Thread: Is there any truth to this?

Originally Posted by PhilosopherStoned

The "God Particle" is the higgs, not the graviton. We know nothing about the graviton other than that we expect it to have spin 2.

Also, everything moves in a straight line unless there's some force acting on it. Gravity doesn't count as a force for that statement because gravity is just objects moving in straight lines through curved space. That's right, the moon moves in a straight line around the earth.

Originally Posted by Xei

Although it's important to note that the line is straight in space-time. Otherwise it'd get a bit confusing why faster things (like light) curve less and don't get trapped in orbit like the planets, despite passing through the same place in the same gravitational field.

It still makes no sense at all to me how gravity is just the result of the curvature of space, and yet it's also hypothesised that it can be explained by a virtual particle. That's like... space curvature - particle duality. Too much for me.

Hold on.... wtf? Can either of you explain this more?

How can everything move in a straight line?

Originally Posted by tommo

Hold on.... wtf? Can either of you explain this more?

How can everything move in a straight line?

Not everything, just everything in free fall.

Originally Posted by tommo

Hold on.... wtf? Can either of you explain this more?

How can everything move in a straight line?

A disclaimer that this is just me extrapolating from what I know about geometry and what I know from popsci... I don't intend to study general relativity properly, you'd better ask Phil.

But it's not totally surprising once you realise that it's a straight line in space-time, not space. If you think about an object in classical physics moving at a fixed velocity, and its graph of distance (from some point) against time, it's straight. As it's moving at fixed velocity, we're talking about an object with no force applied to it, by Newton's first law. But if you do apply a constant force, the object accelerates and you get a curved path in space-time. However, in the same way that Galileo and Newton had realised that physics is the same whether you are still or moving at a constant velocity (so, if you're making a straight line in space-time), and hence the notion of a special fixed frame of reference which objects decelerate to was incorrect, Einstein realised that physics is the same whether you are standing on Earth, floating in space, or in free fall under gravity; that is to say, objects falling due to gravity, like those under no force with constant velocity, are also making straight lines in space-time. So gravity isn't a 'force' per se, it's just that mass changes the properties (curvature) of surrounding space. Objects continue moving 'unaffected' in straight lines in space-time, but the curvature of the space-time means they are accelerating towards the mass and so it looks like there's a force.

A question for PS is why this doesn't work for other forces.