The New Horizons spacecraft is continuing to make monumental discoveries during mankind's first-ever encounter with Pluto. Astronomers are now reporting the detection of a possible tail, following in a thin trail behind the frozen world.

The dwarf planet is releasing around 500 tons of nitrogen-rich gas every hour. This far exceeds the rate at which Mars is also releasing material, trailing away from the red planet at a rate of just one to every 60 minutes. This tail follows Pluto for 1,000 miles behind the icy dwarf planet and away from the sun, a region of cold, dense ionized gas that is being stripped away by the solar wind.

Pluto is also being revealed in stunning detail in new images from the far-flung observatory, which was launched within the opening weeks of 2006. Since that time, the vehicle has traveled more than 3 billion miles. When the spacecraft arrived near Pluto earlier in July, surface features on the distant, tiny world became visible for the first time. Days before closest approach, mission engineers saw, for the first time, a massive heart-shaped feature on Pluto.

Mission planners explored this region, which is informally being called Tombaugh Regio in honor of Clyde Tombaugh, the astronomer who discovered Pluto in 1930. The spacecraft revealed the heart was rich in carbon monoxide, commonly given off in automobile emissions. This is the only region on the dwarf planet known to contain such rich deposits of the material.

"The landscape is just astoundingly amazing. Some regions have no craters at all.... It shows that geological processes are happening up to the present time," said Jeff Moore, New Horizons lead investigator.

Before New Horizons, many astronomers believed Pluto would reveal itself to be a boring, humdrum frozen world with few surprises. However, the mission has been returning multiple unexpected surprises.

"This terrain is not easy to explain. The discovery of vast, craterless, very young plains on Pluto exceeds all pre-flyby expectations," said Moore, head of the Geology, Geophysics and Imaging Team (GGI) for the New Horizons mission at The Ames Research Center.

New Horizons has also recently returned images of one of Pluto's tiniest moons, Nix. Although the photograph released by NASA has extremely low resolution, the image is still twice as detailed as is possible using the Hubble Space Telescope.

As astronomers continue to investigate previously unseen features and landmarks on Pluto and its moons, names will slowly (and officially) be assigned.

.@NASA just gave #Nepal its 1st landmark in the solar system: the Norgay Montes, huge ice mountains in Pluto! pic.twitter.com/2Yh8YTpPcq

— U.S. Embassy Nepal (@USEmbassyNepal) July 18, 2015