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Posted: Fri Apr 22, 2011 1:30 pm
by rcain
tantalizing paper. so should this be testable via inverted gravitational lensing around intergalactic voids?

Posted: Sat Apr 23, 2011 1:52 am
by KitemanSA
I know that, tell him.
But the point of the hypothesis is that we really don't know what it's "mass" is. Could be anti-mass. Right?
Not that I believe it, but it is interesting and fun to think about. :D

Posted: Sat Apr 23, 2011 12:10 pm
by Giorgio
When boredom levels gets high anything is good to pass some time :D

Posted: Sat Apr 23, 2011 10:09 pm
by chrismb
So if gravity is reversed for antimatter, why aren't the strong and weak nuclear forces not also reversed? (Which'd mean antimatter self-disintegrates immediately... which we know it doesn't.)

Posted: Sun Apr 24, 2011 1:26 am
by KitemanSA
chrismb wrote:So if gravity is reversed for antimatter, why aren't the strong and weak nuclear forces not also reversed? (Which'd mean antimatter self-disintegrates immediately... which we know it doesn't.)
As I understand this, and I probably don't so ICBW, anti-matter attracts antimatter but repels matter and the same with regular matter. So the anti-weak and anti-strong nuke forces would hold/disrupt anti-things just like weak and strong acts on regular stuff. No? It only acts the opposite with the opposite stuff. Nonsense, but fun!

Posted: Sun Apr 24, 2011 5:25 pm
by ladajo
So yesterday my 7 year old son tells me (as he is playing with his Lego Space Police Galactic Intruder), "Dad, you know that gravity doesn't pull, it pushes. All the stuff up in space and the universe pushes down on us. That's what holds this guy down..."

:shock:

Posted: Sun Apr 24, 2011 5:52 pm
by Skipjack
Funny theory, unfortunately it does not explain why biger bodies have more gravity then (e.g. the gas giants).

Posted: Sun Apr 24, 2011 5:55 pm
by Giorgio
Are you already feeding him with Arxiv.org papers? :D

Kidding apart, I wish we could have had the kind of access to knowledge that this generation has. It's really amazing.

Posted: Sun Apr 24, 2011 7:40 pm
by CaptainBeowulf
So if antimatter behaves "normally" around other antimatter, but repels regular matter, shouldn't the antimatter in the voids condense into antimatter galaxies? Or does he think it's just a much lower volume of intergalactic antihydrogen etc. floating around out there, too little to form structures?

Posted: Sun Apr 24, 2011 8:34 pm
by KitemanSA
Skipjack wrote:Funny theory, unfortunately it does not explain why biger bodies have more gravity then (e.g. the gas giants).
Sure it does! Gravitons push. They get partially blocked by mass. There is a fairly uniform push from all sides throughoput your body except for the direction of large masses that block some of the push. The bigger/denser the body, the more of the push gets blocked.

So if you are standing on earth you get pushed equally in all directions except up cuz the earth blocks the up push a bit. so on average you get pushed down. Simple, elegant, and quite an old hypothesis.

It is kind of awesome that a kid thought of it too.

Posted: Sun Apr 24, 2011 9:12 pm
by Skipjack
So if you are standing on earth you get pushed equally in all directions except up cuz the earth blocks the up push a bit. so on average you get pushed down. Simple, elegant, and quite an old hypothesis.
Hmm, I am not so sure about this making sense. I have to think about it when I am feeling better. I am laborating on a terrible cold right now and feel very numb.
One quick question: If the gravitons are pushing and the earth is simply blocking them, then even a very thin, rod that had the same density as earth and was 12000km long would have the same amount of gravity on its tip in the direction of its length as earth has.
I do seriously doubt that this is the case and there should be rather simple experiments to verify that.

Posted: Sun Apr 24, 2011 10:23 pm
by ladajo
Well. this all goes towards how to do the math.
Is it a point source, line source or an infinite plane?

Most all our modern concepts are based on point source and expanded sphere models. The fallacy in the math comes from the fact that as the sphere gets larger, it becomes less and less accurate at the data scale in use. Thus to keep it accurate, you must increase the data fidelity, or you make interpolations as you go.

As Chris likes to point out, 3 counts is not a lot of info. I agree, 3 counts scaled up to the size of a star probably will not track between what is real and what is mathmatically predicted.
The trick is knowing the limits of your spherical scaling.

Posted: Sun Apr 24, 2011 10:30 pm
by ladajo
In regards to my kid having this thought, he is sometimes frighteningly bright. His life goal (currently) is to grow up to be a Mad Scientist.
I think he has a shot at it.
Once he made me chuckle when he was between 5 and 6. He noted one day as I used a napkin and tossed it in the garbage that I was reducing oxygen on earth. I got it when he said it, but let him calmly explain to me, "that I should use the napkin until it is fully dirty and wet, because each time we throw away a paper napkin, it means another must be made, and that paper comes from trees, and trees make oxygen, so if there are less trees..."
Still makes me chuckle when I think about it. :)

Skip: Treasure these moments with your son, I am sure you will have also have them.

As for gravity, I am sticking with my son's idea. I like it.

Posted: Mon Apr 25, 2011 12:35 am
by KitemanSA
Skipjack wrote: One quick question: If the gravitons are pushing and the earth is simply blocking them, then even a very thin, rod that had the same density as earth and was 12000km long would have the same amount of gravity on its tip in the direction of its length as earth has.
It would if gravitons came from only one direction, but since it is a 360x360 situation almost all of the gravitons from "below you" wouldn't be blocked as much by the rod. Those that come from "zero" degrees would perhaps be blocked by the same amount of mass, but those that came from 0.5 degrees would only go through a portion of the rod, and those that come from 1 degree might not pass thru much of the rod at all. The blockage is integrated across all the mass/angle of the entire earth and the rod can't do the same thing.