NASA's Mars Reconnaissance Orbiter and two planet-based explorers are tracking a huge dust storm, offering scientists an opportunity to study the planet's weather like none they've had before.
The regional dust storm was first spotted on Nov. 10 in the planet's southern hemisphere. Even though the storm is considered only "regional," it's big enough that it has lowered air pressure on either side of the planet and increased temperatures on the opposite pole by changing the atmosphere's circulation.
Scientists are waiting to see whether it will develop into a "dust haze" that will engulf the planet.
"For the first time since the Viking missions of the 1970s, we are studying a regional dust storm both from orbit and with a weather station on the surface," Rich Zurek, chief Mars scientist at NASA's Jet Propulsion Laboratory in La Canada Flintridge, said in a written statement.
The storm has come within 900 miles of Mars rover Opportunity, which landed on the planet in 2004 and depends on the sun for energy. On the other side of the planet is Curiosity, the 1-ton, nuclear-powered mobile laboratory that landed this year.
If the dust storm expands, the two rovers, combined with the Reconnaissance Orbiter, should give scientists an unprecedented view.
"One thing we want to learn is why do some Martian dust storms get to this size and stop growing, while others ... keep growing and go global," Zurek said.
Between Nov. 10 and Nov. 16, the region around the dust storm heated up by about 45 degrees Fahrenheit, scientists say. The dust is absorbing sunlight instead of reflecting it.
If the dust engulfs Mars, it could reduce Opportunity's energy supply. Curiosity's power would not be affected. Photos from its cameras could be hazy, however, not unlike its first images after it landed on the planet in the summer.
LOS ANGELES TIMESDWARF PLANET LACKS ATMOSPHERE
Not much is known about Makemake, a dwarf planet that circles the sun beyond Pluto. But scientists got a closer glimpse of it last year, when it passed briefly in front of a star, according to the current issue of the journal Nature.
Researchers had believed that because its surface temperature is heterogeneous, it might have a significant atmosphere. But new measurements indicate that does not.
Researchers also determined that Makemake -- pronounced MAH-keh MAH-keh -- reflects about 77 percent of the sun's light, comparable to the reflection made by dirty snow, and that it is flattened at both poles.
NEW YORK TIMES