This is not from a scientific minded member. I was watching Nova the other day and they were talking about gravity. The program indicated that gravity waves travel across the universe if the event is big enough. Like a supernova that causes waves of energy to spread out but also gravity waves, a big disturbance in the univesal gravity field. What I am trying to ask is does mass indicate the force of gravity? Could gravity be considered dark matter? How do these gravity waves spread? (I know, like a ripple in a pond) It just seems there is something more to it. I am a biology major so physics is a domain that I have not really studied. Thanks guys/gals.

look into string theory

Thanks dragon!

http://www.gravitywaves.com/

This is not from a scientific minded member. I was watching Nova the other day and they were talking about gravity. The program indicated that gravity waves travel across the universe if the event is big enough. Like a supernova that causes waves of energy to spread out but also gravity waves, a big disturbance in the univesal gravity field. What I am trying to ask is does mass indicate the force of gravity?

Gravity is caused by the presence of mass.


Could gravity be considered dark matter?

No. Gravity is a force. Dark matter is a substance.


How do these gravity waves spread? (I know, like a ripple in a pond) It just seems there is something more to it.

There's a lot more to it. Gravity waves, in Einstein's theory of general relativity, are self-sustaining and propagating distortions in spacetime. They obey the usual field equations of general relativity.

An analogy would be to light waves, that are self-sustaining and propagating excitations of the electromagnetic field. They obey Maxwell's equations of electromagnetism.

Gravity is caused by the presence of mass.

Then why does a black hole have such a gravitational force when its only a HOLE? :shrug:

What do you mean it's a "hole", a hole in what?

What do you mean it's a "hole", a hole in what?

Well I thought that a black hole was just that something that had no mass to be seen.

Then why does a black hole have such a gravitational force when its only a HOLE? :shrug:

It's a hole in spacetime. The spacetime inside and around a black hole is highly curved, in the same way that the spacetime is curved around any massive object (like a planet or star), only moreso.

For all practical purposes, though, from a reasonable distance away, a black hole is gravitationally indistinguishable from a normal star of the same mass. A planet like Earth could quite happily orbit a black hole in the same way that Earth orbits the Sun, as far as gravity is concerned.

So what makes a black hole so much mass? What does it contain. We know what the sun is made up of but what about a black hole? :shrug:

A black hole is the final stage in the lifetime of a very massive star - bigger than the Sun. The star's nuclear fusion processes shut down, leaving gravity as the only significant force acting on all the mass in the star, so it collapses under its own gravity. If the star starts off massive enough, it may be that nuclear forces are insufficient to prevent the total collapse of the star to something like a geometrical point in space.

So, a black hole ends up containing the entire mass of a star (apart from some layers blown off earlier) in a very small space.

Why "black"? Because the spacetime around a black hole is so curved that anything getting closer than a particular distance from the centre (known as the Schwarzschild radius) is unable to escape back into normal space - and that includes light. Therefore, since no light can propagate out from the centre of the hole it looks black.

An existing black hole can continue to "sweep up" any matter it comes into contact with, thus increasing its mass over time.

Physicists believe that most galaxies have supermassive black holes at their centres. Our Milky way has at least one black hole with a mass several million times the mass of our Sun.

Thank you. :)

Then why does a black hole have such a gravitational force when its only a HOLE? :shrug:

OMG! THANK YOU...:eek:

Anyone wanting to read much more than they ever wanted to know about mainstream gravity theory ( General Relativity ) and who has an extra two hundred US wearing out their money pocket can beg, borrow or buy :eek: the book GRAVITATION by MISNER, THORNE AND WHEELER.