Thread: Was Einstein wrong?

Einstein rejected an infinitely old universe because he said everything would come together under gravity over time.

But would they? I was in the first Galaxy Zoo project a few years back and found a number of colliding galaxies and the results of what had happened afterwards. They are not unusual.

As an example, our galaxy and the Andromeda galaxy are moving towards each other. As they get closer, they will move ever faster towards each other due to gravitational attraction.

Eventually they will "collide". In reality there is so much room in galaxies that for the most part they will travel through each other though there is some transfer of material.

Then they separate and move away. Essentially like a photon, they will blueshift as they approach each other then redshift as they move away, so overall balancing out their speeds to approximately what they were before.

Instead of all galaxies eventually ending up in one universe sized black hole, they can move about, having interactions every so many tens of billions of years and then go on as before, finally settling down in appearance as local gravities take over to look like they did before.

You do not need to worry about what Einstein thought. Later research has shown that the universe is 13.7 billion years old.

[quote=". . . Then they separate and move away. Essentially like a photon, they will blueshift as they approach each other then redshift as they move away, so overall balancing out their speeds to approximately what they were before.

Instead of all galaxies eventually ending up in one universe sized black hole, they can move about, having interactions every so many tens of billions of years and then go on as before, finally settling down in appearance as local gravities take over to look like they did before.[/quote]

I am sorry for a naive question. I know about blue and red shifts of light; but what does it mean in the context of galactic collisions? Are you referring to "gravitational waves" ? What was learned about them in the last two decades?

Originally Posted by skeptic

You do not need to worry about what Einstein thought. Later research has shown that the universe is 13.7 billion years old.

I was not querying the age of the universe but Einstein's assumption.

Originally Posted by kowalskil

I am sorry for a naive question. I know about blue and red shifts of light; but what does it mean in the context of galactic collisions? Are you referring to "gravitational waves" ? What was learned about them in the last two decades?

I'm not quite sure what you are getting at. The Andromeda galaxy is heading towards an eventual collision with our galaxy so mutual gravity is speeding up the process and both will continue to travel faster till the "collision".

The galaxies will essentially pass through each other with few collisions since both are mostly empty space. Then they will separate and go on their way, but as they pull away from each other, gravity will again try and attract them and so finally slow them down to somewhere around their original speeds.

The galaxies would then settle back into their spiral shapes over time, due to local forces which keep them in their present shape when there are no outside influences.

What we call our "local group" may just be a temporary arrangement and both galaxies may one day be tens of millions of light years from each other.

Gravity waves does not sound right to me, though far better than gravitons. We still don't know exactly what gravity is, so how it propagates.

You are describing two different things, of which one is portrayed wrongly. Universal expansion has nothing to do with the relative movement of galaxies. Simple gravitational theory predicts that a finite distribution of masses will become gravitational unstable, while an infinite distribution will keep its average density, while on smaller scales, local perturbations may lead to localised density enhancements. This is exactly what we observe. So, while the universe is expanding on a global scale (or as Einstein first believed is stable and not collapsing), individual galaxies and galaxy groups may attract each other gravitationally and eventually merge.

You are correct, when you write that galaxies are practically empty, and basically stars don't collide during a galaxy merger event. However, this does not mean that the galaxies themselves are not affected. They "feel" their gravitational potential and react accordingly. For example, the Milky Way has a warped disc (it is slightly distorted) due to the gravitational interaction with the Magellanic Clouds. The merging of two galaxies usually proceeds in several steps:

1. Encounter: Gravitational attraction pulls galaxies towards another. Their momenta and directions determine, how the encounter occurs (grazing, direct hit, etc.)

2. First interaction: Usually, galaxies cannot merge during the first hit. Depending on their sizes, speed and directions they distort the shape of the galaxies, while they fly apart again. Some matter can be exchanged in this process. The gravitational interaction can induce an era of intense star formation (starburst).

3. Final merge: Gravitational breaking due to friction destroys momentum, so that after some time of separation, they start to fall back onto each other and then finally merge. For a while, both galactic nuclei can be distinguished, but they also eventually merge.

To my knowledge, the picture you are describing, where two colliding galaxies end up basically unharmed is wrong.

If it was just a matter of all galaxies falling into each other, that would have happened to most billions of years ago when the universe was far smaller and expansion was even less than it is now.

The galaxies would only merge if one or both had insufficient escape velocity from the other's gravity. We have a number of misshapen galaxies which have been the results of collisions where other galaxies have gone off on their own way.

If the spiral shape is natural for a galaxy, why should it not reform eventually into that shape once all outside influences have gone as local gravity takes over?

The galaxies would then settle back into their spiral shapes over time, due to local forces which keep them in their present shape when there are no outside influences.

Cyberia I tend to agree with Dishmaster on this one. I did read all the post on this subject and I noticed nothing was said or commented about large elliptical galaxies and how they got that way. I've yet to hear of any large elliptical galaxy ever changing back into a spiral galaxy. If what you said was true then there should be evidence somewhere in the visible universe of elliptical galaxies changing into spiral galaxies. My personal thoughts on this subject is that there is a size limit on how big a spiral galaxy can be and after it passes that limit it will naturally form up into the elliptical shape.

Quoted: "Think big! If you have a gun, you can rob a bank. If you have a bank, you can rob everybody."

I am intrigued by your statement. You have something in mind, what do you mean?

jsaldea12
11.15.10

Originally Posted by Cyberia

Einstein rejected an infinitely old universe because he said everything would come together under gravity over time.

Many speculate about "The Big Crunch" but there are nothing as of now suggesting that theory to be true, quite the contrary, it is expanding!

If I smash an egg to a wall, it will be all over the place just like the big bang, but there would be no mechanics to reverse the process.

..so imo Einstein was utterly wrong.

Originally Posted by HexHammer

Originally Posted by Cyberia

Einstein rejected an infinitely old universe because he said everything would come together under gravity over time.

Many speculate about "The Big Crunch" but there are nothing as of now suggesting that theory to be true, quite the contrary, it is expanding!

If I smash an egg to a wall, it will be all over the place just like the big bang, but there would be no mechanics to reverse the process.

..so imo Einstein was utterly wrong.

Einstein was wrong about what ?

The "big crunch" is one possible outcome in modern cosmology, but is not consistent with accelerating expansion. Einstein did not predict a crunch.

Unlike unsmashing an egg, there is a force that could, but given the accelerating expansion of space probably will not, cause a contraction of space. It is called gravity. In fact, until about 1998 when the accelerating expansion was discovered, a major open question in cosmology was whether there was sufficient mass in the universe to halt the expansion and cause eventual contraction.

Before making ridiculous statements like "Einstein was utterly wrong", you ought to first find out what Einstein actually said.

Originally Posted by Cyberia

Einstein rejected an infinitely old universe because he said everything would come together under gravity over time.

But would they? I was in the first Galaxy Zoo project a few years back and found a number of colliding galaxies and the results of what had happened afterwards. They are not unusual.

As an example, our galaxy and the Andromeda galaxy are moving towards each other. As they get closer, they will move ever faster towards each other due to gravitational attraction.

Eventually they will "collide". In reality there is so much room in galaxies that for the most part they will travel through each other though there is some transfer of material.

Then they separate and move away. Essentially like a photon, they will blueshift as they approach each other then redshift as they move away, so overall balancing out their speeds to approximately what they were before.

Instead of all galaxies eventually ending up in one universe sized black hole, they can move about, having interactions every so many tens of billions of years and then go on as before, finally settling down in appearance as local gravities take over to look like they did before.

I have a question about the future collision between Andromeda and the Milkyway. Do you know the angle of the collision? Is it like a head on collision or maybe at an angle where they are both heading in the same direction but say off only by maybe 30 degrees. If both galaxies are coming together at a small angle, the collision will look a lot different as the galaxies will stay together and interact with each other much longer, plus there won't be much blue shifting and red shifting from our point of view.

Originally Posted by DrRocket

Originally Posted by HexHammer

Originally Posted by Cyberia

Einstein rejected an infinitely old universe because he said everything would come together under gravity over time.

Many speculate about "The Big Crunch" but there are nothing as of now suggesting that theory to be true, quite the contrary, it is expanding!

If I smash an egg to a wall, it will be all over the place just like the big bang, but there would be no mechanics to reverse the process.

..so imo Einstein was utterly wrong.

Einstein was wrong about what ?

The "big crunch" is one possible outcome in modern cosmology, but is not consistent with accelerating expansion. Einstein did not predict a crunch.

Unlike unsmashing an egg, there is a force that could, but given the accelerating expansion of space probably will not, cause a contraction of space. It is called gravity. In fact, until about 1998 when the accelerating expansion was discovered, a major open question in cosmology was whether there was sufficient mass in the universe to halt the expansion and cause eventual contraction.

Before making ridiculous statements like "Einstein was utterly wrong", you ought to first find out what Einstein actually said.

This?

he said everything would come together under gravity over time.

Originally Posted by HexHammer

Originally Posted by DrRocket

Before making ridiculous statements like "Einstein was utterly wrong", you ought to first find out what Einstein actually said.

This?

he said everything would come together under gravity over time.

Einstein never said that. Cyberia is not a reliable source for statements made by Einstein, or anything else.

Originally Posted by DrRocket

Einstein never said that. Cyberia is not a reliable source for statements made by Einstein, or anything else.

Bohoo? I have answerd accordingly to asked question in OP, that's all there is to it.

Originally Posted by HexHammer

Bohoo? I have answerd accordingly to asked question in OP, that's all there is to it.

So, no reference to text books, no literature searches, no contemplation of information, just a knee jerk reaction. It's certainly an approach, but is it the best one?

Originally Posted by Ophiolite

Originally Posted by HexHammer

Bohoo? I have answerd accordingly to asked question in OP, that's all there is to it.

So, no reference to text books, no literature searches, no contemplation of information, just a knee jerk reaction. It's certainly an approach, but is it the best one?

OP made a postulation and asked a question, to which I gave an answer, is that wrong?

Originally Posted by HexHammer

Originally Posted by Ophiolite

Originally Posted by HexHammer

Bohoo? I have answerd accordingly to asked question in OP, that's all there is to it.

So, no reference to text books, no literature searches, no contemplation of information, just a knee jerk reaction. It's certainly an approach, but is it the best one?

OP made a postulation and asked a question, to which I gave an answer, is that wrong?

You gave an unsupported unscientific opinion regarding to a bogus assertion, not a question (the question was in the thread title not in the passage that you quoted), by a suspended posteer. Both the assertion and the opinion are worthless.

Originally Posted by HexHammer

Originally Posted by Ophiolite

Originally Posted by HexHammer

Bohoo? I have answerd accordingly to asked question in OP, that's all there is to it.

So, no reference to text books, no literature searches, no contemplation of information, just a knee jerk reaction. It's certainly an approach, but is it the best one?

OP made a postulation and asked a question, to which I gave an answer, is that wrong?

See Dr. Rocket's response for my position on this matter.

Originally Posted by Ophiolite

Originally Posted by HexHammer

Originally Posted by Ophiolite

Originally Posted by HexHammer

Bohoo? I have answerd accordingly to asked question in OP, that's all there is to it.

So, no reference to text books, no literature searches, no contemplation of information, just a knee jerk reaction. It's certainly an approach, but is it the best one?

OP made a postulation and asked a question, to which I gave an answer, is that wrong?

See Dr. Rocket's response for my position on this matter.

I'm not sure I got the situation down right.

But is it my duty to know if an assertion is right or wrong? Or should I have specifyed "if this assertion is right ..then bla bla"?

Based on this matter, I'v tryed to locate the forum rules, but I havn't been able to locate it, could anyone please provide link?

Originally Posted by HexHammer

[But is it my duty to know if an assertion is right or wrong? Or should I have specifyed "if this assertion is right ..then bla bla"?

Based on this matter, I'v tryed to locate the forum rules, but I havn't been able to locate it, could anyone please provide link?

It is not a matter of rules, but yes, in normal discussions you are expected to understand a question if you intend to provide an answer. Understanding a question includes knowing if the premise is valid. This expectation applies to all normal discourse, and not just to this forum.

On the other hand, if your goal is just to hear the sound of your own voice, then that expectation is moot.

didn't einstein predict that there was some sort of cosmological constant (dark energy) which must be expanding the universe, but soon dismissed it for lack of proof, calling it his biggest blunder. he then went back to his initial belief in the big crunch, as it seemed to fit the bill

Originally Posted by uncleslam

didn't einstein predict that there was some sort of cosmological constant (dark energy) which must be expanding the universe, but soon dismissed it for lack of proof, calling it his biggest blunder. he then went back to his initial belief in the big crunch, as it seemed to fit the bill

No

Einstein initially thought that the universe was static. A static universe, with a zero cosmological constant is not possible -- gravity will cause it ti collapse.

So Einstein inserted a cosmological constant in the field equations. Edington showed that solution to be unstable.

When Einstein became aware of Hubble's data he accepted the expansion of space and abandoned the cosmological constant.

Einstein, so far as I know, never had anything to say about a "big crunch".

Dark energy is not necessary for an expanding universe. It is an explanation for an accelerating expansion.