Can someone explain to me this about gravity please

In summary, the conversation discusses the concept of gravity and its range of attraction. While some argue that gravity has an infinite range, others point out that infinity is not a number and cannot be used in calculations. The basic equation for gravity suggests that as r approaches infinity, the force approaches zero, but this does not mean that gravity has a finite range. Instead, it means that the force becomes small but not zero at large distances.
  • #1
Does gravity have a limited range in which it can attract objects? I looked up on google, most people are saying it's infinite.. if it really is infinite then I'm confused, because if the denominator is infinite, then the result is just zero.. and in gravity's law F=[g(m1m2)] / r^2 .. if r is so big doesn't gravity simply become ineffective? so how would gravity have an infinite range?

Sorry if this question is silly I'm not a specialist.. I'm just curious
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  • #2
The basic equation is - as you have said

##F = G \frac{m_1\,m_2}{r^2}##

Of course the force F goes to zero if r goes to infinity. But that's not how we would interpret infinite range. We should better say that if we let the distance r become arbitrary large but finite, then the force F becomes small but not zero.
  • #3
The problem is that you are trying to treat infinity as if it were a number- and it isn't. Yes, if you were to replace "r" with infinity you would get a force of 0. But saying that the "range of gravity is infinite" just means that if you were to put any distance in for r you would get a non-zero gravitational force. That does not include setting r equal to "infinity" because, as I said, infinity is not a number and you cannot be an infinite distance away from a gravitating body.
  • #4
yeah. Something with a finite range would have some cut-off ##r## value, and for any ##r## greater than this, the force is zero. (and gravity does not have this property).
  • #5

I can explain that the concept of gravity having an infinite range is based on our current understanding of the laws of physics. According to the theory of general relativity, gravity is a force that is caused by the curvature of space and time. This means that the effects of gravity can potentially reach an infinite distance, as the curvature of space and time extends infinitely.

However, it is important to note that the strength of gravity decreases with distance, so while it may have an infinite range, its influence becomes weaker as the distance between objects increases. This is why we do not feel the effects of gravity from distant objects, such as stars and galaxies, as strongly as we do from objects closer to us.

In terms of the equation you mentioned, F=[g(m1m2)] / r^2, the denominator does not represent the distance between objects, but rather the square of the distance. This means that as the distance increases, the denominator becomes larger, but the overall force still exists.

It is also worth noting that gravity is not the only force at play in the universe. There are other forces, such as electromagnetism, that can counteract the effects of gravity and prevent objects from being pulled in by it.

I hope this explanation has helped clarify the concept of gravity and its range. It is a complex and fascinating topic, and it is completely understandable to have questions about it. Keep asking questions and exploring the wonders of science!

1. What is gravity?

Gravity is a force that exists between all objects with mass. It is responsible for keeping planets in orbit around the sun, and for keeping objects on Earth from floating away into space.

2. How does gravity work?

Gravity works by pulling objects towards each other. The strength of the 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. Why do objects fall to the ground?

Objects fall to the ground because of the force of gravity. The Earth's mass creates a gravitational force that pulls objects towards its center. This is why objects always fall downwards towards the ground.

4. What is the difference between mass and weight?

Mass is a measure of the amount of matter an object contains, while weight is a measure of the force of gravity acting on an object. Mass remains constant regardless of location, while weight can change depending on the strength of gravity at that location.

5. How was the concept of gravity discovered?

The concept of gravity was discovered by Sir Isaac Newton in the 17th century. His famous law of universal gravitation explained the relationship between mass, distance, and the force of gravity. It was later refined by Albert Einstein's theory of general relativity in the 20th century.

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