Well, that one is real, though looks quite weired on Hubble’s shot.

Yeah, it looks much weirder on the Hubble shot. On the others it’s just an indistinct blue glob, probably a distant galaxy. I’m suspecting some type of defect in the Hubble camera or how the picture was put together. Whatever it is, it’s at:

R.A. 13h 00m 20.36s Dec +28deg 04′ 30.1″

Well, that one is real, though looks quite weired on Hubble’s shot. SDSS shows pretty strong signal from that spot and DSS2 also has something above noise level out there.
Hubble image:
http://www.wikisky.org/?ra=13.00563601413349&de=28.07489268436532&zoom=14&img_source=IMG_all
SDSS:
http://www.wikisky.org/?ra=13.00563601413349&de=28.07489268436532&zoom=14&img_source=SDSS
DSS2:
http://www.wikisky.org/?ra=13.00563601413349&de=28.07489268436532&zoom=14&img_source=DSS2

I didn’t go through other cases. it is fun, but takes quite some time to locate the spot

It can be a lot of fun to grab a big version (6000×4260, 33Mb)

There are several weird things in this JPEG file. Using Microsoft Paint check out the following:

1.) 4424,1181 – Camera defect or really a blue glob of something?

2.) 1885,1716 – Blue distant galaxy or blue foreground nebula in our galaxy?

3.) 1653,1440 – Check out the foreground dust lanes in the biggest and brightest spiral galaxy. It really gives you a 3D effect with the dust in front of the galaxy.

4.) 1041,2262 – Bright blue foreground star. You can see the 4 vane spikes telling you that Hubble’s secondary mirror is supported by 2 vanes that cross each other perpendicularly.

5.) 5658,1852 – Elliptical galaxy in which you can almost resolve the stars, or perhaps they are globular clusters surrounding it.

6.) 3928,2222 – You can make this one out to have a bar running from 7 o’clock to 2 o’clock so it’s a barred lenticular galaxy?

7.) 1291,2866 – Whoa!, is that a foreground star in our galaxy or a supernova in the outskirts of the lenticular galaxy? Probably the former.

8.) 5065,3101 – The blueist galaxy in the whole field. I wonder why it’s so blue.

I didn’t see much evidence of obvious radio galaxies with black hole produced jets shooting out the sides but that’s a pretty awesome pic.

There is gas in between the galaxies, and they ram through this gas while they orbit the cluster. Any gas inside the galaxy is stripped away by this gas outside the galaxy, like the way you can blow a smell out of a car by opening the windows and letting outside air blow in.

Hmmm, I would have thought that at the gas densities involved the gasses would pass through each other effortlessly. Let’s do a little calculation.

Let RHO = gas density in number of atoms (typically Hydrogen) per cubic centimeter. A typical value for interstellar space is ~1 for this.

Let R = the radius of an atom (we can use the Bohr radius of 5.29E-9 cm for this)

Let L = mean free path of atom before collision with another atom (in centimers)

So we have:

PI * R^2 * L = 1 / RHO

or

L = 1 / (PI * RHO * R^2) = 1.14E16 cm = 0.012 light-years

So if the gas particle is moving in the plane of the galactic disc (about 100,000 light-years across) it suffers about 8.3 million collisions. If it is moving perpendicular to the plane of the galactic disk (about 10,000 light-years thick of gas) it suffers 830,000 collisions. I guess these are enough collisions to strip off the gas from the galaxy. I was thinking if the number came up like 100,000 light-years then the gas particle will pass clean through the other galaxy without colliding with anything.

There are also pockets of gas and dust in the galaxy where the particle density is much higher, say 1,000 atoms per cm^3 or 10,000 atoms per cm^3. The stripping process will be even more for these pockets of high gas density.

So does the European version have…like…nudity in it or something?

Have there ever been any examples of a face to face galaxy collision? Almost like a stack of two pancakes merging? Would the gravitational pull of the two galaxy’s super-massive black holes cause it to look like a spiraling hourglass?

- Alan

Still curious,

-Powerdroid

http://adsabs.harvard.edu/abs/1988ARA%26A..26..631B

“Loner galaxies like the Milky Way are a bit unusual. We live out in the suburbs of space, but most galaxies prefer the hustle and bustle of the urban environment: the galaxy cluster.”

I remember from my extragalactic class that something like 50% or more of galaxies live in groups, like our own Local Group, not in clusters. Only a few to a few 10s% live in clusters, and less in rich clusters. Thus we are not violating any Copernican principles if we note that he Milky Way lives in a group much like most other galaxies! Of course these are rough percentages depending on what your definition of galaxy is, from every tiny dwarf to the typical L-star galaxies like our own.

And then we go and find other galaxies so far away that if we split up the distance into units of measurement that we have actual practical experience with, you and your great grandchildren wouldn’t live long enough to count it. And not just one. Hundreds.

Doesn’t anyone else find the sheer…… size of everything we’re talking about here scary, or at the least intimidating? It even makes me sad, because I see these types of images all the time, but barring some immense leap in technology in the next 20 or so years, we’ll never actually get there to have a mooch around.

Why does everything in the Universe spin?

Basically because most systems of matter you look at has been gravitationally bound from former more or less independent particles. It would be fantastically improbable if all their momenta cancel out exactly, so there is bound to be a remaining angular momentum (as well as regular momentum) pointing in some direction. (I.e. some axis of rotation for the system (as well as a direction of straight line motion).)

That’s a great analogy, and one that will amuse my friends tremendously on this summer’s road trip, after we make the traditional stop at Taco Bell.

I’ve got an old text book that uses the term “Andromeda Nebula”. I love the way that sounds, it flows beautifully, but unlike “Island Universe” which is poetical, “Andromeda Nebula” is now officially incorrect. ):

… But hey, its too late /early here & I’m just trying to amuse …

“BTW. Thinking galaxies did you get my email or otherwise hear Bad Astronomer that the structure of our galaxy has been revised via the Spitzer scope – apparently we have lost two spiral arms!”

Relax though PZ! The ‘we’ that’s lost two spiral arms is just our Milky Way galaxy NOT the squid!

Oh and back on topic – awesome images Phil of a very, ridiculously very, large area of space THX!

Plus I too like the “Island Universes” phrase. Wasn’t it Harlow Shapely who coined that one before we even knew what the “spiral nebulae” like Andromeda and theWhirlpool (M51) really were?

I also emailed you about an odd red supergiant recently studied in the Large Magellanic Cloud! Any thoughts on those ones?

Why does everything in the Universe spin?