So this is very exciting! Today Scientists at LIGO have came forward and claim to have evidence of Gravitational Waves.
This is awesome news, it is the missing piece is Einstein's Theory of Relativity and proves what we have been able to agree on but has been very difficult to test.
Ok so what is a gravitational wave? not everyone wants to read the general theory of relativity.
In short its a ripple in space time/fabric of the universe. It warps Gravity around an object. The larger the mass of the object the larger the Gravity. The larger the gravity the larger the ripple in space time as it moves throughout space.
The Verge have a good you tube video on this.
So because we need really massive objects in space to detect the waves, though even waving your hand will make Gravitational waves is so small it is with today's technology currently undetectable, we need to look at things like Pulsars and Black Holes.
The Video explains it better than I can.
So this opens up a whole new area of Astrophysics and would mean in time we can observe black holes!