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jajopl subscribed to SpaceRip
(6 days ago)
The Mars rover Opportunity was supposed to last three months. It's now g...
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The Mars rover Opportunity was supposed to last three months. It's now going on Nine Years. It's proved so durable that in 2011 it was essentially sent on a whole new mission.
Opportunity reached a multi-year driving destination, Endeavour Crater, in August 2011. At Endeavour's rim, it has gained access to geological deposits from an earlier period of Martian history than anything it examined during its first seven years. It also has begun an investigation of the planet's deep interior that takes advantage of staying in one place for the Martian winter.
Opportunity landed in Eagle Crater on Mars on Jan. 25, 2004, Universal Time and EST (Jan. 24, PST), three weeks after its rover twin, Spirit, landed halfway around the planet. In backyard-size Eagle Crater, Opportunity found evidence of an ancient wet environment. The mission met all its goals within the originally planned span of three months. During most of the next four years, it explored successively larger and deeper craters, adding evidence about wet and dry periods from the same era as the Eagle Crater deposits.
In mid-2008, researchers drove Opportunity out of Victoria Crater, half a mile (800 meters) in diameter, and set course for Endeavour Crater, 14 miles (22 kilometers) in diameter.
"Endeavour is a window further into Mars' past," said Mars Exploration Rover Program Manager John Callas, of NASA's Jet Propulsion Laboratory, Pasadena, Calif.
The trek took three years. In a push to finish it, Opportunity drove farther during its eighth year on Mars -- 4.8 miles (7.7 kilometers) -- than in any prior year, bringing its total driving distance to 21.4 miles (34.4 kilometers).
The "Cape York" segment of Endeavour's rim, where Opportunity has been working since August 2011, has already validated the choice of Endeavour as a long-term goal. "It's like starting a new mission, and we hit pay dirt right out of the gate," Callas said.
The first outcrop that Opportunity examined on Cape York differs from any the rover had seen previously. Its high zinc content suggests effects of water. Weeks later, at the edge of Cape York, a bright mineral vein identified as hydrated calcium sulfate provided what the mission's principal investigator, Steve Squyres of Cornell University, Ithaca, N.Y., calls "the clearest evidence for liquid water on Mars that we have found in our eight years on the planet."
Mars years last nearly twice as long as Earth years. Entering its ninth Earth year on Mars, Opportunity is also heading into its fifth Martian winter. Its solar panels have accumulated so much dust since Martian winds last cleaned them -- more than in previous winters -- the rover needs to stay on a sun-facing slope to have enough energy to keep active through the winter.
The rover team has not had to use this strategy with Opportunity in past winters, though it did so with Spirit, farther from the equator, for the three Martian winters that Spirit survived. By the beginning of the rovers' fourth Martian winter, drive motors in two of Spirit's six wheels had ceased working, long past their design lifespan. The impaired mobility kept the rover from maneuvering to an energy-favorable slope. Spirit stopped communicating in March 2010.
All six of Opportunity's wheels are still useful for driving, but the rover will stay on an outcrop called "Greeley Haven" until mid-2012 to take advantage of the outcrop's favorable slope and targets of scientific interest during the Martian winter. After the winter, or earlier if wind cleans dust off the solar panels, researchers plan to drive Opportunity in search of clay minerals that a Mars orbiter's observations indicate lie on Endeavour's rim.
"The top priority at Greeley Haven is the radio-science campaign to provide information about Mars' interior," said JPL's Diana Blaney, deputy project scientist for the mission. This study uses weeks of tracking radio signals from the stationary rover to measure wobble in the planet's rotation. The amount of wobble is an indicator of whether the core of the planet is molten, similar to the way spinning an egg can be used to determine whether it is raw or hard-boiled.
Other research at Greeley Haven includes long-term data gathering to investigate mineral ingredients of the outcrop with spectrometers on Opportunity's arm, and repeated observations to monitor wind-caused changes at various scales.
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jajopl favorited a video
(6 days ago)
How big can they get? What's the largest so far detected? Where does an ...
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How big can they get? What's the largest so far detected? Where does an 18 billion solar mass black hole hide?
We've never seen them directly...
yet we know they are there...
Lurking within dense star clusters...
Or wandering the dust lanes of the galaxy....
Where they prey on stars...
Or swallow planets whole.
Our Milky Way may harbor millions of these black holes...
the ultra dense remnants of dead stars.
But now, in the universe far beyond our galaxy, there's evidence of something even more ominous...
A breed of black holes that have reached incomprehensible size and destructive power.
It has taken a new era in astronomy to find them...
High-tech instruments in space tuned to sense high-energy forms of light -- x-rays and gamma rays -- that are invisible to our eyes.
New precision telescopes equipped with technologies that allow them to cancel out the blurring effects of the atmosphere...
and see to the far reaches of the universe.
Peering into distant galaxies, astronomers are now finding evidence that space and time can be shattered by eruptions so vast they boggle the mind.
We are just beginning to understand the impact these outbursts have had on the universe around us.
That understanding recently took a leap forward.
A team operating at the Subaru Observatory atop Hawaii's Mauna Kea volcano looked out to one of the deepest reaches of the universe...
And captured a beam of light that had taken nearly 13 billion years to reach us.
It was a messenger from a time not long after the universe was born.
They focused on an object known as a quasar... short for "quasi-stellar radio source."
It offered a stunning surprise...
A tiny region in its center is so bright that astronomers believe it's light is coming from a single object at least a billion times the mass of our sun...
Inside this brilliant beacon, space suddenly turns dark...
as it's literally swallowed by a giant black hole.
As strange as they may seem, even huge black holes like these are thought to be products of the familiar universe of stars and gravity.
They get their start in rare types of large stars... at least ten times the mass of our sun.
These giants burn hot and fast... and die young.
The star is a cosmic pressure-cooker. In its core, the crush of gravity produces such intense heat that atoms are stripped and rearranged.
Lighter elements like hydrogen and helium fuse together to form heavier ones like calcium, oxygen, silicon, and finally iron.
When enough iron accumulates in the core of the star, it begins to collapse under its own weight.
That can send a shock wave racing outward...
Literally blowing the star apart:...
a supernova.
At the moment the star dies, if enough matter falls into its core, it collapses to a point, forming a black hole.
Intense gravitational forces surround that point with a dark sphere... the event horizon... beyond which nothing, not even light, can escape.
That's how an average-size black hole forms.
What about a monster the size of the Subaru quasar?
Recent discoveries about the rapid rise of these giant black holes have led theorists to rethink their view of cosmic history.
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jajopl favorited a video
(1 month ago)
The online, sci-fi FPS game Tribes is back, as fast as ever, and free to...
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The online, sci-fi FPS game Tribes is back, as fast as ever, and free to play.
The original, ultimate eSport returns.
Register for the Beta and PLAY NOW at www.tribesascend.com
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