Tag Archives: P4

Pluto gets a new moonand still isn’t a planet

All eyes seem to be pointed on Jupiter and Mars these days, with NASA probes being planned for both of them, and it’s easy to forget that there’s a spacecraft currently heading towards the edge of the solar system, aimed straight at Pluto at a speed of 80,000 kilometers per hour.

Even at this speed though, it will still take 4 more years before it gets there, so astronomers have been spying ahead with the Hubble telescope, in the attempt of finding anything that could damage or even destroy the shuttle. What they found was something nobody really expected – a new moon, not noticed by anyone else before.

Nicknamed P4, until it gets a real name, this new moon joins Charon, Nix and Hydra, but there’s a good reason why nobody noticed it so far. With a diameter varying somewhere between 13 and 33 km, it is all but impssible to see from Earth.

“We always knew it was possible there were more moons out there,” says Alan Stern of the Southwest Research Institute in Boulder, Colo., the principal investigator of the New Horizons mission and a co-discoverer of the new moon. “And lo and behold, there it was.”

It’s extremely unlikely that the new found Moon will have any impact on the mission. In the meantime, Pluto still maintains its status as a dwarf planet, much to the dismay of some. Showalter, on the other hand, doesn’t think it matters what you call Pluto.

“I don’t see dwarf planet as a demotion,” he says. “Think of bonsai trees. The fact that they’re so small is what makes them interesting. So if you don’t like the term dwarf planet, just think of Pluto as a bonsai planet.”

Pluto's moon system. (c) NASA, ESA, and A. Feild (STScI

Hubble discoveres new moon around Pluto

Hubble image revealing new moon, P4. (c) NASA, ESA, and A. Feild (STScI)

Hubble image revealing new moon, P4. (c) NASA, ESA, and A. Feild (STScI)

Astronomers have discovered a fourth moon orbiting Pluto via the famous Hubble telescope, NASA announced this Wednesday.

Some of you might be wondering, just exactly how was it possible for astronomers to have missed it so far, considering NASA’s been tracking space rocks even from the edge of the solar system. The truth is, our solar system is vast, and more or less everything revolves around a game of chance. In case of pluto’s newly discovered forth moon, temporarily dubbed P4 until a more mythologically-suited title can be attained, the object is so small that it simply didn’t stood out yet.

Actually, NASA says there’s a chance it appeared as a very faint smudge in 2006 images, but was overlooked because it was obscured by the short exposure time.

Discovered during a Hubble survey that was looking for rings around the dwarf planet, P4 has an estimated diameter between eight to 21 miles and is located between the orbits of Nix and Hydra, Pluto’s second and, respectively, third-largest moons, which were discovered by Hubble in 2005. Charon is the largest, with a diameter of more than 1,000 kilometers.

“I find it remarkable that Hubble’s cameras enabled us to see such a tiny object so clearly from a distance of more than three billion miles,” says Mark Showalter of the SETI Institute, who led the observations.

Pluto's moon system. (c) NASA, ESA, and A. Feild (STScI

Pluto's moon system. (c) NASA, ESA, and A. Feild (STScI

The discovery comes right in the nick of time, as NASA scientists prep for the much anticipated New Horizons mission, scheduled to fly through the Pluto system in 2015.

“This is a fantastic discovery,” said New Horizons’ principal investigator Alan Stern of the Southwest Research Institute in Boulder, Colo. in the statement. “Now that we know there’s another moon in the Pluto system, we can plan close-up observations of it during our flyby.”

NASA scientists believe Pluto’s moons formed after another large object collided with it in the early years of our solar systems. As a result of the clash, material was sprung out and thus Pluto’s four moons, that we know of, were formed. Looking for rings around Pluto that might have been coalesced around the same period with the moon formations, Hubble caught a glimpse of P4 absolutely by chance with its Wide Field Camera 3 on June 28, and confirmed the sightingĀ  in pictures taken on July 3 and July 18.

Pluto has been caught up in a continuing astronomical debate over the definition of a planet since a 2006 International Astronomical Union vote to make it a dwarf planet.