Gravity & Universe: Is Everything Falling?

In summary, the conversation discusses the concept of free fall and gravity in the universe. It is mentioned that the universe is expanding and that there is no reason to believe that everything is in free fall. The idea of everything falling at the same speed is also discussed, but it is noted that in relativity, there is no concept of absolute velocity. The conversation also touches on the fact that gravity only knows one direction - towards the largest nearby center of mass.
  • #1
cottonkat5
2
0
I'm sure this will sound like quite a childish question, but Is it possible that there are high amounts of gravity throughout the whole universe (probably not the right wording), and that all celestial bodies are falling in "nothing" at the same rate of speed.
 
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  • #2
The universe is expanding and the expansion is accelerating, opposite of the effect that you are asking about.
 
  • #3
There is no reason to believe that everything in the universe is in free fall.
 
  • #4
After reading Koestler's The Sleepwalkers, and not being a mathematician, the construct that seemed to best fill the requirements of orbiting bodies and gravity was a universe in which everything was in free fall relative to its location. That is to say that our star, the Sun, is in free fall as part of the larger galaxy, taking along with it Earth and the other planets. As there is no center to the universe, it would seem silly to say falling "down," rather everything is in free fall regardless of direction. As larger objects fall, they draw in smaller objects. I won't go on--although I could.
 
  • #5
cottonkat5 said:
I'm sure this will sound like quite a childish question, but Is it possible that there are high amounts of gravity throughout the whole universe (probably not the right wording), and that all celestial bodies are falling in "nothing" at the same rate of speed.

There seem to be two aspects of your question:
1) 'free fall' / 'gravity' --- this doesn't make sense. The universe is effectively defined as the region of spacetime that is interacting... thus anything causing gravity is necessarily 'in' the universe. Additionally, what's almost always important is the difference in gravity between regions---thus if there were a 'constant' gravitational field the entire universe 'felt' --- it wouldn't have any effect (for the most part).

2) It sounds like you're asking if ever object in the universe is moving in some direction, at the same speed. In relativity there is no concept of absolute velocity (speed). Therefore if everything were moving at the same relative velocity, we would just call that 'zero velocity'.
 
  • #6
Agreed. All bodies in orbit are in free fall. The Earth falls around the sun, but, is moving too fast to fall into it [which is good]. A satellite launched into orbit free falls around the earth, but, is going too fast to crash into it. All courtesy of gravity. The only direction gravity knows is towards the largest nearby center of mass.
 

1. What is gravity?

Gravity is a force of attraction between objects that have mass. It is one of the four fundamental forces in the universe and is responsible for holding planets in orbit around stars, as well as keeping objects on Earth's surface.

2. How does gravity work?

Gravity works by pulling objects towards each other. The strength of the gravitational force depends on the mass of the objects and the distance between them. The larger the mass and the closer the distance, the stronger the gravitational force.

3. What is the relationship between gravity and the universe?

Gravity plays a crucial role in the structure and evolution of the universe. It is responsible for the formation of galaxies, stars, and planets. Without gravity, the universe would not be able to hold itself together.

4. Is everything falling due to gravity?

In a sense, yes. Everything with mass in the universe is affected by gravity, causing it to be pulled towards other objects. However, the effect of gravity is not always noticeable, especially for smaller objects like humans and everyday objects.

5. Can gravity be manipulated or controlled?

At our current level of scientific understanding, we do not have the technology or knowledge to manipulate or control gravity. However, scientists are continuously researching and exploring ways to harness and manipulate gravity for potential future applications.

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