12 replies to this topic

[j6p]

                                                  I like the theory but I have to disagree with their finality scenario. I think it's ripping itself apart right. But while dark energy's foot is on the accelerator, gravity's foot is on the brake.
I would guess that new energy will fill in the space created by the expansion




Link to article                                                  

[Althalus]

                                                  The theory does look good, but will gravity beome weaker as the universe spreads further appart, I know that gravitational force remains constant and that only the effet lessens the further you get from the source, but as there are numerous sources will it happen as they said?

Or is there only one ultimate source for gravity.                                                  

[j6p]

                                                  Well the jury is out on this one. In fact I don't think there is even a court hearing the case yet but I am going to speculate that gravity isn't constant. I think it will be shown to increase as the universe expands. Sort of like a rubber band.
This variation would be so slight though that some pretty sensitive instruments will have to be used to detect the variation. I'm not sure that the  technology exists yet to detect this.
I'm going to research further.                                                  

[Homer]

                                                  As the distance between mass increases due to the expansion of the universe, the gravitational influence one mass has on another decreases. This doesn’t mean that there is or is not a gravitational constant. Regardless whether gravity is constant or not, the influence gravity has on other bodies of mass will decrease as the distance increases.

Personally, I don’t know if gravity is constant or not, but in my opinion, gravity is constant, and always relative to the mass that creates it.

Back to the theory. The article really didn’t get into why or how the ‘big rip’ would happen. The way I interpret the theory, the forces that keep atoms together are caused by the collective gravitational influence of the mass of the universe. As gravitational influences weaken as the distance between mass increases, gravity’s ability to maintain stability weakens proportionately until it can’t hold things together anymore. There you have the ‘big rip’.

I don’t know about this theory, but it is an interesting article j6p                                                   

[j6p]

                                                  I think you are right on the money about gravity. For any given mass the gravitational force it exerts is constant so when the mass varies the force would adjust to the changing mass. With this in mind I believe that as the universe expands new mass would be created therefore the gravity of the universe, as a whole, would be varying and is not a constant. This would leave the individual gravitational force of any one mass on another constant but the gravitational force of the universe as a whole should vary. More mass = more gravity. Thats what I was referring to when I said gravity varies.                                                  

[Althalus]

                                                  Yep, like it,  sounds good Homer                                                     

[neen]

                                                  Wow everything Homer & J6P posted was exactly what i was going to post.....I was ......honest.....don't you believe me?                                                       

[Sageghost]

                                                  I believe ya Neen

                                                  

[Homer]

                                                  Actually, neenron sent me a private message, telling me what to post

Thanks neenron, I owe you one                                                   

[neen]

                                                  Thanx Sageghost



Ohhh Homey your sooo sweet                                                     

[Occam's Razor]

You're right on the money about gravity, Homer - there's a constant, G, which is the gravitational constant.  One of the many gifts that dapper chap Newton bestowed upon the scientific world.  It is indeed true that the effect of gravity lessons as distance between two bodies increases, while the gravitational constant remains the same.  More accurately, it lessens as the distance between two object's center of mass increases.  We would get heavier as we approached the Earth's center.

They have equations for this and everything.  Very slick.  You could find out the gravitational force between yourself and a lady you happen to fancy.  Just work out the figures, hand her a slip of paper and she'll have no choice but to succumb to the scientific evidence.  

But I dunno about this "ripping atoms apart" aspect of the theory.  It's actually not gravity that holds atoms together... gravity is the weakest of the Four Fundamental Forces (F3 - dramatic, imposing, yet elegant  ).  It's the strong (and weak, I think) nuclear  forces that bind atoms together.  These forces are so powerful that they supply the energy that can result in nuclear explosions.  They are ridiculously more powerful than gravity - there's a lot of decimal places involved, I remember that much.

I don't know enough to say that it's *impossible* for this supposed anti-gravity to one day (in the absurdly distant future) overcome these forces, but it seems highly doubtful.

[skaterblues]

what is the relation between mass nag gravity... why is there no gravity if there is no mass... is there possibility thet there can be mass without gravity or vice versa?   

[j6p]

skaterblues, here's a way for you to examine this situation in the comfort of your home, at your leisure.
Experiment: take an embroidery hoop and a balloon. Put the balloon in the hoop and make it secure. This would represent the fabrick of space. Now take a weighted object and place it in the center of the stretched balloon. You are now looking at what mass does to space.
If ya wanna take your brain for a real ride, imagine if you placed an extremely heavy object in the center of that contraption. An object so massive that it sinks into the rubber and disappears, you can't see it anymore. There's your black hole.  Further mind bending: Imagine if that massive object were made of rubber, the same as the balloon that you stretched. What would happen if after it sank out of sight, it melted into the balloon, became part of it?  
Now to address the second part of your question, "is there possibility thet there can be mass without gravity or vice versa?" You have the answer to this. Take that balloon hoop that you've built and begin stretching, pulling, bending and twisting it. Try to get it to dimple. No dimple = no gravity.
Of coarse this experiment can be done in your mind, no need for apparatus.