T. Riecken / NASA
Fanciful visions of planets orbiting other stars aren't so fanciful anymore.
What's the best way to stay on top of the coming planet boom? You'll find resources galore on the Web, including tart tweets from the planets themselves. We'll start with the solar system, and work our way out:
Solar system: NASA's Solar System Exploration Web page rounds up everything that's going on in our celestial neighborhood, including planetary profiles and previews of missions to come, such as the Juno mission to Jupiter. For images, the space agency's Photojournal is a must-see site. Bill Arnett's Nine Planets Solar System Tour is a great resource, and the nonprofit Planetary Society offers its own roundup of solar system objects. You can explore the solar system online using Web-based planetarium programs such as WorldWide Telescope, Google Sky, Neave Planetarium or Heavens-Above.
The sun: The Solar and Heliospheric Observatory's Web site keeps watch on our nearest star, with updates from the long-running SOHO mission as well as more recent probes such as STEREO. SpaceWeather.com covers sunspots, solar storms and other manifestations of the sun's power. And the sun's Twitter updates don't let you forget about that power: "Does your fancy iPhone and sat TV work when I unleash my wind? The sun always wins."
Mercury: The Messenger Web site serves up the latest and greatest images from NASA's Mercury probe, which has flown by three times. Stay tuned for much, much more when Messenger actually enters orbit around Mercury in 2011. The planet itself can hardly wait, judging from its Twitter updates: "Why doesn't anyone visit? Only Mariner 10 came by; and that was so long ago I'm getting lonely."
Venus: The European Space Agency's Venus Express probe is in the midst of its extended mission, in orbit around our closer-in planetary neighbor. NASA still maintains a hefty archive from its Magellan mission, even though that one ended more than 15 years ago. Venus' bio on Twitter suggests that the old girl can still turn heads: "Brighter than any other planet, baby!"
Earth: You really don't know our own home planet until you visit NASA's Earth Observatory. The space agency also maintains a "Looking at Earth" Web site to round up the goings-on in Earth science. The European Space Agency does something similar with its "Observing the Earth" portal. And yes, our planet has a Twitter account, too: "I'm feeling a little warm today, wonder what those hairless apes are doing?"
Mars: Sometimes it seems as if Mars is Grand Central Station for interplanetary missions. The Spirit and Opportunity rovers are still in business (and tweeting away), more than five years after their landing, although Mars' tweets have voiced concern about Spirit's predicament. "I really hope Spirit can get moving soon," the planet said. "In the future, please clean up your tracks - you are messing up my drifts!" You'll find tweets as well from the Mars Reconnaissance Orbiter's high-resolution camera and the frozen Phoenix Mars Lander. Europe's Mars Express and NASA's Mars Odyssey are still flying above. NASA's Mars Exploration Program Web site rounds up a lot of missions, including the Curiosity rover's future sojourn.
Ceres and other asteroids: NASA's Dawn mission is heading for Ceres, the smallest known dwarf planet, in 2015. The spacecraft has already entered the asteroid belt and is on track to fly by the asteroid Vesta in 2011. The Jet Propulsion Laboratory offers an Asteroid Watch Web site plus a Twitter account. A different NASA Web site concentrates on cosmic hazards, while the Minor Planet Center catalogs asteroids and comets. (See if your favorite name is on the list.) If you want to live in nearly perpetual fear of asteroids, check the tweets from Low Flying Rocks.
Jupiter: It's been six years since NASA's Galileo probe plunged into the Jovian atmosphere, but this Web site keeps the mission's legacy alive. Juno (named after Jupiter's mythological wife) is the next mission to target the giant planet. Other spacecraft, such as Cassini and New Horizons, occasionally pass by to steal a gravitational boost. This year the Hubble Space Telescope caught sight of a fresh black mark on the planet, likely left behind by a comet collision. "You are right, my hairless ape friends - that is a huge scar," Jupiter tweeted. "What I wouldn't give for a large mirror!"
Saturn: The ringed planet and its moons have been the stars of the show lately, thanks to all the attention from the Cassini orbiter. Just this week, the mission's imaging team came through with some fresh views of the planet's six-sided storm and the two-toned moon Iapetus. All these pictures are making Saturn self-conscious on Twitter: "Did my rings look fat?"
Uranus and Neptune: The last space probe to visit the solar system's ice giants was the Voyager 2 spacecraft, back in the late 1980s. Voyager's flyby yielded great pictures of Uranus and Neptune as well as their moons. Since then, it's pretty much been up to the Hubble Space Telescope and ground-based telescopes to watch all those worlds. Uranus' Twitter tweets have been getting a bit surly ("So you think my name is funny? You suck") while Neptune dwelled on its Great Dark Spot ("How embarrassing was that!?").
Pluto and other ice worlds: In my book, "The Case for Pluto," I observed that Pluto was one funny planet - and its tweets don't disappoint: "Even though I am at the far reaches of your solar system, that doesn't mean you Hairless Apes can try to reset my password. #FAIL." But seriously, folks: The New Horizons Web site provides plenty of information on the dwarf planet as well as the spacecraft's progress toward a 2015 rendezvous. Caltech astronomer Mike Brown offers a Web site about dwarf planets, and Uruguayan astronomers have set up a Dwarf Planet and Plutoid Headquarters. UCLA's David Jewitt maintains a Kuiper Belt Web site. To get the perspective of a hard-core Plutophile, check out Laurel Kornfeld's Pluto Blog.
Exoplanets: The discoveries of planets beyond our solar system are mounting up so quickly (400-plus and counting) that you need a database to keep track of them. The Extrasolar Planets Encyclopedia ranks among the most authoritative Web sites, and the Planetary Society's Catalog of Exoplanets looks like the most fun. (Here's a guide to exoplanets from earlier this year.) For Twitter updates, the Exoplaneteers list, managed by Exoplanetology, is the best place to start. But how will we name all those alien planets? Astronomer Wladimir Lyra has some suggestions, but not everyone's willing to go along. Maybe scientists can sell exoplanet naming rights to raise money for research, as is done with biological species. What do you think?
Correction for 8:23 p.m. ET: David Jewitt has moved from the University of Hawaii to the University of California at Los Angeles, but I didn't catch up with the move until he called the outdated information to my attention. Thanks, Dave!
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