tue, 24 Jun 2008 06:28:19 +0000 http://www.universetoday.com/?p=15247#comment-24407 I don't understand why black holes would take material from neighboring galaxies but leave the stars in their own galaxy untouched. I say untouched because they are all still there or it would not be a galaxy. So how does it suck in gas from neighboring galaxies but not consume much closer stars? I don't understand why black holes would take material from neighboring galaxies but leave the stars in their own galaxy untouched. I say untouched because they are all still there or it would not be a galaxy. So how does it suck in gas from neighboring galaxies but not consume much closer stars?

]]> By: Jon Hanford http://www.universetoday.com/2008/06/23/unusual-galaxies-eat-their-neighbors/comment-page-1/#comment-24401 Jon Hanford Tue, 24 Jun 2008 04:55:31 +0000 http://www.universetoday.com/?p=15247#comment-24401 Again it should be emphasized that many QSOs, BL Lacs & blazars appear to be in interacting systems, although their higher luminosities can make detection of companion extremely difficult. Again it should be emphasized that many QSOs, BL Lacs & blazars appear to be in interacting systems, although their higher luminosities can make detection of companion extremely difficult.

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