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APOD: HCG 87: A Small Group of Galaxies (2015 Aug 09)
Posted: Sun Aug 09, 2015 4:11 am
by APOD Robot
HCG 87: A Small Group of Galaxies
Explanation: Sometimes galaxies form groups. For example, our own
Milky Way Galaxy is part of the
Local Group of Galaxies. Small, compact groups, like
Hickson Compact Group 87 (
HCG 87)
shown above, are interesting partly because they slowly self-destruct. Indeed, the galaxies of
HCG 87 are gravitationally stretching each other during their 100-million year orbits around a common center. The
pulling creates colliding gas that causes bright bursts of
star formation and feeds matter into their
active galaxy centers.
HCG 87 is composed of a large
edge-on spiral galaxy visible near the image center, an
elliptical galaxy visible to its right, and a
spiral galaxy visible near the top. The small spiral near the center might be far in the distance. Several stars from
our Galaxy are also visible in the foreground. Studying groups like HCG 87 allows insight into how all
galaxies form and evolve.
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Re: APOD: HCG 87: A Small Group of Galaxies (2015 Aug 09)
Posted: Sun Aug 09, 2015 4:50 am
by Ann
Today is repeat day at APOD, and today's picture is from 2003. In my opinion, the most interesting thing about it is
this link, which not only provides a comparison between the Gemini telescope image of HCG 87 and the HST image of the same group, but also explains why we should bother with ground-based telescope images of deep space objects at all:
"Historically, the main advantage of large ground-based telescopes, like Gemini, is their ability to collect significantly more light for spectroscopy than is possible with a telescope in space," said Phil Puxley, Associate Director of the Gemini South Telescope. He explains, "The Hubble Space Telescope is able to do things that are impossible from the ground. However, ground-based telescopes like Gemini, when conditions are right, approach the quality of optical images now only possible from space. One key area - spectroscopy of faint objects, which requires large apertures and fine image quality - is where large telescopes like Gemini provide a powerful, complementary capability to space-based telescopes."
Ann
Re: APOD: HCG 87: A Small Group of Galaxies (2015 Aug 09)
Posted: Sun Aug 09, 2015 9:45 am
by hoohaw
The discussion, under "Curiosity's View," is still a repeat of the previous day's APOD (Full Earth, Full Moon) discussion. Is it only my computer somehow? I had wanted to comment on Curiosity's View, and never got the chance!
Re: APOD: HCG 87: A Small Group of Galaxies (2015 Aug 09)
Posted: Sun Aug 09, 2015 9:48 am
by hoohaw
Think of going to the fair, and going on Bumper Cars! That's what our Universe is, bumper cars for Galaxies! (Better than Clown Cars, I suppose!)
Re: APOD: HCG 87: A Small Group of Galaxies (2015 Aug 09)
Posted: Sun Aug 09, 2015 1:52 pm
by hoohaw
...though, now that I think of it, those black holes, with impossible jets coming out of them, are pretty analogous to clown cars, aren't they!
Re: APOD: HCG 87: A Small Group of Galaxies (2015 Aug 09)
Posted: Sun Aug 09, 2015 2:35 pm
by Chris Peterson
hoohaw wrote:The discussion, under "Curiosity's View," is still a repeat of the previous day's APOD (Full Earth, Full Moon) discussion. Is it only my computer somehow? I had wanted to comment on Curiosity's View, and never got the chance!
It's only your computer, apparently. Maybe a caching issue. Each of the last two days' APODs have their own, separate discussions.
Re: APOD: HCG 87: A Small Group of Galaxies (2015 Aug 09)
Posted: Sun Aug 09, 2015 2:50 pm
by Meekmoe
hoohaw wrote:The discussion, under "Curiosity's View," is still a repeat of the previous day's APOD (Full Earth, Full Moon) discussion. Is it only my computer somehow? I had wanted to comment on Curiosity's View, and never got the chance!
I get the same, full earth full moon discussion under the curiosity view...
Re: APOD: HCG 87: A Small Group of Galaxies (2015 Aug 09)
Posted: Sun Aug 09, 2015 2:58 pm
by Chris Peterson
Meekmoe wrote:hoohaw wrote:The discussion, under "Curiosity's View," is still a repeat of the previous day's APOD (Full Earth, Full Moon) discussion. Is it only my computer somehow? I had wanted to comment on Curiosity's View, and never got the chance!
I get the same, full earth full moon discussion under the curiosity view...
You get this when you go directly to that discussion heading under "The Bridge: Discuss an Astronomy Picture of the Day", or when you click on the "Discuss" link at the bottom of the "Curiosity's View" APOD? Because the link in the latter is pointing to the wrong place. But the discussion is
still here if you simply go to it directly from the Asterisk forums, and not from APOD.
Re: APOD: HCG 87: A Small Group of Galaxies (2015 Aug 09)
Posted: Sun Aug 09, 2015 6:03 pm
by Coil_Smoke
At first glance
the small spiral galaxy in the center looked like a human hand.(Sorta pointing to 8 O"Clock position) Must be those old 'Star Trek' episodes like "Who Morns For Adonis' with the huge outstretched hand in space.
Re: APOD: HCG 87: A Small Group of Galaxies (2015 Aug 09)
Posted: Sun Aug 09, 2015 6:31 pm
by Boomer12k
Why does the edge on Galaxy have an "X" looking pattern???
Nice Pic.
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Re: APOD: HCG 87: A Small Group of Galaxies (2015 Aug 09)
Posted: Sun Aug 09, 2015 6:39 pm
by Boomer12k
Went to the telescope website for Gemini.....watched the video....I WANT ONE....
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Re: APOD: HCG 87: A Small Group of Galaxies (2015 Aug 09)
Posted: Sun Aug 09, 2015 6:39 pm
by neufer
Boomer12k wrote:
Why does the edge on Galaxy have an "X" looking pattern???
It is gravitationally warped by the elliptical galaxy.
Re: APOD: HCG 87: A Small Group of Galaxies (2015 Aug 09)
Posted: Sun Aug 09, 2015 8:29 pm
by LocalColor
Boomer12k wrote:Why does the edge on Galaxy have an "X" looking pattern???
Nice Pic.
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Thanks for pointing that out, I miseed it.
Lovely photo and very educational.