Hubble shows Milky Way is destined for head-on collision with Andromeda galaxy

May 31, 2012
This illustration shows the collision paths of our Milky Way galaxy and the Andromeda galaxy. The galaxies are moving toward each other under the inexorable pull of gravity between them. Also shown is a smaller galaxy, Triangulum, which may be part of the smashup. (Credit: NASA; ESA; A. Feild and R. van der Marel, STScI)

(Phys.org) -- NASA astronomers announced Thursday they can now predict with certainty the next major cosmic event to affect our galaxy, sun, and solar system: the titanic collision of our Milky Way galaxy with the neighboring Andromeda galaxy.

The Milky Way is destined to get a major makeover during the encounter, which is predicted to happen four billion years from now. It is likely the sun will be flung into a new region of our galaxy, but our Earth and solar system are in no danger of being destroyed.

"Our findings are statistically consistent with a head-on collision between the and our ," said Roeland van der Marel of the Space Telescope Science Institute (STScI) in Baltimore.

The solution came through painstaking measurements of the motion of Andromeda, which also is known as M31. The galaxy is now 2.5 million light-years away, but it is inexorably falling toward the Milky Way under the mutual pull of gravity between the two and the invisible dark matter that surrounds them both.

"After nearly a century of speculation about the future destiny of Andromeda and our Milky Way, we at last have a clear picture of how events will unfold over the coming billions of years," said Sangmo Tony Sohn of STScI.

The scenario is like a baseball batter watching an oncoming fastball. Although Andromeda is approaching us more than 2,000 times faster, it will take 4 billion years before the strike.

Computer simulations derived from Hubble's data show that it will take an additional two billion years after the encounter for the interacting galaxies to completely merge under the tug of gravity and reshape into a single elliptical galaxy similar to the kind commonly seen in the local universe.

Although the galaxies will plow into each other, stars inside each galaxy are so far apart that they will not collide with other stars during the encounter. However, the stars will be thrown into different orbits around the new galactic center. Simulations show that our will probably be tossed much farther from the galactic core than it is today.

This illustration shows a stage in the predicted merger between our Milky Way galaxy and the neighboring Andromeda galaxy, as it will unfold over the next several billion years. In this image, representing Earth's night sky in 3.75 billion years, Andromeda (left) fills the field of view and begins to distort the Milky Way with tidal pull. (Credit: NASA; ESA; Z. Levay and R. van der Marel, STScI; T. Hallas; and A. Mellinger)

To make matters more complicated, M31's small companion, the Triangulum galaxy, M33, will join in the collision and perhaps later merge with the M31/Milky Way pair. There is a small chance that M33 will hit the Milky Way first.

The universe is expanding and accelerating, and collisions between galaxies in close proximity to each other still happen because they are bound by the gravity of the dark matter surrounding them. The Hubble Space Telescope's deep views of the universe show such encounters between galaxies were more common in the past when the universe was smaller.

A century ago astronomers did not realize that M31 was a separate galaxy far beyond the stars of the Milky Way. Edwin Hubble measured its vast distance by uncovering a variable star that served as a "milepost marker."

Hubble went on to discover the expanding universe where galaxies are rushing away from us, but it has long been known that M31 is moving toward the Milky Way at about 250,000 miles per hour. That is fast enough to travel from here to the moon in one hour. The measurement was made using the Doppler effect, which is a change in frequency and wavelength of waves produced by a moving source relative to an observer, to measure how starlight in the galaxy has been compressed by Andromeda's motion toward us.

Previously, it was unknown whether the far-future encounter will be a miss, glancing blow, or head-on smashup. This depends on M31’s tangential motion. Until now, astronomers had not been able to measure M31's sideways motion in the sky, despite attempts dating back more than a century. The Hubble Space Telescope team, led by van der Marel, conducted extraordinarily precise observations of the sideways motion of M31 that remove any doubt that it is destined to collide and merge with the Milky Way.

"This was accomplished by repeatedly observing select regions of the galaxy over a five- to seven-year period," said Jay Anderson of STScI.

"In the worst-case-scenario simulation, M31 slams into the Milky Way head-on and the stars are all scattered into different orbits," said Gurtina Besla of Columbia University in New York, N.Y. "The stellar populations of both galaxies are jostled, and the Milky Way loses its flattened pancake shape with most of the stars on nearly circular orbits. The galaxies' cores merge, and the stars settle into randomized orbits to create an elliptical-shaped galaxy."

The space shuttle servicing missions to Hubble upgraded it with ever more-powerful cameras, which have given astronomers a long-enough time baseline to make the critical measurements needed to nail down M31's motion. The Hubble observations and the consequences of the merger are reported in three papers that will appear in an upcoming issue of the Astrophysical Journal.

Explore further: The changing laws that determine how dust affects the light that reaches us from the stars

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Telekinetic
1.9 / 5 (15) May 31, 2012
Who says you can't predict the future? These astronomers make the collision seem like it's going to be a sleigh ride, but I think whatever is left of our human identity in four billion years, we had better be established a good distance away from the event. I sure hope we don't wind up looking like a smart phone with arms and legs.
MorituriMax
1.7 / 5 (12) May 31, 2012
So when exactly did we suddenly start approaching each other? Last time I looked, we were both heading for the Great Attractor but the Milky Way was slowly overhauling Andromeda.
GDM
1 / 5 (6) May 31, 2012
AAAHHHHHHH!
Argiod
2.8 / 5 (9) May 31, 2012
So when exactly did we suddenly start approaching each other? Last time I looked, we were both heading for the Great Attractor but the Milky Way was slowly overhauling Andromeda.


Yeah, I agree, overhauling is the right word... Milky Way is going to get a major overhaul when the two galaxies meet, up close and personal. The way world politics is going now, I seriously doubt any human from this earth will make it very far off-planet any time soon. I don't deny that humanity could overcome war, famine, overpopulation, global warming, and the technology needed to effectively leave the Earth permanently; but I sure won't bet good money on it.
NickFun
4.1 / 5 (9) May 31, 2012
I'm not worried. I'll be an old man by then!
kaasinees
1.9 / 5 (22) May 31, 2012
Not in our lifetime, still too many capitalist pigs and religious nutbags.
Meyer
3.3 / 5 (6) May 31, 2012
I know they say the stars are unlikely to collide, but I'm digging a hole to live in, just in case.
Parsec
4.5 / 5 (10) May 31, 2012
Oops sorry, but in 4 billion years the sun will be approaching its red giant phase and the earth will certainly be affected big time. I don't think a galactic collision will be big deal, all other things considered for our immediate neighborhood.
Noumenon
1.9 / 5 (17) May 31, 2012
Not in our lifetime, still too many capitalist pigs and religious nutbags.


The two galaxies are colliding because of liberals.
simplicio
4 / 5 (3) May 31, 2012
So when exactly did we suddenly start approaching each other? Last time I looked, we were both heading for the Great Attractor but the Milky Way was slowly overhauling Andromeda.

I didn't hear about the overhauling part. If is true then maybe this is the reason; Milky Way and Andromeda are bound by gravity to each other and others in local group. If they made pass of each other in the past, we could be seeing Andromeda now as moving away, but only to come back for closer pass/collision, like in animation.
Vendicar_Decarian
4 / 5 (7) May 31, 2012
Last Thursday at 3:15.4768221 Coordinated Universal time.

"So when exactly did we suddenly start approaching each other?" - Mortuary

Vendicar_Decarian
3.7 / 5 (15) May 31, 2012
Yes, Liberals are generally attractive. Republicans generally repulsive.

"The two galaxies are colliding because of liberals." - NumenTard
Vendicar_Decarian
4.5 / 5 (4) May 31, 2012
Whenever I see simulations of galactic mergers I see lots of material thrown into space never to return.

What fraction is generally retained?
elektron
2.1 / 5 (9) Jun 01, 2012
Wow, this was discovered in 1929 and it's only just hit the headlines? Not to worry we will have lost our moon by then so it's doubtful that there's be any humans to witness the non event.
elektron
1.9 / 5 (7) Jun 01, 2012
This article has a whiff of 'The Onion' about it. Rotation of Earth plunges North America into Darkness! http://www.theoni...co,1905/
Kedas
5 / 5 (4) Jun 01, 2012
Since everything will happen so slow I would prefer to call it merging instead of collision.
Noumenon
1.3 / 5 (15) Jun 01, 2012
Our findings are statistically consistent with a head-on collision between the Andromeda galaxy and our Milky Way galaxy,"


Ooooh no, save us far left liberals, save us. Maybe a tax on angular momentum is in order.
ccr5Delta32
4.2 / 5 (5) Jun 01, 2012
This is really exciting .I can't wait , I'm serious I mean I can't
We will one day be a super galaxy ,joining forces with Andromeda and no other galaxy will mess with us then
Deathclock
2.4 / 5 (8) Jun 01, 2012
Wow, this was discovered in 1929 and it's only just hit the headlines? Not to worry we will have lost our moon by then so it's doubtful that there's be any humans to witness the non event.


No... I've known about this inevitable collision for pretty much my entire life...
kaasinees
2.3 / 5 (10) Jun 01, 2012
Whenever I see simulations of galactic mergers I see lots of material thrown into space never to return.

I think most of it returns slowly though, One of the galaxies are the most attractive force anyway.
GSwift7
2.8 / 5 (8) Jun 01, 2012
As the article suggests, head on collisions between stars and planets should be relatively rare as a percentage of total objects in the two galaxies. However, even one out of a million would still be a fairly large number of collision events. It's only a small number when compared to the total number of objects.

Those kinds of events tend to be unpleasant to be anywhere near. Supernovea, new active black holes that shoot out x-ray jets, pulsars from one star slowly eating another, etc. You don't need to be directly hit by a rogue planet or star in order to have the Earth cleansed. Gamma ray bursts and such can sterilize a planet like Earth from many light years away.

In the case of x or gamma rays, you would never even see it coming, since the initial waves would be traveling at the speed of light towards you. It probably wouldn't be instant planetary death, but there wouldn't be any warning before it started.
GSwift7
2.6 / 5 (8) Jun 01, 2012
Whenever I see simulations of galactic mergers I see lots of material thrown into space never to return.

I think most of it returns slowly though,


Yeah, not much actually gets permanently ejected. The stuff that almost gets ejected but then falls back into the galaxy has to be one of the most terrifying thoughts though. Imagine a planet like jupiter getting hurled out of the galaxy into a long eliptical arc that eventually brings it back around and through the galaxy again, moving like a bat out of hell relative to the objects it will pass near. Only visible when it gets near enough to reflect light back from your own star.

there's an interesting thought: What would it look like to see an Earth-like planet fall into a Jupiter type? That would really be something to see.
Noumenon
2.1 / 5 (11) Jun 01, 2012
As the article suggests, head on collisions between stars and planets should be relatively rare as a percentage of total objects in the two galaxies. However, even one out of a million would still be a fairly large number of collision events. It's only a small number when compared to the total number of objects.


I think the odds are far far less than even one in a million. If we take the distance between stars out near us as 3.5 LY and half that because of the other galaxy merging, and the sun as 1.38 million km diameter,... it would be like two grains of sand 1 mm in diameter, colliding when they are the only grains within 14 miles.
Deathclock
1.5 / 5 (8) Jun 01, 2012
There is very little chance for any collisions to occur. It will most likely be the case that the two galaxies merge and pass through each other without any collisions at all, though stars will likely be thrown outwards away from either of the two galaxies.

Like Noumenon said, the diameter of these objects (stars and planets) compared to the average distances between them is such that it would be like two golf balls colliding in mid air on a golf course.
Jeddy_Mctedder
1 / 5 (4) Jun 02, 2012
4 billion years.....i....can't ....wait.
Meyer
3.7 / 5 (3) Jun 02, 2012
it would be like two grains of sand 1 mm in diameter, colliding when they are the only grains within 14 miles.

I'd be more concerned about the billions of smaller particles being nudged from their orbits around the grains of sand. Though, our descendants will probably have figured out how to deflect or evade comets and asteroids if anyone is still around in 4 billion years.
vidyunmaya
1 / 5 (8) Jun 02, 2012
Sub: Heart to milky Way
Space Science needs to catch-up with Cosmology Vedas interlinks
Plasma Regulated Electromagnetic phenomena in magnetic field environment. see projections in my books- http://vidyardhic...spot.com
NOTES: East West Interaction helps to advance space-Cosmology Studies
btb101
4.6 / 5 (5) Jun 02, 2012
i don't care what the experts at nasa say about the hubble telescope. it might be old but with images like this, she deserves to be kept going.
that single piece of orbiting technology has done more to further our understanding of the universe we live than any land based telescope.
long live hubble.
antialias_physorg
2.7 / 5 (6) Jun 02, 2012
it would be like two grains of sand 1 mm in diameter, colliding when they are the only grains within 14 miles.

It's unlikely but not quite that unlikely since the masses get drawn towards one another by gravity on the approach - so there is somewhat of a 'funneling' effect.

And there will be many passes for each body passing through the other galaxy before the whole thing settles into one common plane. There will be some fireworks.
Mastoras
5 / 5 (1) Jun 02, 2012
East West Interaction helps to advance space-Cosmology Studies

Perhaps. But it's not necessary. There are a lot of fools in the West, too.
-.
MarkyMark
5 / 5 (2) Jun 02, 2012
it would be like two grains of sand 1 mm in diameter, colliding when they are the only grains within 14 miles.

I'd be more concerned about the billions of smaller particles being nudged from their orbits around the grains of sand. Though, our descendants will probably have figured out how to deflect or evade comets and asteroids if anyone is still around in 4 billion years.

Thats assuming such a thing matters to whatever entities once known as 'Human' are arround at that time.
Moebius
1 / 5 (8) Jun 02, 2012
The sky is falling, the sky is falling. No really, just reeeeaaaalll ssssssllllllloooooooowwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwww
TheGhostofOtto1923
1.6 / 5 (7) Jun 02, 2012
Intelligence will have evolved by that time to be able to use the situation to it's advantage. As it already does with similar Inevitable situations here on earth.
Noumenon
1 / 5 (10) Jun 02, 2012
You do know that Star Trek is just a show, right?
Lurker2358
1 / 5 (10) Jun 02, 2012
The Milky Way is destined to get a major makeover during the encounter, which is predicted to happen four billion years from now. It is likely the sun will be flung into a new region of our galaxy, but our Earth and solar system are in no danger of being destroyed.


If you believe the Sun and Earth will survive that merger, you're out of your damned mind.

Almost everything in both galaxies will be destroyed at the molecular level, or ejected from the system, or collapse into black holes, eventually.

When you watch more detailed simulations of this event, the fricken explosions and gravitational collapses are so powerful that by the second and third passes, both galaxies are almost totally obliterated, and then they keep collapsing into a super-galactic mass black hole at the end of the simulations...

http://www.youtub...cBlvfjow

Why people, even idiotic scientists, always make the false claim that the stars arn't going to be destroyed is beyond me.
Lurker2358
1 / 5 (10) Jun 02, 2012
Also, it's the physical contact between different objects and nebulas which slows the galaxies down and causes them to lose relative momentum through contact of matter.

If there was no physical contact due to COLLISIONS the galaxies WOULD NOT SLOW DOWN due to conservation laws, and would go into a pogo orbit that never lost relative momentum.

In the real collision, momentum is conserved, but matter interacts through collisions of planets, stars, dust, gases, etc, and THIS, not gravity, is what slows the galaxies down and causes them to merge.
TheGhostofOtto1923
2.9 / 5 (16) Jun 02, 2012
Almost everything in both galaxies will be destroyed at the molecular level, or ejected from the system, or collapse into black holes, eventually.
Off your meds again I see. To the unmanic eye the vid appears to say that the collision results in an elliptical galaxy, a very stable form indeed.
Why people, even idiotic scientists, always make the false claim that the stars arn't going to be destroyed is beyond me.
But the bigger question that you need to be concerned with is why you perceive your intellect as being superior to those found in mainstream science, especially when repeatedly presented with hard evidence that this is so?

If your intellect was up to par, it would accept this evidence and draw rational conclusions. And you would choose to remain on your meds.
TheGhostofOtto1923
2.6 / 5 (12) Jun 02, 2012
"But the bigger question that you need to be concerned with is why you perceive your intellect as being superior to those found in mainstream science, especially when repeatedly presented with hard evidence that this is [NOT] so?"

-is what I meant to say. See QC? Otto admits it when he makes a mistake. Give it a try. It is a sign of relative mental stability.
You do know that Star Trek is just a show, right?
No I think Vger is real. And Inevitable.
Lurker2358
1.3 / 5 (14) Jun 02, 2012
Off your meds again I see. To the unmanic eye the vid appears to say that the collision results in an elliptical galaxy, a very stable form indeed.


That is nowhere near a stable elliptical galaxy, you idiot.

Look at the simulation again, especially the one on youtube.

It is not even finished collapsing yet, and is a mere fraction of the radius of either of the original galaxies.

The light is not coming from stars, you moron. The light is coming from a 2 trillion solar mass black hole eating obscene amounts of matter.

At the end, the only thing holding the galaxy up is the insane amount of radiation coming out of the accretion disk, blowing some of the matter away, plus the fact that a few "tails" were ejected so far away that it takes a few billion years for those fall back into the core...

Besides that, this thing is freaking history. What, one faint ring of stars in that particular version that "somehow" found a stable orbit, does not count, especially compared to
Lurker2358
1.3 / 5 (14) Jun 02, 2012
The camera position on the video above is set too far away to see the scale of matter very well, all you see is hazy cast-off from the first two passes, which is misleading you.

the youtube video model run shows much more close up detail, in which it's obvious that the system keeps right on collapsing (even past the end of the video itself).
Lurker2358
1.3 / 5 (15) Jun 02, 2012
Although the galaxies will plow into each other, stars inside each galaxy are so far apart that they will not collide with other stars during the encounter.


Absolutely unscientific bullshit.

Gravity alone does NOT cause a pogo orbit to decay. If all matter was weakly enteracting the galaxies would pass through one another and fly back t the same distance they started at.

It is only PHYSICAL COLLISIONS of dust, stars, gas, planets, and other matter, which allows momentum to be conserved while actually permanently "Merging" the galaxies, over a period of a few passes.

Otherwise, they'd just pass right through one another and fly until kinetic energy was overwhelmed by gravity, and then the new potential energy would be exactly the same as it was to begin with.

Therefore, if they don't even know that, then they could not have even programmed the model to run correctly, therefore the article is mis-representative of the real science.
Lurker2358
1.3 / 5 (15) Jun 02, 2012
The final merger in fact is caused by the fact that almost everything in either of the original galaxies actually does either collide, explode, implode, or gets ejected.

That's what the output shows CONSISTENTLY on all galaxy merger simulations.

I can show many different versions of this, and they all show basically the same thing with different details depending on parameters.

http://www.youtub...cBlvfjow

At 1,00 mark, there is a polar jet coming out of SMBH which is enormous, and indicative of a TREMENDOUS amount of matter being consumed by the SMBH, not just a few stars worth, but entire star clusters or spiral bands worth...in a relative pinch of time...but the double galactic mass gravity is so high that even a polar jet can't escape...

http://www.youtub...e=fvwrel

and

http://www.youtub...Ml2SO6_I

Simulation has NOT "finished" and is definitely not "stable" for orbits, particular as more "tails" fall back into core..
Lurker2358
1.3 / 5 (13) Jun 02, 2012
This is the same form as Hooke's Law for a mass on a spring. It would cause the trans-Earth traveler to oscillate back and forth through the center of the Earth like a mass bobbing up and down on a spring. The angular frequency and period for this oscillation are


http://hyperphysi...ole.html

this explains how gravity behaves without interaction.

Because there is no interaction in the "hole through the earth" example, momentum is conserved and the "faller" oscillates from one side of the Earth to the other.

This example PROVES that galaxies do NOT stop moving past one another in space due to gravity alone, but that only COLLISIONS of matter stops them, by bringing their centers of mass and momentum to ultimately rest in the same place.

*I should also make a slight correction to my previous posts in that WIMPS would still be caught by black holes if they had a collision with the event horizons...
Lurker2358
1.3 / 5 (14) Jun 02, 2012
...and "in the same place" above, I might add, "in the same place with no relative linear momentum," as RELATIVE linear momentum is permanently brought to net zero almost exclusively through physical contact, and NOT gravity alone.

Read it and weep, OTTO.

You lose again.

But I know you will never admit it, but that's just your problem.
Lurker2358
1 / 5 (11) Jun 02, 2012
Also, an important distinction.

http://www.youtub...Ml2SO6_I

In that video, the dot does NOT represent the Sun and the Earth. It represents the space occupied by the solar system. It shows nothing about how many other stars or nebulas have been smashed into that space while it orbited the galaxy's core into extremely elliptical orbits which become more and more unstable as the simulation progresses.

also, there are still enormous tails on multiple plains which are continuing to collapse back into the core, which still have many opportunities to totally destroy other stars in the core or spiral bands, or cause further gravitational collapse by falling into the core and increasing the gravitation felt by the other stars that have somehow managed to maintain currently in "meta-stable" orbits.

The claim that this is a stable system is total BS, since it would still take a few billion years just to clear the remaining tails and see what's left of this mess...
Noumenon
1 / 5 (9) Jun 03, 2012
naaa aaah.
Noumenon
2.5 / 5 (15) Jun 03, 2012
Gravity alone does NOT cause a pogo orbit to decay. If all matter was weakly enteracting the galaxies would pass through one another and fly back t the same distance they started at.

It is only PHYSICAL COLLISIONS of dust, stars, gas, planets, and other matter, which allows momentum to be conserved while actually permanently "Merging" the galaxies, over a period of a few passes.


This is incorrect. Your error wrt the pogo effect is that you assume the gaxaxies remain as independent gravitational "solid objects" as they pass through one another. The individual stars in each galaxy are disrupted purely by gravity, and NOT some sort of mechanical "friction" as you seem to imply is required.

Simulations must calculate EACH individual stars path, NOT each galaxies,... which is very complicated and very much disrupted, and only gives the impression that there is mechanical collisions.

Noumenon
2.1 / 5 (14) Jun 03, 2012
,... The general discussion above about the low probability of stars actually colliding concerns the initial merging of the galaxies. That video you posted looks like it models a trillion years into the future (?) and issue final state will depend on initiial conditions.

My estimate above about only two grains of sand within 15 miles assumes stars that are a distance out near our solar system,.. but even for stars nearer the center, the distances are comparable to 2 ping-pong balls being separated by 2 miles (wiki example).
Burnerjack
1 / 5 (5) Jun 03, 2012
Ya know, with enough tax revenue thrown at this problem....
Noumenon
1.9 / 5 (13) Jun 03, 2012
The light is not coming from stars, you moron. The light is coming from a 2 trillion solar mass black hole eating obscene amounts of matter.


Two trillion solar mass?

I verified the wiki example above; Even if there is 10 million stars per cubic parsec in the inner region of the galaxy, this is still equivalent to 2 ping-pong balls separated by 2.5 miles. [1/(10 million)^1/3 X (miles/parsec)] = ~ 89 billion miles between stars at the relatively dense center of the galaxy.

Obviously by far mostly space.

The supermassive black hole is tiny as well, being only comparable to half the orbit of the earth around the sun.
Lurker2358
1.4 / 5 (10) Jun 03, 2012
Like Noumenon said, the diameter of these objects (stars and planets) compared to the average distances between them is such that it would be like two golf balls colliding in mid air on a golf course.


That argument ignores the fact that gravity forces future physical encounters between objects on each subsequent pass.

It also ignores the fact that much of inter-stellar space in each galaxy is filled with dust, diffuse gases, meteors, comets, rogue planets, and nebulas, and failed stars.

It is impossible to imagine something the size of the Horse Head Nebula or the Pillars of Creation passing through multiple passes of Andromeda and not encountering trillions of collisions of planetary scale or larger, and merging with other nebulas and stars from the Andromeda galaxy.

What happens when a solar mass star from Andromeda passes straight through the Horse's head? A feat taht is practically guaranteed to happen given the number of stars in Andromeda.
Lurker2358
1.4 / 5 (10) Jun 03, 2012


Two trillion solar mass?

I verified the wiki example above; Even if there is 10 million stars per cubic parsec in the inner region of the galaxy, this is still equivalent to 2 ping-pong balls separated by 2.5 miles. [1/(10 million)^1/3 X (miles/parsec)] = ~ 89 billion miles between stars at the relatively dense center of the galaxy.

Obviously by far mostly space.

The supermassive black hole is tiny as well, being only comparable to half the orbit of the earth around the sun.


At the moment, yes, but the existing orbits inside each galaxie's core will be totally de-stabilized after the two original SMBHs each get inside the opposite galaxy's "hub" (really as the hubs make tangential contact and then begin to pass through one another), which you see clearly in the last video I linked to, that enormous amounts of matter is merged into stellar mass and SMBH's during the second and third pass, some of these will orbit one another, some will fall all the way into the binary core.
Lurker2358
1.4 / 5 (10) Jun 03, 2012
Look, if you took two Milky Way's with exactly the same internal characteristics and mechanics, and you superimpose them in space, and rotate them so that as few objects overlapped as possible, and THEN start the model, the damned thing will STILL collapse to a black hole, because the stars' orbits will no longer be stable. They will be experiencing much, much more gravity pulling them towards the center.

Ultimately, this is the fate of Andromeda and Milkyway, except that yes, SOME of the stars will receieve enough angular momentum to either get ejected or end up in stable orbits just from the relative momentum of the Galaxies being redistributed during the encounters...but even the models I showed make it clear that the majority of the mass is totally consumed.

http://www.youtub...Ml2SO6_I

Now even that doesn't run to the final conclusion, which is at least run the damned model until all of the "tails" are re-absorbed, so we can see the final state of the system.
Lurker2358
1.4 / 5 (10) Jun 03, 2012
Moreover, that naive argument ignored the fact that every Nebula "A" from Milky Way will almost certainly collide with a Nebulas "B, C, and D" from Andromeda, and vice versa, on at least one occasion, and probably many times.

Nebulas are massive, and they are extended over distances much larger than mere "interstellar space" whereby it is impossible for them to avoid contacting one another, certainly, and inconceivable that they won't slam into stars and planets from the other galaxy.

Even if our solar system never encountered an object of planetary mass or larger, it WILL pass through countless nebulas during the full course of this event, and the mass of the Sun and planets, particularly Jupiter and Saturn, will grow significantly as clouds of hydrogen, helium, lithium, and other elements are encountered.

It's entirely possible that since they have large seed mass to begin with, Jupiter and Saturn could obtain brown dwarf or stellar mass, or even merge by the time all is done....
Lurker2358
1.4 / 5 (10) Jun 03, 2012
Unfortunately, all of the model runs on this focus on the wrong damn thing anyway.

They spend half to 2/3rds of their simulation time on the run-up to the first encounter, and then the big lapse between the second encounter, when really the most important part of the model run regarding this question is actually from the THIRD encounter forwards...the shit happening in the first and second encounter is pretty intuitive and obvious.

They need to run the model for like another 30 seconds to a minute of model time so they can get all of the tails re-absorbed and watch what happens as remaining matter streams are forced back into the same planes by gravity and collisions.
Lurker2358
1.4 / 5 (10) Jun 03, 2012
Also, the example seen on Discovery Channel, I think, of using two shotgun blasts at a 90 degree angle and observing no collisions fails for several reasons.

1, the "scaled" velocity in the shotgun blast is wrong compared to galactic matter. The Sun weighs about 10^34 times more than a shotgun pellet, but it's velocity relative to andromeda is "only" about 500 times greater than the relative velocity of pellets from the two different shotgun blasts. 10^34 times more gravity vs 500 times faster...the real collision is far more likely than the naive example.

2) Gravity forces future passes of all of the "shots" in the real galaxy, whereas the naive model example does not.

3) the timing in the naive model example could be wrong. We've seen on Mythbusters any number of times that if you work out the timing on these sorts of events, collisions can be shown to not only be possible, but highly probable.

4) Gravity would force the timing to be right, eventually, as the SMBH merger finishes
Lurker2358
1.4 / 5 (10) Jun 03, 2012
Anyway, you can be pissed off at me and disagree, but how the hell do you claim that extended objects the size of Nebulas won't collide and cause all new stars to form from combined masses?

Moreover, once shit like that starts to happen, stellar and planetary scale collisions will be a given, since their own gravitational environments will be modified so heavily.

Like I said above, be realistic.

Something the size of the Horse Head Nebula makes a close encounter or even a collision with a similar size nebula from Andromeda.

Or how do you deal with more massive systems, such as globulars and dwarf galaxies caught up inside of the bands of both Milky Way and Andromeda? You think stuff that size and mass is just going to harmlessly "blow through" one another, or nebulas or star systems from the opposite galaxy?

On the contrary, collisions are ultimately more likely than not.
TheGhostofOtto1923
1.8 / 5 (9) Jun 03, 2012
It is not even finished collapsing yet, and is a mere fraction of the radius of either of the original galaxies.
Ahhaaahaaa lurker/QC thinks that celestial mechanics is done by watching YouTube videos. Sorry but 20 posts and a sweaty brow are still not sufficient for doing science - only for demonstrating dysfunction. You're super-gifted - why can you not realize this?? Could it be that there is something majorly askewed with your cognition?
TheGhostofOtto1923
2.1 / 5 (11) Jun 03, 2012
Anyway, you can be pissed off at me and disagree, but how the hell do you claim that extended objects the size of Nebulas won't collide and cause all new stars to form from combined masses?
No the question is how do YOU explain it? With no education, with no experience, with no instruments, with little self-control and with only outrageous psychotic audacity? Which is just not enough you must admit.

We can wait until a relatively competent celestial mechanic comes along to diffuse your entire argument in a few sentences by pointing out only a few of the very many major things YOU DO NOT KNOW; or we can look at the general character of your posts and the outrageous nature of the things you are attempting to do, and reasonably conclude that you are a nutcase.

Why don't you join us in this assessment QC?
TheGhostofOtto1923
1.8 / 5 (10) Jun 03, 2012
Like I said above, be realistic.
Wise words indeed. Can you follow them? Picture yourself having a conversation with some 25yo postdoc. Against your rantings he calmly offers examples of the many things YOU DO NOT KNOW, which nullify each of your arguments. And then picture your mind desperately searching for reasons to proclaim that you are still right, despite the evidence he is presenting which proves this is just not so.

Can you see it QC? the essence of your profound disconnect? Your need to be RIGHT overshadows any desire you might have to understand. What might the clinical term for this condition be? I am sure you've heard it before.
Lurker2358
1.6 / 5 (12) Jun 03, 2012
Using the lower mass estimate of 4.1 million solar masses for the SMBH at the center of Milky Way, the distance from the Black Hole where the escape velocity equals the relative velocity of the Milky Way and Andromeda (120km/s,) is actually, very, very large, at a staggering 7.98 LIGHT YEARS radius.

Translation: virtually All matter passing within that distance will be trapped and consumed on each pass.

This is roughly the distance from here to Sirius... in every direction...

The Andromeda Galaxy's black hole is currently believed to be betweeen ten and 100 times more massive, which means the "no escape" zone would have a radius of between 3 and 10 times larger, or about 24 to 80 light years in every direction for Ve at that distance equaling 120km/s...

Now that's a little over simplified, because you have to deal with the angular momentum and local motion of individual objects in each galaxy, but it gives you the damned picture plainly.
TheGhostofOtto1923
1.5 / 5 (8) Jun 03, 2012
Now that's a little over simplified
Wise words indeed even if extremely understated. Can you learn to appreciate them? I fear not.
Lurker2358
1.4 / 5 (10) Jun 03, 2012
Otto, you fool, the models themselves do not even agree with the claims of this article.

YOU CANNOT CLAIM THAT THESE OBJECTS TENS OF LIGHT YEARS WIDE ARE GOING TO MISS ONE ANOTHER. THAT'S ABSOLUTELY BULLSHIT.

THE MODELS CLEARLY SHOW THE GALAXIES TOTALLY CONSUMING THE MAJORITY OF ONE ANOTHER'S MATTER.

You can't handle that fact, when an article and even the scientist contradicts the real output of their own model.

http://www.youtub...Ml2SO6_I

that is most certainly NOT some rosy "no collisions" picture like this article tries to spin it.

If there was another 50 seconds added at the end, like the mostly uneventful first 50 seconds, you'd see it keeps getting worse.

Things I do not know.

Like the fact that I correctly predicted the latest model simulation of Solar System dynamics 3 years before the profession astronomers?

I guess you forgot that one eh?

Several other things I have proved in the past, got mocked by fools like yourself, and then later proven right.
Lurker2358
1.4 / 5 (9) Jun 03, 2012
The Nebulas in our own galaxy are often several times larger than the average distance between stars in our own galaxy. The same is probably true for Andromeda.

Therefore, it is completely, physically IMPOSSIBLE for DIRECT Nebula-on-Nebula and star-on-nebula collisions to NOT occur.

If you can't see that then you're a freakin idiot.

And when they do occur, ordinary mass stars are going to eat up enormous amounts of matter, since their escape velocity from surface greatly exceeds to relative motion. In fact, the Sun's gravity is strong enough that the matter cannot escape even several solar radii out from itself due to gravity.

And again, this does not consider stars that are already more massive than the Sun, nor neutron stars or black holes, or globulars.

How can a globular miss a Nebula?

Couple light years across each, in some cases, they are going to collide, and they are going to totally destroy each other's stability, either through ejection or collapse.
Lurker2358
1.4 / 5 (9) Jun 03, 2012
Further, just assuming mechanical collision and average density of each galaxy, the cross sectional area of each Earth mass planet sweeps out a certain "volume" of space as it passes through the 100,000ly diameter of the other galaxy.

Using only head-on mechanical collision of gas and dust representative of the average density of each galaxy, an Earth mass planet should gain about 540 trillion kilograms, per pass. this does not count gravitation nor "t-bone" collisons, but just treats it as passing through a cloud with that average density.

However, objects near the CORE of each galaxy orbit their own cores at a velocity greatly exceeding the relative velocity of the galaxies, consequently, each object in each galaxy's core would actually get multiple "passes" through the core of the other galaxy for every one pass of the galaxy's through one another.

That is based on the fact that objects in the cores orbit at velocities of several thousand km/s... cont...
Lurker2358
1.4 / 5 (9) Jun 03, 2012
Therefore, said stellar mass objects in each core will have dozens, perhaps even hundreds or thousands of close encounters from stellar mass objects in the other core, on EACH pass of the galaxies, although the first pass in some of the simulations is a glancing blow and largely inconsequential, but the second and third pass are direct hits.

Why do you think the gas temperature goes off the scale on that one simulation video during the second and third pass? In astronomy, temperature is proportional to density of stars, or energy coming out of neutron stars and accretion disks or supernovas. It doesn't just heat up because it "feels like it". No, it's an insane number of stellar mass and even NEW SMBH mass collisions as many millions and even tens of billions of stellar collisions and black hole mergers occur over a relatively tiny period of time compared to the age fo the existing galaxies and normal circumstances.
TheGhostofOtto1923
1 / 5 (3) Jun 03, 2012
Otto, you fool, the models themselves do not even agree with the claims of this article.
How would YOU know? You don't have the faculties to judge.
Therefore, said stellar mass objects in each core will have dozens, perhaps even hundreds or thousands of close encounters from stellar mass objects in the other core, on EACH pass of the galaxies, although the first pass in some of the simulations is a glancing blow and largely inconsequential, but the second and third pass are direct hits.
Blah. Thank god for real scientists. With pristine brains.
Code_Warrior
5 / 5 (6) Jun 03, 2012
Lurker, arguing your case here using your model is unlikely to convince anyone. Einstein spent many lonely years in that Swiss patent office toiling away on relativity before he made his case public. You, on the other hand, make your case public with little to no toiling.

If you are convinced of the accuracy of your model, feel free to produce your own simulation and publish your results. After all, it is much easier to get physics papers published these days than in Einstein's day, just ask dtyarbrough. Nobody will stop you from posting your simulation on YouTube. You can upload a 10 minute video if you like.
Anda
5 / 5 (3) Jun 03, 2012
Oops sorry, but in 4 billion years the sun will be approaching its red giant phase and the earth will certainly be affected big time. I don't think a galactic collision will be big deal, all other things considered for our immediate neighborhood.


When the sun expands there will be a nice climate in ... Titan? Europa? Etc...
Lurker2358
1.5 / 5 (8) Jun 03, 2012
Lurker, arguing your case here using your model is unlikely to convince anyone. Einstein spent many lonely years in that Swiss patent office toiling away on relativity before he made his case public. You, on the other hand, make your case public with little to no toiling.

If you are convinced of the accuracy of your model, feel free to produce your own simulation and publish your results. After all, it is much easier to get physics papers published these days than in Einstein's day, just ask dtyarbrough. Nobody will stop you from posting your simulation on YouTube. You can upload a 10 minute video if you like.


That isn't even my simulation.

Those are done by university professors and students.

This is the resume for one? of the guys who programmed that last model,

http://www.aip.de...sume.pdf

again

http://www.youtub...Ml2SO6_I

He gave his name and credentials in the description.

None of this is my models..continued...
Lurker2358
1.4 / 5 (9) Jun 03, 2012
...but if you look at that, it looks absolutely NOTHING like the bullshit rosy, "no/few collisions" crap that this article says twice, or that you normally have people claiming.

LOOK at the damn model.

Pay attention to the diameter of the Milky Way and Andromeda at the start.

Pay attention to the final diameter of the Merged galaxy (ignoring the tails, but just keep in mind the tails will mostly fall into the core eventually).

Now, look how much tinier the Merged galaxy is than either of the parents.

The average density of the NEW main disk has got to be at least 10 or 20 times greater than the original disks, and as stated, all of the matter is not even finished being re-captured by the cores. It would take another billion or two billion years or so to do that.

Look at the TEMPERATURE indicators. Up to a million kelvin for the brightest colors. You don't get a million kelvin by an occasional one atom collisions. It takes entire stars, nebulas, or SMBH polar jets to do that.
Lurker2358
1.4 / 5 (9) Jun 03, 2012
The reason the point representing the "position of the solar system" whips back and forth in such an eccentric and unstable orbit is because it is now orbiting in a 3-dimensional orbit around the center of mass....but there are enormous perturbations caused by the asymmetrical matter plumes from tails both "above" itself relative to the new CoG and "below" itself relative to the new CoG.

In the simulation, the "solar system" also passes through the merged core, very deep in, on several occasions as it whips in and out into more and more eccentric orbits.

At this point from about 1,00 forward, it's basically crammed the vast majority of both Galaxies' masses into a space smaller than either galaxies original core or nucleus.

With the Earth and other stars whipping into this now double or triple mass core, how do you expect no collisions to occur?

IN an individual galaxy, collisions already occur, and that's in an environment where they are otherwise stable over cosmic time.
Lurker2358
1.4 / 5 (9) Jun 03, 2012
This one is extremely good, as it is a generic "galaxy merger" model.

http://www.youtub...LEbOFT2A

Notice, in two or three cases, "supermassive" objects with their own hubs and CoG form and "spin up" from the merger of various matter streams during the first and second pass of the merger.

He also discusses the "rapid star formation" during this event, which is obviously caused by non other than nebula scale collisions.

As it happens, after the first pass, two "super massive" star clusters formed from the chaos in the right-most galaxy and spun up, and then fell down into the core of the parent galaxy, having not enough velocity to escape the gravity of the CoG and the original SMBH (plus the merged and consumed mass).

This is a damn near perfect representation of what I would anticipate, but I still have the complaint of it not quite running long enough to clear out the "debris".

THIS IS NOT MY MODEL.
Lurker2358
1.4 / 5 (9) Jun 03, 2012
Basically, the right-most galaxy temporarily became a "trinary quasar" as two smaller SMBH formed from wrecked, colliding matter streams, spun up and became AGNs in their own right as "dwarf galaxies," and then eventually fell into the original SMBH.

Notice the resolution is far better here than any of the other models as well.

Then, after the next pass, at about 1,20, there is actually a fifth SMBH "AGN-like" object, which forms in one of the matter streams in the tails and is orbiting the merged nucleus. You may have to watch it two or three times to catch it.

The first two of such "NEW" SMBH/AGN objects are easily seen in both versions of the simulation.

The third one is much fainter and is seen about 1,15 to 1,25 going behind the pair an coming back around the left side, before it becomes too faint to distinguish. It is too faint in the second version of the model run at the end.

But the first two "objects" are incredibly massive and energetic, and both die to the main SMBH..
Lurker2358
1.4 / 5 (9) Jun 03, 2012
As you can see, that is most certainly not a joke.

That particular model run makes the "no collisions" claim look like a complete and utter lie, as matter is utterly consumed by newly formed, enormous black holes, short lived dwarf galaxies, and other star clusters which form during early passes from various castoff and matter collisions, and are themselves later consumed in future passes.

The articles claim is so bogus it's ridiculous that it was even considered science.

Recommend downloading the full screen movie and watching on your monitor, it's even better than the youtube video version, and clearly shows that I am actually right.

Though once again, my only complaint is that the models don't run "long enough," and need to run for another 1 or 2 billion years worth, but nobody's perfect. Maybe they don't have enough memory to run their renderer for that much longer to produce the simulations.
Lurker2358
1.4 / 5 (9) Jun 03, 2012
One other thing.

The apparent "eliptical" nature of the object is an illusion caused by the fact that there are still so many tails going in every direction, which have not fully been re-absorbed.

The majority of the matter is contained in the new merged SMBH and the ridiculously dense core of stars immediately surrounding it, which is many times denser than either of the original galaxies.

this final object is an almost "hollow" shell of stars and dust orbiting a super-massive, ultra-dense core of black holes and stars. This is completely different than "giant elliptical" ordinarily observed in telescopes, which are quite the opposite, and often much larger in area and volume than the Milky Way, for example.

It's not an eliptical.

It's a freakin galactic mass black hole, with a multi-axis accretion disk, which still needs a few billion years to finish collapsing and re-alligning into a single plane...
TheGhostofOtto1923
2 / 5 (8) Jun 03, 2012
The postdoc simulation author arman states on his Facebook page:

"To explore parameter space for AGN model I use disk galaxy mergers. In collaboration with A.Cattaneo and M.Steinmetz and S.Gottlber we are went further to analyze the evolution of elliptical galaxies with and without AGN."

-Without further research I think I can conclude that he and his collaborators believe that the simulations you are looking at are of disk galaxies merging to form ellipticals. This seems to be his forte. His raisin d'etre.

So ask yourself 'What am I missing? What is it that convinces these professionals that their simulations are creating ellipticals and not whatever it is I am thinking they show?'

THEY created the simulations to convince others that this is so. THEY fully understand what went into these simulations, and what it is they demonstrate. WHY is it you do not understand all this? WHAT is it that makes you think you can disregard the great bulk of what they know?
Code_Warrior
5 / 5 (6) Jun 03, 2012
Lurker, do you think these guys are doing this simulation on some high powered desktop PC?

That little snippet of video more than likely represents a large amount of processing time and memory resources on a supercomputer. Running the simulation for another couple of billion years means about a 25% increase in that supercomputer time. Supercomputer time is not free and it is a shared resource. In addition, all simulations have increasing error as they run due to limited resolution, limited accuracy in the specification of the initial conditions, model simplifications, and round-off error. While there are techniques to reduce the effect of these sources of error, you can't eliminate it completely and the error will always grow with time. The researchers must decide the acceptable level of error and use their supercomputing budget wisely. They are not going to waste their budget running a simulation longer if their estimate of the error exceeds what they deem acceptable.
Nikstlitselpmur
1 / 5 (5) Jun 03, 2012
Repent the world ends in four billion years.

The whole Universe appears to be moving away at an increasing speed, as supported by red shifting, except these galaxies known as the Local Group, of which Andromeda and the Milkey Way are a part of, they all exhibit blue shifting, the local group is rushing at the speed of 1000 kps towards a body of mass 100 quadrillion times greater than our sun and span of 500 million light-years known as the Great Attractor, There can be no other explanation than we are in the tractor beam of a black hole and will all end up in the same place eventually;

Please take your seat and fasten your seat belt. And also make sure your seat back and folding trays are in their full upright position. If you are seated ... please assume the bracing position
PS3
1 / 5 (3) Jun 04, 2012
The views would be so amazing!
ROBTHEGOB
1 / 5 (4) Jun 04, 2012
In 4 billion years, we will all be dust. Let us revere the Earth while we can.
A_Paradox
1 / 5 (1) Jun 04, 2012
gswift:
here's an interesting thought: What would it look like to see an Earth-like planet fall into a Jupiter type? That would really be something to see.

A key issue of importance to at least some observers could be the fact of them being on the small planet :)

They will be happy days for those running sweepstakes and official betting franchises.
NewOrleansLib
5 / 5 (1) Jun 06, 2012
I just got a letter from my insurance company stating they are not covering this collision.
BeeVeeDee
1 / 5 (1) Jun 29, 2012
Oops sorry, but in 4 billion years the sun will be approaching its red giant phase and the earth will certainly be affected big time. I don't think a galactic collision will be big deal, all other things considered for our immediate neighborhood.


Not to worry. Predicted for the same time frame: a cool death for Earth's magnetosphere as molten core phase-shifts to solid.
When it rains. . .

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