The bright heart of Pluto has been burned into our consciousness, thanks to scads of high-resolution pictures. But a new set of images from NASA’s New Horizons mission provides an all-around view of the dwarf planet, including the splotchy shapes that went out of view days before the time of closest approach on July 14.
Another 10-picture set shows Pluto’s biggest moon, Charon, from all sides.
The imagery was captured over the course of a full Plutonian day, which is 6.4 Earth days long. New Horizons’ Long Range Reconnaissance Imager and the Ralph / Multispectral Visible Imaging Camera were trained on the icy worlds as the distance to Pluto decreased from 5 million miles on July 7 to 400,000 miles on July 13.
Astronomers say they’ve identified the most distant celestial object in our solar system – a speck of light more than three times farther out than Pluto, called V774104.
The object is smaller than Pluto or Eris, which rank as the largest known worlds beyond Neptune with diameters of a little less than 1,500 miles (2,400 kilometers). V774104’s brightness suggests that it’s just 300 to 600 miles (500 to 1,000 kilometers) wide. But based on a limited number of observations by the Subaru Telescope in Hawaii, astronomers estimate its distance at more than 9.5 billion miles, or 103 times the distance between the sun and Earth.
The sun-Earth distance, known as an astronomical unit or AU, provides the best measuring stick for distant objects in the solar system. Pluto is currently 33 AU from the sun, and Eris’ distance is 96 AU. V774104 is farther out, in a twilight zone that’s between the belt of icy material called the Kuiper Belt and a halo of comets called the Oort Cloud.
Scientists with NASA’s New Horizons mission say that at least a couple of the miles-high mountains on Pluto look as if they’re ice-belching volcanoes, providing further evidence that the dwarf planet is geologically active.
Although the case for cryovolcanoes isn’t yet rock-solid, it’s the “least weird explanation” for the observations of 2-mile-high Wright Mons and 3-5-mile-high Piccard Mons, said Oliver White of NASA’s Ames Research Center, a member of the mission’s geology team.
If the mountains’ status is confirmed, “that would be one of the most phenomenal discoveries of New Horizons,” White told reporters. “Whatever they are, they’re definitely weird.”
Pluto’s potential status as a volcanic world was just one of the revelations that came to light on Monday during a review of New Horizons’ latest discoveries at the annual meeting of the American Astronomical Society’s Division for Planetary Sciences in National Harbor, Md.
“The New Horizons mission has taken what we thought we knew about Pluto and turned it upside down,” Jim Green, director of planetary science at NASA Headquarters, said in a news release about the findings.
The first peer-reviewed scientific paper about the New Horizons probe’s July flyby past Pluto lays out puzzling evidence that suggests the dwarf planet isn’t frozen in time. Rather, its smooth plains, high mountains and nitrogen glaciers are leading the NASA mission’s researchers to suspect that it’s geologically active even now.
“Pluto’s still got an engine, and it’s still running,” principal investigator Alan Stern of Southwest Research Institute told journalists in advance of the paper’s publication today by the journal Science.
The Dawn mission’s principal investigator says those shiny sides may be connected to Ceres’ other big mystery: the bright spots that shine out from the mini-world’s dark surface.
“The bright material on the mountain and in the bright spots are probably the same material,” UCLA’s Christopher Russell told GeekWire in an email. “How the material got on the sides of the mountain and also in the bottom of the craters is unknown.”