Archive for the ‘Pluto’ Category

By Jareen Imam

Last Thursday, NASA released a photo of what they are calling Pluto’s “floating hills.” The images were captured by New Horizons spacecraft during its historic 2015 fly by.

The hill clusters lie in a vast ice plain inside the dwarf planet’s “heart” region. It’s believed that the frozen formations stretch for miles. Experts at NASA theorize that the mysterious floating hills are fragments of water ice that resemble giant glaciers, similar to the icebergs we see on Earth.

Since water ice is lighter than nitrogen ice, the hills are floating above a sea of nitrogen. These huge chucks of water ice move much like the icebergs that float in Earth’s Arctic Ocean, NASA scientists said in a statement.

It’s likely that the floating hills are fragmented water ice that have broken away from the rugged uplands and are gliding towards the Sputnik Planum.

This photo comes after NASA announced in January that the dwarf planet is covered with way more water ice than the American space agency initially expected. The water ice discovery came after NASA stitched together two infrared images taken by New Horizons.

Since it’s initial flyby, the images captured by New Horizons continue to reveal new characteristics about the dwarf planet.

The floating hills are joining Pluto’s already fascinating geographic activity from its towering ice mountains to its potential ice volcanoes.

http://www.cnn.com/2016/02/06/us/pluto-floating-hills-irpt/index.html

pluto

Pluto’s orbit may host a formation of 10 or more tiny undiscovered moons, which would each measure just 1 to 3 kilometres across, astronomers say.

This preliminary finding could make life even more difficult for the team planning NASA’s New Horizons mission, which is slated to take the first-ever up-close look at the Pluto system in July 2015.

After Pluto’s fifth known moon, a small satellite known as P5, was discovered last year, officials said they may need to redraw the spacecraft’s path to avoid such obstacles.

In the new study, astronomers led by Scott Kenyon of the Harvard-Smithsonian Center for Astrophysics used computer simulations that treat smaller particles statistically.

Once objects get above a certain size, roughly 1 km across, then the programme renders them individually – and this is when the satellites pop up.

It’s hard to say how many there are, the researchers said, as it’s difficult to simulate collisions among these tiny satellites. There could be anywhere from one to more than 10 objects lurking beyond Hydra’s orbit.

While the team can simulate these satellites, they said it’s unlikely they could be spotted, if they exist, from Earth.

The brightness of the potential objects dance with the edge of the Hubble Space Telescope’s capabilities, Kenyon said, and they are likely beyond the reach of even the most sensitive ground-based telescopes, such as the Keck Observatory in Hawaii.

New Horizons might be able to spot smaller satellites before it gets there, but Kenyon said he wasn’t sure when the objects would appear big enough for the spacecraft to detect.

The satellites would be “easily visible” during the spacecraft’s closest approach to Pluto in 2015, researchers said.

The study was submitted for publication in The Astronomical Journal.

http://www.phenomenica.com/2013/03/pluto-may-have-10-more-undiscovered-moons.html

 

An as yet undiscovered planet might be orbiting at the dark fringes of the solar system, according to new research.

Too far out to be easily spotted by telescopes, the potential unseen planet appears to be making its presence felt by disturbing the orbits of so-called Kuiper belt objects, said Rodney Gomes, an astronomer at the National Observatory of Brazil in Rio de Janeiro.

Kuiper belt objects are small icy bodies—including some dwarf planets—that lie beyond the orbit of Neptune.

Once considered the ninth planet in our system, the dwarf planet Pluto, for example, is one of the largest Kuiper belt objects, at about 1,400 miles (2,300 kilometers) wide. Dozens of the other objects are hundreds of miles across, and more are being discovered every year.

(See “Three New ‘Plutos’? Possible Dwarf Planets Found.”)

What’s intriguing, Gomes said, is that, according to his new calculations, about a half dozen Kuiper belt objects—including the remote body known as Sedna—are in strange orbits compared to where they should be, based on existing solar system models. (Related: “Pluto Neighbor Gets Downsized.”)

The objects’ unexpected orbits have a few possible explanations, said Gomes, who presented his findings Tuesday at a meeting of the American Astronomical Society in Timberline Lodge, Oregon.

“But I think the easiest one is a planetary-mass solar companion”—a planet that orbits very far out from the sun but that’s massive enough to be having gravitational effects on Kuiper belt objects.

Mystery Planet a Captured Rogue?

For the new work, Gomes analyzed the orbits of 92 Kuiper belt objects, then compared his results to computer models of how the bodies should be distributed, with and without an additional planet.

If there’s no distant world, Gomes concludes, the models don’t produce the highly elongated orbits we see for six of the objects.

How big exactly the planetary body might be isn’t clear, but there are a lot of possibilities, Gomes added.

Based on his calculations, Gomes thinks a Neptune-size world, about four times bigger than Earth, orbiting 140 billion miles (225 billion kilometers) away from the sun—about 1,500 times farther than Earth—would do the trick.

But so would a Mars-size object—roughly half Earth’s size—in a highly elongated orbit that would occasionally bring the body sweeping to within 5 billion miles (8 billion kilometers) of the sun.

Gomes speculates that the mystery object could be a rogue planet that was kicked out of its own star system and later captured by the sun’s gravity. (See “‘Nomad’ Planets More Common Than Thought, May Orbit Black Holes.”)

Or the putative planet could have formed closer to our sun, only to be cast outward by gravitational encounters with other planets.

However, actually finding such a world would be a challenge.

To begin with, the planet might be pretty dim. Also, Gomes’s simulations don’t give astronomers any clue as to where to point their telescopes—”it can be anywhere,” he said.

Other astronomers are intrigued but say they’ll want a lot more proof before they’re willing to agree that the solar system—again—has nine planets. (Also see “Record Nine-Planet Star System Discovered?”)

“Obviously, finding another planet in the solar system is a big deal,” said Rory Barnes, an astronomer at the University of Washington. But, he added, “I don’t think he really has any evidence that suggests it is out there.”

Instead, he added, Gomes “has laid out a way to determine how such a planet could sculpt parts of our solar system. So while, yes, the evidence doesn’t exist yet, I thought the bigger point was that he showed us that there are ways to find that evidence.”

Douglas Hamilton, an astronomer from the University of Maryland, agrees that the new findings are far from definitive.

“What he showed in his probability arguments is that it’s slightly more likely. He doesn’t have a smoking gun yet.”

And Hal Levison, an astronomer at the Southwest Research Institute in Boulder, Colorado, says he isn’t sure what to make of Gomes’s finding.

“It seems surprising to me that a [solar] companion as small as Neptune could have the effect he sees,” Levison said.

But “I know Rodney, and I’m sure he did the calculations right.”

http://news.nationalgeographic.com/news/2012/05/120511-new-planet-solar-system-kuiper-belt-space-science