A big black hole 800 million light years away from us ate… something. We’re not sure what.

It might have been a much smaller black hole. It might’ve been a whopping big neutron star. Either way, it literally made the Universe itself shake. https://www.syfy.com/syfywire/a-big-black-hole-just-ate-a-much-smaller-black-hole-or-a-neutron-star-maybe

1.5/ [Just after I tweeted that, I see this illustration RTed by @LIGO:

https://twitter.com/Gmv2_c4r/status/1275791943708991490

]

2/ The big black hole had a mass of 23 times the Sun so yeah, black hole for sure. The other object was 2.5x the Sun, which is… weird. A little over the upper limit for a neutron star but pretty lightweight for a black hole. So either way this is a nice astrophysical find.

3/ The event was detected by @LIGO and @EGO-Virgo when they felt the gravitational waves pass through the Earth. These are quite literally ripples due to shaking the fabric of spacetime. How big were the ripples? About 0.001 times the diameter of a proton.

!!!!!

4/ This is the largest disparity of mass between the two merging objects seen so far. That’s good! These emit gravity waves differently than more equal mass mergers, and help scientists measure various things more easily, like distance. I explain how in my article.

5/ This diagram shows how big a deal this is. Most mergers are from back holes of nearly equal mass to make a bigger BH. This one (the glory trail) is WAY unequal and makes a slightly bigger BH.

6/ Massive stars form BHs, and usually if the two stars are born together the physics works out such that they have nearly equal masses. That’s not the case here so something weird happened to get two BHs like this together.

7/ Maybe they formed near a MUCH bigger black hole with gas around it, changing the physics. Maybe they started as a triple system and a complicated dance wound up with a small BH orbiting a bigger one. No one really knows (again, deets in the article).