A Look at Space: Part 2: Galaxies, page 1

A Look at Space: Part 2: Galaxies

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Source of this picture: antwrp.gsfc.nasa.gov...

I have a collection of links from APOD for pictures of galaxies.
I thought I should share the links of some of the interesting ones. Any comments appreciated. Feel free to add more links/pictures. Thanks!

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Also Check out:
> A Look at Space: Part 1: The Weirdest and The Mysterious
> A Look at Space: Part 3: Nebulae


[edit on 8/7/2004 by jp1111]

Interacting pair/s of galaxies and galaxy collisions
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Source: see Spirals in Collision below.

Pictures of collisions between galaxies are just amazing! Check them out yourself...

"When Mice Collide:"
NGC 4676: The pair is also known as "the mice" due to the long tails.

Spirals in Collision
NGC 2207 and IC2163: According to the astronomers, the larger one will eventually "eat" the small one!

Disorder in Stephen's Quintet
Although called as a quintet, only three of these are actually "in midst of a titanic collision"

A Galaxy Collision in NGC 6745
a collision aftermath

Cosmic Collisions in a Galaxy Cluster
Many collisions in the cluster MS 1054-03.

M51: Cosmic Whirlpool
NGC 5194 and NGC 5195

Galaxy Wars: M81 Versus M82
On the brink of a war!

Seyfert's Sextet
Four galaxies are interacting in this Sextet.

Arp 81: 100 Million Years Later
NGC 6622 and NGC 6621 possible to merge in far future!

More links coming soon...

[edit on 8/7/2004 by jp1111]

heritage.stsci.edu...
hubble.stsci.edu...

my choise goes for:

heritage.stsci.edu...

heritage.stsci.edu...

[edit on 7-8-2004 by kangaxx]to putt the right objects.

[edit on 8-8-2004 by kangaxx]

[edit on 8-8-2004 by kangaxx]

Small collection of mine

A few more:

Edge-Ons:

Edge-on galaxies are just very picturesque! Take a look here:

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NGC 4565, One of my favorites!
Source & Description: antwrp.gsfc.nasa.gov...

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M104, The Sombrero Galaxy
Source & Description: antwrp.gsfc.nasa.gov...

antwrp.gsfc.nasa.gov...
A mosaic of different Edge-ons: "top NGC2683, M104, NGC4565, middle; NGC891, NGC4631, NGC3628, and bottom; NGC5746, NGC5907, and NGC4217"


[edit on 8/7/2004 by jp1111]

What happens when close interactions occur between galaxies?

A look at some of the interesting distorted galaxies:
Also included here some descriptions of the pictures posted by other users in this thread.

The Ring Galaxy (third picture in pushkin's post) : AM 0644-741
Description: antwrp.gsfc.nasa.gov...
"The ring-like shape is the result of the gravitational disruption caused by an entire small intruder galaxy passing through a large one."

Warped Spiral Galaxy (fifth picture in E_T's post) : ESO510-13
Description: antwrp.gsfc.nasa.gov...
"The causes of spiral warps are still being investigated, but some warps are thought to result from interactions or even collisions between galaxies."

The Polar Ring Galaxy (second picture in E_T's post) : NGC 4650 A
Description: antwrp.gsfc.nasa.gov...
"What creates Polar Ring Galaxies is still being researched, but a leading theory is the collision of two distinct galaxies in the distant past. Polar Ring Galaxies allow astronomers to estimate the amount of dark matter in galaxies by measuring the rotation rate of the highly extended ring."

Hoag's Object: A Strange Ring Galaxy (sixth picture in E_T's post) :
Description: antwrp.gsfc.nasa.gov...
"How Hoag's Object formed remains unknown, although similar objects have now been identified and collectively labeled as a form of ring galaxy. Genesis hypotheses include a galaxy collision billions of years ago and perturbative gravitational interactions involving an unusually shaped core."

Arp 188 Tadpole
external image
Description & Source: antwrp.gsfc.nasa.gov...
"During the close encounter, tidal forces drew out the spiral galaxy's stars, gas, and dust forming the spectacular tail. The intruder galaxy itself, estimated to lie about 300 thousand light-years behind the Tadpole, can be seen through foreground spiral arms at the upper left."

A Cosmic "Bridge" : Arp 295
external image
Descriptin & Source: antwrp.gsfc.nasa.gov...
"The cosmic bridge between the galaxies and the long tail extending below and right of picture center are strong evidence that these two immense star systems have passed close to each other in the past, allowing violent tides induced by mutual gravity to create the eye-catching plumes of stellar material."

More coming up...

A few more...Distorted galaxies:

The Pinwheel Galaxy : M101
Description & Picture : antwrp.gsfc.nasa.gov...
"Recent evidence indicates that a close gravitational interaction with a neighboring galaxy created waves of high mass and condensed gas which continue to orbit the galaxy center. These waves compress existing gas and cause star formation."

"A fried Egg" : NGC 7742 : A Ring Galaxy
external image
Description & Source: antwrp.gsfc.nasa.gov...
"NGC 7742 is known to be a Seyfert galaxy - a type of active spiral galaxy with a center or nucleus which is very bright at visible wavelengths."

Swirls in a cup of coffee : NGC 4622
external image
Description & Source: antwrp.gsfc.nasa.gov...
"But a closer look at this galaxy reveals that a pronounced inner spiral arm winds in the opposite direction. So which way is this galaxy rotating? Recent evidence combining ground-based spectroscopy and the sharp Hubble image data surprisingly indicates that the galaxy is likely rotating clockwise in the picture, its outer spiral arms opening outward in the direction of rotation. There are further indications that a past collision with a smaller companion galaxy has contributed to this bizarre rotational arrangement of spiral arms, essentially unique among known large spiral galaxies, in NGC 4622."

An Unsual Spiral Galaxy : M66
Description & Picture: antwrp.gsfc.nasa.gov...
"Why isn't spiral galaxy M66 symmetric? Usually density waves of gas, dust, and newly formed stars circle a spiral galaxy's center and create a nearly symmetric galaxy. The differences between M66's spiral arms and the apparent displacement of its nucleus are all likely caused by the tidal gravitational pull of nearby galaxy neighbor M65."


[edit on 8/7/2004 by jp1111]

[edit on 8/7/2004 by jp1111]

Descriptions of pictures posted by other users, continued...

The Whirlpool Galaxy : M51 (fourth picture in E_T's post)
Description: antwrp.gsfc.nasa.gov...
"The Whirlpool Galaxy is a classic spiral galaxy. At only 30 million light years distant and fully 60 thousand light years across, M51, also known as NGC 5194, is one of the brightest and most picturesque galaxies on the sky."

When Galaxies Overlap : NGC 3314 (first picture in E_T's post)
Description: antwrp.gsfc.nasa.gov...
"In fact, NGC 3314 consists of two large spiral galaxies which just happen to almost exactly line-up."

Galaxy Group : HCG 87 (sixth? picture in pushkin's post)
Description: antwrp.gsfc.nasa.gov...
"Posing for this cosmic family photo are the galaxies of HCG (Hickson Compact Group) 87, about four hundred million light-years distant toward the amphibious constellation Capricornus."

Grains of Sand : NGC 300 (eighth picture in pushkin's post)
Description: antwrp.gsfc.nasa.gov...
"Like grains of sand on a cosmic beach, individual stars of large spiral galaxy NGC 300 are resolved in this sharp image from the Hubble Space Telescope's Advanced Camera for Surveys (ACS)."

pushkin, please try to find the descriptions to your remaining pictures so that the fellow viewers can know what they are looking at, thanks! I'll try to search too.

[edit on 8/7/2004 by jp1111]

The Sunflower Galaxy : M63 (ninth picture in pushkin's post)
Description: antwrp.gsfc.nasa.gov...
"One of the bright spiral galaxies visible in the north sky is M63, the Sunflower Galaxy. M63, also catalogued as NGC 5055, can be found with a small telescope in the constellation of Canes Venaciti. Visible in the above picture are long winding spiral arms glowing blue from a few bright young stars, emission nebulae glowing red from hot ionized hydrogen gas, and dark dust in numerous filaments. M63 interacts gravitationally with M51 (the Whirlpool Galaxy) and several smaller galaxies."

Here is one of my favorites...

The Sleeping Beauty Galaxy : M64
external image
Source & Description: antwrp.gsfc.nasa.gov...
"The Sleeping Beauty galaxy may appear peaceful at first sight but it is actually tossing and turning. In an unexpected twist, recent observations have shown that the gas in the outer regions of this photogenic spiral is rotating in the opposite direction from all of the stars!"

Originally posted by kangaxx
yup, i have seen some pics of M64 when i was chosing some pics today, it is just astonishing!!what you think about the theory that can exist a black hole in the center of the majority of the spiral galaxies? i think it is a extremly interesting theory.

I agree, M64 is one weird looking galaxy, but I find it very fascinating! Did you notice in the description how the gas of outer region is rotating in the opposite direction, that makes it even more weird! A collision with some other small galaxy is responsible for that behavior (as given in the description).

A black hole in the center? Sure, I believe that!
It has been found that stars near the center move faster indicating the presence of a black hole.

Here is one picture/animation:

external image
Description & Source: antwrp.gsfc.nasa.gov...
"If these fast stars are held to the Galactic Center by gravity, then the central object exerting this gravity must be both compact and massive. Analysis of the stellar motions indicates that over one million times the mass of our Sun is somehow confined to a region less than a fifth of a light-year across. Astronomers interpret these observations as strong evidence that the center of our Galaxy is home to a very massive black hole."

Originally posted by SpockO_o
Does pictures are truly amazing, If I remember correctly our neighbor galaxy will be colliding with ours in a couple billion years.

You are right, both are moving towards each other at a rate of around 300000mi/hr and so it will probably take over 2-3 billion years for the collision to occur. They will finally merge after a long cosmic battle!

The interesting part in an intergalactic collision is that the individual stars of the galaxies hardly ever interact/collide! Only gas and dust are involved in the "war".

Here is an article worth reading:
www.space.com...


[edit on 8/9/2004 by jp1111]

[edit on 11-8-2004 by pushkin]

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