3 ms·

It blows my mind that accelerating a mass gives off gravitational waves. But it makes total sense since mass increases with speed, if only the tiniest bit until

It blows my mind that accelerating a mass gives off gravitational waves. But it makes total sense since mass increases with speed, if only the tiniest bit until you get close to the speed of light. Which is probably why you can't detect the waves unless you have some massive event (pun intended) like 2 black holes colliding. Do those waves come at a cost of energy? Just what the heck is a gravitational wave?

dumbfounder 9y ago
And can those waves be refracted, reflected, and/or focused?
- comicjk 9y ago
  Sure - you manipulate gravity waves using large masses (the only thing we know of which interacts with gravity). It's not very practical to move stars around in order to make a lens, though.
- BenjiWiebe 9y ago
  Let's make a gravitational wave telescope.
mikeash 9y ago
The waves do come at a cost of energy. That's why these black holes collide in the first place: they're orbiting each other, but the orbits decay because they radiate away kinetic energy as gravitational waves. Eventually it decays enough that they collide. The same thing happens for all orbits, but the amount of energy radiated away is so small that it basically doesn't matter. Black holes are so massive and so small that they can get close enough for it to become significant. The amount of energy involved is colossal. The first detected collision was estimated to have converted the equivalent of three solar masses to energy, which is about 2 x 10^47 joules of energy. Released over 20 milliseconds, it briefly output more power than all the stars in the universe combined by a factor of 50.
empath75 9y ago
> Just what the heck is a gravitational wave? A ripple in space time as two massive bodies orbit each other. Mass bends space time, if the mass moves, it's going to change how it bends space time, if it moves in a regular pattern (an orbit), that creates a wave.

dumbfounder 9y ago

And can those waves be refracted, reflected, and/or focused?

comicjk 9y ago
Sure - you manipulate gravity waves using large masses (the only thing we know of which interacts with gravity). It's not very practical to move stars around in order to make a lens, though.
BenjiWiebe 9y ago
Let's make a gravitational wave telescope.

mikeash 9y ago

The waves do come at a cost of energy. That's why these black holes collide in the first place: they're orbiting each other, but the orbits decay because they radiate away kinetic energy as gravitational waves. Eventually it decays enough that they collide. The same thing happens for all orbits, but the amount of energy radiated away is so small that it basically doesn't matter. Black holes are so massive and so small that they can get close enough for it to become significant. The amount of energy involved is colossal. The first detected collision was estimated to have converted the equivalent of three solar masses to energy, which is about 2 x 10^47 joules of energy. Released over 20 milliseconds, it briefly output more power than all the stars in the universe combined by a factor of 50.

empath75 9y ago

> Just what the heck is a gravitational wave? A ripple in space time as two massive bodies orbit each other. Mass bends space time, if the mass moves, it's going to change how it bends space time, if it moves in a regular pattern (an orbit), that creates a wave.