# The Naked Scientists Forum

### Author Topic: How does gravity reconcile with Newton's law of motion?  (Read 3826 times)

#### DoctorBeaver

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##### How does gravity reconcile with Newton's law of motion?
« on: 29/06/2008 09:04:07 »
If it were possible to instantaneously materialise 2 objects in space close enough that they were gravitationally attracted to each other, they would move together. Where is the "equal & opposite reaction"?

I know it must be there somewhere - but where?

#### LeeE

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##### How does gravity reconcile with Newton's law of motion?
« Reply #1 on: 29/06/2008 14:30:09 »
They move in opposite directions.

#### Andrew K Fletcher

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##### How does gravity reconcile with Newton's law of motion?
« Reply #2 on: 29/06/2008 18:30:57 »
Take a group of atoms joining together to form a larger object large enough to generate its own gravity. Where does the opposite reaction / repelling force go?

Good on yer Doc

#### DoctorBeaver

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##### How does gravity reconcile with Newton's law of motion?
« Reply #3 on: 29/06/2008 20:55:46 »
They move in opposite directions.

#### DoctorBeaver

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##### How does gravity reconcile with Newton's law of motion?
« Reply #4 on: 29/06/2008 20:56:16 »
Take a group of atoms joining together to form a larger object large enough to generate its own gravity. Where does the opposite reaction / repelling force go?

Good on yer Doc

erm...

#### Andrew K Fletcher

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##### How does gravity reconcile with Newton's law of motion?
« Reply #5 on: 01/07/2008 08:08:48 »
And the opposite direction to an attracting force is?

#### Alan McDougall

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##### How does gravity reconcile with Newton's law of motion?
« Reply #6 on: 01/07/2008 09:40:53 »
Large objects must move together , if this were not the case the earth would never have formed as it did.

Tiny quantum particles might move apart, they are not constrained by Newtons law.
« Last Edit: 01/07/2008 09:42:39 by Alan McDougall »

#### lightarrow

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##### How does gravity reconcile with Newton's law of motion?
« Reply #7 on: 01/07/2008 12:27:27 »
Large objects must move together , if this were not the case the earth would never have formed as it did.

Tiny quantum particles might move apart, they are not constrained by Newtons law.
What do you mean?

#### DoctorBeaver

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##### How does gravity reconcile with Newton's law of motion?
« Reply #8 on: 01/07/2008 19:32:39 »
And the opposite direction to an attracting force is?

That would be repulsive, then.

#### Alan McDougall

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##### How does gravity reconcile with Newton's law of motion?
« Reply #9 on: 02/07/2008 00:48:04 »

Quote
Large objects must move together , if this were not the case the earth would never have formed as it did.

Tiny quantum particles might move apart, they are not constrained by Newtons law.

What do you mean?

You perhaps noticed I said "MIGHT" anything might happen at that micro level

The early universe and antigravity are still theorised. There must have been a repulsive force in the early universe or it would not exist, .The universe would have come on like an incandescence light and immediately vanished.

Something pushed against the huge gravity of the singularity. Exactly what is still not known. Perhaps our universe is a white hole of a hugeblack hole from somewhere else or we might be living within the confines of a huge black hole we call the universe.

Debating the repulsive force of quarks etc would mean going into the extreme complexities of quantum mechanics ad fundamental physics and theory.

« Last Edit: 02/07/2008 00:52:19 by Alan McDougall »

#### Flyberius

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##### How does gravity reconcile with Newton's law of motion?
« Reply #10 on: 02/07/2008 03:38:56 »
I thought that gravity was basically making matter trying to move in a straight line in curved space.  If so wouldnt this have nothing to do with newton.  ie newtons law does not apply because no planet would actually be pulling the other.  Infact anyone on the planet would be oblivious to the acceleration.  They would appear and immediately begin drifting towards each other.  Please correct me if I am wrong on the above.

Just makes you realize how wierd gravity really is.

Oh and could you imagine if it was an earthlike planet.  Two spinning planets getting closer and closer.  The weather systems would be immense.  I wonder if at any point the gravity between two such objects could cause the sea to rise over mainland in some sort of Uber tidal flood.
« Last Edit: 02/07/2008 03:42:54 by Flyberius »

#### Alan McDougall

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##### How does gravity reconcile with Newton's law of motion?
« Reply #11 on: 02/07/2008 04:14:04 »
Hello Flyeberius and welcome. I am also new to this forum and grounding myself so to speak.

Quote
The weather systems would be immense.  I wonder if at any point the gravity between two such objects could cause the sea to rise over mainland in some sort of Uber tidal flood

Absolutely the moon when it was much much nearer the earth did or could of produced huge tidal waves of 10 000+ feet racing across the infant continents.

Big planets like earth and Venus coming too close would rip each other apart due to the enormous tidal forces betwen them.

Of course your terrible weather scenario would also be true even it they were still millions of miles apart.

Regards

Alan

#### The Naked Scientists Forum

##### How does gravity reconcile with Newton's law of motion?
« Reply #11 on: 02/07/2008 04:14:04 »