"Inflation" is a concept some physicists thought up in the 1980s to deal with the trickier parts of the Big Bang theory. One of those physicists was Andrei Linde — and he's about to get some really surprising news!
This concept of "inflation" explains why deep space looks the same in all directions. We'd know that theory was on track if scientists could find, essentially, the "oldest light" in the universe, made just fractions of a second after the Big Bang.
That's about all I could explain without making my brain explode, but if you'd like to learn more about what this is and what it means, check out some extra reading over at the BBC.