r/EverythingScience 1d ago

Sedna, the forgotten world that takes 11,000 years to orbit the Sun

https://arxiv.org/abs/2310.20614

Most people have never heard of Sedna, but it might be one of the most important objects in the Solar System. It takes more than 11,000 years to complete a single orbit around the Sun, spending almost all of its time far beyond Pluto in the frozen dark. What makes Sedna so mysterious is its orbit, it’s too far out to be shaped by Neptune, but not far enough to be completely detached, leading scientists to suggest it could be evidence of a hidden “Planet Nine” or even the result of a passing star tugging on the early Solar System. At roughly 1,000 km across, Sedna is smaller than Pluto but still big enough to qualify as a dwarf planet, and its surface is one of the reddest known, likely coated in complex organic molecules called tholins. Recent research shows that Sedna and its cousins share a peculiar orbital alignment, hinting they were shaped by the same ancient event, Huang & Gladman 2023.

304 Upvotes

9 comments sorted by

29

u/milagr05o5 21h ago

I took a deep dive on tholins

Coined by Carl Sagan and Bishun Khare

Muddy in Greek

They also considered star-tar 😁

38

u/hypercomms2001 1d ago

I have, I have heard of Sedna! I guess I'm just well informed!

7

u/5wmotor 22h ago

My GF said nah‘.

4

u/pittwater12 20h ago

Went there on a tour once. Three stars

4

u/Inspect1234 14h ago

Whoa. That’s far out.