science

A story about a black-hole merger

“About 1.1 billion years ago, two black holes coalesced. They had danced around each other for billions of years, losing energy and swinging closer, until they could no longer resist each other's embrace. Spiraling in, they merged, and released a quaking shout of gravitational waves that echoed across the cosmos.”

Phil Plait on syfy.com has a nice story about a black-hole merger.

Sizhao Yang tweets on “thinking” alvin December 13, 2017 - 5:46pm

Sizhao Yang has a nice series of tweets about thinking, starting with the one shown in this image.

Galaxies can (and do) move apart at faster than light speed alvin December 4, 2017 - 2:53pm

Another good tweet from Brian Greene: “Special Relativity tells us that nothing can travel through space faster than the speed of light, but this does not constrain the speed at which space itself expands. Galaxies can — and do — move apart at faster than light speed.”

The universe is 13.8 billion years old and yet ...

The universe is 13.8 billion years old, and yet we can “see” objects that are now more than 45 billion light-years away. Let that twist up your brain as you drop off to sleep tonight.

~ From physicist Brian Greene on Twitter

If an alien in a galaxy 65 million light years away ...

“If an alien in a galaxy 65 million light years away is looking at us through a telescope right now, then they are looking at dinosaurs.”