While for most people Pluto is the most distant planet in the Solar System, things get a lot more fuzzy once you pass Neptune and enter the realm of trans-Neptunian objects (TNOs). Pluto is probably ...

A rendering of the farthest object in our solar system, Sedna, is seen. Sedna is a mysterious planet-like body three times farther from Earth than Pluto. What’s three times further out than the planet ...

When the distant planetoid Sedna was discovered on the outer edges of our solar system, it posed a puzzle to scientists. Sedna appeared to be spinning very slowly compared to most solar system objects ...

Planetary scientists continue to debate what Sedna’s presence says about the history of our solar system. Now, S. Alan Stern of the Southwest Research Institute in Boulder, Colorado, says large bodies ...

Sedna, the most distant known object in the solar system, appears to rotate about every 20 days, so slowly that scientists thought it had to have a moon, but a month of searching since its discovery ...

In 2076, the dwarf planet Sedna will make its closest approach to the Sun in 11,400 years, and scientists are now figuring out the best way to visit the outer solar system visitor before its too late.

Sedna was initially observed to possess an unusually slow rotation period of 20 days, leading astronomers to hypothesize the presence of an unseen companion moon responsible for this sluggish rotation ...

In the frozen outskirts of the solar system, a reddish dwarf planet orbits in silence. Known as Sedna, it is so distant that one trip around the Sun takes more than 11,000 years. For much of that time ...

Astronomers studying 35 NASA Hubble Space Telescope (HST) images of the solar system's farthest known object, unofficially named Sedna, are surprised the object does not appear to have a companion ...

Sedna, the Solar System's farthest known object, does not have a moon, puzzled astronomers have revealed. Its slow spin was thought to be due to the gravity of a small, companion body. Researchers ...