A NEW COSMOS ON THE WEB

This screenshot from the Web-based version of WorldWide Telescope shows Venus'surface, mapped by the Magellan probe and enhanced with other imagery.A year after making its debut as a downloadable software program, Microsoft Research's WorldWide Telescope is going public on the World Wide Web. It's the latest move aimed at widening the "market" for free online exploration of the cosmos.

There's lots of software that gives you the universe on your computer - ranging from the kind of programs you pay good money for (such as Starry Night, Redshift and TheSky), to free programs available over the Internet (Sky on Google Earth, Stellarium and Celestia, as well as the classic WorldWide Telescope, a.k.a. WWT), to Web-based planetariums (Google Sky and Heavens-Above).

Today Microsoft took the wraps off its own Web client, based on the standalone version of WWT, at the annual MIX conference in Las Vegas. (Msnbc.com is a joint venture of Microsoft and NBC Universal.)

Many of the WorldWide Telescope's features have been carried over: You can see thousands of the night sky's coolest sights in multiple wavelengths, thanks to a rich database of imagery from space telescopes as well as ground-based observatories.

For example, you can bring up the Whirlpool Galaxy (M51) in optical wavelengths, load in Spitzer's infrared view, and then use a slider button to morph one view into the other. The dark, dusty swirls in the optical view turn out to be exactly where the infrared emissions are the brightest.

You can also sit back and let someone show you around, thanks to tours that have been prepared by space fans ranging from professional astrophysicists to a 6-year-old kid. And you can load up panoramas created by probes on Mars, Apollo astronauts on the moon, or photographers visiting the Mauna Kea observatories in Hawaii (or the lobby of Microsoft Research's headquarters, for that matter).

The release is meant to make the WorldWide Telescope available to non-Windows computer users as well as Windows users who may be reluctant to install a big piece of software, said Jonathan Fay, one of WWT's co-creators at Microsoft Research. He said 2 million users have downloaded the standalone program, but for every Web site visitor who has done the download, there have been almost 100 visitors who have not.

You still need to have Microsoft's multimedia plug-in, known as Silverlight, but Fay said he hopes users won't find that to be a huge hurdle.

"If they've seen Web advertising, they've probably already installed Silverlight," he said. (The plug-in was used for NBC video streaming during last year's Olympics, and it's also playing a supporting role in this month's "March Madness" tournament.)

Also, there are some features that haven't been carried over - such as the ability to create those cool guided tours, or navigate the universe in 3-D. "If you can use the 3-D mode, that's what you want to install," Fay said.

Fay keeps a MacBook Air laptop sitting on the edge of his desk at Microsoft Research, connected to the Internet through a flaky wireless connection, just to get a sense of how the Web client works for real-world users. The graphics aren't as high-resolution as they are in the classic WWT, and the imagery is slower to load - mostly due to the connection speed - but at least it works.

Fay and the other main man behind the project, Curtis Wong, are focusing on making the high-quality version of WorldWide Telescope good enough for professional researchers to rely on. Astronomers at the Harvard-Smithsonian Center for Astrophysics are already using WWT to help keep track of their image databases, and Fay hints that more announcements are on the way. (I'll provide updates at the end of this item if and when they are announced.)

Amateur astronomers are also taking to the WorldWide Telescope, in part thanks to efforts such as the Astrometry site on Flickr. Photographs of celestial sights can be coded up so that they drop right into the WWT Web view. Fay said the WorldWide Telescope plays well with the Virtual Astronomy Multimedia Project, an effort to standardize how astronomical photos are tagged.

In the past few weeks, it seems as if the competition between Microsoft and Google has been heating up in the celestial sphere: Google Earth has added the ability to create guided tours, a la Microsoft's WWT, and rolled out an eye-pleasing array of Martian imagery. (Google's "Live From Mars" image stream, drawing upon the latest pictures from Mars orbiters, came online shortly after last week's launch.)

Now Microsoft has raised the bar for Web-based space exploration, moving into a realm where Google Sky has had the lead.

Fay said the way WWT uses Silverlight could be adapted to other applications as well, including Web-based gaming environments and experiments in geographic-based crowdsourcing. "This is a game-changer in terms of what people are going to expect from the Web," he said.

And in fact, the folks from Microsoft and the folks from Google are learning from each other. Neither Google Sky nor WorldWide Telescope are being done for the money, since both programs are free. Rather, they're helping to blaze a technological trail for other pursuits - while at the same time providing something useful and fun for scientists as well as the general public.

"The more, the better - and the science is going to benefit in the end," Fay said.

RACE TO FIND ALIEN EARTHS

NASA is gearing up for a space race that's expected to point to the first truly Earthlike worlds beyond our solar system - and, like the race to put the first human on the moon, this marathon will take several years to run.

The roots of the race go back more than a decade, as astrophysicist Alan Boss explains in his new book, "The Crowded Universe: The Search for Living Planets." That's when pioneers in the planet-hunting field started detecting worlds around suns beyond our own.

The techniques used back then couldn't find other Earths in planetary systems like our own. The first method, pioneered by Polish astronomer Alexander Wolszczan at the Arecibo Observatory in 1991, could detect Earth-scale planets (and perhaps even the first known extrasolar dwarf planet) around radio pulsars - but those planets were thought to be burned-out cinders and not Earthlike at all.

In 1995, astronomers began reporting the detection of Jupiter-scale planets around normal stars, by precisely measuring the gravitational wobble those planets induce in the stars themselves. (Our interactive tutorial explains how it's done.) As the years have gone by, planet-hunters have gotten smarter about using that "Doppler wobble" technique, and they've also trained sensitive telescopes on faraway stars to measure the slight dimming in their light as alien planets make their transits over the stars' disks.

This transit method takes center stage in the next phase of the planet-hunting space race: The European Space Agency's Corot satellite, which was launched a little more than two years ago, has a head start. Just this month, members of the Corot science team announced the discovery of a "hot super-Earth" that is less than twice Earth's size.

Next month, NASA picks up the pace with the launch of its Kepler satellite, equipped with a planet-seeking telescope that has some advantages over Corot. Astronomers expect Kepler to turn up some true Earthlike planets, in Earthlike orbits, around sunlike stars.

"If Kepler comes up empty-handed - boy, it'll turn out to be virtual harakiri," Boss, a member of the Kepler science team, told me earlier this month. "But there's little chance of that."

The first fruits of the $550 million Kepler mission won't be the coolest alien Earths, Boss cautioned. "Often the oddballs are the earliest ones to find, for some reason," he said. Boss expects the Kepler team to announce the mission's first discoveries of hot Jupiters and hot super-Earths within a month after science operations begin.

The biggest factor behind that schedule has to do with the time scale of a planet's orbit. It takes at least three orbits for astronomers to confirm that the dimming of the star is really caused by a planet rather than, say, the brightness cycles of a variable star or a binary-star system. If the planet is extremely close to its star - which would be an oddball orbit by solar system standards - that won't take long. For example, the hot super-Earth identified by Corot completes an orbit in just 20 hours.

Farther-out planets will require more time to orbit, and therefore more time to detect.

"The earth, by definition, will take at least three years to get," Boss said. "Roughly four years from now, we will be beginning to make our claims for Earthlike planets around solar-type stars."

Boss' book traces the buildup to the Kepler mission through a series of time-stamped entries, reading almost like a diary. It's often been said that politics can get as messy as sausage-making - and based on Boss' accounts of Kepler's budgetary travails, the same can be said for pre-launch mission planning.

Along the way, Boss also delves into the deep scientific issues of the planet search:
Are new planets built from the core up, like dirty snowballs, or do they whirl into shape like stars are thought to do? (Boss says both processes come into play.)

How do you define stars, brown dwarfs, sub-brown dwarfs, planets and dwarf planets? (Boss was involved in many of those discussions, including the IAU's efforts to define planethood.)

What will it mean if (or when) Kepler finds those alien Earths? (Boss says finding out how many such planets exist among the more than 100,000 star systems that Kepler is expected to survey will reveal "the most basic parameter in any estimate of the prevalence of life in the universe.")

Kepler's primary mission is due to last three and a half years, but Boss hopes that the spacecraft will be up for some extra laps around the racetrack. Which mission will be the first to reveal just how common alien Earths are? Corot or Kepler? Considering that Boss is on Kepler's team, he's not the best person to handicap this race objectively. But in the end, it doesn't really matter who reaches the finish line first.

"Either way," he writes, "after centuries - if not millennia - of speculation and wondering, we will finally know just how crowded the universe really is."