Colliding Galaxies

[Red Shift]

Last night i was reading about colliding galaxies and i got to thinking, would we be able to detect the blue shift if a galaxy was travailing toward us?
And how close can an object get before we see it as the light has not yet traveled to earth?

Could a speeding galaxy be coming toward us now, perhaps andromeda was traveling away from us 2,500,000 years ago but some thing we don't understand happened and now its on its way here?

Sounds unlikely to me but does anyone have any ideas?

[Doomer]

Amdromeda is in fact on a collision course with the Milky Way but it's not gonna happen any time soon so no need to worry. :sardonic:

[Red Shift]

cool, so my thoughts were right, i always thought it was travailing away from us, any idea of its speed?

[Achluophobia]

That kind of thing wont happen for Millions of years, I dont think any of us will be unfortunate enough to witness, but still I suppose we shouldnt rely on an astronomers judgement because we may get a shock.

[Red Shift]

Im not woried about it but im worried for our childrens childrens blah blah blah imagine if earth took a head on blow, i doubt the planets life would survive!

[Achluophobia]

Our civilisation might have moved to a different galaxy by then too.

[WoOp_De_DoO]

No i dont think we will every leave are galaxy we were not ment to so i dont think we ever will.

[lotrfan55345]

If we find a viable alternative to fossil fuel's, and get all the infastructure, and people willing "AMERICAN WAY OF LIFE" and lead more efficient, low-energy lifestyles within 3~7 years, we will probably will move to other galaxies...

If not, say hello stone age v2.

[stewey]

You're a bit too involved with this peak oil thing.

Anyways, colliding galaxies basically mean they absorb each other, as is my understanding, and not like an impact of two solid objects, but rather is more like them coming together. I don't think it would really effect us.

[Rage_Garden]

I think we are just far enough away from both the outer part of the Mikly Way and the black hole in the center that it would just be a good show for us. Once that happens our galaxy becomes a full sized galaxy. Thats what I heard on discovery anyways.

[Red Shift]

I think we can expect more than a show, well our desendents

Heres the story of the Antennae:

The Antennae were two seperate galaxies 1.2 billion years ago.
The galaxies began to smash into each other 900 million years ago.
The galaxies became distorted as they span around each other 600 million years ago.
By 300 million years ago, stars from the spiral arms had been flung out of both galaxies.
Today, two stramers of ejected stars extend far beyond the original galaxies.



For those people who don't know we are in the Orion arm, so our sun is likely to be flung out, if it still exists, and us with it!

Here is a picture of the Antennae.

[Doomer]

2 galaxies colliding is more like 2 water drops melting together than a real collision. At least on the grand scale that can be observed from afar. However, on a planetary scale where we are, it would be utterly devastating. Planetary systems are very fragile and anything like a close encounter with another star would tear it apart. Any life on a world in such a system would surely be snuffed out.

[Red Shift]

Any life on a world in such a system would surely be snuffed out

Yes it would, imagine the intense heat if a start just sail past us not to mention its gravitational force.

I wonder if there was any life in those two galaxies before and now wiped out, and i wonder if life has come about since and takes the irregular galaxy shape as the norm.

Oh and one more question, if a planet like the earth were close enough for its gravity to act on us but not crash into the earth, if thats even possible, what would happen if we jumped up would we fall upwards once its gravitational field caught us?

[playmaker88]

If you can't be bothered to wait 5 billion years to see what will happen, click the link.

http://www.virtualstar.fsbusiness.co.uk/andromeda.htm

[Zach]

if you guys are still interested in this, they have a small news report about colliding galaxies at www.astronomydaily.com

You do have to sign up for this but its free. They dont have much info but they are watching 2 galaxies that are currently colliding now.

[dutchie]

Here's a (very cool, I might add) picture of two colliding galaxies:
http://imgsrc.hubblesite.org/hu/db/2002/11/images/h/formats/full_jpg.jpg

[dutchie]

if you guys are still interested in this, they have a small news report about colliding galaxies at www.astronomydaily.com

You do have to sign up for this but its free. They dont have much info but they are watching 2 galaxies that are currently colliding now.
Thnx for the link, Zach.

[Zach]

yep, if u guys want me to try to find out more about what they are finding out about it, tell me and i will keep an eye out for it.

[Zach]

http://www.esa.int/export/esaCP/SEMSKV9DFZD_FeatureWeek_0.html

Just an update about the galaxies.

[Zach]

I have a question. If anyone knows the answer to it or can find it, that would be great.

Anyways, we now know that galaxies can collide and form into one, but is it possible for a galaxy to split apart and divide?

[WoOp_De_DoO]

Well here is my thoughts kinda hard to explain. Say if one galaxy was going N to S and another was going W to E and they colided. Would they do like a Buzz saw and just cut each other apart? And then form into 4 smaller galaxys. Now I have no clue if this is possible because I dont no alot about space but I dont no why it couldnt happen.

[Zach]

i think speed might have an efffect on that, so i wouldnt know unless we knew the speeds that they were traveling at(i think).

[Keeblergiant]

I have a question. If anyone knows the answer to it or can find it, that would be great.

Anyways, we now know that galaxies can collide and form into one, but is it possible for a galaxy to split apart and divide?

You would have to have two huge gravitational sources in the galaxy before it splits, and for some odd reason the two gravitational forces would have to be pulled apart...extremely unlikely

[Zach]

You would have to have two huge gravitational sources in the galaxy before it splits, and for some odd reason the two gravitational forces would have to be pulled apart...extremely unlikely


So some giant explosion inside of the galaxy wouldnt do it, would it?
I mean, i know that galaxies are huge but explosions could be big too depending on what they "feed" off of.

[Red Shift]

You would have to have two huge gravitational sources in the galaxy before it splits, and for some odd reason the two gravitational forces would have to be pulled apart...extremely unlikely


But not impossible ;)

[Keeblergiant]

So some giant explosion inside of the galaxy wouldnt do it, would it?
I mean, i know that galaxies are huge but explosions could be big too depending on what they "feed" off of.

An explosion big enough to seperate the two gravitational sinks would more than likely destroy them instead (depending on what the gravitational sinks are)

[marglarg]

I have a question. If anyone knows the answer to it or can find it, that would be great.

Anyways, we now know that galaxies can collide and form into one, but is it possible for a galaxy to split apart and divide?

A single galaxy on its own without any form of interaction from another source ... no. Gravity is an attractive force so unless there is some other form of attractor close enough to disturb the galaxy, it will not split apart.

From the point of an explosion within, that won't do it either because there isn't a repulsive explosive force big enough to accomplish that.

GRB's, Hypernovae and the like, outshine their host galaxies briefly with tremendous amounts of energy being released, but this is still not enough to 'split' a galaxy as such. These are the largest energetic explosions that we are currently aware of. (apart from the big bang of course)




You would have to have two huge gravitational sources in the galaxy before it splits, and for some odd reason the two gravitational forces would have to be pulled apart...extremely unlikely

Not a case of them being pulled apart ... it depends more on the initial velocity and masses of the two impacting gravitational sources (by this I assume you mean 2 galaxies, if not, refer to my reply above), as to what the end result will be. ie. 2 galaxies approach, interact, and as a result we may have 1 larger galaxy or 2 resultant separate galaxies.

Unless of course there is maybe 1 or more 'attractor/s' in the equation, within a close enough proximity to influence this little dance by pulling one away more than the other resulting in a split.

[Keeblergiant]

Not a case of them being pulled apart ... it depends more on the initial velocity and masses of the two impacting gravitational forces (by this I assume you mean 2 galaxies, if not, refer to my reply above), as to what the end result will be. ie. 2 galaxies approach, interact, and as a result we may have 1 larger galaxy or 2 resultant separate galaxies.

Unless of course there is a maybe 1 or more 'attractor/s' in the equation, within a close enough proximity to influence this little dance by pulling one away more than the other resulting in a split.

I assumed he was talking about one galaxy...

[marglarg]

Cool ... here's another pretty neat picture of what they think may have been 2 colliding galaxies.



http://www.brainyencyclopedia.com/encyclopedia/h/ho/hoag_s_object.html

[dutchie]

http://chandra.harvard.edu/photo/2005/smg/
http://chandra.harvard.edu/photo/2005/smg/smg_comp_420.jpg
The illustration shows two young galaxies in the process of merging. The merger has triggered a prodigious burst of star formation and is providing fuel for the growth of the galaxies' central supermassive black holes.

The inset shows an image from the Chandra Deep Field-North of two central black holes in merging galaxies (known as SMG 123616.1+621513). Although the black holes appear to be very close in this image, they are actually about 70,000 light years apart. The different colors in the image are due to differences in X-ray absorption by gas and dust around the black holes with blue indicating more absorption than red.

By combining data from the Chandra Deep Field-North (CDFN) with observations at submillimeter and optical wavelengths, an international team of scientists has found evidence that many extremely luminous adolescent galaxies and their central black holes underwent a phenomenal spurt of growth 10 billion to 12 billion years ago. This growth spurt may have set the stage for the appearance of quasars, distant galaxies that contain the largest and most active black holes in the Universe.

The galaxies in the image are known as submillimeter galaxies, because they were originally identified by the James Clerk Maxwell submillimeter telescope (JCMT) on Mauna Kea in Hawaii. Hubble Space Telescope observations indicate that most of the submillimeter galaxies are actually two galaxies that are colliding and merging.

Recent sophisticated computer simulations have shown that such mergers drive gas toward the central regions of galaxies, triggering a burst of star formation and providing fuel for the growth of a central supermassive black hole. This explains the observational evidence that in submillimeter galaxies stars are forming at a prodigious rate at the same time that the central black holes are growing rapidly.

A combination of observation and theory suggests that in a few hundred million years the submillimeter galaxies will become quasars, and ultimately, large spherical galaxies that harbor central supermassive black holes with masses of about a billion Suns.

[Mezurashi]

if it helps anyone visualize the situation, galactic collisions isn't like two solid objects (like big frisbees) hitting each other, it's more like two really big and chunky twisters puishing into each other's space. this isn't a happy and harmonious time, there is going to be lots of vector and velocity change, radiation spikes, interstellar dust and all the other sequelae of major cosmological events.

but remember the Time Frame of these collisions. If another galaxy Started crashing into our today, Humanity might have died off from naural causes long before any effects of the collsions could be percieved. Galactic collisions take millions of years to play out from beginning to end. it would be like watching a huge stop-motion film production where all the sand on a beach had to be organized and choreographed grain by grain. once it's done it would look cool, but watching it happen would drive me to drink even more :crazy:

[Swordsbane]

if it helps anyone visualize the situation, galactic collisions isn't like two solid objects (like big frisbees) hitting each other, it's more like two really big and chunky twisters puishing into each other's space. this isn't a happy and harmonious time, there is going to be lots of vector and velocity change, radiation spikes, interstellar dust and all the other sequelae of major cosmological events.

but remember the Time Frame of these collisions. If another galaxy Started crashing into our today, Humanity might have died off from naural causes long before any effects of the collsions could be percieved. Galactic collisions take millions of years to play out from beginning to end. it would be like watching a huge stop-motion film production where all the sand on a beach had to be organized and choreographed grain by grain. once it's done it would look cool, but watching it happen would drive me to drink even more :crazy:

The timeframe takes all the drama out of it. It's hard to get all worked up about something that doesn't really affect us even if we're right in the middle of it. Any changes that occur during such collisions are, for all intents and purposes permanent when you consider the life span of human beings. However transient they seem on a galactic scale, we won't see the changes. Even if all the bad stuff missed the solar system and the night sky was lit with all sorts of colors and lights, you, your parents, their parents, and their parents and their parents, etc would have all grown up with that sky and wouldn't give it a second thought. It would be a fixture, never changing. Even the bible and the oldest records of humanity would never describe the sky as being different. The scientists of the day would be wondering what it would be like millions of years from now when the two galaxies have settled down some and if you asked them what it would feel like to have a dark sky with simple white dots of stars all around and only the vague suggestion of the galaxy's disk as a faint strip in the night sky, they would probably think THAT was wild and beautiful compared to their boring, everyday sky.