NPR's Madeleine Brand talks with NPR's Ira Flatow, host of Talk of the Nation Science Friday, about this week's announcement of the discovery of a new "planetoid" astronomers have dubbed Sedna. This ...

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 ...

While new discoveries about Mars continue to make headlines, another “red planet”—known as Sedna (or 90377 Sedna)—is making its way into the inner solar system. At this moment, the crimson-hued dwarf ...

Astronomers announced Monday they had discovered the most distant object ever detected in the solar system -- a fiercely cold object neither planet nor comet, but a mysterious fossil remnant of a time ...

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 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 ...

Scientists say they have found the first example of a new breed in the solar system's menagerie: a planetoid that spends all its time far beyond Pluto, in a chilly region that was once thought to be ...

More than a decade after an oddball world named Sedna was discovered on the solar system's far frontier, a fresh discovery reveals that it's not so odd after all. Sedna and the newly found object, ...

Astronomers have identified an icy, red, planet-like object orbiting the sun 8 billion miles away, a distance that is nearly three times as far as Pluto and stretches the limits of the solar system ...

Astronomers have detected what could be the Solar System's 10th planet. It was first seen by astronomers using California's Palomar Observatory, and has been given the name "Sedna" after the Inuit ...