A Look at Space: Part 2: Galaxies

Originally posted by MrJingles
Seeing these galaxies makes me feel insignificant.

Just think of all the things we don't know about in those galaxies each holding their own secrets and civilizations.

Artwork of greg martin rocks!

yea...sometimes i feel that way too. our earth..no..our solar system...wait...even our galaxy is like a tiny tiny spec of dust compared to the universe. and to think we can never ever set foot on other galaxy, or rather step outside of our solar system...

awesome stuff

I think it would be cool to have some ameteur photos posted.... I would do it myself, but I dont have a camera for my scope.. and my scope is only 6".... And... (yes there's more) I havent been able to find a galaxy yet.. only a few nebulae and the planets

Here is some information for pushkin's pictures from Post 719554:

First Picture
Antennae Galaxies : NGC 4038 and NGC colliding
Description: antwrp.gsfc.nasa.gov...

Third Picture:
A Galaxy so Inclined : NGC 331
Description: antwrp.gsfc.nasa.gov...

I couldn't find description for the second picture. I'll post it whenever I find it. Please post the description if you have it.


[edit on 8/11/2004 by jp1111]

[edit on 8/11/2004 by jp1111]

Originally posted by 2009

Originally posted by MrJingles
Seeing these galaxies makes me feel insignificant.

Just think of all the things we don't know about in those galaxies each holding their own secrets and civilizations.

Artwork of greg martin rocks!

yea...sometimes i feel that way too. our earth..no..our solar system...wait...even our galaxy is like a tiny tiny spec of dust compared to the universe. and to think we can never ever set foot on other galaxy, or rather step outside of our solar system...

Me too. We are almost nothing in this huge universe, yet still some of us demand too much from life, some are so greedy for material things, some fight for little things! I feel bad for these people

Lenticular Galaxies: "The lenticular galaxies are disk galaxies without any conspicuous structure in their disks. This is probably because they have either used up most of their interstellar matter, so that they consist of old stars only, which have found a smooth and even distribution in the disk by the time, or because the galaxy has not closely encountered any neighbor in the past few hundred million (or few billion) years." From: www.seds.org...

One example:

A Barred Lenticular Galaxy : NGC 2787
external image
Source & Description: antwrp.gsfc.nasa.gov...
"Recent pictures and evidence, however, indicate that lenticulars can be both photogenic and scientifically interesting. For example, the above image of NGC 2787 taken with the Hubble Space Telescope shows that the center of this lenticular galaxy has interesting structure. The image was taken to help determine how lenticular galaxies formed, and what happens in their centers. The span of NGC 2787 in the above image is about 4500 light years, while the galaxy lies about 25 million light years away toward the constellation of Ursa Major."

Flocculent Galaxies: These are galaxies without well-defined spiral arms.

One example:

A Flocculent Spiral Galaxy : NGC 4414
external image
Description & Source: antwrp.gsfc.nasa.gov...
" How much mass do flocculent spirals hide? The above true color image of flocculent spiral galaxy NGC 4414 was taken with the Hubble Space Telescope to help answer this question...A bright foreground star from our Milky Way Galaxy shines in the foreground of the image. Although NGC 4414's center likely holds little dark matter, understanding its matter distribution helps calibrate the rest of the galaxy and, by deduction, flocculent spirals in general. By determining a precise distance to NGC 4414, astronomers also hope to help calibrate the scale to the more distant universe."

if the center of the galaxy is a black hole wont we be sucked in?........................and yea i saw a show on the discorvery channel that said something about the black holds at the center of a universe

Originally posted by CookieMonster000
if the center of the galaxy is a black hole wont we be sucked in?........................and yea i saw a show on the discorvery channel that said something about the black holds at the center of a universe

Yes, we would be sucked in if we were a lot closer to the black hole. But our solar system is about 26,000 LY away from the blackhole/center of milky way out towards one of the spiral arms. And it revolves around the center at around 250 km/s. Now, the life of the sun is going to end in the next 4-5 billion years. So, before getting "eaten up" by a black hole, the earth's life would have already ended along with that of our sun forming a planetary nebula.

Also, I just found out from intrepid's article in part1 that the black hole eats only one star in 5000 years.

[edit on 8/11/2004 by jp1111]

How about the galaxy NGC 4622 that somehow rotates backwards yet does not break apart.


[edit on 11-8-2004 by Raphael]

Originally posted by Raphael
How about the galaxy NGC 4622 that somehow rotates backwards yet does not break apart.

I have already posted a picture of NGC 4622 on the first page, but your diagram makes it really easy to understand how its rotating. Looks like the outer spiral is rotating clockwise and the inner counterclockwise. That's very weird. I heard that a collision with a smaller galaxy could have caused that behavior. It has to be the dark matter that's keeping the galaxy from breaking apart. What do you think?

If the Dark matter is small, heavy particles (WIMPS) moving relatively slowly (Cold Dark Matter) structure will have formed on smaller scales, like the size of galaxies.

Originally posted by Raphael
If the Dark matter is small, heavy particles (WIMPS) moving relatively slowly (Cold Dark Matter) structure will have formed on smaller scales, like the size of galaxies.

You might know about this, but
I find it very interesting that galaxies have spherical dark matter halos around them. I will try to find some links.

Here:

"For the first time, astronomers have found direct evidence of a phenomenon long thought to play an important role in the formation of giant galaxies: the ongoing disruption of a small galaxy as it orbits within the dark matter halo of a much larger galaxy. Images from the Hubble Space Telescope, confirmed by detailed observations at the W. M. Keck Observatory in Hawaii, show a dwarf satellite galaxy in the process of being torn apart by gravitational forces due to the larger spiral galaxy and its halo of dark matter."
From: www.spaceref.com...

Pictures: astronomy.swin.edu.au...

"Basically, according to careful observations, we know that up to 90% of the matter in galaxies must be in the form of "dark matter" to account for the dynamics we observe. On top of that, the dark matter appears to be distributed in a spherical halo around the Milky Way, while the luminous matter is located largely in the flat disk."
From: imagine.gsfc.nasa.gov...

[edit on 8/12/2004 by jp1111]

Here are some very beautiful galaxies:

Southern Pinwheel Galaxy : M83
external image
Source: antwrp.gsfc.nasa.gov...
More Information: www.seds.org...
"M83 was classified as intermediate between normal and barred spiral galaxies by G. de Vaucouleurs, in his classification this is SAB(s)c. It is magnificient in our image, has very well defined spiral arms and displays a very dynamic appearance, appealing by the red and blue knots tracing the arms. The red knots are apparently diffuse gaseous nebulae in which star formation is just taking place, and which are excited to shine by its very hot young stars. The blue regions represent young stellar populations which have formed shortly (i.e., some million or some dozens of million years ago). Between the pronounced spiral arms are regions with fewer stars. Dark dust lanes follow the spiral structure throughout the disk, and may be traced well into the central region to the nucleus, which has only 20" diameter. This nucleus shows strong emission lines. It is composed of an older yellowish stellar population which dominates the whole central region, and extends along the barlike structure."

A Grand Spiral Galaxy and its Companion : NGC 1232
external image
Source & Description: antwrp.gsfc.nasa.gov...
"Open clusters containing bright blue stars can be seen sprinkled along these spiral arms, while dark lanes of dense interstellar dust can be seen sprinkled between them. Less visible, but detectable, are billions of dim normal stars and vast tracts of interstellar gas, together wielding such high mass that they dominate the dynamics of the inner galaxy. Invisible are even greater amounts of matter in a form we don't yet know - pervasive dark matter needed to explain the motions of the visible in the outer galaxy. What's out there?"
Press Release: www.eso.org...

Small Nucleus & Sprawling Arms : NGC 2997
external image
Source & Description: antwrp.gsfc.nasa.gov...
" Its small nucleus and sprawling spiral arms give it a type Sc designation. NGC 2997, pictured above, is speeding away from us at about 1100 kilometers per second, which would place it at about 55 million light years distant, given current estimates of the expansion rate of our universe. NGC 2997 is thought to have a mass of about 100 billion times that of our Sun, but is probably less massive than our own Milky Way galaxy. NGC 2997 is not seen face-on - it is thought tilted by about 45 degrees. NGC 2997 is particularly notable for a nucleus surrounded by a chain of hot giant clouds of ionized hydrogen."
More information: www.cosmicastronomy.com...

A Cosmic Superwind from an Irregular Galaxy : Galaxy M82, the Cigar Galaxy.
external image
Source & Description: antwrp.gsfc.nasa.gov...
"What's lighting up the Cigar Galaxy? M82, as this irregular galaxy is also known, was stirred up by a recent pass near large spiral galaxy M81... Recent evidence indicates that this gas is being driven out by the combined emerging particle winds of many stars, together creating a galactic 'superwind'."

Two more (copyrights, so only links are given here, not pictures):

A beautiful spiral galaxy NGC 6946: antwrp.gsfc.nasa.gov...
"The big beautiful spiral galaxy is located just 10 million light-years away, behind a veil of foreground stars in the high and far-off constellation of Cepheus. Looking from the bright core outward along the loose, fragmented spiral arms, the galaxy's colors show a striking change from the yellowish light of old stars in the galaxy's center to young blue star clusters and reddish star forming regions."

Bright Galaxy M81 : antwrp.gsfc.nasa.gov...
" Big and beautiful spiral galaxy M81, in the northern constellation Ursa Major, is one of the brightest galaxies visible in the skies of planet Earth. This superbly detailed view reveals its bright nucleus, grand spiral arms and sweeping cosmic dust lanes with a scale comparable to the Milky Way. Hinting at a disorderly past, a remarkable dust lane runs straight through the disk, below and right of the galactic center, contrary to M81's other prominent spiral features. The errant dust lane may be the lingering result of a close encounter between M81 and its smaller companion galaxy, M82." (See above for M82's picture)

What happens when a small spiral galaxy falls into a big elliptical galaxy? At least in the case of Centaurus A, you get a parallelogram!

Take a look here:
external image
Source & Description: antwrp.gsfc.nasa.gov...
"Peering deep inside Centaurus A, the closest active galaxy to Earth, the Spitzer Space Telescope's penetrating infrared cameras recorded this startling vista. About 1,000 light-years across, the twisted cosmic dust cloud apparently shaped like a parallelogram is likely the result of a smaller spiral galaxy falling into the giant Centaurus A. The parallelogram lies along the active galaxy's central band of dust and stars visible in more familiar optical images. Astronomers believe that the striking geometric shape represents an approximately edge-on view of the infalling spiral galaxy's disk in the process of being twisted and warped by the interaction. Ultimately, debris from the ill-fated spiral galaxy should provide fuel for the supermassive black hole lurking at the center of Centaurus A."

Press Releases:

www.spitzer.caltech.edu...
www.spitzer.caltech.edu...

One more:

A Beautiful Barred Galaxy : NGC 613
external image
Source & Description: antwrp.gsfc.nasa.gov...
"One result was this stunning view of beautiful barred spiral galaxy NGC 613, a mere 65 million light-years away in the southern constellation Sculptor. Over 100 thousand light-years across, NGC 613 seems to have more than its fair share of spiral arms laced with cosmic dust clouds and bright star forming regions near the ends of a dominant central bar. Radio emission indicates the presence of a massive black hole at the center of NGC 613."

Our galaxy, Milky Way is also considered to be a barred galaxy.
Read more about barred galaxies here:
campus.lakeforest.edu...
www.astro.princeton.edu...
www.psi.edu... (a list of known barred galaxies)

Antennae

NGC 7320

Those are some amazing pictures

Coming from a guy who is not "into" space, my hats off to you.

Some great links:
www.astr.ua.edu... (not very high res. but interesting ones)
www.noao.edu...
www.galacticsurf.com...
www.astro.princeton.edu...

Pushkin, I'm glad you're back!
I will post more soon.

Originally posted by American Mad Man
Those are some amazing pictures

I'm glad you liked the pictures.
I would also recommend checking out the pictures in the third part of this topic:
Nebulae
For discussion of various kind of objects check out the first part here

Coming from a guy who is not "into" space, my hats off to you.

That was my original purpose of making these threads. This stuff is all on the web and I am trying to get the best of it here so that the ATSers can appreciate the wonders of our amazing universe, which seems to work!

new picture colition of two galaxies:

WOW Great Thread!