This is a common question that appears together with new scientific discovery: can gravitational waves is? Is it possible for them to swim? In General, can I do anything useful? For example, to build anti-gravity machine. Or warp drive. All these ideas are wonderful, but they are missing the point. We study the gravitational waves not to do something. We study gravitational waves, because they want to understand gravitational waves.
Very well this was said by Richard Feynman:
"Physics is like sex: sure, it may give some practical results, but we do it isn't it." Obviously, it is difficult to predict the emergence of new technologies, which could take from this opening. Take, for example, laser. When it was created in 1960, many thought that he will not have practical application. Of course, they were wrong. Lasers are everywhere today.
Detection by LIGO does not prove the existence of gravitational waves
But let's start with the fact "evidence." Science never proves the truth of something — she just can't do it. Science builds models. If these models correspond to the real data, fine — but it does not confirm the validity of the model. On the contrary, if you find data that is inconsistent with your model, this may indicate the fallacy of the model. So the word "proof" can not be used.
Further. LIGO has failed to prove the existence of gravitational waves. But this project first gathered evidence in support of gravitational wave model. Is it better? No. The problem is. Back in the past. In 1993, Russell Hulse and Joseph Taylor Jr. was awarded the Nobel prize in physics for their discovery of the binary pulsar with the changing orbital period. According to the General theory of relativity, these pulsars should emit gravitational waves and reduce the orbital period, as exactly found Hulse and Taylor. You could say they first received a convincing proof of the existence of gravitational waves.
But does LIGO have not found the waves instead of just find an indication of their existence? You could say that, but it all depends on what is considered "direct measurement". No one has seen a gravity wave. LIGO was looking at the movement of the mirror, armed with ideas about gravity waves. Don't get me wrong, discovery is really serious.
LIGO has not detected this signal without Advanced LIGO
Advanced LIGO increased the sensitivity of the detectors. Since the signal strength of gravitational waves weaken with the distance traveled, the more sensitive the detector will "see" the Universe next. A lot more.
Without Advanced LIGO would require a gravitational event (like a collision of neutron stars is much closer to the Ground. If these events are rare, have to wait long. Increasing the viewing distance, LIGO increases the chances of detection of future events.
In LIGO has invested quite a lot
The national science Foundation of the United States is investing in the search for gravitational waves from 1970-ies. Since then, it has invested about $ 1.1 billion. It's plenty of money separated for quite a long time. Of course, all would return early, but not always it turns out. Science can wait, endure, do not see progress for a long time (although there is progress). Whether this project is a billion dollars? Absolutely. However, in 2015 the US military has spent $ 600 billion, so against this background, investments in LIGO seem to be nonsense.
There are plans to send a gravitational wave detector in space
So. The detector in space will be spared from the annoying noise on earth. And vacuum too. Space gravitational Observatory will also be quite big, because you have to arrange the mirrors in different places. The associated technical challenges will be plenty, but we'll try.
It is the goal of the program eLISA. The programme launched two test masses of LISA Pathfinder. This particular mission will test how accurately you can position the two masses is a necessary step towards the construction of space gravitational Observatory.
Low-frequency gravitational waves can be measured with the radio telescope
Pulsars similar to the clock of the universe. Timing (clocking) of the pulsar is measured with radio telescopes (which use radio waves instead of visible light). How they could be used as detectors of gravitational waves? For example, look at the signals of pulsars in different places. When low-frequency gravitational wave passes through the pulsars, their own timing is changing. On the basis of changes of time and location of pulsars, you can create essentially a giant version of LIGO in space (huge). This is called the pulsar arrays temporary arrays, and they are quite real.
Perhaps in the LIGO happy that reported the detection of gravitational waves before it made the radio telescopes.