The Absurdity of Detecting Gravitational Waves

You don't need something to "wave" to have a wave. EM is composed of photons, but the "waves" are electric and magnetic fields. There are no particles "waving" like water and air waves.

We predict that once LIGO reaches its most sensitive state we could detect about 40 per year, but that's just from merging neutron stars. There will be even more if we detect other sources like supernovae or more merging black holes (which is precisely what LIGO detected for the very first time on September 14, 2015). You might now ask, "how is this possible if such events are so rare in our galaxy?" If LIGO couldn't hear anything outside of our own galaxy (say beyond 80,000 light years), we would probably have to wait a very long time to detect a gravitational wave. But LIGO’s advanced detectors can hear thousands of times father away than this, listening for gravitational wave vibrations from galaxies hundreds of millions of light years away.

Gravitational waves probably won't be useful in helping us understand processes on the Earth, but they will help us understand processes that occur in outer space, such as the collisions of pairs of black holes. We've already learned a lot from our very first detection, such as (a) binary black holes actually exist, and (b) black holes with masses about 30 times that of the sun also exist Neither of these facts were known before LIGO's historic detection! The knowledge that astronomers gain from measuring gravitational waves could also improve our understanding of space, time, matter, energy, and the interactions between all of these things. In so doing, this field of study could revolutionize humanity’s knowledge and understanding of the nature of existence itself.

Also, LIGO's impact on science in general will reach far beyond just the fields of astronomy and astrophysics. To learn even more, visit Why Detect Them? in Learn More.

What kinds of information can gravitational waves provide?

Gravitational waves will provide a test of Einstein's theory of general relativity under extreme conditions of gravity where it has never before been tested. They will also give us more information about the unimaginably dense form of matter that makes up neutron stars. Neutron stars contain more matter than our sun packed into a sphere the size of a city--about 10 km (6 mi.) across. These objects are so dense that a person weighing 150 lb (68 kg) on Earth would weigh 21,000,000,000,000 pounds (9,545,000,000,000 kg) on a neutron star! Packed so closely and densely together, the matter that makes up a neutron star is called "degenerate matter", which is not well understood.

LIGO will help improve our understanding of degenerate matter. Gravitational waves will also tell us about how many objects like black holes and neutron stars exist in the Universe. They will give us insight into what happens during some of the Universe's most violent explosions such as supernovae and gamma ray bursts.

Someday, gravitational waves might even allow us to listen to what was happening in the earliest moments of the Universe, when it was so dense and hot that no light could move around. Any photons emitted during that time were long ago absorbed by a plasma of hot ions, but gravitational waves from that era could travel directly to us on Earth with little interference from the matter in the Universe. For a longer list of ways in which LIGO data will contribute to science, read the answer to the above question, "How does LIGO use the data that it collects?"

What discoveries does LIGO hope to make?

LIGO's historic 2015 detection of two colliding black holes will open up a new field of astrophysics. Whether gravitational waves are detected from colliding black holes, supernovae, remnant radiation from the Big Bang, or even just the tiniest imperfections on rapidly spinning ultra-dense neutron stars, the amount of potentially new fundamental knowledge of the extreme Universe (extreme because we’re studying extreme forces of gravity, extreme explosions, and extreme collisions) that we stand to gain is astounding. Even better, as with any science, the best rewards come from discovering things we never knew before nor could even have imagined. As with every other time we've looked up at the sky in a different way, be it through infrared, x-ray, or gamma-ray goggles, we will almost certainly be surprised and intrigued by what we didn’t expect to find once gravitational wave astronomy becomes its own genuine field of inquiry.

We've already learned a lot from our very first detection, such as (a) binary black holes actually exist, and (b) black holes with masses about 30 times that of the sun also exist Neither of these facts were known before LIGO's historic detection! The knowledge that astronomers gain from measuring gravitational waves could also improve our understanding of space, time...

originally posted by: intrptr
a reply to: Bedlam

You don't need something to "wave" to have a wave. EM is composed of photons, but the "waves" are electric and magnetic fields. There are no particles "waving" like water and air waves.

Tilt.

So far, everything that makes waves is comprised of particles. In the case of light-- photons, water and sound-- molecules, sand dunes-- grains, clouds-- water drops.

Every spectrum detectable from both ends inclusive is detected as waves of particles...

originally posted by: intrptr
a reply to: intrptr

I'm still trying to get around how such a far away source is 'louder' than our own close up sun?

I think this is another reason why it is so important. It isn't particles. Its a wave in space-time itself! If you think about it they are only detecting it because of the effect it has on other things.

Because remember that collision put out 50X the amount of energy then everything else in the observable universe COMBINED! The sun doesn't even come close to that.

originally posted by: intrptr
a reply to: FauxMulder

I think this is another reason why it is so important. It isn't particles. Its a wave in space-time itself! If you think about it they are only detecting it because of the effect it has on other things.

The old wave vs particle argument...

too bad. The world around us is comprised of energy striking us as waves... of particles.

In case of conundrum go outside on a windy day, (wind is invisible) or go surfing. Or stand in front of a MW laser, an X-ray machine, the core of a reactor...

The electromagnetic force, for example, is transmitted by photons, and light is nothing but a large number of photons. Photons/light show wave and particle properties."

originally posted by: intrptr
a reply to: intrptr

I'm still trying to get around how such a far away source is 'louder' than our own close up sun?

I believe the answer to this is that the gravitational waves the sun puts out are way too small for us to detect.

The sun doesn't emit gravity waves very much.