One astronomical method used
that provided an insight about the universe is the LIGO (the Laser
Interferometer Gravitational Wave Observatory). This method helps us detect
gravitational waves emitted by astronomical bodies. The finding of
gravitational waves will lead into understanding the behavior of other bodies
that we did not know exist. The consequences are; one, we can measure the
activity between two bodies in orbit in the universe, two, scientist can
estimate the merging of two bodies in the universe every 15 minutes by using.
I think a is the best one