This is Cosmos Quickly, I'm Lee Billings.

Gravitational waves, ripples in the fabric of space time, first predicted by Einstein

more than a century ago, are one of astronomy's hottest topics.

Ever since their first direct detection in 2015, most gravitational waves and astronomers

catalogs have come from pairs of colliding middleweight black holes.

Other sources should exist, however, chief among them, mergers of supermassive black holes

weighing millions to billions of suns.

But these giant collisions make correspondingly huge gravitational waves, so big in fact that

their wavelengths are larger than our entire solar system and measurable in light years.

That enormity makes them enormously hard to detect, crest to trough a single such

wave could take more than a decade to pass through our solar system, despite moving

at the speed of light.

So how can we see them?

The best solution astronomers have stumbled upon is to effectively build a galaxy-sized

detector, looking for the wave's tell-tale tweaks to the spins of dead stars called pulsars

scattered throughout the Milky Way.

Several of these so-called pulsar timing array projects exist, and after more than 15

years of operations, one called nanograph has now found the best evidence yet for the

super-size, super-hard to see gravitational waves they've all been looking for.

Today on the show, we have three members of the nanograph team to talk about this exciting

development.

Hey, everybody.

...