Pluto Has a ‘Tail,’ Say Researchers

Artist's concept of the New Horizons spacecraft during a planned encounter with Pluto and its moon, Charon. John Hopkins University Applied Physics Laboratory/Southwest Research Institute

Researchers have discovered that Pluto, the dwarf planet, has a “tail.”

In mid-July, the New Horizons space probe flew past Pluto and it went directly into its shadow, giving an opportunity to see how the Sun affects its atmosphere.

NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute

According to New Horizons researchers, there’s “a region of cold, dense ionized gas tens of thousands of miles beyond Pluto — the planet’s atmosphere being stripped away by the solar wind and lost to space.”

The probe’s instrument “observed a cavity in the solar wind — the outflow of electrically charged particles from the Sun.”

Similar plasma tails have been observed behind Venus and Mars.

This Monday, July 13, 2015 combination image released by NASA shows Pluto, left, and its moon, Charon, with differences in surface material and features depicted in exaggerated colors made by using different filters on a camera aboard the New Horizons spacecraft. In this composite false-color image, the apparent distance between the two bodies has also been reduced. NASA/APL/SwRI via AP

“This is just a first tantalizing look at Pluto’s plasma environment,” said co-investigator Fran Bagenal with University of Colorado, Boulder, who leads the New Horizons Particles and Plasma team.

“We‘ll be getting more data in August, which we can combine with the Alice and Rex atmospheric measurements to pin down the rate at which Pluto is losing its atmosphere. Once we know that, we’ll be able to answer outstanding questions about the evolution of Pluto’s atmosphere and surface and determine to what extent Pluto’s solar wind interaction is like that of Mars.”

This Tuesday, July 14, 2015 image provided by NASA on Wednesday shows a region near Pluto's equator with a range of mountains captured by the New Horizons spacecraft. NASA/JHUAPL/SwRI via AP