Is this just a "ring galaxy"?

[Floridian]

http://apod.nasa.gov/apod/ap100822.html

Very interesting picture. Since the picture was discovered in 1950, have they come up with a more detailed explanation other than that it might be a collision of two galaxies or a new type of galaxy.

Its also very interesting that theres another ring galaxy in the background.

I would be interested to know if there is a zoomed in picture of that ring galaxy. Maybe theres a nothing ring galaxy inside that one. LOL

I wonder if it a galaxy could have collided with a giant cloud of gas and for some reason there was a giant explosion in the core that slowly pushed the gas outward and it formed a ring. Guess nothing could generate an explosion that large though could it.

Also, maybe two galaxies flew by eachother and their outer rings of stars were both pulled out but just barely stayed with this galaxy. I suppose there'd be evidence of this nearby though? Or maybe a really young galaxy was just torn asunder and it forms a ring. Its interesting that the ring seems perfectly formed. Really seems like there is another source or gravity or was at some point.

 

[MeteorWayne]

That's a fascinating object. I've never seen it before in all of my decades of astro curiousity. Thanx for pointing it out! (and of course, thanx to APOD, the one of the top 5 sites on Teh Interwebz)

 

[ZenGalacticore]

Very cool pic! Ring galaxies rock!

And the one in the background, wow! How often is that two ring galaxies appear to be in such close proximity? Anyone know the actual (approximate) distances between the two?

Imagine what it would be like to be on a planet orbiting a star on the inner edge of the ring. Would there ever be night time? That big ball of older stars would always be in the sky, it seems like. And if there was a night sky, what a view of the rest of the edge of the ring that must be!

 

[silylene]

That's a fascinating object. I've never seen it before in all of my decades of astro curiousity. Thanx for pointing it out! (and of course, thanx to APOD, the one of the top 5 sites on Teh Interwebz)

Same here, and I have seen many thousands of interesting space photos. I have never seen a picture of Hoag's ring galaxy before either. And the background ring galaxy at 1AM within Hoag's is fascinating too.

 

[SteveCNC]

sweet picture just wish it was higher resolution so it would make good wallpaper . If I were guessing I say it was the result of a very large star going supernova and the gap is caused by the difference between gas not able to reach escape velocity in time and is being pulled back in and gas that did escape and continues to spread . But that's just my guess .

 

[MeteorWayne]

It's a galaxy, they are stars, not a ring of gas!

 

[SteveCNC]

It's a galaxy, they are stars, not a ring of gas!

lol , and what pray tell were the stars made from ? I guess in some cases I should carry things to their logical conclusion so as to not create confusion among those who look for things wrong , it's just that some things seem like they should be a given .

 

[MeteorWayne]

A single supernova, even the most massive ever could not create a galaxy sized ring.

 

[SteveCNC]

the thing is (and maybe its a result from the angle we are viewing it) it seems to be to perfectly round to be the result of a collision . A collision should at least be like an oval or egg shape the way I see it , if there is no way a single supernova created it then what did ? I just don't buy the collision theory , it's too perfect and collision causes chaos .

It's 600 million light years away so not really a huge time distance by galactic standards , but there's no mention of it's age only older and younger but older/younger to what I don't know . Couldn't it be the result of a huge nebula disk that had a super large star in the middle go super nova , it would look like this ? I don't have much doubt that there's a black hole in the center of that thing we just can't see it through the glow maybe .

 

[SpeedFreek]

the thing is (and maybe its a result from the angle we are viewing it) it seems to be to perfectly round to be the result of a collision . A collision should at least be like an oval or egg shape the way I see it , if there is no way a single supernova created it then what did ? I just don't buy the collision theory , it's too perfect and collision causes chaos .

It's made of millions of stars! Are you suggesting that whole galaxies can form from the result of a single supernova?

 

[SteveCNC]

the thing is (and maybe its a result from the angle we are viewing it) it seems to be to perfectly round to be the result of a collision . A collision should at least be like an oval or egg shape the way I see it , if there is no way a single supernova created it then what did ? I just don't buy the collision theory , it's too perfect and collision causes chaos .

It's made of millions of stars! Are you suggesting that whole galaxies can form from the result of a single supernova?

Did you only read the first paragraph and then throw a comment out ? A single supernova all alone by itself would not do that however a nebula with a early star far more massive than any today or maybe even a multi star system in the center may have had enough mass to cause that , some of the stars that were in the early formation of the universe were short lived but far more massive than anything we can see today . What would happen if a star were to draw in more mass than it can handle or two or more super massive stars came together .

 

[MeteorWayne]

You're still off by a hundred orders of magnitude That's 10^100.

 

[trumptor]

Imagine what it would be like to be on a planet orbiting a star on the inner edge of the ring. Would there ever be night time? That big ball of older stars would always be in the sky, it seems like. And if there was a night sky, what a view of the rest of the edge of the ring that must be!

That would be an awesome night sky if it were that bright. Looking at a spiral galaxy from a distance shows a very bright core, but we live in one and it doesn't brighten our night sky. Would the view of the core in the ring galaxy be alot different assuming that there is much less matter between those inner stars and the core as compared to our solar system and our core?

 

[MeteorWayne]

Actually, if you are far enough from light pollution, the Milky Way DOES light the night sky, and the ground. Enough to walk around without a flashlight. However, in today's world, such places are far too rare.

 

[trumptor]

Really? Wow, I'd love to see it that way. I've seen the Milky Way as a band across the sky many times during planetarium shows when they proceed to show the sky as it would appear without all the light pollution, but I've never been able to see it outside in the actual night sky. Can you actually locate the center if you're at the right place at the right time?

So then the view from one of those inner stellar systems of the ring galaxy probably would be pretty remarkable!

 

[MeteorWayne]

The center of the MW, is hard to see; that's the direction the most dust is in. It's in the constellation Sagittarius. Looking outward is where it's the brightest.

 

[SpeedFreek]

Did you only read the first paragraph and then throw a comment out ? A single supernova all alone by itself would not do that however a nebula with a early star far more massive than any today or maybe even a multi star system in the center may have had enough mass to cause that , some of the stars that were in the early formation of the universe were short lived but far more massive than anything we can see today . What would happen if a star were to draw in more mass than it can handle or two or more super massive stars came together .

No, I did read both paragraphs, but I'm not sure you are appreciating the scales involved here. The stars you are suggesting would still have to be millions of times more massive that the later generations of stars. To put this into context, we have no observational evidence for stars of more than ~300 solar masses, and no theoretical basis for there ever having been stars approaching anything near 1000 solar masses (current estimates for "early type" pop III stars put their mass between ten and a few hundred solar masses).

Nebulae tend to form from either a gravitational collapse of the interstellar medium, where stars form at the centre, or they form the other way around, from supernova events. The interstellar medium tends to be very diffuse, which is why only a relatively few stars could form from a nebula. Of course, a supernova event could never cause a nebula with more mass than the original star.

Stars form when mass gets concentrated enough in one place. How would a supernovae event, even in a very dense nebula, cause the mass of that nebula to form into millions of stars? Surely it would blast the nebula apart, forming a larger but even more diffuse nebula?

A very large and compact nebula like the Tarantula nebula is around 500 light years across and contains around 450,000 solar masses. There are a few small stars in it's central region, and it may eventually become "concentrated enough" form itself into a globular cluster, but I do not see how any supernova event in a nebula could form something like the ring galaxy which is around 100,000 light years across and contains millions, if not billions, of stars.

To me, the ring galaxy looks like an elliptical galaxy surrounded by the remnants of a spiral.

 

[ZenGalacticore]

Imagine what it would be like to be on a planet orbiting a star on the inner edge of the ring. Would there ever be night time? That big ball of older stars would always be in the sky, it seems like. And if there was a night sky, what a view of the rest of the edge of the ring that must be!

That would be an awesome night sky if it were that bright. Looking at a spiral galaxy from a distance shows a very bright core, but we live in one and it doesn't brighten our night sky. Would the view of the core in the ring galaxy be alot different assuming that there is much less matter between those inner stars and the core as compared to our solar system and our core?

What I'm saying is, if you were on a planet in orbit around a star of the very edge, or near edge, of the inner ring. In other words, you're not in the middle of the ring, or towards the outside of it, therefore, there wouldn't be other stars, gas, and dust obscuring your view of either the core of older stars, or the rest of the inner ring itself in the nightime sky of said hypothetical planet.

I think it'd be an awesome view of both the ring and the core.

Well, I tried posting a photo similar to what I'm talking about, but it wouldn't post. Take a look at page 243 of Sagan's "Cosmos" to get an idea of what I'm visualizing. It's a painting by Adolf Shaller of a galaxy rise on a hypothetical world above the plane of the Milky Way.

 

[SpaceTas]

There are good computer simulations;http://burro.astr.cwru.edu/models/models.html (go to New Movies and look at Cartwheel simulations) they show that it is possible to form a ring galaxy when a spherical galaxy collides head on with a disk (spiral) galaxy. The stars get rearranged and a wave off star formation spreads outward (the hot blue stars in ring) while the old (redder) stars of the spherical galaxy and the spiral accumulate at the center.

In the case of Hoags objcet we are seeing the result face on. Notice the one in the background is tilted[ just a viewing angle effect.

Other ring galaxies: cartwheel, AM0644-741 (both imaged by HST).
Polar ring galaxies are those caught mid collision: eg NGC4650A

 

[ZenGalacticore]

The way that ring galaxies are formed is well known. They are of course temporary configurations. As Sagan put it, "a splash in the cosmic pond..."