Weigh in: What should the new moon be named?
The cosmos loves irony. Five years after Pluto was stripped of its planet status, astronomers have discovered yet another moon in orbit around it, bringing its entourage to four.
The tiny body may have been born in the same collision that gave birth to Pluto鈥檚 other moons.
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The Hubble Space Telescope spotted the new moon, which has been designated P4 for the time being. Astronomers estimate it is between 13 and 34 kilometres across. 鈥淚 find it remarkable that Hubble鈥檚 cameras enabled us to see such a tiny object so clearly from a distance of more than 3 billion miles [5 billion kilometres],鈥� says of the SETI Institute in Mountain View, California, who led the observing team.
Three other moons of Pluto were already known. Charon, discovered in 1978, is by far the largest at about 1000 kilometres across. Nix and Hydra, discovered in Hubble images in 2005, are tiny by comparison: both are estimated to be between 32 and 113 kilometres in diameter.
Smashing time
All four moons are thought to have formed at the same time. 鈥淭he discovery of this moon reinforces the idea that the Pluto system was formed during a massive collision 4.6聽billion years ago,鈥� says discovery team member of Johns Hopkins University鈥檚 Applied Physics Laboratory in Laurel, Maryland.
鈥淎 big impact produced Charon, and the remaining three [moons] formed from the debris scattered further out,鈥� Showalter told 快猫短视频.
Team member Alan Stern of the Southwest Research Institute in Boulder, Colorado, also heads the that will fly by Pluto in 2015.
He is excited by the discovery but says it reinforces the need to keep scanning the Pluto region for more objects that could pose a hazard to New Horizons.
鈥淲e don鈥檛 want our spacecraft running into any debris that鈥檚 still hanging around from the massive collision that spawned the formation of Pluto鈥檚 smaller satellites,鈥� he says.
