Planetorama!

It’s been a big week for interplanetary vistas: We've already dealt with the flap over the "Mermaid on Mars," of course, but NASA has also put out a new panorama of the Opportunity rover's surroundings to mark this week's fourth anniversary of its landing. We have the first color image from the Messenger mission to Mercury, the first radar image of an asteroid heading for a close encounter with Earth next week, and the first "high-definition" view of Pluto (sorry, it still looks like a dot). The next week should bring even more cool stuff, including the first full-scale science briefing following the Mercury flyby. Here's a quick look at the latest from our solar system:

Mercury

The team behind NASA's Messenger probe has been churning out pictures from the closest-in planet on a daily basis - including Tuesday's offering, which is arguably the best color picture of Mercury released so far. The Mariner 10 spacecraft sent back color views in 1974 and 1975, but Messenger's camera captures a wider spectrum.

The picture above was taken during Messenger's Jan. 14 flyby from a distance of about 17,000 miles (27,000 kilometers). The hues are a bit more colorful than what the human eye can see, because the image has been color-coded to indicate infrared wavelengths as well as far red and violet. Scientists can analyze those color variations to figure out the planet's surface composition - and piece together a better picture of Mercury's formation and evolution.

You can expect to hear much more about Mercury at 1 p.m. ET Wednesday, when NASA is due to present a news briefing about the Messenger flyby.

Venus

The European Space Agency's Venus Express orbiter is still on the job, and the latest burst of scientific findings was published in the journal Nature back in November. This week, Voice of America provided an audio update (read in "special English"), including an explanation of why the planet is so dry.

Near-Earth asteroid

Asteroid 2007 TU24 is due to come within 334,000 miles (538,000 kilometers) of Earth next Tuesday, and astronomers are gearing up to watch the space rock as it passes by. The asteroid should be visible through backyard telescopes with apertures of at least 3 inches. This Web page has a sky chart that can help you find it in the night sky.

When it comes to determining the asteroid's actual shape, pointing a huge radar antenna at the darn thing is the best way to go.

That's exactly what scientists at NASA's Jet Propulsion Laboratory did, using the 230-foot (70-meter) Goldstone antenna in California's Mojave Desert. The radar readings reveal that 2007 TU24 is asymmetrical, with a diameter of about 800 feet (250 meters), JPL said today.

The highly pixellated views remind me of a smaller version of asteroid Itokawa, which was visited by Japan's Hayabusa probe a couple of years ago.

"With these first radar observations finished, we can guarantee that next week's 1.4-lunar-distance approach is the closest until at least the end of the next century," JPL's Steve Ostro, principal investigator for the asteroid-watching project, said in today's image advisory. "It is also the asteroid's closest Earth approach for more than 2,000 years."

Ostro and other astronomers will be watching the asteroid using an even bigger dish, the 1,000-foot-wide (305-meter-wide) Arecibo Observatory in Puerto Rico, just before and after next week's close approach.

Mars

The latest color picture from the twin rover missions to Mars shows Opportunity's surroundings inside an alcove called Duck Bay, in the western portion of Victoria Crater. The panorama, assembled from imagery captured between Oct. 23 and Dec. 11, shows the promontory known as Cape Verde on the left, and Cabo Frio on the right.

The image was released on Thursday, exactly four years after Opportunity landed in Mars' Meridiani Planum region (if you're on Pacific Time, that is). Back then, mission managers would have counted themselves lucky if the rovers lasted for three months and drove four-tenths of a mile (600 meters). To date, Opportunity has driven about 20 times that far - and both rovers are still in good shape.

Jupiter

The latest news about our solar system's biggest planet comes from researchers who studied Jupiter's weather patterns, using imagery from the Hubble Space Telescope. They focused on an outburst of atmospheric jet plumes, and said the jets appeared to be powered by Jupiter's internal heat. Check out the full story.

Saturn

The hits just keep on coming from the Cassini orbiter: Visit the home page for the Cassini imaging team, or NASA's Saturn Web site, for fresh black-and-white views of the planet's rings and moons.

Pluto

We'll skip over Uranus and Neptune and end today's tour with Pluto, the solar system's best-known and most controversial dwarf planet. NASA's New Horizons probe won't pass by Pluto until 2015, but it already has the icy world in its sights. On Thursday, the New Horizons team released the first picture of Pluto taken using the high-resolution mode on the spacecraft's Long-Range Reconnaissance Imager.

The picture was taken on Oct. 6, from a distance of 2.2 billion miles (3.6 billion kilometers), and Pluto still looks like nothing more than a dot. If you're looking for a better view, you'll just have to wait: New Horizons won't be able to see Pluto and its satellite Charon as separate objects until the summer of 2010, and it will be 2014 before the camera will be able to resolve any details on the plan ... er, dwarf planet's surface.