APOD: M51: The Whirlpool Galaxy (2012 Jun 02)

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APOD: M51: The Whirlpool Galaxy (2012 Jun 02)

Post by APOD Robot » Sat Jun 02, 2012 4:06 am

Image M51: The Whirlpool Galaxy

Explanation: Follow the handle of the Big Dipper away from the dipper's bowl until you get to the handle's last bright star. Then, just slide your telescope a little south and west and you might find this stunning pair of interacting galaxies, the 51st entry in Charles Messier famous catalog. Perhaps the original spiral nebula, the large galaxy with well defined spiral structure is also cataloged as NGC 5194. Its spiral arms and dust lanes clearly sweep in front of its companion galaxy (top), NGC 5195. The pair are about 31 million light-years distant and officially lie within the angular boundaries of the small constellation Canes Venatici. Though M51 looks faint and fuzzy to the human eye, deep images like this one can reveal the faint tidal debris around the smaller galaxy.

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Re: APOD: M51: The Whirlpool Galaxy (2012 Jun 02)

Post by starstruck » Sat Jun 02, 2012 7:04 am

Okay, I'm sold on it! Never seen this galaxy with my own eyes, but I'm going to make a point of trying to locate it through my low-powered scope at the next opportunity (which, in all honesty, may be a little while 'cos it doesn't get dark on a night 'til late at this time of year and I'm usually much too tired to stay up!) Good picture though, thanks.

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Re: APOD: M51: The Whirlpool Galaxy (2012 Jun 02)

Post by nstahl » Sat Jun 02, 2012 7:36 am

I really like this APOD. A great image and a lot of pretty accessible science going on.

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Re: APOD: M51: The Whirlpool Galaxy (2012 Jun 02)

Post by Boomer12k » Sat Jun 02, 2012 8:06 am

Awesome picture. Lots of Star forming regions. Lots of dust. It really shows the power of a galaxy on another galaxy, looks like it was just torn asunder. Far flung stars.

reminds me of a previous apod computer animation of colliding galaxies and the pattern created as stars are flung around.

:D

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Re: APOD: M51: The Whirlpool Galaxy (2012 Jun 02)

Post by saturno2 » Sat Jun 02, 2012 11:50 am

The spiral Galaxy M51 ( NGC 5194 ) is brillant and seems very active in the company of NGC 5195 is back. It¨s trick spiral arms have an extension that connects
( apparenty) with NGC 5195. Rarely we see a galaxy as sharp as this.

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Re: APOD: M51: The Whirlpool Galaxy (2012 Jun 02)

Post by orin stepanek » Sat Jun 02, 2012 12:49 pm

A Beautiful picture indeed! There is a lot of color in today's APOD! :clap: :thumb_up: :thumb_up: :-D
Orin

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Re: APOD: M51: The Whirlpool Galaxy (2012 Jun 02)

Post by FloridaMike » Sat Jun 02, 2012 4:47 pm

Absolutely beautifully image. The composition is fantastic. My favorite part is the flying saucer just up and to the left, watching the whole interaction play out.
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Re: APOD: M51: The Whirlpool Galaxy (2012 Jun 02)

Post by ritwik » Sat Jun 02, 2012 5:58 pm

this external beauty is only a disguise... inside it lurks the all-devouring blackh•le ..when we say M51 M31 we are actually referring to a blackhole which contains most of the mass of galaxy

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Re: APOD: M51: The Whirlpool Galaxy (2012 Jun 02)

Post by Chris Peterson » Sat Jun 02, 2012 6:52 pm

ritwik wrote:this external beauty is only a disguise... inside it lurks the all-devouring blackh•le ..when we say M51 M31 we are actually referring to a blackhole which contains most of the mass of galaxy
In neither M31 nor M51 are the central black holes consuming a significant amount of matter. And in neither case is the mass of the central black hole very large compared with the entire galaxies. M51 is about 160,000 times more massive than its black hole, and M31 is about 35,000 times as massive as its. If the central black holes instantly disappeared, it would have virtually no impact on the dynamics of either galaxy.
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Re: APOD: M51: The Whirlpool Galaxy (2012 Jun 02)

Post by ritwik » Sat Jun 02, 2012 8:30 pm

Chris Peterson wrote: In neither M31 nor M51 are the central black holes consuming a significant amount of matter. And in neither case is the mass of the central black hole very large compared with the entire galaxies. M51 is about 160,000 times more massive than its black hole, and M31 is about 35,000 times as massive as its. If the central black holes instantly disappeared, it would have virtually no impact on the dynamics of either galaxy.
are you sure on that assesment :roll: because according to my info Blackholes acts like an engine swirling rest of the stuff around it :?: so shouldn't it be MASSIVE

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Re: APOD: M51: The Whirlpool Galaxy (2012 Jun 02)

Post by Ann » Sat Jun 02, 2012 9:02 pm

Chris is right, ritwik. The black hole in the center of a galaxy only holds a small part, sometimes a really tiny part, of all the mass in the galaxy. And it isn't true that a black hole just "sucks everything in". Think of it like that. We orbit the Sun, but the Sun doesn't "suck us in". We just keep orbiting the Sun.

Now image that the Sun had somehow turned into a black hole. The Sun can't do that, because it isn't massive enough, but let's pretend, for the sake of the argument, that it could and that it did. Let's assume, too, that the transition from an ordinary star into a black hole was smooth, so that the transition in itself caused no upheavals in the Solar system.

Okay, so what would happen? Would the Sun eat us up now that it had become a black hole? No, it wouldn't. We would just keep orbiting the black hole in the same way as we had orbited the Sun. Similarly, black holes in the center of galaxies don't usually "eat" anything.

I'd like to add that today's APOD is beautiful, and it does a particularly good job at showing the tidal star streams that are drawn out thanks to the interaction between the galaxies. The interaction between M51 and NGC 5195 is just right for sculpting M51 into an unusually wonderful spiral galaxy, with long, symmetrical, very bright spiral arms.

It's a pity that the future interaction between the Milky Way and the Andromeda galaxy is going to be a lot messier, with a head-on collision and the destruction of the spiral patterns of these two galaxies.

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Re: APOD: M51: The Whirlpool Galaxy (2012 Jun 02)

Post by neufer » Sat Jun 02, 2012 10:30 pm

Chris Peterson wrote:
ritwik wrote:
..when we say M51 M31 we are actually referring to a blackhole which contains most of the mass of galaxy
In neither M31 nor M51 are the central black holes consuming a significant amount of matter. And in neither case is the mass of the central black hole very large compared with the entire galaxies. M51 is about 160,000 times more massive than its black hole, and M31 is about 35,000 times as massive as its. If the central black holes instantly disappeared, it would have virtually no impact on the dynamics of either galaxy.
..when we say Messier 51/31 we are actually referring to a blackhole which contains most of the Entropy of the galaxy.
messy, messier, messiest [Perh. corrupt. fr. OE. mesh for mash: cf. muss.]
1. marked by confusion, disorder, or dirt : untidy
2. lacking neatness or precision : careless, slovenly
http://iopscience.iop.org/1475-7516/2003/11/011;jsessionid=F833213E4478259ED1ECFB66330F10DB.c1 wrote:
Black holes, mergers and the entropy budget of the Universe
Journal of Cosmology and Astroparticle Physics Volume 2003 November 2003
Thomas W Kephart and Y Jack Ng JCAP11(2003)011 doi:10.1088/1475-7516/2003/11/011

<<Vast amounts of entropy can be produced in black hole formation, and the amount of entropy stored in supermassive black holes at the centres of galaxies is now much greater than the entropy free in the rest of the Universe. Either mergers involved in forming supermassive black holes are rare, or the holes must be very efficient at capturing nearly all the visible entropy generated (while emitting a huge number of coherent quanta in the process). We give two models of entropy production in the Universe due to black hole mergers and argue that this information can be used to constrain supermassive black hole production. This may eventually provide a check on numerical results for mergers involving black holes.>>
http://www.usnews.com/science/articles/2009/10/05/new-calculations-suggest-universe-may-be-a-bit-closer-to-heat-death wrote:
New Calculations Suggest Universe May be Closer to Heat Death
U.S. News, October 5, 2009 RSS Feed Print
By Ron Cowen, Science News

<<A new calculation of entropy upholds that general result but suggests that the universe is messier than scientists had thought—and slightly further along on its gradual journey to death, two Australian cosmologists conclude.

An analysis by Chas Egan of the Australian National University in Canberra and Charles Lineweaver of the University of New South Wales in Sydney indicates that the collective entropy of all the supermassive black holes at the centers of galaxies is about 100 times higher than previously calculated. Because supermassive black holes are the largest contributor to cosmic entropy, the finding suggests that the entropy of the universe is also about 100 times larger than previous estimates, the researchers reported online September 23 at arXiv.org.

Entropy quantifies the number of different microscopic states that a physical system can have while looking the same on a large scale. For instance, an omelet has higher entropy than an egg because there are more ways for the molecules of an omelet to rearrange themselves and still remain an omelet than for an egg, notes cosmologist Sean Carroll of the California Institute of Technology in Pasadena.

A black hole is the entropy champ because there are myriad ways for all the material that has fallen into it to be arranged microscopically while the black hole retains the same numerical values for its observable properties—charge, mass and spin.

Researchers who previously calculated the cosmic sum of black hole entropy had assumed that, on average, each galaxy houses a 10 million solar-mass black hole at its center. Under this assumption, researchers had determined that supermassive black holes contribute an entropy of about 10102, in units derived from a quantity known as Boltzmann’s constant.

In contrast, Egan and Lineweaver relied on new data that included a fuller range of the masses of supermassive black holes rather than just using the average mass. “The upshot was that much more entropy is contributed by a smaller population of much larger, 1-billion-solar-mass black holes,” Egan says.

Carroll says that the team’s calculation looks sensible. “I see no reason to doubt their numbers,” he says.

Having a more reliable entropy estimate is important, says Egan, because for life or other complex phenomena to exist, the entropy of the universe must be less than the maximum possible value. Consider, he notes, when hot water is poured into a cold bath. Initially the hot and cold water are separate and the system is orderly — it has low entropy. But once the hot and cold water are thoroughly mixed, the entropy is maximized and no further heat flow is possible.

In the case of the universe, Egan says, “we'd like to know [when and] if the entropy will eventually reach a maximum value, marking the end of all dissipative processes, including life.” Physicists have dubbed that maximum entropy “heat death.”

Egan and Lineweaver’s new value for the entropy of the universe is still a billionth of a billionth the maximum possible entropy that researchers have estimated. Nonetheless, the new value “indicates that that the universe is a bit closer to the heat death than previously computed,” comments theorist Paul Davies of Arizona State University in Tempe.

Not everyone agrees that the higher entropy contributed by supermassive black holes puts the universe closer to heat death. Theorist Ned Wright of the University of California, Los Angeles says that because the extra entropy is locked inside the black holes, the rest of the universe should have lower entropy and be further away from heat death.

The new entropy calculation also highlights a cosmic puzzle, Carroll says. The entropy was relatively small in the early universe (1088), bigger now (10104), but still falls far short of the maximum (10122). No known physical principle can explain why the cosmic entropy is so low. But it’s a good thing because the low value “is responsible for everything we experience about the [unidirectional] flow of time — breaking eggs, growing older and dying, remembering the past but not the future,” notes Carroll. “The universe is incredibly more orderly than it has any right to be. Egan and Lineweaver have shown that it's just a bit more disorderly than we thought.”>>
Art (incredibly more orderly this time than he has any right to be) Neuendorffer

Wha?

Re: APOD: M51: The Whirlpool Galaxy (2012 Jun 02)

Post by Wha? » Sun Jun 03, 2012 1:53 am

neufer wrote: ..when we say Messier 51/31 we are actually referring to a blackhole which contains most of the Entropy of the galaxy.
Art (incredibly more orderly this time than he has any right to be) Neuendorffer
Does dark matter also contain entropy? Or because it doesn't act like a shredder, does it contain little or less?

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Re: APOD: M51: The Whirlpool Galaxy (2012 Jun 02)

Post by neufer » Sun Jun 03, 2012 3:09 am

Wha? wrote:
neufer wrote:
..when we say Messier 51/31 we are actually referring to a blackhole which contains most of the Entropy of the galaxy.
Art (incredibly more orderly this time than he has any right to be) Neuendorffer
Does dark matter also contain entropy?
  • Certainly.
Art Neuendorffer

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Re: APOD: M51: The Whirlpool Galaxy (2012 Jun 02)

Post by Beyond » Sun Jun 03, 2012 3:20 am

neufer wrote:
Wha? wrote:
neufer wrote:
..when we say Messier 51/31 we are actually referring to a blackhole which contains most of the Entropy of the galaxy.
Art (incredibly more orderly this time than he has any right to be) Neuendorffer
Does dark matter also contain entropy?
  • Certainly.
But it's just that you can't see it??
To find the Truth, you must go Beyond.

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Re: APOD: M51: The Whirlpool Galaxy (2012 Jun 02)

Post by ritwik » Sun Jun 03, 2012 6:17 am

YEs !! entropy :wink: i had to google it http://www.universetoday.com/51887/define-entropy/

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Re: APOD: M51: The Whirlpool Galaxy (2012 Jun 02)

Post by ta152h0 » Sun Jun 03, 2012 6:01 pm

This was the target for the first HUBBLE image, if my aged memory still works ? Hope lessons learned is well applied for the next telescope. Saving money by cutting tests will earn you a nice plaque on the wall and attaboys in group meetings but that is all.
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Black Hole Growth Out of Whack in Some Galaxies

Post by neufer » Tue Jun 12, 2012 3:53 pm

Chris Peterson wrote:
ritwik wrote:
this external beauty is only a disguise... inside it lurks the all-devouring blackh•le ..when we say M51 M31 we are actually referring to a blackhole which contains most of the mass of galaxy
In neither M31 nor M51 are the central black holes consuming a significant amount of matter. And in neither case is the mass of the central black hole very large compared with the entire galaxies. M51 is about 160,000 times more massive than its black hole, and M31 is about 35,000 times as massive as its. If the central black holes instantly disappeared, it would have virtually no impact on the dynamics of either galaxy.
http://www.universetoday.com/95806/black-hole-growth-out-of-whack-in-some-galaxies/#more-95806 wrote:
Black Hole Growth Out of Whack in Some Galaxies
by Nancy Atkinson on June 12, 2012
From a Chandra press release: <<New evidence from NASA’s Chandra X-ray Observatory challenges prevailing ideas about how black holes grow in the centers of galaxies. Astronomers long have thought that a supermassive black hole and the bulge of stars at the center of its host galaxy grow at the same rate — the bigger the bulge, the bigger the black hole. However, a new study of Chandra data has revealed two nearby galaxies with supermassive black holes that are growing faster than the galaxies themselves.

The mass of a giant black hole at the center of a galaxy typically is a tiny fraction — about 0.2 percent — of the mass contained in the bulge, or region of densely packed stars, surrounding it. The targets of the latest Chandra study, galaxies NGC 4342 and NGC 4291, have black holes 10 times to 35 times more massive than they should be compared to their bulges [i.e., 2-7%] The new observations with Chandra show the halos, or massive envelopes of dark matter in which these galaxies reside, also are overweight.

This study suggests the two supermassive black holes and their evolution are tied to their dark matter halos and did not grow in tandem with the galactic bulges. In this view, the black holes and dark matter halos are not overweight, but the total mass in the galaxies is too low. “This gives us more evidence of a link between two of the most mysterious and darkest phenomena in astrophysics — black holes and dark matter — in these galaxies,” said Akos Bogdan of the Harvard-Smithsonian Center for Astrophysics (CfA) in Cambridge, Mass., who led the new study.

NGC 4342 and NGC 4291 are close to Earth in cosmic terms, at distances of 75 million and 85 million light years. Astronomers had known from previous observations that these galaxies host black holes with relatively large masses, but are not certain what is responsible for the disparity. Based on the new Chandra observations, however, they are able to rule out a phenomenon known as tidal stripping.

Tidal stripping occurs when some of a galaxy’s stars are stripped away by gravity during a close encounter with another galaxy. If such tidal stripping had taken place, the halos mostly would have been missing. Because dark matter extends farther away from the galaxies, it is more loosely tied to them than the stars and more likely to be pulled away.

To rule out tidal stripping, astronomers used Chandra to look for evidence of hot, X-ray-emitting gas around the two galaxies. Because the pressure of hot gas — estimated from X-ray images — balances the gravitational pull of all the matter in the galaxy, the new Chandra data can provide information about the dark matter halos. The hot gas was found to be distributed widely around NGC 4342 and NGC 4291, implying that each galaxy has an unusually massive dark matter halo and that tidal stripping is unlikely. “This is the clearest evidence we have, in the nearby universe, for black holes growing faster than their host galaxy,” said co-author Bill Forman, also of CfA. “It’s not that the galaxies have been compromised by close encounters, but instead they had some sort of arrested development.

How can the mass of a black hole grow faster than the stellar mass of its host galaxy? The study’s authors suggest a large concentration of gas spinning slowly in the galactic center is what the black hole consumes very early in its history. It grows quickly, and as it grows, the amount of gas it can accrete, or swallow, increases along with the energy output from the accretion. After the black hole reaches a critical mass, outbursts powered by the continued consumption of gas prevent cooling and limit the production of new stars. “It’s possible that the supermassive black hole reached a hefty size before there were many stars at all in the galaxy,” said Bogdan. “That is a significant change in our way of thinking about how galaxies and black holes evolve together.

The results were presented June 11 at the 220th meeting of the American Astronomical Society in Anchorage, Alaska. The study also has been accepted for publication in The Astrophysical Journal.>>
Art (not overweight but rather tied to his dark halo) Neuendorffer