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 ...

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 ...

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 ...

Object 90377 Sedna—a distant trans-Neptunian object known best for its highly elliptical, 11,390-year long orbit—is currently on its way toward perihelion (its closest approach to the sun) in 2076.

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 ...

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 ...

In 2004, astronomers announced the discovery of a red, frigid planet-like body at the outskirts of our solar system. Michael E. Brown, the Caltech astronomer who spotted the object (and who would ...

The astronomers who discovered Sedna were so certain that a satellite accompanied the object that when they announced its existence, they released an artist’s rendition of the supposed moon. It ...