Europa has a thick crust of ice over an ocean. Lake Vostok, miles beneath the Antarctic ice, is similar. But lessons from one may not apply to the other. NASA image

It was a thrill to learn that on Sunday, Russian scientists managed to poke a drill tip through miles of Antarctic ice into Lake Vostok. Samples of water from this extreme environment promise to provide one of biology's severest tests of life on Earth. Scientists are talking up the possibility that this experiment, the first of several in progress in Antarctica, could tell us more about possible life on the icy satellite of Jupiter named Europa. Is that a stretch?

We're asking different questions here. At Vostok, we want to know if life has survived; at Europa we want to know if life could have arisen. In that context I think that Vostok and Europa are worlds apart; their similarities are superficial. Let's look at the two places in a bit more detail.

Lake Vostok is a large tectonic basin, rather like Lake Tahoe, that happened to be overrun some 15 million years ago by the growing Antarctic ice cap. It has been sealed in profound darkness and freezing cold ever since, with the ice flowing slowly over it. Here's a diagram of the situation.

National Science Foundation image

The lake is kept unfrozen because of a trickle of heat from the Earth's crust beneath plus the effect of great pressure in depressing the freezing point. Ice melts at the upstream end and lake water freezes at the downstream end, so on the geological time scale there's an exchange of water, and the water itself must be charged with air carried in by the ice. But the amount of minerals and nutrients entering the lake this way must be astronomically small. Somewhat larger amounts may come from the rock and sediment of the lake's floor, but the picture is still disheartening.

And yet we have found life everywhere on Earth, from temperatures above the boiling point to below freezing. Microbes are recovered from within the ice cap itself. I believe that the microbes originally sealed into Lake Vostok survive today, because that's the way to bet on this planet. However, from everything we know, life could never have arisen in such a place. The raw ingredients and energy required are absent.

Is that true for Europa? It's colder on its warmest day than anywhere on Earth, true. But Europa should have much more of the assets for life than Vostok.

Europa is an old world that formed along with the rest of the planets. Like Earth, Europa separated into a dense interior and a light shell, only with a greater share of water. Its rocks, like those of the early Earth, had lots of natural radioactivity that must have generated enough heat to keep part of the overlying water melted throughout its history. (More recently, Jupiter's four major satellites have fallen into mutually resonant orbits that wring them with changing tidal forces. The innermost moon, Io, is heated to volcanism this way, and Europa and Ganymede are heated to lesser extents.) The heat must have expressed itself in hydrothermal vents, too, exactly like Earth's seafloor "black smoker" vents.

In a word, as far as planetary scientists can tell Europa should have started out with the same setting that is commonly thought to have spawned life on Earth. The first structures that served as cell membranes could have arisen at hydrothermal vents, which would exist on Europa just as they do on Earth: springs of hot, chemically active water on the floor of a big cold sea. The water itself should contain ammonia, sulfates, even hydrocarbons. All of this is straightforward modeling based on what we already know about the solar system.

Model of the icy crust of Europa. Jet Propulsion Laboratory image

Planetary modelers are finding that the thick ice shell of Europa should have some interesting activity, too. The eerie striped pattern of Europa's surface shows that the ice fractures regularly due to tidal forces. When that happens, water would rise and its dissolved gases would come out in bubbles. These "Perrier ocean" eruptions would spray over the surface, where the ice and its organic compounds would bake and polymerize and react in the radiation from Jupiter and the Sun.

Eventually, after approximately a billion years, the entire icy crust would become replaced with ice bearing this baked material. And at that point you would have a nutrient cycle. In sum, it's quite plausible for life to arise and persist on Europa where it's quite impossible in Lake Vostok. If we ever get a spacecraft to Europa—proposals keep being submitted—our experience drilling to Vostok would help us drill through Europa's crust. But a more elegant proposal is to simply swoop over Europa in low orbit and scoop up bits of dust from its icy surface raised by micrometeorite impacts. Just like on Earth, if life is on Europa its signs should be everywhere.

Artist's rendering of the LCROSS spacecraft and its upper stage Centaur rocket. Image courtesy of NASA.

Reported for KQEDnews.org.

Last year, NASA scientists in Mountain View made international headlines when they crashed a rocket into a permanently shadowed crater on the moon's south pole and announced they had found water there.

On Thursday, they unveiled new findings about the amount of water on the moon and a "treasure trove" of gases and metals buried within the lunar soil, which along with the water, could be extracted to make rocket fuel on the moon. The research appears in the October 22nd edition of the journal Science.

"If you took the 10 kilometer region around the LCROSS site, that is said to have 5 percent concentration of water, that would be equivalent to a billion gallons of water," said Tony Colaprete, the principal investigator on the Lunar Crater Observation and Sensing Satellite mission to search for water on the moon. A billion gallons is enough to fill 1500 Olympic-sized swimming pools. The lunar scientists now suspect that there is 50 percent more water than they had previously estimated.

Colaprete also said that given the large number of craters on the moon, which function as "cold traps" that accumulate molecules of water over billions of years, "potentially, you could have 10 to 100 times that total amount of water."

"We found some of the coldest places in the solar system and they’re on our moon. These places have temperatures that are so cold that they can preserve water ice in a vacuum for billions of years," said Michael Wargo, a chief lunar scientist at NASA headquarters in Washington, D.C.

The lunar water is thought to exist in "oases," or deposits, instead of being uniformly distributed across the moon. It also exists mainly in the form of water ice crystals.

"That's good news because water ice is very much a friendly resource to work with. It's easy to extract and turn it into a resource, you don’t have to warm it very much, you can pull it out of the dirt really easy," said Colaprete, who described a process of extraction whereby the ice-bearing lunar soil could be heated to 100 degrees Celsius to collect the water vapor.

During the live NASA teleconference, the scientists said that the amount of other materials they detected on the moon – including mercury, ammonia, methane, carbon dioxide, sodium and silver – may make up as much as 20 percent of the lunar dust plume kicked up by the impact of the LCROSS rocket.

Both discoveries could be instrumental in one day making it easier to set up a lunar colony, the researchers said, because of the high cost of transporting materials to the moon, which can exceed thousands of dollars per pound.

Last year, NASA shot a Centaur rocket carrying the LCROSS and Lunar Reconnaissance Orbiter from Cape Canaveral, Florida, and in October, they deliberately crashed the rocket at 6,000 mph into Cabeus, a cold, dark crater on the moon’s south pole that hasn’t seen sunlight in billions of years.

The impact sent up a plume of lunar soil and debris several miles over the crater’s rim, exposing it to sunlight. Meanwhile, the spacecraft collected data for four crucial minutes, allowing scientists to analyze the chemical makeup of the ejected lunar soil, before it too crashed into the crater. Since then, the LCROSS team has been sifting through the information to glean clues about earth’s 4.5 billion year-old neighbor.

So how did the water get there? According to Colaprete, it’s likely a combination of sources. One way it could have arrived is from solar wind depositing hydrogen into the lunar granules which contain oxygen atoms. Another way is from impacts by icy comets slamming into the moon, a theory supported by the observation of these other chemicals and hydrocarbons that also exist in comets.

The last manned lunar mission was Apollo 17 in 1972. In recent years, the U.S., along with Japan, China and India have launched various unmanned lunar mission. NASA is scheduled to launch two other lunar exploratory missions, GRAIL and LADEE in 2011 and 2012, respectively, to map the moon’s interior structure and further analyze the moon’s dust.

Sometime in the next several decades, a new generation of astronauts may return to set up a lunar outpost, setting the stage for future missions to Mars.

“In the next 20 years, next 10 years, you’re going to see the moon continue to expand in its diversity, and its complexity and its interest, among the communities of both laypeople and professionals and that’s going to pull us there,” said Colaprete.

Instruments currently orbiting the moon are allowing the scientists to map in much greater detail hydrogen-rich, lunar "permafrost" regions that may contain deposits of water ice and other compounds that could help support a future lunar colony.

But before that lunar colony can be set up, there has to be a more sophisticated understanding of where exactly the water is and how easy or difficult it will be to mine when it's found.

"The next step is to look at smaller and smaller scales at the lunar surface of the distribution of water as a resource," said Colaprete.

"If I were an astronaut walking along, how far do I have to walk before I find some water and how extensive are these pockets of water?"

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Artist's rendering of the LCROSS spacecraft and its upper stage Centaur rocket. Image courtesy of NASA.

Originally reported for KQED News.

Last year, NASA scientists in Mountain View made international headlines when they crashed a rocket into the moon and announced they had found water there.

On Tuesday, they revealed that the water – which exists as ice and vapor – isn’t spread out in vast oceans, but rather is concentrated in oases, and that the lunar surface appears to contain a wealth of other materials, from mercury to magnesium.

Both discoveries could be instrumental in one day making it easier to set up a lunar colony, the researchers said, because of the high cost of transporting materials to the moon, which can exceed thousands of dollars per pound.

“It’s water and much more,” said Anthony Colaprete, an astrophysicist at NASA Ames Research Center in Mountain View. “The others, from a scientific standpoint and a resource standpoint may prove to be as important or more important.”

Colaprete is the principal investigator on the mission to find water on the moon, which is known as LCROSS or the Lunar Crater Observation and Sensing Satellite. Last year, the scientists shot an unmanned spacecraft from Cape Canaveral, Florida, and in October, they deliberately crashed its rocket at 6,000 mph into Cabeus, a cold, dark crater on the moon’s south pole that hasn’t seen sunlight in billions of years.

The impact sent up a plume of lunar soil and debris several miles over the crater’s rim, exposing it to sunlight. Meanwhile, the spacecraft collected data for four crucial minutes, allowing scientists to analyze the chemical makeup of the ejected lunar soil, before it too crashed into the crater. In the nine months since then, the LCROSS team has been sifting through the information to glean clues about earth’s 4.5 billion year-old neighbor.

How wet is the moon?

“As wet as the Sahara, perhaps wetter in some places”, said Colaprete.

On Tuesday, at the third annual Lunar Science Forum at NASA Ames, researchers discussed everything from the physics of the LCROSS impact to the complex chemistry of the moon. Among their findings:

- The distribution of water on the moon is not uniform, but “chunky”, occurring in deposits in dark craters like the one LCROSS struck.
- The range of chemicals found on the moon is wider than once thought and includes mercury, magnesium, sulfur dioxide and possibly, formaldehyde, along with sodium, hydrogen sulfide, carbon dioxide and methane.
- The total amount of water in the target site and the plume observed by LCROSS: 26 gallons

So how did the water get there? According to Colaprete, it’s likely a combination of sources. One way it could have arrived is from solar wind depositing hydrogen into the lunar granules which contain oxygen atoms. Another way is from impacts by icy comets slamming into the moon, a theory supported by the observation of these other chemicals and hydrocarbons that also exist in comets.

The last manned lunar mission was Apollo 17 in 1972. In recent years, the U.S., along with Japan, China and India have launched various unmanned lunar mission. NASA is scheduled to launch two other lunar exploratory missions, GRAIL and LADEE in 2011 and 2012, respectively, to map the moon’s interior structure and further analyze the moon’s dust.

Sometime in the next several decades, a new generation of astronauts may return to set up a lunar outpost, setting the stage for future missions to Mars.

“In the next 20 years, next 10 years, you’re going to see the moon continue to expand in its diversity, and its complexity and its interest, among the communities of both laypeople and professionals and that’s going to pull us there,” said Colaprete. “There’s a lot you can do with the moon. It’s fundamental to understanding our place in the solar system and we’ve always appreciated that and recent studies have accentuated it.”

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The Thirty Meter Telescope would be built in Hawaii, atop Mauna Kea at around 13,000 feet. Artist's interpretation courtesy of TMT Observatory Corporation.

Originally reported for KQEDnews.org.

Scientists from the University of California are working with a team of international researchers on one of the most high-profile science projects of this decade: an effort to construct the largest optical telescope on Earth.

The $986 million project is planned for the summit of Mauna Kea, on Hawaii’s Big Island, and will feature a primary mirror 98-feet in diameter.

Scientists working on the project hope to begin construction next year and complete it by 2018 or 2019. They say the facility, dubbed the Thirty Meter Telescope, will allow astronomers to observe with much more clarity some of the earliest stars and galaxies of the universe and investigate what they’re made of.

“We’ll be able to look back at the baby pictures of the universe and trace how it developed,” said Michael Bolte, director of the University of California Observatories and a member of the board of directors for the new telescope.

The telescope won approval last month from the University of Hawaii Board of Regents, which holds the lease to the site.

In addition to exploring the farthest reaches of the universe, the telescope also will be able to routinely and easily produce images of the more than 450 planets that have been discovered orbiting stars outside of our solar system.

Today, the existence of these so-called “exoplanets” can only be inferred by measuring the gravitational tugging forces exerted by the stars they orbit. The telescope also could help determine if some of them have atmospheres similar to Earth’s – the precursor to finding life on another planet.

“It will be one of the most important scientific facilities of the 21st century,” said Bolte, who is also a professor of astronomy at UC-Santa Cruz. “When we look back, it’s going to be the Large Hadron Collider and the Thirty Meter Telescope and I’m not sure what else.”

The project is a joint effort of the University of California, the California Institute of Technology and the Association of Canadian Universities for Research in Astronomy.

A sizable amount of its funding is coming from the Bay Area. The Betty and Gordon Moore Foundation, in Palo Alto, has pledged $200 million toward the telescope’s construction. The University of California and Caltech each plan to raise $50 million. And contributions are expected from the Canadian universities, as well as the governments of China, India and Japan. But 10 to 20 percent of the telescope’s budget still remains to be raised, said Bolte.

The new telescope’s 98-foot (30 meter) mirror would be three times as big as the mirrors on the twin Keck telescopes in Hawaii, currently the biggest in the world, and also owned by the University of California and Caltech. The telescope would produce images three times as sharp as the 33-foot Keck telescopes on Mauna Kea, and would be able to look at objects that are nine times fainter. This would make it possible for scientists to better understand the origins of the universe.

“The universe is 13.7 billion years old and we can see objects that are 13 billion years away, but all we get is fuzzy blobs,” said UC-Santa Cruz astronomer Garth Illingworth, chair of the telescope’s Science Advisory Committee. “We’d like to learn more about these stars and galaxies.”

In January of 2010, Illingworth and his team announced that they had observed the most distant galaxies ever seen. Looking back in time 13 billion years, they found galaxies that were just 600 or 700 million years from the Big Bang. Photographs of these galaxies, which appear as several tiny dots, were made by the Hubble Space Telescope.

Space-based telescopes like Hubble have an advantage over ground telescopes because they don’t have to contend with the blurring caused by the Earth’s atmosphere. But they’re more expensive and therefore, smaller. Hubble’s mirror is less than 8 feet in diameter.

Bigger ground-based telescopes can gather more light than small space-based telescopes. So they make objects that once were faint appear brighter. And the additional light gives researchers information on the chemical composition of objects like stars.

When astronomers understand what a star is made out of, they can better establish its age. And this allows them to plot out the history of the universe more accurately. What’s understood now is that the Big Bang was followed by a period of darkness that astronomers call the Dark Ages. But it’s not clear how long that period lasted.

“There’s controversy about the period before which there were no stars,” said Jerry Nelson, UC-Santa Cruz astronomer and project scientist for the telescope. “The idea is to establish bounds on this. The question is when do you get stars forming that burn holes through this opaque stuff?”

In addition to answering questions about the history of the universe, observers say the telescope could also eventually lead to new energy sources based on the nuclear fusion that fuels stars.

“All those points of light are nuclear furnaces,” said bestselling San Francisco author Timothy Ferris, who wrote “Seeing in the Dark” and other books about astronomy and telescopes. “And they have something to teach us.”

The telescope’s mirror will be made out of 492 closely fit individual hexagonal glass mirrors. The Keck telescopes were the first to use these segmented mirrors to get around the problems created by gigantic individual mirrors. The Keck telescopes were so successful, said Illingworth, that UC and Caltech envisioned the Thirty Meter Telescope as a way to scale-up the Keck model.

TMT Fly-Through from Thirty Meter Telescope on Vimeo.

But big ground-based telescopes have their limitations. Though they can give astronomers more light to study, they can’t by virtue of their size alone make objects appear sharper. To reduce the blurring caused by the atmosphere, scientists use a series of techniques called adaptive optics.

“Adaptive optics is like putting glasses on a big telescope,” said Nelson. A telescope with adaptive optics not only sees sharper images of stars, it also sees more stars.

An expensive and technically complicated process, adaptive optics was used on telescopes for the first time to correct distortions on the Keck telescopes. The technique takes advantage of a layer of the atmosphere that starts about 50 miles above the Earth. This layer is made up of sodium atoms brought in by small meteorites that vaporize as they enter the atmosphere.

Scientists point an orange laser toward the sodium layer. The laser excites the sodium atoms, which become like artificial stars, radiating light back toward the telescope. The process allows researchers to correct for atmospheric turbulence, which causes phenomena such as the twinkle that we see around stars.

Other telescopes in the range of the Thirty Meter Telescope are in the works. An 80-foot mirror called the Giant Magellan Telescope is being spearheaded by a group that includes the Carnegie Institution for Science in Pasadena, Harvard University, the universities of Texas and Arizona and the government of Korea. That telescope is scheduled to be completed in 2018. And Europe is working on the aptly named Extremely Large Telescope, which would have a 138-foot mirror.

“They’re strongly complimentary,” said Bolte. “The Giant Magellan and the European telescope will be in the southern hemisphere, in Chile. So we’ll have access to the entire sky.” Having several of these instruments, he said, would make valuable telescope time more readily available to astronomers.

The Thirty Meter Telescope, which would be built at an elevation of about 13,000 feet, has not been without controversy. Environmentalists say its construction would harm the wekiu bug, a native species that lives atop high Hawaiian peaks. Some Native Hawaiians have come out in opposition, saying that the summit of Mauna Kea is sacred and should not have any more construction.

Scientists hope that the Thirty Meter Telescope will provide answers for many current astronomy questions: What is the invisible matter that makes up 25 percent of universe? What is the mysterious energy that is making it expand faster and faster? But Bolte suspects that just as telescopes in the past surprised scientists by revealing that the planets orbit the Sun and that the universe is expanding, the new telescope’s contributions are impossible to fully predict.

“Every time you build a new telescope with significant new capabilities, you usually solve the problems of the day and find new things you didn’t even know were there,” Bolte said. “The Thirty Meter Telescope will be a bigger jump than any other jump we’ve had, so the new discoveries will be all the more unexpected.”

***

TMT Overview from Thirty Meter Telescope on Vimeo.

Check out these QUEST TV and Radio stories about other University of California astronomy projects:

Illuminating the Northern Lights

Exoplanets

SETI: The New Search for ET

The Planet Hunters

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Depiction of Galileo demonstrating his astronomical telescope.

(Almost as famous as this act of opening our eyes to wonders we'd never witnessed, Galileo was tried by the Inquisition for pointing out that there were more things in heaven than were imagined by Church doctrine–but that's another story altogether…)

It's an intriguing fact that, beyond the Sun merely being a bright disk, the Moon a not-so-bright and slightly mottled disk, the stars pinpoints of light and the planets pinpoints of light that move, everything we have learned about the universe and the objects in it we have learned in the last four centuries, since the invention of the telescope and Galileo's putting it to it's most famous use: astronomy.

Galileo saw on the Moon craters, mountains, and valleys, and likened the "uneven, rough… depressions and bulges" to Earth's geographical features. Venus was revealed to undergo lunar-like phases, which provided controversial insight into the layout of the Solar System. Jupiter had four small "star-like" moons that moved around it–which defied Church doctrine holding that everything in the universe goes around the Earth. And Saturn possessed jug-handle-like protrusions, whatever those were!

It may be difficult to imagine what Galileo was feeling when he made these discoveries of things we take for granted. How exciting to peer through that celestial peephole and discover that the Moon is another world, and that there are worlds out there that had never been seen or imagined before. Sure, new discoveries about Mars keep rolling in, and we're finding a new extrasolar planet about every month–but the excitement about these discoveries is tempered by the fact that we already suspected things like these as possibilities. For Galileo, the magnified astronomical sky was practically a blank canvass.

Back to IYA 2009–what's going on? Who's promoting this, and what is being done to celebrate?

NASA is promoting it, and many different organizations (including Chabot and the Eastbay Astronomical Society) are participating in a number of ways: star parties, special programs, special events, and good old fashioned put-your-eye-to-this-telescope-and-gawk public observing activities.
Honestly, there's nothing like looking through a telescope–and it doesn't have to be a large one. I don't doubt that I first became inspired into astronomy when, as a child, my family would take me to Chabot Observatory to look through the telescopes.

When the new Chabot Space & Science Center reopened the telescopes after the move to our present site, I found all of the childhood wonder flooded back when I put my eye to the eyepiece to regard Saturn. There's an excitement that simply can't be achieved by looking at photographs. You just have to experience it for yourself, as Galileo did four centuries ago…

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MESSENGER's color filter imaging capability reveals variations
in color on Mercury too subtle for the human eye.
Photo credit: NASA/MESSENGER

Did MESSENGER find anything new, since its first flyby back in January? Here are a few highlights:

• Prominent "ejecta" rays streaking out from several large craters–previously revealed only by radar imaging from Earth, now photographed for the first time.

• 30% more of Mercury's largely unexplored surface than had been revealed by the Mariner 10 flybys in the 70's and MESSEGNER's own first flyby last January (spacecraft–namely Mariner 10 and MESSENGER–have now imaged 95% of Mercury's surface).

• "Hyper-color" (my own word) imaging of surface features that reveal variations in color too subtle for the human eye to notice, providing information on soil and rock composition.

I'm a planet junkie–and Mercury has always had a special place in my imagination. One might think of Mercury as the least interesting planet, in our Solar System as well as among dozens of "exoplanet" systems yet discovered. After all, it's a small, dry, cratered, and airless lump of rock and dust, resembling for the most part Earth's Moon. Consider, however, the point of view of someone who's favorite place on Earth is dry, dusty Death Valley, and my enamorment might not come as such a surprise.

In my imagination I see towering cliffs, enormous, deep crevasses, wide, flat dusty plains, bright brights in sunlit patches and dark darks in shadow….

But it's really its differences from Earth that make Mercury such an appealing exotic vision. Being where it is, 36 million miles from the Sun (about a third the Earth-Sun distance), the sunlight striking the Mercurian landscape is six times brighter–imagine that! And not just the visible light spectrum, but all the wavelengths of light the Sun puts out are free to impact Mercury's surface, unimpeded by an atmosphere: infrared, ultraviolet, X-rays, and potent burst of gamma rays rain down intensely on the planet's plains, mountains, and craters.

Speaking of the Sun, its behavior in Mercury's skies is, to say the least, zany. Mercury orbits the Sun in about 88 days (Earth days), but rotates so slowly that a single Mercurian day (the time from one high noon to the next) is about 115 Earth days. Not only does that mean sun-up to sun-down lasts roughly a couple of months, but that Mercury's orbital motion has a greater effect than its rotation on the Sun's apparent motion through its sky. The complicated relationship between Mercury's year and its day also causes the Sun to go "retrograde" at times–that is, periodically halt its progress from one horizon to the other and temporarily go in the opposite direction.

So, our prodigal vacationer MESSENGER has its itinerary straight: a climate with the brightest, warmest sunlight, pristine landscapes, long sunny days, and big skies that perform tricks for its amusement. Now, if only there was a beach…

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Artistic rendition of exoplanet Gilese 436 b, created in Celestia

Once astronomers have found an extrasolar planet, also called an exoplanet, they look to see if it is in the Goldilocks zone. This is an area of space in which a planet is just the right distance from its' parent star so that the surface is neither too hot nor too cold. A habitable temperature means that the planet could possibly host liquid water, an ingredient for life.

A number of exoplanet findings have come from astronomy teams in Switzerland and near San Jose at Lick Observatory. Astronomers at Lick made news in the fall of 2007 when they discovered 55 Cancri. The discovery of the five-planet system came after nearly 20 years of observations. Also in 2007, astronomers with the Geneva Extrasolar Planet Search Program discovered the most earth-like planet ever found. Gilese 581 c lies in the Goldilocks Zone, it's surface temperature ranges from an estimated 32 degrees Fahrenheit to 102 degrees Fahrenheit. The research team that discovered the new planet believes it may have a developed atmosphere and be covered with oceans.

Curious to see how astronomers hunt for extrasolar planets, I took the trip up the long, windy road to the top of Mt. Hamilton. It is a beautiful drive up to the observatory and it's wise to take your time so that you can enjoy the ideal California landscape of rolling hills dotted with oak trees and wildflowers. The 365 sharp curves along the 19 mile road will also slow you down.

At the top of Mt. Hamilton are several white domes dotting the 4,200-foot crestline. From Lick Observatory you can see forever– not just across the vast northern California landscape but out into our own galaxy and beyond. By coincidence, the night I was there astronomer Debra Fischer confirmed five new planets outside our solar system. The discovery was the culmination of five years of watching these specific planets from Lick's 3-meter Shane Telescope. Fischer and her colleague Geoff Marcy will publish their findings soon. These two astronomers are obsessed with looking for exoplanets, they just returned from the Andes mountains in Chile, where they spent day and night for several weeks hunting for planets. But Fischer and Marcy are not the only ones who have caught the exoplanet bug.

Scientists at NASA are nearly ready to launch a bus-sized telescope into space. NASA's Kepler Telescope which will orbit our sun, will be trained on a hundred thousand stars at a time. It may be our best chance yet for finding new life in outer space. The telescope is scheduled to launch in February. Kepler will find planets by looking for tiny dips in the brightness of a star caused by planetary transits.

Make sure to check out our photo set on Flickr which includes: photos of Lick Observatory; the Kepler testbed at NASA Ames in Mountain View; the Kepler spacecraft assembly in Boulder, Colorado; and artists' renditions of exoplanets discussed in this report.You can also hear our radio story on the search for exoplanets, watch the Planet Hunters TV story online and find additional links and resources.

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Artist concept of a Neptune-sized planet
orbiting the star 55 Cancri. Credit: NASA

The star, 55 Cancri, a Sun-like star in the constellation Cancer, has been under exoplanet surveillance for 20 years, and yielded the secret of its first planet in 1996. Over the years of continued observations, one by one more planets in its retinue have been coaxed out of the data.

Personally, moments like this are an impetus to step back and reflect on the state of our understanding of the universe. How much more we know now than we did when I was a starry-eyed child back in the 1960s! We knew of no planets beyond our Solar System when I was a kid. In fact, further observation of our own Solar System has, ironically, reduced the number of planets at home from nine to eight! Even pictures of places like Mars, and certainly the moons of outer solar system planets like Jupiter and Saturn, were blurry, grainy images lacking much detail.

Now, more than 260 planets orbiting other stars have been found (although we don't have actual pictures of them at this point). Still, going from my childhood, when exoplanets were theoretical and the question was still asked whether our Solar System is somehow special, even unique, to have planets at all, to today's solid body count of "worlds out there"…is simply breathtaking.

Most exoplanet detections are made by the measurement of the slight wobbling motion a star makes due to the gravitational pull of any planets it might possess. You might be imagining astronomers taking video of a star and playing it back at high speed to see it slither like a snake– but that isn't how it's done. Instead, the measurement is made using the Doppler Shift– observing changes in the star's speed by measuring the corresponding change in the wavelength of its light. (This is the same way that the Highway Patrol nabs speeders on the freeway, using radio-frequency waves.)

So what’s the 55 Cancri system like? Well, by virtue of the fact that current exoplanet detection techniques can only reveal large planets–gas giants like Jupiter, Saturn, Uranus, and Neptune– all five of the 55 Cancri planets are such. One of them, in fact, is four times the size of Jupiter–and another, Neptune-sized world orbits so close that it only takes only 2.8 days to make one circuit around its star. Not much like the Solar System we know and love–but there's plenty of room for variety in the universe, after all.

The next big move in the exoplanet hunt will be for Earth-sized planets orbiting their stars at Earth-like distances– a feat to be attempted by NASA's Kepler mission coming up in 2008. As always, stay tuned…

Benjamin Burress is a staff astronomer at The Chabot Space & Science Center in Oakland, CA.

latitude: 37.8148, longitude: -122.178