The New Horizons spacecraft is closing in on Pluto, and every day it sends fascinating new images of the dwarf planet that–as expected–are exceeding our expectations. The most recent photos show two distinct faces and a series of intriguing spots in full color. Earlier worries of lethal space debris have been reneged, much to the New Horizons’ NASA team’s relief.
IMAGE ORIENTATION
The newest images of Pluto and its moon Charon, captured by New Horizons’ Long-Range Reconnaissance Imager (LORRI) and its Ralph Instrument, show the two bodies as they would appear to the naked eye, with half of Pluto imaged over its circular body (on the right). This would mean that what looks like the south pole is actually the equator.
INTRIGUING FEATURES TO NOTE
Around the equator, or what appears as the South Pole, are spots of about 300 miles (480 km) in diameter, with a surface area approximately the size of Missouri. These spots seem to have consistent size and spacing, and they trace a band across the dwarf planet. Their origin is still a mystery to scientists, but some answers may be revealed upon New Horizons’ arrival on July 14th.
“It’s a real puzzle – we don’t know what the spots are, and we can’t wait to find out,” Dr. Alan Stern of Southwest Research Institute (SwRI) announced from Boulder, Colorado. He is also New Horizons’ principal investigator.
CHARON IS MYSTERIOUS, TOO
Another puzzle lies in wait in the form of finding out why and how Pluto differs so much from its dark and gray moon Charon. When two bodies form in space, they are generally composed of the same material, and so are expected to appear as such.
BACK TO PLUTO
Pluto’s color has been confirmed by these images. It is a brown planet, whose color is the result of “radiation chemistry acting on the methane and nitrogen ices there,” said Dr. Stern. But a stranger surprise is yet to come, for both the Lorri and Ralph Instrument are going to search for clouds.
CLOUDS ON PLUTO?
Science team postdoc Kelsi Singer of SwRI said “we’re looking for clouds in our images using a number of techniques…if we find clouds, their presence will allow us to track the speeds and directions of Pluto’s winds.”
Some artist renderings of what Pluto may look like from low orbit can really take one aback–thin, wispy systems of white contrails all but rotating across the brown and yellow landscape. If this surreal possibility turns out to be true, it could indicate that Pluto has a much more complex weather system than we’d originally thought.
NEW HORIZONS ITINERARY UPDATES
NASA gave the all clear for the spacecraft to continue its approach to the Plutonian system yesterday, after several weeks of scanning for dust clouds, rings, hidden moons or other interplanetary hazards posing an imminent threat to the probe. As a last ditch effort, the team even considered the possibility of using the large high gain antenna dish (used to communicate with us, on Earth) as a physical shield against debris. Space dust is lethal because, regardless of size, a particle travelling at 30,800 miles per hour (49,600km/h) would turn anything we’ve built into swiss cheese.
The New Horizons team engaged a 23 second thruster burn to increase the probe’s speed, but overall “we’re breathing a collective sigh of relief knowing that the way appears to be clear,” remarked Jim Green, director of NASA’s planetary science division. The New Horizons team was worried they’d have to adopt a Safe Haven by Other Trajectory (SHBOT), a decision they needed to have made by this week, but it turned out to be an unnecessary precaution.
PRELIMINARY CONCLUSIONS
The New Horizons team partially expected to detect new moons or rings, but the lack of either was a “bit of a scientific surprise,” to Dr. Stern. “As a scientist I’m a bit disappointed that we didn’t spot additional moons to study, but as a New Horizons team member I am much more relieved that we didn’t find something that could harm the spacecraft,” added John Spencer of SwRI, leader of the New Horizons hazard analysis team. The possibility of a faint ring does exist, but it would be extremely sparse and almost invisible to equipment.
The path is open and the stage is set for New Horizons to make history in the age of interplanetary exploration in twelve days’ time.
