NASA noted that the spots are evenly spaced and most appear to have a rough diameter of 480 kilometers (300 miles). But nobody knows what the are.
Alan Stern, New Horizons principal investigator, said in a statement that the spots are puzzling and so is the long-standing and dramatic difference in colors and appearance of Pluto in comparison to its grayer moon Charon.
Pluto and its largest moon Charon are being seen like never before as the New Horizons spacecraft closes in on the system. The image is the latest from the New Horizons spacecraft, which is en route to a Pluto fly-by on 14 July, and is a composite of pictures taken by two of the spacecraft’s instruments.
The new pictures, which combined black-and-white images of Pluto and Charon, shows Pluto has two remarkably different faces. That may have been an artifact of the processing technique called oversampling that New Horizons imaging experts are using to improve the resolution of the instrument. This was not surprising, since the presence of the odorless, colorless gas on Pluto was first detected by Earth-based astronomers back in 1976. The brief acceleration pushed New Horizons’ velocity by just 27 centimetres per second, about a half mile per hour, to slightly adjust the arrival time and close approach target point on Pluto.
Professor Stern gladly shared that, “We’ll eventually get to a resolution of 80m per pixel with LORRI”, which was the camera used to see Pluto and Charon growing bigger and bigger as the probe gets nearer Pluto.
Methane was first detected on Pluto back in the 1970s by New Horizons team member Dale Cruikshank, who now works out of NASA’s Ames Research Center in Mountain View, California.
Scientists have also found very bright spots in places on the icy dwarf planet, and that juxtaposition of dark and light on the same cosmic object is somewhat odd in the solar system, Buie added.
It’s not bad, considering it was taken as the probe closed in from 56 million to 22 million kilometres away.
New Horizons will come within 7,800 miles of Pluto’s surface at its closest approach.
“Pluto’s atmosphere is alive and well, and has not frozen out on the surface”, noted New Horizons deputy project scientist Leslie Young.
The New Horizons spacecraft has been sending home a steady stream of photos as it has closed in on Pluto.
Those streaks are really too small to say much about them just yet.