# I Does anything ever repel gravity?

1. Aug 7, 2016

### Prasun-rick

I was studying electrostatics when I came across an idea if gravity just like electrostatics be repulsive in nature with something..Is there such things which repel gravity???...Thanks in advance

2. Aug 8, 2016

### Drakkith

Staff Emeritus
There is not. Gravity is solely attractive.

3. Aug 8, 2016

### Simon Bridge

Loosely: gravity is the force attracting masses so "repel gravity" makes no sense. Forces may be repulsive, but you cannot repel forces.

You'll see that with electromagnetic charges, like charges repel ... whereas, if we treat mass as the gravitational charge then we see like charges attract (and we only ever find positive charges).
This, I suspect, is the idea you have come across.

All this means is that it may not be useful to think of gravity as a force like the electromagnetic force between charges.
(This is pretty much the standard way to understand gravity: as a pseudoforce arising from geometry vaguely analogouse to centrifugal force arising from rotation. A negative gravity would be like postulating an inwards-pointing centrifugal effect.)

Still, there is quite a lot of discussion about a possible physical basis for antigravity ... ie. see "cosmological constant" and "exotic matter".

4. Aug 8, 2016

### Prasun-rick

Sir @Simon Bridge thanks for the comments,I would definitely surf for the "anti gravity" discussion !.

5. Aug 8, 2016

### Papa Doyle

..nothing substantive here except to compliment Simon on the generous answer. Particular genius in the "repelling a force" argument and the parallels drawn with centrifugal force; so easy to just give the short answer. Highest regards to you.

6. Aug 13, 2016

### Simon Bridge

One of the aims of these forums (fora? forae?) is to improve scientific literacy. Science is a process which involves asking questions, investigating them, and refining the questions for further investigation. So ven though a question may itself be simple to answer, it can be useful to refine the question.

@Prasun-rick
I'm not convinced that researching "anti-gravity" will be all that useful, since a naive google of the term produces wikipedia and a lot of crackpots. I did provide good search terms that would lead to decent science. I encourage you to also look up "critical thinking" and "skepticism". These are essential tools for assessing anything you read online.

7. Aug 13, 2016

### Staff: Mentor

Please do not post nonsense here at the PF. Please re-read the PF rules under INFO at the top of the page. Thread is closed.

Last edited: Aug 13, 2016