# So.... thoughts on gravity and the universe?

Discussion in 'Off Topic [BG]' started by Davidoc, Aug 29, 2004.

1. ### Davidoc

Sep 2, 2000
Northern VA and JMU
Hey, so I have some semi-random thoughts about stuff in the universe etc. My first concern is as to why we have the vast empty vaccum that is space between the masses of our universe. Unless there's some form of structure that keeps everything place, shouldn't everything get sucked together? What keeps the distances between objects to maintain the vaccum? Does this somehow tie into the mystery that is gravity? Perpaps gravity represents the force of the vacuum fighting against the structure that keeps everything from collapsing?

2. ### Josh Ryan- that dog won't hunt, Monsignor.Supporting Member

Mar 24, 2001
there are some great, accesible books out there by people like Stephen Hawking and Michio Kaku, Rudy Rucker etc. that you might be interested in. A google on any of those names will get you somewhere.

3. ### nonsqtrThe emperor has no clothes!

Aug 29, 2003
Burbank CA USA

Gravity "is" the force pulling everything together.

The force countering that is the "big bang" that provided the massive amount of energy that still keeps the universe expanding.

What's in the vacuum? Well, clearly, something other than "nothing". As you say, there is structure. Why it isn't obvious to enquiring minds is something that some future Einstein will discover.

4. ### Benjamin StrangeCommercial User

Dec 25, 2002
New Orleans, LA
Owner / Tech: Strange Guitarworks
Actually, there is no vacuum. It's a sort of dark matter (some call it the ether) that is not really understood presently.

There's the theory that gravity is actually a thing, not a force. Think of it like this: you have a sheet. It's stretched out flat. Put a bowling ball in the middle. Put a tennis ball a few feet from it. Eventually the weight of the bowling ball forces the sheet (gravity) to dip, and the tennis ball rolls towards the bowling ball. Some say this is how gravity works.

Check out the Holographic Universe by Michael Talbot if you want to get really confused about reality theory and how the universe may truly work. Don't blame me if you lose whatever faith you might have had before you read it, though.

5. ### Jazzin'...Bluesin' and Funkin'

the reason everything isnt getting sucked together is cause the vacuum is all around each object in space, so theres equal lack of pressure from every angle.

6. ### Jazzin'...Bluesin' and Funkin'

your example only works because gravity makes the bowling bass sink and the tennis ball roll to it. so if thats how gravity worked, then it wouldnt work unless there was another force to help it work.
edit: sorry for the double post.

7. ### IvanMikePlayer Characters fear me...Supporting Member

Nov 10, 2002
Middletown CT, USA
gravity warps spacetime and is "created" by mass
scientists are still searching for the elusive "graviton" particle
ben's example is a classic one, but is oversimplified by necessity because it's hard to envision a 3 dimensional space being warped like that (not to mention the 10 or 11 dimensions that superstring theory implies, and M theory and the F theory being worked on by C. Vafa)
so far the universe proves to be expanding without halt, although the evidence supports the idea of "Dark matter" because the total amount of gravitaional force exceeds what would be cause by the observable mass in the universe
space isnt a vacuum, but has very very little matter in it, especially when considering the space in between galactic clusters
the force of the big bang is what keeps everything moving "out", and has yet to become overcome by gravity, (if it ever will)
lots of good books and articles exist on the subject, the amount of equasions and math you encounter will vary

8. ### Jazzin'...Bluesin' and Funkin'

how can it stop expanding if theres no friction and so much momentum?

9. ### Da_Niet

Jan 23, 2003
California
Have you guys heard of String Theory? I saw this topic on an episode of Nova last year. I was soo enthralled, I can easily say it was the best informational show I had ever watched. Anyways, scientists including Hawking and Carl Sagan, have put forth their support and opinions behind the possibilities of other dimensions beyond what we see. If you get the chance to order this, do so. It was a revelational moment, for me.

Auf wiedersehen

10. ### IvanMikePlayer Characters fear me...Supporting Member

Nov 10, 2002
Middletown CT, USA
good chance it can't
the overwhelming opinion at the moment is that there is not sufficient matter (which creates gravity) in the universe to stop the expansion

11. ### nonsqtrThe emperor has no clothes!

Aug 29, 2003
Burbank CA USA

Semantics. Forces need love too.

12. ### IvanMikePlayer Characters fear me...Supporting Member

Nov 10, 2002
Middletown CT, USA
actually gravity is one of the big 4 forces that make physicists search for the "grand unified theory"
the forces are the strong force, the electromagnetic force, the weak force, and gravity
gravity proves to be very daunting in being combined with the other 3
use the force luke................

13. ### nonsqtrThe emperor has no clothes!

Aug 29, 2003
Burbank CA USA
A "force" is just a model. It's an "explanation" of the observed reality. Things "act as if" there's a force operating between them. Whether this is due to the curvature of spacetime, or the exchange of virtual photons between elementary particles, is of no consequence at that level of description.

Last I heard there was some new evidence that the universe really isn't going to expand forever. Who knows, they go back and forth on that one every few years.

Does anyone know what's up with the LIGO these days?

14. ### Mike MoneyBanned

Mar 18, 2003
Bakersfield California
Avatar Speakers Endorsing Hooligan
Here is my big question:

IF the universe has unlimited space... That means we don't take any of it up.

Which means..

We cannot possibly exist.

right?

15. ### Nick man

Apr 7, 2002
Tampa Bay
One thing to consider is that the force of gravity is related to the inverse square of the distance (1/d^2) menaing that the farter you get the much smaller the force of gravity becomes.

If the force of gravity is slowing down the expansion of the universe its doing it very slowly, an dthe deceleration rate is dropping all the time. Who knows if it will continue expanding forever or eventually slow down and collapse upon itself?

16. ### nonsqtrThe emperor has no clothes!

Aug 29, 2003
Burbank CA USA

Non sequitur! You're equating "existence" with "taking up space". Consider a note from a bass guitar. It "exists", right? Does it take up space?

17. ### Mike MoneyBanned

Mar 18, 2003
Bakersfield California
Avatar Speakers Endorsing Hooligan
Well... A note sounds out a soundwave which moves atoms... So although it is a bit of a stretch, you could say a sound has mass...

18. ### Aaron Saunders

Apr 27, 2002
Ontario
Not so. The universe is constantly expanding, and hence, it has finite dimensions -- just so large as to be completely and utterly out of our comprehension.

19. ### Aaron Saunders

Apr 27, 2002
Ontario
Also note so. The soundwave causes air to move at certain speeds, as sound is caused by vibration. The sound itself has no actual physical mass, because there's no such thing as a "sound particle" -- hence, sound does not exist -- it's just the way our brains interpret vibration.

20. ### ApeIsHigh81

Aug 24, 2004
CA
Thats why I stopped smoking the ganj a while ago.... you'll drive yourself nuts thinking of explanations to why the universe exists, there aren't any! I believe this is the whole reason religion was developed long ago, along with a governing society, to keep some sort of order. I grew up Roman Catholic going to private schools, praying, believing in God, now thanks to the Science channel and the simple explanation of man's evolution, it just doesn't seem like there's a reason for anything. Like we're just random clutters of cells & mass. I know it's a horrible way to live life, but it gives me some sort of solace and understanding when a loved one dies or tragedies happen. I need God more than ever right now, so I try to pray, although most of the time my thoughts & sincerity while praying seem hollow, like I'm fooling myself. Then knowing that our galaxy is a spec of nothing in our immesurable universe? That crap really makes me feel like nothing sometimes. When I wake up I try to have the best time possible with everyone I meet. Smiles, laughter, achievement, helping & comforting are some of the main things that make me want to still live. Of course making music is in the top 5!