Gravitational Waves and LIGO

Question

Last month, we as a species did something remarkable. We detected the presence of gravitational waves. While we all are celebrating and excited about the newest discovery of mankind. I could use answers to a few questions to be able to understand gravitational waves better and the importance of LIGO :-

1. What if we didn't have LIGO ready before the wave that was detected passed through the Earth?
2. What if later events were not as powerful as the colliding of two massive black holes that caused the wave that was detected?
3. How did they exactly come to a conclusion that the wave detected were due to the result of collision of two black holes?
4. Will they keep trying to detect more gravitational waves given that now we already know that these waves do exist? Why?
5. I was taught that gravity is a force of attraction between two bodies acting on each other due to their masses and is directed towards their center and that explained most the things to us. But now with gravitational waves into picture. What exactly is going to change in the High School Physics where they teach about "Gravity" and everywhere else?

Answer 1

The answer to your points 1 and 2 will be mere speculations and so I cannot help with that. As for your 3rd question, LIGO had many sample templates based on theoretical predictions of different models of binary massive systems. The spectrum that the detector received was matched with the templates to see which one they corresponded exactly to. Thus they came to the conclusion that the wave detected was due to the result of collision of two black holes.

The answer to your 4th question is that it is generally believed that analysis of gravitational waves is going to reveal newer insights into astronomy and the detection was just the first step in this regard. The topic of gravitational wave astronomy will be an important component of astronomy from now onwards.

The answer to the 5th question is, almost no change will take place in the school curriculum. Further doubts can be settled by observing that the Bohr model of the Hydrogen atom, instead of quantum electrodynamics is taught at the school level, even though everone knows that the former is not a complete/ totally accurate theory.