# A layman with an idea, foolish perhaps

1. Jun 12, 2014

### Deuterium1971

Hello, I've been thinking lately about the strange orbit speeds of galaxies and I came up with a little loony idea. What if gravity has a minimum attraction? To put it a different way, the attraction of any mass continues with a constant force no matter the radius after a certain distance. Stars at a "generic" orbital distant of 25000 light years from the center orbit at a "generic" 200 Kilometers per second speed, and so do stars with an orbital distance of 50000 light years. Going a little farther, that same attraction would continue all the way to the edge of the universe. So the force that cause any "generic" star to orbit at 200 kilometers per second would be the same force pulling on galaxies at the edge of the universe. Strong Nuclear Force is the strongest force, but its influence ends at the nucleus of a given atom. Electromagnetism has a defined strengths many times that of gravitation, but its influence is very limited beyond a certain distance. Could gravity have influence all the way to the edge of the universe, creating a micro-gravity constant force at a given distance and beyond? I have heard that there is a microscopic discrepancy in Newton's Law of Gravity. Just a curious idea, could that discrepancy be that gravity has a minimum force as well as a force. If all galaxies are alike then this minimum force could be measured, and if there is a discrepancy, this would be the reason why.

Lambaste as needed, I'm just a layman and have no real knowledge of anything, thank you for your time.

2. Jun 12, 2014

### Drakkith

Staff Emeritus
This doesn't match observations, specifically that the strength of gravity falls off with distance enough to allow galaxies to become unbound due to the metric expansion of space. Also, there is no "edge" to the universe as far as we know.

By the way, this probably violates the rules of the forum in that personal theories aren't allowed to be discussed, so I wouldn't get too attached to it.

3. Jun 12, 2014

### mathman

Both gravity (Newton's law) and electromagnetic force obey inverse square law. General relativity is more accurate than Newton's law for gravity, but, except for extreme circumstances, the observations are essentially the same.

4. Jun 12, 2014

### UltrafastPED

Gravitation has been studied extensively since Newton's day, and several small discrepancies have been discovered, starting in the late 1700s. This lead to the search for additional planets beyond Uranus - Neptune was located this way, in the 1840s. A discrepancy with the orbit of Mercury was resolved when Einstein's General Relativity replaced Newtonian gravitational theory as our most accurate tool.

The problem of galactic rotation was first recognized in the 1930s; the term "dark matter" was invented at that time: matter which cannot be seen by a telescope is "dark", and if the missing matter is "dark", then it is understandable that telescopes don't see it. The alternative is to modify the gravitational theory.

A great many proposals have been considered, and mostly rejected, because they disagree with observations. Many of them can be expressed in the "Parameterized post-Newtonian" formalism:
https://en.wikipedia.org/wiki/Parameterized_post-Newtonian_formalism

You can explore some of the proposals in C.M. Wills "Was Einstein Right?"; this book was written for the interested non-specialist.

5. Jun 12, 2014

### Deuterium1971

Thank you for the information on C.M. Wills. I am definitely a Non-specialist, and interested. Sorry for portraying a theory, was just curious if a minimum force to gravity would be feasible. And as for using the "edge", chalk it up to vernacular of a layman please.

6. Jun 12, 2014

### Drakkith

Staff Emeritus
No worries. If I had a nickel for every nitpicky thing I've been called out on I could afford my own science forum. :tongue:

7. Jun 12, 2014

### Deuterium1971

Curious thought, is there a place on this forum to place original thoughts without worry of a deletion? Thanks again for humoring me.

8. Jun 12, 2014

### ZapperZ

Staff Emeritus