Images from New Horizons, currently within 15 million miles of its target, show Pluto is an orangey beige color and Charon is gray.
“The scientists are mulling over that one,” Lisa Hardaway, a manager with New Horizons camera-builder Ball Aerospace, told Discovery News. “They were expecting the two objects to be of the same material, but they’re obviously not.”
Even before the difference in color was known some scientists theorized that Charon coalesced from debris jettisoned into space after an object smashed into Pluto. A similar event is believed to be responsible for forming Earth’s moon.
Charon, which was discovered in 1978, is nearly half the size of Pluto and it has enough mass to be a co-orbiting partner, the only known binary pair in the solar system.
Like Earth’s moon, one side of Charon permanently faces its parent body, a configuration known as tidal locking. But Charon never rises or sets in Pluto’s skies, appearing pinned over the same patch of real estate.
Like the gas giant Uranus, Pluto and Charon rotate the sun tipped on their sides, possible evidence of a massive impact.
Among the mysteries New Horizons should be able to solve is whether any of Pluto’s atmosphere is winding up at Charon.
Computer models dating back to the late 1980s show that particles escaping from Pluto’s atmosphere have to pass Charon’s orbit, said New Horizons lead researcher Alan Stern, with the Southwest Research Institute in Boulder, Colo.
“Charon’s gravity can pull some of that atmospheric gas into orbit around itself or even onto the surface of Charon and create a secondary atmosphere,” Stern said. “We’re on the lookout for that.
“This would be fantastic if we discovered something like this,” he added. “Never in the history of planetary exploration have we seen two bodies with a shared atmosphere like we may see at the Pluto system. It could be quite a wonderland.”
Images released on Monday show a distinct, and unexplained, dark region on Charon’s north pole.
Read more at Discovery News
No comments:
Post a Comment