Why is Pluto no longer a planet? Discover the real reason behind Pluto’s reclassification as a dwarf planet and the science that led to this change.

The team’s reanalysis finally pinpointed Eris on Jan. 5, 2005. At that time ... others were formally recategorized not as planets but as “dwarf planets” — objects orbiting the Sun that ...

Saturn, Venus, Neptune, Uranus, Jupiter, Mars and Mercury will be visible in an uncommon planetary alignment this month.

“New Horizons shattered a major paradigm of planetary science,” says Alan Stern, the mission’s principal investigator. “Pluto ...

Explore the planets with NASA There are five officially recognized dwarf planets in our solar system: Ceres, Pluto, Haumea, Makemake, and Eris ... Nov. 5: 8:19 a.m., Beaver Moon Thursday, Dec. ...

Trans-Neptunian objects (TNOs) are icy bodies that vary widely in size, from large dwarf planets like Pluto and Eris—each ...

Brown’s team discovered a dwarf planet, Eris, in January 2005 ... interacting with nitrogen and methane in the atmosphere. 5 - Pluto has an ionized tail like a comet — probably from nitrogen ...

Over the course of the past 4.5 billion years, that water has been ... For all of this promise, Pluto struggles for respect, with the “dwarf planet” label continuing to rankle Pluto partisans.

It takes Pluto slightly over 248 Earth years to orbit the sun, which means that on March 23, 2178, one Plutonian year will have elapsed since the dwarf planet ... of the past 4.5 billion years ...