See a blue sunset on Mars


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The “blue-tinged” sky is caused by fine dust in the atmosphere, according to a statement from Mark Lemmon, a Curiosity team member from Texas A&M University in College Station.

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“The colors come from the fact that the very fine dust is the right size so that blue light penetrates the atmosphere slightly more efficiently,” Lemmon said in the statement. “When the blue light scatters off the dust, it stays closer to the direction of the sun than light of other colors does. The rest of the sky is yellow to orange, as yellow and red light scatter all over the sky instead of being absorbed or staying close to the sun.”

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This is the first sunset captured in color by the rover, according to NASA.

Source: USA TODAY

Scientists Discover Why Jupiter’s Great Red Spot Is Red


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We know that Jupiter’s Great Red Spot is red. Its color is right there in the name. However, why is it red? A team of NASA scientists recently found out.

Previous theories about the reddish color of Jupiter’s Great Red Spot suggested that the color comes from chemicals beneath Jupiter’s clouds, with certain chemicals forming lower in Jupiter’s atmosphere and then rising to the top of the spot.

However, after studying new data from NASA’s Cassini spacecraft, along with laboratory experiments, scientists think that the red in the Red Spot comes from sunlight hitting chemicals higher up in Jupiter’s upper atmosphere.

After studying Cassini’s data, researchers used ultraviolet light to mimic sunlight, and blasted it at two gases known to exist on Jupiter: ammonia and acetylene. The result was a red material that matched Cassini’s observations of Jupiter’s Great Red Spot.

“Our models suggest most of the Great Red Spot is actually pretty bland in color, beneath the upper cloud layer of reddish material,” says Kevin Baines, a Cassini team scientist. “Under the reddish ‘sunburn’ the clouds are probably whitish or grayish.”

The Great Red Spot is actually a massive storm on the surface of Jupiter. It’s so big that three Earths could easily fit inside it. Discovered in the 1600s, the storm reaches high into Jupiter’s upper atmosphere.

“The Great Red Spot is extremely tall,” Baines says. “It reaches much higher altitudes than clouds elsewhere on Jupiter.”

This high altitude is why the Great Red Spot’s color is so intense: the storm’s winds bring ammonia ice particles into the upper atmosphere, exposing it to more sunlight. Because the storm is spinning, similar to a hurricane, the ammonia particles can’t escape. This creates a constant red color at the top of the storm.

So why is the Great Red Spot’s color so important? Jupiter only has a few elements, with its body mostly formed of hydrogen and helium. By examining the colors on the planet’s surface, scientists can identify those elements and get a better idea of the planet’s chemical composition.

Jupiter displays a variety of similar shades across its surface: oranges, browns and other shades of red. These colors suggest areas with thinner and higher clouds, which lets us see deeper into Jupiter’s atmosphere.

The Great Red Spot, though, stands out as one of Jupiter’s more mysterious features. Jupiter has no land mass, so a storm of that magnitude should have disappeared quickly in such a turbulent atmosphere. However, the Great Red Spot is still there, although recent measurements show that it’s possibly shrinking.

Source : techtime

Asteroids Offer Stepping-Stones to Mars, Expert Says


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Rather than lassoing asteroids, NASA could use the space rocks to prepare for a visit to Mars.

Nearby asteroids are humanity’s ticket to Mars, says a planetary scientist who’s calling for an ambitious survey to map ones that could serve as stepping-stones to the red planet.

NASA sees Mars as its “ultimate human destination” and is making plans for a flyby past, or even a landing on, the red planet sometime after 2030. In preparation for that trip, the space agency plans to retrieve a truck-size asteroid, or a boulder off a bigger one, for astronauts to explore. That project, known as the Asteroid Redirect Mission and scheduled for around 2025, would provide an interim goal for the large Space Launch System (SLS) rockets that NASA hopes will someday carry humans to Mars.

“There is a better way,” writes MIT planetary scientist Richard Binzel Wednesday in the journal Nature. “Thousands of shipping-container-sized and larger asteroids pass almost as close as the Moon each year.”

Hop, Skip, and Jump

Instead of retrieving an asteroid, Binzel suggests mapping the nearly ten million uncharted space rocks more than 33 feet (10 meters) wide that orbit between Earth and Mars. He estimates that ground-based telescopes have located only about 0.1 percent of them so far.

Once they were all located, the space agency could plot a series of missions that would allow astronauts to visit some of them. The trips would be for progressively longer periods, which would build experience and confidence to take on the years-long voyage to Mars itself.

To pull off the asteroid mapping, Binzel says, the space agency, which now has a $17.8-billion budget, would need to launch a roughly $800-million space telescope dedicated to detecting space rocks.

As an added bonus, he points out, the mapping effort would help us detect any asteroids that might be headed for Earth, like the 66-foot-wide (20-meter-wide) one that slammed into central Russia in 2013.

“We have to leave the cradle of Earth sometime,” Binzel says. “Asteroid missions could be a win-win for exploration-and for safety.”

Moonstruck

Unveiled in 2010, NASA’s goal of asteroid retrieval has faced some criticism, mostly from those who would rather see astronauts head back to the moon.

Last May, Congressman Steven Palazzo, a Republican of Mississippi and chairman of the space subcommittee of the House Committee on Science, Space, and Technology, called the asteroid-retrieval mission a “detour for a Mars mission.”

Supporters of the mission, such as Louis Friedman of the Planetary Society, have countered that learning to retrieve a small asteroid will offer lessons for possible future missions to divert an asteroid headed toward a catastrophic encounter with Earth.

An asteroid-hopping campaign essentially splits the difference, Binzel argues. “Sooner or later we are headed to Mars,” he says. “We have to find positive ways to move us closer.”