High-Resolution Topographical Map of Moon released

Astronomers at Arizona State University have used NASA’s Lunar Reconnaissance Orbiter (LRO) to build this jaw-dropping map of the Moon. It’s the highest-resolution, near-global topographic image of our lunar neighbour yet.

The map reveals the Moon’s surface shape, and uses different colours to represent the elevations of the craters, miniature mountains and ridges that dot the surface. White parts are highest, down through red, orange, green, blue and violet, which represents the deepest pits.
The entire map in all of its glory, which is dubbed the the Global Lunar DTM 100 m topographic model (GLD100), shows almost the entire moon with a scale close to 100 meters per pixel.
The map was created with the orbiting probe’s Wide Angle Camera (WAC), a tiny photographic device that can fit in the palm of your hand. But despite its petite body, it can capture a high resolution shot of the Moon with a 70km swath. Because the equatorial distance between orbits is about 30km, the WAC can build a new picture of the Moon every month.
That might sound like overkill, but because the Moon’s lighting changes every month the WAC can build a record of how different rocks reflect and shade the light, to build this 3D topographic atlas.
The little camera can’t quite do it all by itself. The poles of the Moon are in almost perpetual darkness, so the WAC can’t complete the map at the highest latitudes. But never fear, because the LRO’s Lunar Orbiter Laser Altimeter (LOLA) excels at scanning the topography of the poles, it can fill in the gaps.
“Our new topographic view of the moon provides the dataset that lunar scientists have waited for since the Apollo era,” said Mark Robinson, Principal Investigator of the Lunar Reconnaissance Orbiter Camera (LROC) from Arizona State University, in a press release.
“We can now determine slopes of all major geologic terrains on the moon at 100 meter scale. Determine how the crust has deformed, better understand impact crater mechanics, investigate the nature of volcanic features, and better plan future robotic and human missions to the moon.”
The WAC was built by Malin Space Science Systems in San Diego. A very similar camera from the same firm, called the the Mars Reconnaissance Orbiter (MRO) Mars Color Imager (MARCI), is currently orbiting Mars.

Source: Wired UK/Image: NASA

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Failed Russian Mars Probe Could Crash to Earth in January

An artist's impression of Phobos-Grunt in Mars orbit.

Russia's failed Mars probe could come crashing down to Earth in January unless scientists can find a way to blast it out of low-Earth orbit, the head of the Roscosmos space agency said Monday.
The unmanned Phobos-Grunt spacecraft blasted off toward the Red Planet last Wednesday where it was hoped to bring back rock and soil samples from the moon Phobos.
But its engines failed to put in the correct course, and the craft only managed to reach an orbit about 125 miles from Earth. Scientists were still trying to regain communication with spacecraft.
"We estimate that the Phobos-Grunt will fly until January, and to make it perform its mission, we still have time until the beginning of December," Roscosmos general director Vladimir Popovkin was quoted as saying by the Ria Novosti news agency.
Popovkin said there was little chance that the probe would hit a populated area when it crashed down.
"There are 7.5 metric tons of fuel in the aluminum tanks on board. We have no doubts that they will explode [and destroy the probe] upon re-entry," Popovkin said. "It is highly unlikely that its parts would reach Earth."

| NewsCore

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Pluto's "Twin" Has Frozen Atmosphere

Dwarf planet Eris could be coated in frost made from collapsed gases, study hints.

Despite being three times farther from the sun than Pluto, the dwarf planet Eris could almost be the demoted planet's twin—just with a truly icy atmosphere.
According to new observations, Eris is not only close to Pluto in size, it's also so highly reflective that it's one of the brightest objects in the solar system.
We can't see Eris with the naked eye due to its great distance. Right now, the tiny world is almost at its farthest point from the sun, roughly 9 billion miles (14.5 billion kilometers). By contrast, Pluto's farthest distance from the sun is just over 4.5 billion miles (7.3 billion kilometers).
Still, combined with other data, the dwarf planet's brightness suggests that Eris once had a Pluto-like atmosphere that's frozen solid, existing as a thin layer of frost on the surface, astronomers say.
Eris has what's called an eccentric orbit—rather than a perfect circle, its path around the sun is shaped more like a squashed egg.
In about 250 years, Eris will make its closest pass by the sun, coming within 3.4 billion miles (5.6 billion kilometers). The added heat will allow its frozen gases to sublimate—turn directly from a solid to a gas—making Eris even more Pluto-like.
Pluto's orbit is also a bit eccentric, though not as much as Eris's, said study leader Bruno Sicardy of the Paris Observatory in France.
"Pluto is now receding from the sun, and the expectation is that in 20 years or so, the atmosphere of Pluto will be cold enough to collapse, and then little by little, Pluto should turn into an Eris."

Tales of the Occultation

Astronomers gathered the new data on Eris by watching an occultation event, when the dwarf planet passed in front of a distant star, as seen by two telescopes in Chile.
By observing how the star's light dimmed as it was blocked by Eris, scientists could calculate the planet's radius as well as better measure its reflectivity.
The data show that Eris has a radius of about 722 miles (1,163 kilometers)—very close to Pluto's most recently estimated minimum radius of 715 miles (1,150 kilometers).
Previous direct imaging of Eris showed that its surface composition includes methane and probably nitrogen. Due to the body's brightness, astronomers think those chemicals exist as ice—leading to the idea of a frozen atmosphere.

Frozen Eris a Lucky Break?

If Eris really does have a seesaw atmosphere, astronomers are lucky to be seeing the dwarf planet in its icy phase: Even Pluto's thin atmosphere is enough to obstruct accurate occultation-based measurements of the dwarf planet's size.

"The starlight is defocussed to near invisibility by the atmosphere before it is cut off by Pluto's solid surface," said astronomer Leslie Young of the Southwest Research Institute in Colorado, who was not involved in the new Eris research.

"This means we can't use occultations alone to measure Pluto's radius," Young said.

NASA's New Horizons spacecraft should settle the matter when it reaches Pluto and sends back closeup images in 2015.

For now, at least, occultation data hint that Eris and Pluto are very similar—but people shouldn't read too much into the notion that the dwarf planets are practically twins, study leader Sicardy said.

"It's just a coincidence."

The paper describing the Eris occultation appears in the October 27 edition of the journal Nature.

National Geographic News

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