Rosetta images reveal crack hundreds of meters long in comet 67P


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Image of Comet 67P taken by ESA’s Rosetta (Click Image to Download)

The European Space Agency (ESA) succeeded in delivering the Philae lander to the surface of comet 67P several months ago, but its Rosetta probe hasn’t been twiddling its robotic thumbs since then. It’s still in orbit of 67P/Churyumov–Gerasimenko to study the comet as it gets closer to the sun. In the newest set of images published by the ESA, scientists reveal 67P is coming apart at the seams. A huge crack was discovered running hundreds of meters along the surface.

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To visualize what’s happening, it’s important to know a little about the shape of 67P/Churyumov–Gerasimenko. Many of us have an idea of comets as being more or less round, but many of them are actually quite oddly shaped. For example, 67P has two lobes, one smaller than the other, connected by a narrow neck. It looks a little like a rubber duck. The crack detected by Rosetta’s Osiris camera is in the neck region, which is also where most of the gas and dust is being expelled.

The crack is about one meter in width, which wouldn’t be so impressive if it wasn’t covering such a large area. The neck region where the crack was found is only 1km wide after all, so a few hundred meters is nothing to sneeze at. In the image above, the crack is visible in two locations on the surface, but the middle section is obscured by layers of dust, which the ESA team has found is plentiful on the surface of 67P, especially in the neck region where the object’s minimal gravity is even less substantial.

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67P won’t reach its closest approach to the sun for several months, but it’s already losing more than 11kg of gas and dust every second. Scientists are unsure if the crack will worsen or close up as the comet continues to lose weight. If the stresses on the neck increase, the comet could fracture and break in two .
Some researchers believe that 67P’s shape is the result of two smaller objects colliding in the distant past, so this crack could be following an existing “fault line” in the structure. It’s also possible this crack is nothing out of the ordinary for porous comets like 67P as they erode. It’s hard to say for sure — this is the first time we’ve gotten such a close-up look at a comet.

Rosetta dropped the Philae lander off on 67P back in November, but it didn’t quite go as planned. The lander’s harpoons failed to fire, which caused it to bounce along the surface, eventually coming to rest in a shadow that prevented the solar panels from creating enough power. After doing most of its science, Philae went to sleep. The ESA has continued to monitor conditions on the comet with Rosetta and hopes that when the comet nears the sun, it will shine more light on Philae, allowing it to come back online.

Philae isn’t close enough to the neck region to offer any insights about the newly discovered crack, but it can certainly tell us more about the composition of 67P. Even if Philae never comes back online, Rosetta will keep an eye on the surface from a few kilometers up. It will be there through 67P’s solar perigee in August, and will follow as it heads back out toward Jupiter.

Source : Geek.com

The Rosetta comet landing has made history


After 10 years of hard work and one nerve-wracking night, the Rosetta mission has made history by landing on the surface of a comet.

The lander Philae was confirmed to touch down on the surface of the comet more than 300 million miles away at 11:03 a.m. Eastern. Now, scientists expect it to send a panoramic image home and begin analyzing the comet for scientists back on Earth.

Philae is already transmitting scientific data back home, but we’re still waiting to see whether the probe is in a stable position. Until we know it’s anchored tight, it could roll onto its back and never get back up.

Tensions were high in the European Space Agency’s German mission control center, especially as the landing window approached. Because the comet that Philae landed on is so far from Earth, there’s a communications delay of 28 minutes. So as the minutes ticked by, the Rosetta team knew that Philae had already either landed or failed — and there was nothing they could do but wait for the data to reach them. Those following the video online were nearly as desperate for news, and Twitter became a sounding chamber of anticipation and excitement.

But a few minutes after 11 a.m., the stern, cautious expressions of the mission control team melted into smiles. And just like that, the world swiveled from anxiety to elation: Philae was on the surface of the comet and ready to do some science.

The comet contains the materials that originally formed our solar system, frozen in time. By digging them out, we can learn more about the origins of our planet. The Rosetta spacecraft has made invaluable observations about the comet’s attributes, and it will continue to do so as it follows it around the sun for the next year. But Philae will be able to look more closely at the comet’s physical and molecular composition.

“It’s a look at the basic building blocks of our solar system, the ancient materials from which life emerged,” said Kathrin Altwegg of the University of Bern in Switzerland, one of the Rosetta project’s lead researchers. “It’s like doing archaeology, but instead of going back 1,000 years, we can go back 4.6 billion.”

It’s no easy thing to land on a comet’s surface: These chunks of rock and ice are constantly spinning, and Comet 67P/Churyumov-Gerasimenko, which was discovered in 1969, orbits the sun at a speed of about 85,000 mph. It’s irregularly shaped — like a toddler’s play-dough impression of a duck, or something — and its surface is uneven and pitted. And in a universe of unimaginable proportion, Rosetta’s target is just 2.5 miles in diameter — smaller than Northwest Washington’s Columbia Heights neighborhood.

So Rosetta has taken an onerous journey to get in sync with the comet’s orbit, which would allow it to drop down a lander. In 2004, the spacecraft began what would be three looping orbits around the sun, altering its trajectory as it skimmed Mars, just 150 miles from the surface, and enduring 24 minutes in the planet’s shadow to align with Churyumov-Gerasimenko. The cumulative distance traveled by the craft – with all its looping and gravity assists – is a stunning 4 billion miles. “When the Rosetta signal reappeared after the passage behind Mars, shortly after the end of the ‘shadow’ period, there was a collective sigh of relief,” ESA said.

At one point in 2011, the spacecraft even had to hibernate for nearly three years. It flew so far from the sun — nearly 500 million miles — that its solar panels couldn’t leech enough energy to keep the spacecraft operational. But in January of this year, Rosetta woke up, and quickly approached its target.

The last leg of this landing has not been without its bumps. Even as the mission approached its most critical moment, controllers at the European Space Agency on Tuesday night reported a problem with the thruster on the lander that could make for a rough landing. The gravity of the problem — and the extent to which it threatened the mission — remained unknown. “We’ll need some luck not to land on a boulder or a steep slope,” blogged Stephan Ulamec, lander manager for the project.

Source : washington post