Author Options:

Gravitational Waves? Answered

While I was watching a show on the Science Channel about Black holes, it mentioned that black holes send out spiraling waves of gravity. If we were hit with said wave, ( on the occasion we survive a black hole) that had traveled from a far distance, would everything become much heaver and everyone would fall over? Would we lose our moon? What would/could happen?



Best Answer 10 years ago

That's a bit of an oversimplification. An isolated black hole does not generate gravitational waves (GW). You need a non-zero quadrupole distribution of matter to do that. The most likely source of observable GW is the merger of two black holes. As they spiral around one another, they'll send out uniform GW in all directions, with increasing frequency and amplitude (a "chirp"). Mergers of any two compact objects (two neutron stars, or a NS and a BH) will do the same thing, but with different amplitudes.

GW don't make things heavier. Rather, they act more like tides, stretching spacetime in one direction and compressing it in the other. Unfortunately, you are not ever going to feel a GW (even though they're passing through you right now!).

The magnitude of the stretch/compress expected from a BH-BH merger in our galaxy is about 10-21 or so. For a ten-kilometer length object (such as the Laser Interferometer Gravitational-wave Observatory, that's a change in length about the diameter of proton.

Lithium RainFizzxwizz

Answer 10 years ago

Yeah...that happens a lot of you hang out with Kelsey at all. :D I got learned hard the first conversation I ever had with him... XD


Answer 10 years ago

Not you, the show you watched :-( Seandogue's comments are unfortunately all too accurate, and some of the better "popular" science magazines are falling prey to the same sensationalism (New Scientist often, and Scientific American occasionally). Given what you saw, you asked some very reasonable questions! Thank you :-)


10 years ago

The simplified answer is no. Picture a black holes' effect like that of a cliff. you just don't feel it until you're right on top of it. Any warping of the fabric of space time will be so small outside the local environment of the black hole that it takes incredibly precise measurement to detect. That is, if we were near enough to feel it ourselves, we'd have alot more important things to worry about. Being a watcher of Sci channel and similar programming myself, I have this to say. FWIW, some or all of these programs have fallen victim to TV sensationalism, so the viewer really needs to have a healthy disrespect for their programs. Much as I'd like to say otherwise, they have begun programming little short of "The sky is falling" scenarios over the last few years. Doomsday is a great way to keep people staring at the tv waiting for a shred of hope from the guests or narrator. (About one third to one half of current programminng is advertisements) A healthy dose of skepticism is in order.