Dark Matter as a solution to unstable orbits in 4d

Ideas about how a world with more than three spatial dimensions would work - what laws of physics would be needed, how things would be built, how people would do things and so on.

Dark Matter as a solution to unstable orbits in 4d

Postby anderscolingustafson » Fri Jun 12, 2015 7:23 pm

I was just thinking about how in our universe the orbital speeds of stars in the outer parts of galaxies are faster than they should be based on the visible matter in galaxies because galaxies have more dark matter than visible matter and the amount of matter in the galaxy slows down the drop off rate of gravity in the galaxy. In a solar system the drop off rate for gravity is r-2 because we live in three dimensions and because most of the mass of a solar system is concentrated in the star. If most of the mass of a solar system were outside the star then depending on how much mass was outside the star gravity could drop off at a slower rate than the inverse square law within the solar system even in four spatial dimensions.

In any number of dimensions if there is a hypersphere with uniform density gravity will increase linearly with distance from the center within the hypersphere. If most of the mass of a 4d solar system was in the form of dark matter outside the star then the drop off rate for gravity in the solar system could be slower than the inverse cube law which could help planets stay in stable orbits without having to come up with some weird force law.
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
anderscolingustafson
Tetronian
 
Posts: 316
Joined: Mon Mar 22, 2010 6:39 pm

Re: Dark Matter as a solution to unstable orbits in 4d

Postby granpa » Thu Jun 18, 2015 4:43 am

Never occurred to me
granpa
Dionian
 
Posts: 20
Joined: Sat Nov 10, 2012 12:21 am

Re: Dark Matter as a solution to unstable orbits in 4d

Postby Teragon » Sun Aug 09, 2015 6:25 pm

No, because the density of the star is much higher than the density of dark matter. The slope of the linear increase is so flat that it doesn't do anything to the 1/r³-law, provided dark matter density is not absurdly high.
What is deep in our world is superficial in higher dimensions.
Teragon
Trionian
 
Posts: 136
Joined: Wed Jul 29, 2015 1:12 pm

Re: Dark Matter as a solution to unstable orbits in 4d

Postby granpa » Sat Aug 22, 2015 5:39 am

What are you talking about? Dark matter radically altars the orbits of the stars. That's how it was detected
granpa
Dionian
 
Posts: 20
Joined: Sat Nov 10, 2012 12:21 am

Re: Dark Matter as a solution to unstable orbits in 4d

Postby Teragon » Mon Aug 24, 2015 12:46 pm

It's alters the orbits of solar systems and dwarf galaxies around galaxies, not the orbits in solar systems.
What is deep in our world is superficial in higher dimensions.
Teragon
Trionian
 
Posts: 136
Joined: Wed Jul 29, 2015 1:12 pm


Return to Higher Spatial Dimensions

Who is online

Users browsing this forum: No registered users and 7 guests

cron