1. The speed of gravity is pretty much identical to the speed of light! This year, for the first time ever, scientists were able to photograph a collision between two neutron stars. By conducting simultaneous optical and gravitational wave observations, they were able to accurately measure the speed of gravity for the first time.
2. A brand new human organ has been classified, and it's been hiding in plain sight this whole time. Everyone, meet your mesentery.
3. It is mathematically possible to build an actual time machine - what's holding us back is finding materials that can physically bend the fabric of space-time.
4. There's an entirely new type of diabetes, and most people wouldn't know they have it. The newly classified type 3c diabetes is being misdiagnosed as type 2.
Read more at:
https://www.sciencealert.com/23-science-facts-we-didn-t-know-at-the-start-of-2017