Phoebe and Saturn. Credit: NASA/Cassini

Who's Phoebe? That quirky blonde from Friends? The mysteriously magical nanny from that old sitcom? A bird? A plant? All that–but the one I'm talking about is the moon of Saturn, once thought to be a captured comet, and now believed by some scientists to be something much rarer: a captured planetesimal.

Phoebe: a bit more than 120 miles across—and more potato-shaped than spherical—with a surface gravity approximately 200 times weaker than Earth's (yes, I'd weigh about one pound standing on the surface), Phoebe is not of the stature of its larger, rounder fellow moons of greater fame: Luna, Ganymede, Titan, and the rest.

We've known of Phoebe's existence since 1899, when it was discovered by astronomer W. H. Pickering, and from the start Phoebe was observed to be different from Saturn's "mainline" moons—ones organized into a common orbital plane in close alignment with Saturn's equator, with nice, nearly circular orbits. Phoebe is too much a nonconformist for that; orbiting at a steep, rakish angle from Saturn's equatorial plane, backwards with respect to the conformist crowd, and with great elliptical eccentricity, Phoebe is a fringe radical! And at 30 times the distance from Saturn as our Moon is from Earth, it takes Phoebe longer to orbit Saturn (1.5 years) than Earth does to round the Sun!

All of these peculiarities added up to the hypothesis that Phoebe was not an "indigenous" satellite of Saturn—one that formed with Saturn early in the ages of the solar system—but a solar system object that was captured by Saturn at some point, and since has remained in orbit. And due to its low density (little more than one and a half times as dense as water ice), Phoebe was assumed to be a former comet. Comets passing close to gas giant planets like Saturn are sometimes flung in different directions, sometimes broken up, and sometimes even crash into the planet. But they can also be captured into orbit, as probably many of Jupiter's smaller satellites, and Mars' brood of two, were: former asteroids from the neighboring asteroid belt.

But a comet is a bit of material—ice and rock—left over from the formation of the solar system, about 4.5 billion years ago, pristine and barely altered from its original state. Recently, NASA's Cassini mission has suggested a different origination story for Phoebe, based on imagery and data obtained from our first up-close look at this object by the Cassini spacecraft, in 2004.

Phoebe may be a "planetesimal"—an object that formed in the young solar system, coalescing from dust and ice into a larger and larger body. Evidence suggests that Phoebe was warmed enough during its formation, and perhaps afterward by decay of radioactive materials, to have achieved a spherical shape, a differentiated rocky core and outer shell of lighter material and ices, and possibly even to have harbored liquid water—all very planet-like qualities. As well, it may have remained in this state for quite some time before cooling down and freezing.

Possibly originating in the Kuiper Belt, beyond Neptune's orbit, Phoebe would have migrated inward and eventually been captured when passing too close to Saturn — at the same time avoiding the typical fate of planetesimals, which is to merge with a forming planet. Planetesimals, once the bread and butter of the young solar system, are the building blocks of planets.

Phoebe, then, may be a very remarkable object–a quirky, mysteriously magical moon; a vision of the early solar system that once swarmed with such objects, even before the planets themselves appeared. It's a messenger from the past, possibly carrying within it evidence that could tell us where we came from.

Artist's concept of mini planetary system. Credit: NASA

NASA’s planet-hunting Kepler space telescope has been given more time to look for life-supporting planets outside our own solar system. The project, which has found more than 2,000 planets since it was launched in 2009, recently edged out several popular space programs to secure an extension in funding. Geoff Marcy is one of the world’s most prolific planet hunters. He’s an astronomer at UC Berkeley and works on the Kepler project. KQED’s Andrea Kissack asked him for an update and his thoughts on the odds that the project may help find life somewhere else in the universe.

I met with Marcy in his office in the astronomy building on the south side of UC Berkeley. If anyone is going to find alien life, it will be Marcy. He has spotted more extra solar planets than most astronomers and he now has taken on yet another project as the new chair of the SETI program at UC Berkeley. Marcy sees his work with Kepler, and the ground based radio receivers of SETI, dovetailing nicely. As the Kepler project continues to find earth like planets, the next step, he says, will be to see if there are intelligent civilizations out there. The way to do that, Marcy says, is to use Kepler to narrow down the choices and then use SETI to point radio receivers at those specific planets, rather than just listening to broad swaths of the sky.

More on the search for exoplanets

SDO Solar Flare--the bright spot on the left--on March 7 2012. Credit: NASA/SDO

The first X-Class solar flare of the year went off on March 7th in spectacular fashion. Fortunately the flare went off where it's supposed to: on the Sun. Had this intense magneto-plasmic explosion gone off on Earth, we'd be toast; one of these releases an amount of energy on the order of 100 billion megatons of TNT.

Solar flares are highly energetic bursts of energy ignited by magnetically active regions on the Sun. Magnetic fields, generated by the motion of the Sun's hot, electrically charged gases, cause many of the Sun's more showy features, including the blemish familiar to most, the sunspot.

And yesterday, that's exactly what we saw from Chabot's observatory deck: a sunspot…and we didn't even need a telescope to see it! Let me explain. The active region that produced the powerful X-class flare only hours earlier left its mark on the Sun's bright complexion with a large cluster of sunspots—such an expansive cluster that it could be seen with the "naked eye."

Now, when I say naked eye, in this case I don't mean we were encouraging our visitors (mostly school kids at the time) to stare at the Sun directly. That would be pointless since the Sun is so bright at midday that it blinds us to any features we might see (and could blind us permanently if we look too long, even with sunglasses).

So, we have the kids look at the Sun through pieces of welder's goggle glass #14. It's a very dark filter—so dark that you pretty much can't see anything other than the Sun, or a welding torch, through it. This Sun-looking glass lets us peer safely into that wonderland in the sky, the solar disk, which ordinarily averts our attention by sheer brilliance.

Through the glass the Sun becomes a greenish disk, the same apparent size as the Moon. Most of the time, that's all we see: a glowing green disk in a sky of blackness. But even that is actually pretty awesome, and the sight routinely catches people by surprise.

Yesterday, however, the sunspot cluster marking the active region that produced the X-class flare was easily seen, unmagnified: a little dark spot on the Sun. And our eyes didn't even sting.

Now, a day after the flare, Earth is in the midst of a blast of plasma that was triggered by the flare activity, and a geomagnetic storm is in progress: the impact of an enormous bubble of plasma (electrically charged gas) that was blown in our direction has clobbered Earth's deflector screen, aka its global magnetic field.

Though the effects of a solar blast like this one and the geomagnetic storm it can produce usually go unnoticed by most, the event can cross over into our lives, if severe enough. Interference in telecommunications from atmospheric disturbance and even the rare power blackout caused by a magnetically induced overload of a power grid, have happened.

In space, satellites have been damaged by these storms, and astronauts on the space station generally take cover and wait them out. And closer to Earth's poles, lucky residents may be treated to a bright display of the Aurora—the Northern and Southern lights—as auroras are powered by solar activity.

We should expect more strong flares over the next year or so as the Sun proceeds through the peak in its current activity cycle, expected to climax sometime in 2013. I fully expect to view more "naked-but-protected-eye" sunspots, and to enjoy plenty of colorful movies of solar activity from NASA's Solar Dynamics Observatory (now on display in Chabot's telescope domes). Drop by Chabot on a sunny day and we'll put spots in your eyes.

NASA's Stratospheric Observatory for Infrared Astronomy, also known as SOFIA. (Photo: NASA)

The new SOFIA observatory isn't your average NASA project. Engineers took a 30-year old 747 airplane, cut a hole in the side and installed a 17-ton telescope. Most telescopes are either on the ground or somewhere in orbit, but SOFIA falls somewhere in the middle, flying around at about 40,000 feet.

I got the chance to hitch a ride on one of its recent research flights as the plane left Moffett Field at the NASA Ames Research Center. It's definitely not the kind of flight where you get a bag of peanuts and movie.

The researchers take advantage of the nighttime sky, so we left at dusk for 10-hour tour flying zigzags across the Pacific Ocean. Each leg of the journey is carefully calculated so the telescope can pinpoint a far away star. The plane interior is packed with computers and equipment. It also lacks insulation since much of it was removed to install the telescope, so it's both cold and loud inside.

At four in the morning, the astronomers are still hard at work. If they're as tired as I am, they certainly aren't showing it.

"For me, this is very exciting," says Ian McLean, a professor at the University of California-Los Angeles. He usually works on the ground. "All my career has been ground-based astronomy. So, it's only my second flight."

McLean says there's a good reason to do astronomy in the stratosphere. The atmosphere is thinner, which means it's easier for the telescope to see the stars. "It's almost as good as space," says McLean. "Not quite, but almost."

And unlike the Hubble Space Telescope, this telescope lands everyday, which means the scientists can update and fix the equipment. "By the time you get a mission into orbit, the technology you're using is relatively old. Here we can stay state of the art all the time," says McLean. NASA began developing SOFIA in 1997 and almost cancelled the project at one point. It flew its first science mission in November 2010 and now costs about $80 million a year to operate.

Searching for a "Holy Grail"

McLean says the SOFIA telescope could show astronomers something that's considered a Holy Grail in their field: seeing a star being born. It happens in huge, dusty clouds – stellar nurseries, as Mclean calls them. "The cloud is huge, light years across and it's gradually contracting to form a whole nursery of stars."

Inside NASA's SOFIA Observatory, somewhere over the Pacific Ocean.

But there's a problem. Astronomers can't see what's happening inside the clouds because, once again, they're made of dust and it's hard to see through.

"We don't mean dust bunnies, but we mean little, tiny little grains of solid material. Doesn't matter how big a telescope you have, you can't see inside it," McLean says.

That's why SOFIA looks at a special kind of light called infrared light. If you look through a telescope on the ground, you're looking at the visible light from space – the light our eyes can see. Infrared light is invisible to us, but it penetrates space dust, which means the telescope can see through the dust too.

"You get to see what you can't see with your eye. It's like a window has been opened," says McLean. They're looking for exactly how stellar nurseries give birth to young stars. McLean says catching a star as it's forming can reveal clues about how own solar system formed.

But star birth isn't the only thing these researchers want to see. They're also looking at the way stars die.

A Star on the Way Out

As the plane makes as sharp right turn, the telescope focuses on an object called NGC 7027. It's a planetary nebula – also known as a dying star. McLean and his team are capturing an infrared image of the nebula, which is about 3,000 light years away. They can also see what it's made of.

"It has a distinctive shape. It's oval. There's a hole in the middle and that's because it literally is a shell of gas that came off the star," says McLean.

7027 is dying because the star has run out of fuel – the same fate that our sun will face in about five billion years. As it dies, the star casts off its outer layers, shedding huge amounts of material to form a cloud around it. But it's not entirely a sad story.

"It won't be wasted," says McLean. "The material that was thrown off by that star in its dying phase, somewhere, millions, perhaps billions of years from now, will find its way into a new star and the planets that form around it."

From dead stars come new stars – and planets like our own. The oxygen and nitrogen in our bodies were once formed inside a star. "The cosmos is within us," as astronomer Carl Sagan once said. "We're made of star stuff."

As sky begins to lighten, we descend towards the Dryden Aircraft Operations Facility in the Mojave Desert, where the plane is based. The SOFIA telescope is now undergoing service upgrades and then will return to the skies three times a week. Astronomers from around the world are lining up to get on board.

Asteroid Vesta - Images from the Dawn Spacecraft

With the New Horizons spacecraft hurtling toward its 2014 encounter with Pluto, and with the Dawn spacecraft now at its most up-close and personal encounter with Vesta, we are in the process of learning scads of information about two objects that are among the poorest understood and least explored bodies in the Solar System.

Before NASA's Dawn settled into orbit around the asteroid Vesta—the second largest object in the Main Asteroid Belt, after the Dwarf Planet Ceres—we knew very little about it. That it is mega-mountain of rock 330 miles across that rotates rather quickly in space and is slightly egg-shaped, these things we knew—but not much more.

What Dawn has revealed to us, however, is a tiny world with unexpected complexities, inside and out.

Inside, Vesta's anatomy may not be unlike Earth and the other Terrestrial planets, which all developed cores heavy with iron and mantles and crusts made of lighter silicate rocks when they were young and molten. This "differentiation" occurs for the same reason that gold particles sink to the bottom of a gold-pan as a prospector shakes the water-sand slurry back and forth: the gold is denser, the sand lighter, so the materials separate.

Outside, Vesta's surface offers amazing landscape vista opportunities for a future robot lander or astronaut: complex topography of valleys, cliffs, troughs, ridges, and a huge mountain, with elevation differences deviating above and below the global average elevation by as much as 15 miles—that's three Mount Everests, or two Marianas Trenches!

Parts of the surface resemble some of the basaltic formations of cooled lava in Hawaii, suggesting that, long ago, there may have been active volcanoes on Vesta, spewing out lava to shape the young surface.

What a sight it must have been—and it makes me smile when I think about the children's book "The Little Prince." My favorite part of that story was the description of how the Prince, on his little asteroid world (which was only twenty or thirty feet across, I'd guess), cooked his meals on a frying pan held over a miniature volcano, which he made sure to keep clean and functional with a periodic cleaning using a giant Q-tip….

All of these revelations—the core/mantle differentiation, complicated geography, possible tectonic features, and signs of past volcanism–have prompted some scientists to ask, should Vesta be reclassified as a Dwarf Planet, along with Ceres, Pluto, and the others thus dubbed?

I have on my desk at work a letter from a 3rd Grader. It starts, "I think Pluto should be a planet (not a Dwarf Planet)…." The letter continues in richer detail and quite a bit of passionate defense of Pluto, but I was struck by the fact that this 3rd Grader was, at the time Pluto was originally "demoted," three years old. (And some thought the Pluto controversy would end with the previous generation of kids….)

But it did get me wondering. If Dawn has changed our view of Vesta from a mere large asteroid to something maybe worthy of promotion to Dwarf Planet, what might New Horizons do to our current view of Pluto? I'm not suggesting the International Astronomical Union will reinstate Pluto as a planet when we get our first up-close images of its surface—after all, no matter what Pluto's surface may hold in store for us, this Dwarf Planet can't meet one of the three conditions for planethood: being massive enough to clear the region of space in which it revolves. Alas, Pluto shares its orbital space with other objects.

But I fully expect that New Horizons will change our perspective on Pluto, as Dawn is doing for Vesta. The more we learn of the rich details of mysterious places like these, the more, I think, we regard them as "worlds"—regardless of their classification as asteroid, dwarf planet, or planet.

Kepler 22B compared to the solar terrestrial planets

It's 600 light years from Earth, orbits a star very similar to our Sun in a period of about 290 days, and has a diameter about two and a half times that of Earth. What is it? It's the NASA Kepler mission's most recent exciting confirmed discovery, the extrasolar-planet (exoplanet) Kepler 22B.

Another real, Earth-sized planet to imagine? Cool! I'm on it….

It's fun to play around with the planetary possibilities, as science fiction writers have done for decades, but having a real find out there to pin our thoughts on is something more. On that blank ball-shaped canvass we can paint whatever atmosphere, hydrosphere, lithosphere–and who knows, biosphere?–we care to imagine, at least until scientific observation starts to fill in those details.

But, Kepler 22B offers something more to our fancy than a mere Earthoid dress-up doll. Being somewhat larger than our world, though still smaller than a Neptune or a Uranus, places it in the category of "super-Earth," a type of planet that we have very little experience with.

What do we know of Kepler 22B beyond the barebone figures revealed by the Kepler spacecraft? In a word, not much. Kepler—a really big camera orbiting the Sun and staring at a patch of 150,000 or so stars in the constellation Cygnus—was designed to detect the presence of Earth-like exoplanets. Using the "transit" method of exoplanet detection, Kepler watches unblinkingly for the slight dimming of a star's light as one of its planets "transits," or moves across, its face.

That dimming can tell us exactly three things: the approximate diameter of the planet by how much of the star's light is blocked, the orbital period of the planet by how often it transits, and the distance between the planet and its star (because once you know the orbital period, you can calculate that distance–or visa versa–as long as you know the mass of the star the planet orbits…which we do).

Being relatively close to the size of the Earth makes Kepler 22B an important find, but maybe more important is the fact of the planet's distance from its star. Kepler's mission isn't merely to find Earth-sized planets, but ones that are within their stars' habitable zones: the right distance so that, given a sufficient atmosphere, liquid water could exist on their surfaces.

Kepler 22B is at that correct distance. Though it is closer to its star than Earth is from the Sun, that star is slightly cooler than the Sun, so its habitable zone is closer in. (Earth is obviously in the Sun's habitable zone; if you're not sure, go get yourself a glass of water.)

But back to what we know, and don't know, about Kepler 22B. Not having a super-Earth in our own Solar System, we don't have an up-close example to study. Is it like Earth, a rocky sphere from the core right up to the visible surface, with an apple-peel thin layer of gas and liquid on top? Or is it more like Uranus, with a solid core deep down with massive layers of fluid and gas upholstered around it? Or something between?

We don't know. Future observations may reveal more about this planet, and others. One day we might know more about Kepler 22B's atmosphere (if it has one) through spectroscopic measurements. If we can make a measurement of the planet's mass, we could calculate its average density and better place it on the spectrum between super-Earth and infra-Uranus.

Were we to travel there, could we land, step outside and breathe the air (as well as strain under a super-Earth's gravity)? Would we sink into the fluid envelope around the hidden core, falling to ever greater depths and atmospheric pressure? Would we find ourselves surrounded by human-sized chimpanzees?

That adventure is yet far in the future…but a lot of fun to imagine in the meantime….

NASA's Juno spacecraft is shown in orbit above Jupiter's colorful clouds in this artist's rendering. Image credit: NASA/JPL-Caltech.

Even though NASA is no longer in the business of deploying manned-missions to outer space, they continue to explore the cosmos in ways that have never before been possible.  Their next target is Earth's bigger, gassier neighbor: Jupiter.

On August 5, 2011 the National Aeronautics and Space Administration (NASA) in conjunction with the Southwest Research Institute launched the Juno mission,  which NASA says will, "improve our understanding of the solar system’s beginnings by revealing the origin and evolution of Jupiter."

This is a pretty big deal in the world of astrophysics.   NASA scientists theorize they will be able to determine the origin of The Giant Planet, "and thereby the solar system" by measuring the amount of water and ammonia in Jupiter's atmosphere.

Scott Bolton, Juno's principal investigator from the Southwest Research Institute in San Antonio explains the significance of the mission:

"Jupiter is the Rosetta Stone of our solar system.  It is by far the oldest planet, contains more material than all the other planets, asteroids and comets combined, and carries deep inside it the story of not only the solar system but of us. Juno is going there as our emissary — to interpret what Jupiter has to say."

But scientists will have to wait a few years to test their theories.  Even though Juno is traveling at a relative speed of over 13,000 miles an hour, it is not scheduled to reach its final destination until July 2016.

And the ride to Jupiter is not exactly a clear path.  Juno will face many obstacles – including large mentors – that can potentially derail the $1.1 billion project.

Thankfully, scientists can rely on old "maps," or astro-photographic images of the night sky to plan a flight path that will steer the spacecraft away from debris.

Dr. Bill Cooke, head of NASA's Meteoroid Environment Office, says the astro-photographic plates housed at the Pisgah Astronomical Research Institute (PARI) contributed directly to the success of the Juno mission;

"Juno, for example, in order for it to be successful they have to design it.  And one of the things they have to design it for is to protect it from meteoroids out in space.  Well we never measured meteoroids around Jupiter, because we don't go there very often, right?  So we have to take what             we've learned here at Earth to help us design that spacecraft to go to Jupiter and those negatives [at the Astronomical Photographic Data Archive] helped formulate the model we used to design that spacecraft to go to Jupiter.

Dr. Cooke is referring to a collection of nearly 150,000 old astro-photographic plates and film known as APDA, or the Astronomical Photographic Data Archive.  The APDA collection is stored at PARI's secure facility in Western North Carolina.

Dr. Cooke became aware of the collection a few years ago and has quickly become on of its biggest advocates:

"The photo archive which contains a lot of the photographs that form the basis of modern meteor science are housed … at ADPA.  They collected them from around the country, but those old photographs, that data, formed the basis for everything we know now in regards to meteors.  So it's kind of like visiting a treasure trove of ancient data.  The great hieroglyphic inscriptions out there in APDA."

Brendan Fallon of the American Meteor Society examines film in the APDA collection.

The connection between APDA and the Juno mission came full orbit during this year's annual NASA Fireball Workshop, which took place at PARI's Rosman, North Carolina campus.  Attendees were able to watch the Juno launch and then walk into the archives to hold the original pieces of film that helped Juno's engineers develop a safe flight path.

By relying on old astronomical plates and film – some of which date over 100 years old – today's astronomers can safely stand on the shoulders of their predecessors and reach for the stars, without fear of being knocked down by meteors.

For more info check out NASA's website for the JUNO mission:

twitter: @NASAJuno

http://missionjuno.swri.edu/

Gale Crater, the destination for NASA's new rover Curiosity. Credit: NASA, Google Earth

Ready for yet another great Martian adventure? Another prestigious interplanetary mission to that fabled world? The next technological ambassadorship of space-age robots and exotic landscapes? Or, how about an inglorious romp to go dumpster diving to sift through a pile of geological garbage…?

In any case, get set; on November 25th the launch window opens for NASA’s next Mars rover, “Curiosity,” which will arrive over yonder next August.

Inglorious dumpster diving? What’s NASA got planned this time, anyway?

Answer: Gale Crater, a large impact blast about 1400 miles to the west of Gusev Crater, where the rover Spirit now sits motionless—and incommunicado—in its last rusting place.

When I heard that Curiosity was bound for Gale Crater, my first impulse was to start up Google Earth, switch to Mars mode, and zoom in on Gale Crater for a landing to see, at least superficially, what might be of interest there to an explorer. (You can do this too; download Google Earth at www.google.com/earth, select Mars, and search for Gale Crater.)

My first Google-vista of Gale, which included several overlaid strips of high-resolution imagery from the Mars Reconnaissance Orbiter (MRO), hinted that there may be a LOT of interest here.

Gale Crater, about 90 miles across, sports a really large mountain right in the middle—mostly filling the bowl, in fact. The mountain, whose peak rises around 2700 feet above average Martian surface level (can’t say sea level there…not in the present day, at least), towers 3 miles above the deepest part of the crater surrounding it.

I zoomed in on an MRO overlay of a canyon high on the mountain, finding what looks like layered deposits exposed by whatever cutting action had carved the canyon in the past. The landscape I find there is stunning, the details rich. I almost feel as though I’ve stood where Curiosity is soon to tread.

The rover will be set down by a sort of rocket-propelled winch, lowered gently to the base of the mountain where an alluvial fan promises potential riches. Not wind-worn pebbles of solid gold, not fist-sized chunks of diamond—well, probably not—but rather the riches of dirt that may have been deposited there by the action of water. A dumpster of chemical, geological, and potentially biological history.

One of the reasons Gale Crater was chosen as Curiosity’s destination is that it is a deep, low-altitude impact crater, situated at a “downhill” destination where water, if indeed it did flow on Mars long ago, is very likely to have converged, dumping all sorts of soil, rock, and whatever else might have come along for the ride.

Curiosity carries ten instruments designed to conduct a range of measurements, including chemical analysis of soil and rock samples in search of organic compounds that may have been preserved. Where Curiosity’s predecessors, Spirit and Opportunity, have looked for the chemical signs of past water to help tell us whether Mars was ever hospital to life, Curiosity will look for the leftovers of life itself. And in the bottom-lands of Gale Crater, at the foot of a huge mountain from which the rubble of layer upon layer of history has been scoured, it will be in a really good place to do it.

Endeavour Crater; Credit: NASA, Google Earth

Who would have imagined three years ago, when the already veteran Opportunity set forth from its two-year prospecting site at Victoria Crater on a long march to the much larger Endeavour Crater, that the Fates would actually NOT stop this Energizer-Bunny dead in its tracks?

Okay, enough jaw-dropping incredulity. Some things CAN be built to last….

About three weeks ago, Opportunity reached the rim of the 14-mile wide Endeavour Crater, after clocking nearly 21 miles since its landing seven and a half years ago. By Earth-rover standards, that’s about one round trip to work and home again for me, and about 25 minutes of my time—but Opportunity’s commute is a far greater feat, alone on another world, long minutes away even by radio waves, no service garages for maintenance, no fuel stations other than the daily dose of energy doled out by the Sun.

One of the first things Opportunity did upon reaching the rim of the giant crater, after taking some pictures to give us the lay of the land, was to examine some rocks. After all, more than anything else, the Mars Exploration Rovers are geologists, or rock hounds, sent to tell us about the Martian environment, today and in the past, through the chemical makeup and stratigraphy of the rocks and soil.

Data from orbital spacecraft have shown that the materials at the rim of Endeavour may date back to early in Martian history, making for fertile ground in Opportunity’s quest to uncover clues to the planet’s past. Evidence for the presence of clay minerals, possibly formed under wet conditions favorable to life, has been brought to light—which really adds some excitement to the rover’s rock hounding exploits to come.

On Opportunity’s approach to the crater rim, it spotted in the distance unusual outcroppings, and a “shelf” of what looks like sedimentary rock with inclusions of material that may have been deposited by water action.

Water water water, the watch-words of Martian exploration for many years. Where there is, or was, water, perhaps there is, or was, some form of life. And while the Mars Exploration Rovers weren’t designed to look for signs of life directly, their larger, better equipped descendant, Curiosity, to be launched in November, is. Curiosity, do tell….

As a child I liked to imagine what it would be like to land on and walk about the surface of Mars. Mind you, back then we had no images from Mars’ surface—not until 1976 when Viking landed. We had low-res images taken from space, and plenty of science fiction sound stage backdrops and sets from various TV shows and films (and a Mars stand-in, Death Valley, in Robinson Crusoe on Mars).

Opportunity still appears to be in good shape, so the odyssey of its exploration seems to have a good chance of delivering yet another episode of the Life (?) and Times of Mars….

From hosting tweetups with space enthusiasts, to sharing space amazing videos on YouTube, NASA has embraced social media as a way to spread its message and further popularize astronomy.

Social media has broadened our access to astronomy and life off Earth. If you've dreamed of owning your own telescope and seeing distant lands, there are more resources than ever to help make your dreams a reality. Here are just a few options for budding armchair astronomers:

Astronomy.net

Photography enthusiasts can share their Flickr photos with Astronomy.net, contributing to astronomers' knowledge base. Using photos from telescopes, cameras and even camera phones, astronomers can build a map of the sky to search for new discoveries, such as the birth or death of a star.

Planet Quest

Part of the Kepler Mission and NASA's Jet Propulsion Laboratory, Planet Quest gives visitors a detailed look at our galaxy. Beautiful videos and interactive games detail the process of searching for habitable exoplanets.

LightBuckets

Rent time on telescopes around the world and collect images of your favorite astronomical sights from the comfort of your home computer. If you're looking to majorly up your nerd cred, this is an excellent option.

Slooh

If space had a cable channel, Slooh might be it. The site broadcasts major astronomical events over the Web. If you can't make it to that eclipse all the way around the world, Slooh is probably broadcasting it.

What other astronomy resources do you like? Share them with us in the comments.