Gravity as Expansion: How Do Orbits Stay Constant?

In summary, the conversation discusses a theory that suggests gravity is caused by the expansion of matter. However, there are questions about how this theory can account for the changes in direction of objects in orbit around larger objects. Additionally, the theory raises concerns about the source and destination of the energy needed for this expansion. The conversation also touches on the tendency for some people to explain things using limited information, potentially leading to far-fetched ideas and theories.
  • #1
breedb
9
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I read about the theory that gravity is caused by the expansion of matter. If this is true, how does this account for the change of direction of a satellite or planet that occurs when it orbits another larger object.

It seems that if the object is moving fast enough to maintain its orbit it would appear to rotate approaching 90 degrees from where it started around the planet but never reaching 90 degrees. Then it would appear to be traveling away from Earth.
 
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  • #2
That "theory" sounds like pure crackpottery to me. For instance, it predicts that gravitational forces depend on size and not the mass. I suspect that if you want details on how it's supposed to work, you need to talk to the people who created it.
 
  • #3
breedb said:
I read about the theory that gravity is caused by the expansion of matter. If this is true, how does this account for the change of direction of a satellite or planet that occurs when it orbits another larger object.

It seems that if the object is moving fast enough to maintain its orbit it would appear to rotate approaching 90 degrees from where it started around the planet but never reaching 90 degrees. Then it would appear to be traveling away from Earth.

I thought about that once. Since the moon and the Earth aren't expanding towards each other really fast that would have to mean that space is expanding along with the matter, but as far as I know there's no good reason either one should ultimately want to do that. You'd have to wonder where the energy to accomplish this comes from and where it goes.

There seems to be a temptation in people to explain everything with what limited information they have on hand, and the ones who get carried away become the crackpots we know and love. I'm suspicious of string theory purely on the grounds that it seems to be reaching to far too fast. I'm learning about physics the old fashioned way to avoid the path of the crackpot but wow is it daunting.
 

1. How does gravity cause objects to stay in orbit?

Gravity is a force that attracts objects with mass towards each other. In the case of orbiting objects, such as planets around a star, the gravitational force between the two objects causes them to constantly fall towards each other. However, the forward momentum of the orbiting object keeps it moving in a curved path, resulting in a stable orbit.

2. Why do orbits stay constant instead of spiraling into the center?

This is due to the balance between the gravitational force and the centrifugal force. The gravitational force pulls the orbiting object towards the center, while the centrifugal force pushes it away from the center. As long as these two forces are equal, the orbit will remain constant. If the forces were to become unbalanced, the orbiting object would either spiral towards the center or drift away from it.

3. Can orbits change over time?

Yes, orbits can change over time due to various factors such as the gravitational pull of other objects, atmospheric drag, and even the expansion of the universe. In the case of our solar system, the gravitational pull of other planets can cause slight changes in the orbits of the planets over long periods of time.

4. How does the expansion of the universe affect orbits?

The expansion of the universe does not directly affect orbits on a small scale, such as the orbits within our solar system. However, it can have an impact on the orbits of objects on a larger scale, such as galaxies. As the universe expands, the gravitational pull between objects becomes weaker, leading to changes in their orbits.

5. Is the concept of gravity as expansion still a widely accepted theory?

Yes, the concept of gravity as expansion is a widely accepted theory in the scientific community. It is supported by various observations and experiments, including the redshift of distant galaxies and the cosmic microwave background radiation. However, it is still an area of ongoing research and there may be refinements or adjustments to the theory in the future.

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