You know a scientific discovery is big when it makes the regular news, and the apparent discovery of primordial gravitational waves has done that.
These results are believed to show what happened in the early universe, right after the Big Bang. If they survive peer review then they’ll be the final confirmation of Einstein’s general theory of relativity, and the first direct evidence of universal inflation. These are big deals because they further strengthen some already very strong theories.
For an interesting illustration of what led to the BICEP2 project and how it was carried out, read this story on Scienceblogs’ Dynamics of Cats.
Being a very clever ant, you realise that you can figure out something about the lake [in which you’re floating]!
For example, you realise that while it is a very deep lake, it is not infinitely deep.
In fact you can, eg by measuring some of the swirls, and where the waves break, figure there are shallows in some parts of the lake.