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.

M9 Solar Flare of January 23 2012; credit: Solar Dynamics Observatory

Let's see, what's the weather like right now (sticks finger into the air). Speed, 1.2 million miles per hour, density 1.1 protons per cubic centimeter, temperature 200,000 degrees Celsius. Sound a bit extreme? Surely climate change hasn't made things THAT batty. As a matter of fact, conditions have calmed down in the last several hours.

Okay, I'm not talking Earth weather—if I were, we'd all be dead, fast. I'm talking space weather, and a subsidence in its condition following a powerful solar flare whose ejecta struck Earth on Tuesday, causing a strong geomagnetic storm, and some pretty Northern and Southern Lights.

The flare in question, associated with the big sunspot numbered 1402, erupted on January 23rd, launching a coronal mass ejection–a "cantaloupe" of plasma that makes Earth look like a grape. Rated as an M9-class flare, it packed umph just shy of what's necessary for adult "X-class" flaredom, the most power kind.

When it reached us the megablob of plasma struck Earth's magnetic field, causing the geomagnetic storm and a minor list of annoyances (communications interference, for the most part, and some reported concern to an electrical grid operator). On the showier side of solar activity, the storm generated spectacular auroras in high latitudes.

The Sun's magnetic activity—the source of disturbances like flares and oft-associated coronal mass ejections—has been on the rise for the last couple of years, heading for a forecasted peak in activity ("Solar Maximum") in 2013. We're in "storm season," with respect to the Sun's 11-year magnetic activity cycle, so we can expect more, and stronger, flares and geomagnetic storms in the next year or two to come.

Back when I was growing up (1960's) I learned that space is a vacuum, void of the gases we find in Earth's atmosphere. It was a stark picture of emptiness, at least as this child comprehended the data. Sure, sunlight and starlight streams through that vacuum, but other than that, Dr. Science explained, if I took one space-step outside of my personal Mercury space capsule without protection, I'd suffocate and my blood would boil and freeze at the same time—not to mention that I'd get cooked by the dangerous ultraviolet and X-ray radiation shining from the Sun.

Okay, close the Time-Life science series book entitled "Space" and open an astrophysics textbook of my 1960's youth era, and I would have learned that there's more to the vacuum of space than nothing.

Our Sun, a gargantuan fusion bomb that consumes a mass of hydrogen comparable to that of the entire human race each second, continually spews more than just sunlight into the space around it. Hot, electrically charged gas (plasma), mostly hydrogen nuclei and electrons, blended with an accompaniment of magnetic fields, blow outward from the Sun's surface and atmosphere all the time.

That's the solar wind, and its conditions, whether normal or stormy, is what makes space weather. So when you're curious about the weather conditions in the space surrounding Earth and its protective magnetic field, poke your finger skyward and extend your arm—oh—about 50,000 miles…or just go to a space weather website like Spaceweather.com.

To those who know rocks, this chondrite meteorite could not be mistaken for an Earthly stone. Photos by Andrew Alden

The other week I mentioned, in talking about concretions, that people can be fixated on the idea that they have found a dinosaur egg or meteorite. This last week meteorites featured in two news stories, one excitingly true and the other almost certainly bogus.

The exciting story was about a set of meteorites recovered in the desert of Morocco, a few months after their fall from space had been recorded. That doesn't happen very often—once meteors arrive in the atmosphere, their unguided trajectory means that a rather large area must be searched to find them. What was extraordinary was that these rocks were from Mars, certified as such this week by an expert scientific panel.

Meteorite hunting has become a cottage industry in the Sahara Desert, where conditions are ideal for space rocks to be preserved and for practiced observers to spot them. The locals who found the new Martian rocks sold them to dealers, who in turn marked up the price to almost a thousand dollars per gram even before the meteorites were formally certified as Martian.

Meteorites are most easily found in two places on Earth, the Sahara and Antarctica. In the case of Antarctica, they fall on the ice cap, where no other rocks exist at all. Movements of the ice can concentrate these meteorites, including the rarest stones from Mars and the Moon, in certain areas that are surveyed regularly and exclusively by scientists. That's good for science. For its part, the Sahara is good for the rest of us who can acquire these rarities for our own pleasure. And scientists can still study Saharan stones because meteorite hunters must donate pieces of their finds to a museum to qualify for authentication, without which the stones have no value. It's a tidy system with little impact on the environment.

The California deserts are also promising places for meteorite hunters. At least one Martian stone has already come from the Mojave. Meteorite hunting is simple in principle, yes, but far from a casual hobby. First you acquire a very intimate knowledge of the rocks that belong there, and then you examine approximately a million rocks to find one that doesn't belong there. And with that, you start to learn about meteorites. I love rocks inordinately, but I think I would still go mad. Dr. Randy Korotev is a genuine meteorite expert at Washington University who gets torrents of email from would-be meteorite finders. On his excellent "What to Do" page, he says that of over 2000 serious inquiries over the years, only eight people had real meteorites.

Easier to dream of fabulous wealth falling into your back yard. That dream, fed by an extremely rare handful of true stories, can blind people to the obvious. And that leads me to the Castro Valley man who got a reporter to feature his story in the San Jose Mercury News last week. His story did not even point to a meteorite, let alone prove it. He said he responded to his dog's barking and found a fresh pit in his back yard with a smoking, red-hot stone in it. That scenario is a old urban legend about meteorites that is never true. He said he talked to experts from Lawrence Livermore National Lab, who had him hold a magnet against the stone and try to cut off a piece of it. He claimed that after finding it both non-magnetic and hard enough to break a hacksaw blade, those experts told him that was positive evidence. None of that is what an expert would say. And the object he showed a photographer had a silvery color and finish (which could not be iron because it was non-magnetic), and a multiply-layered structure that is very common in Earth rocks. In short, it looked nothing like a fresh meteorite and everything like an ordinary metamorphic rock. But he was fervent enough in his belief to fool a reporter, and at least one editor, into running the story anyway.

This is the back side of the chondrite shown at the top. Note the dark fusion crust and the hollows, called regmaglypts, carved by erosion in passing through the Earth's atmosphere. And a magnet sticks to it because it has small grains of iron metal throughout it.

Easier to save up some of your birthday money and buy a nice little meteorite at a rock show from a large, well-run dealership. My advice is to wait until the afternoon of the last day for the best price; dealers hate to pack up their inventory. That's how I got my 1/3-pound chunk of meteoritic nickel-iron from the Sikhote-Alin fall. There's nothing like the feeling of this ancient space metal in your hand.

The Sikhote-Alin fall occurred in eastern Siberia in 1947. Specimens like this are readily available.

I've written more about Martian and lunar meteorites on my About.com site. I also have a photo gallery there. Dr. Tony Irving has a deep and erudite page on Martian meteorites.

Orion rising in Death Valley - Credit: Ben Burress

What brings this on? Well, the skies of Death Valley, actually, which I just returned from (Death Valley, not its skies!) over the holiday break. My daughter and I went down there, mainly to crawl around the sand dunes and canyons, visit sites of the Gold Rush pioneers who gave the valley its [English] name, and get another good, up-close look at the raw Earth….

…but, as always, at night, when the campfire sparks warmly, I end up looking to the stars, which are extraordinarily bright in the dark desert skies. And I just get to thinking…again….

My touchstone on the vastness of the Universe is the knowledge that all the stars we can see in the night sky, with our unaided eyes, are quite starkly the closest things to us in the Universe—and even from those objects, light, traveling at 186,300 miles per second, takes years, decades, even centuries just to reach us. These "local neighborhood" stars are all within our Milky Way galaxy, and all among the very closest of them.

So, the stars of the night sky are a sort of "front drop"—like a big sheet of paper with stars printed on it, held before us–and the stars and galaxies of the rest of the Universe, beyond this "front drop," are too far away for our eyes to perceive their light (without the help of a telescope).

Trying to put the scale into perspective (trying very hard!), if this "sheet of paper" with stars printed on it, held in front of our collective Earthly "face", was, say, 1000 light years away (6000 trillion miles—which is actually about the greatest distance that our unassisted eyes can detect individual stars, and only stars of the most luminous type at that), this would be analogous in scale to an individual person holding a star-printed sheet of paper about two tenths of an inch before their eyes (yeah, I know, too close to focus on the printed stars…), with the surrounding Bay Area representing "the rest of the Universe."

What? I didn’t hear you…. What I said was, if the entire Bay Area represents the Universe, then the stars we can see with our eyes are found within two tenths of an inch of our eyeballs…. Even the Andromeda Galaxy, the most distant object unaided human eyes can perceive (and which I did spot as a very faint smudge on the dark Death Valley sky!), at a distance of about 2.5 million light years, would be less than 4 feet away from you in your Bay-Area-scaled Universe.

It’s here that my mind boggles, and it becomes doubtful to me that our brains have the capacity to really wrap around the Universal scale. It’s hard enough imagining the distances to the "nearby" local stars, a space in which light spends centuries crossing; trying to see beyond that big sheet of paper, to the 13.7 billion light year extent of space and time…boggle…fail….

So, the next time you find yourself gazing at the stars, remember that those are just the spots flittering around in front of our collective eyeball, no more than an eyelash away….

And if that makes you feel small, cheer up; you live in a Universe that is altogether astonishing and magnificent, and not just a run-of-the-mill Universe of comprehendible size. I feel honored and proud….

This solid vein of white mineral near Endeavour crater, up to 2 centimeters thick, has every appearance of the well-known mineral gypsum. NASA/JPL-Caltech/Cornell/ASU image.

We have been studying Mars with spacecraft for almost 40 years now, starting with fly-bys and progressing to landers and then rovers. Each of these scientific missions has been more ambitious than the one before, and each has found more and more Earth-like features on Mars. The latest example was announced last month in San Francisco at the annual AGU meeting: Mars has veins of gypsum. I've seen gypsum veins myself, right here in California. And you can too.

The currently operating Mars rover is named Opportunity, and it has managed to roll across the pristine Martian ground for more than 33 kilometers since it landed in 2004. Nosing around the rampart of the crater Endeavour in a monotonous area of basalt rock, Opportunity came upon the vein of solid bone-white mineral shown above. It approached closer and turned its alpha particle X-ray spectrometer on the stuff, along with its close-up camera. The spectrometer indicated sulfur and calcium in the right proportions, and the camera images reminded NASA scientists of nothing but gypsum, hydrated calcium sulfate or CaSO₄·2H₂O.

Close-up of the Martian gypsum vein. NASA/JPL-Caltech/Cornell/ASU image.

All right, so what? Well, gypsum points directly and unmistakably to liquid water, something that we've been looking for on Mars but never quite proving. There is gypsum-like dust blowing around parts of Mars, like it does at White Sands in New Mexico, but no sign of its origin. The mission's chief scientist, Steve Squyres, said at the AGU press conference, "This stuff was formed right here. There was a fracture in the rock, water flowed through it, gypsum was precipitated from the water. End of story. Okay, there is no ambiguity about this. This is what makes it so cool. . . . Here the chemistry and mineralogy of it just scream of water."

On Earth, gypsum is found in two main settings: wherever seawater begins to dry up, gypsum comes out of solution first and can accumulate in thick beds. And wherever hot-spring type fluids concentrate dissolved matter, gypsum is a likely mineral. The Martian vein appears to be of the latter, hydrothermal type. California's Central Valley, for much of recent geologic time, has been the former type of setting—a shallow sea basin or brackish lake.

Gypsum is especially abundant in the Kettleman Hills, an area of former Central Valley seabed that has been gently lifted by recent tectonic activity. If you have an extra hour next time you're on Interstate 5 going to Los Angeles, turn off at 25th Avenue, south of Kettleman City, and pull over once you enter the hills. Gypsum litters the ground there, and farther south near Lost Hills gypsum is being mined to make drywall, soil additives and plaster of Paris.

Gypsum of the Kettleman Hills. Photo by Andrew Alden.

If you're there in nice weather, enjoy the scene and think of Mars. Maybe you'll share the tantalizing feeling that the discovery of Martian gypsum arouses in geologists despite their best mental effort.

Kettleman Hills, 26 May 2010. Photo by Andrew Alden.

Endeavour crater, Mars, 6 August 2011. NASA/JPL-Caltech/Cornell/ASU image.

Like one of those 1950s-vintage Cuban taxis, Opportunity has hung on far longer than people originally planned. Planetary space missions have a fairly short "prime mission" of a few months or maybe a year, but everyone knows without admitting it that the rugged, overdesigned machinery will last a lot longer. NASA makes a big deal out of extending the mission, a year or so at a time, and we all feel good about getting our money's worth. In the case of Opportunity, its prime mission began eight years ago and the solar-powered contraption is still plugging along. Imagine what its successor, the rover Curiosity, might do once it lands in Gale crater in August of this year.

Read more about the discovery from NASA.

Do you have a unique voice that sets you apart from the crowd? Contribute your stories to QUEST!

KQED QUEST is looking to add new voices to our blog, which already offers commentary from our producers, reporters, and local writers from our partner institutions at Chabot Space & Science Center and The Tech Museum.

We're looking to include folks who are actively involved in the science, environment and nature blogging community – e.g. have a blog, guest post on others' site, and comment / participate in relevant discussions. And we're looking locally. Our blog has a strong SF Bay Area focus, though we do occasionally cover and/or perform analysis on how this stuff elsewhere that affects the Bay Area.

What we cover

QUEST’s geographic coverage is from Mendocino to Monterey and from Sacramento to Santa Clara, and generally covers 9 content areas: astronomy, biology, chemistry, engineering, environment, geology, health, physics and weather.

Requirements

• Original posts, 3-500 words with at least 1 image. Schedule determined on availability, but weekly or bi-monthly is preferred.
• Posts should relate back to at least one of our 9 themes for the program: Astronomy, Chemistry, Engineering, Physics, Weather, Geology, Biology, Environment, Health.
• Topic should be something about which you have some expertise and/or passion.
• A unique voice and ability to follow our QUEST writing guidelines (see below).
• Experience with WordPress or similar blogging platform.
• Willingness to occasionally be assigned a post topic by the editor as current events dictate.
• Respect for copyright and fair use.

Would I get paid?

Yes – we offer a small stipend on a per post basis.

Alrighty, then. How do I apply?

Email us a note and bio to questeditor@kqed.org explaining what you'd like to write for us. Please also include some links to relevant blogs you admire, and/or participate in, and why. Send us a writing sample or two (links are fine), and we'll review it in the next couple weeks. Last day to submit is February 1st. Our hope is to bring aboard a few new bloggers by mid-February.

Some beats we're interested in

Although we want to hear from a wide range of writers, here are a few coverage areas we're keen on in particular:

• Bay ecology background and issues
• Science education
• Silicon Valley / engineering innovations
• Hacks, DIY, and hands-on science activities
• Hiking and outdoors (with a science focus)
• Food science
• Convergence of art & science
• Nature & science photography

Writing Guidelines

(As laid out by our managing editor, Paul Rogers)

Why does my grandmother care? A key requirement of QUEST bloggers will be to explain scientific and environmental issues in a way that the general public can understand. Our audience is mostly made up of people who aren’t scientists or environmental activists. Posts should explain why the topics they are writing about are relevant to Bay Area residents.

Get to the point. Studies have shown that readers spend only a minute or two on most web sites before moving on. The average reader reads about 200 words a minute. Write tight, and lively. Keep it interesting and informative.

Avoid jargon. The purpose of good writing is to communicate clearly. Don’t use complex, esoteric scientific terms. Instead of saying "non-point source pollution," say "polluted runoff." Instead of "extravehicular activity," say “space walk.”

Be personal. Relate personal experiences. Speak in the first person. Tell them where you saw the blue herons or which movie best depicts what a real moon base might look like. Find your own voice and write in a compelling, approachable way.

Be passionate. Write about subjects and topics that you care about. Please don’t feel you have to stick to a script or formula. Express yourself.

Drive traffic to the blog. Place a link in your correspondence and comments to the blog. Mention it on other web forums.

Write for the bigger picture. Don’t view the blog as a place just to promote your institution or pet cause. Keep in mind your audience is made up of a wide diversity of people, with wide interests.

Speak your mind, but check your facts. Or your audience will do it for you with painful results.

Know your fellow bloggers. You'll be part of a vibrant community with fresh ideas and discussions nearly every day. Don't be afraid to comment on their posts, or link to their entries. Have fun with it! Dreary bloggers or insufferable policy wonks need not apply.

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.

From hackerspaces to banana slugs, flying telescopes to cheese — it's been a quite a diverse year of storytelling here at QUEST. Here's a round-up of the top 10 video and audio stories and blog posts (based on page views) that you've enjoyed from the past year. Please let us know what other stories you've enjoyed in the comments section below, and if there's anything you'd like to see in the coming season!



VIDEO:

Nanotechnology Takes Off

Stem Cell Gold Rush
Science on the SPOT: Banana Slugs Unpeeled
Berkeley Lab Physicist Shares Nobel
Science on the SPOT: Open Source Creativity – Hackerspaces
Super Laser at the National Ignition Facility
The World's Most Powerful Microscope
The Science & Art of Cheese
Mt. Umunhum: Return to the Summit
The Fierce Humboldt Squid

AUDIO:

Up All Night on NASA's Flying Telescope</a>

The Lost Lagoon
Energy-Saving Windows Get Smarter
The Amazing Transformation of San Francisco's "Sludge Puddle"
Supercomputers Hit an Energy Wall
From Tunnel to Tap: Quake-Proofing Our Water Supply
"A Big, Captivating Idea": The Bay Area Ridge Trail
Architecture for the Birds
Gulls Threaten South Bay Salt Pond Restoration Work
In a Sea of Energy Data, Utilities Try to Inspire Conservation

BLOG:

Explosive hypothesis about humans' lack of genetic diversity
Diet Sodas May Not Be As Harmless As You Think
Health Officials to Consider Tightening Vaccine Exemptions
Scientists Understand Heart Disease Better, Still Give Bad Advice
The Megalodon's Descendants
Famous African American Scientists & Innovators: Part II
Swine Flu – A Virus or a Bacteria?
Cyber Wolves in (Fire)Sheep Clothing
Why Do Mosquitoes Buzz in People's Ears?
15 Months Later, Rediscovered San Francisco Plant Thrives

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….

Moon today and during the Cretaceous

Although I am a lifelong fan of science, I've also been a lifelong fan of science fiction—so I sometimes experience conflict in the DMZ where the two meet.

Having been raised on Star Trek, where the science and technology routinely violate known scientific principles (faster than light warp drive, for example), I learned to have leniency on some of those violations—at least, the ones that exist in order to make the story work.

But the stories that get the science completely wrong, for no good reason, get my militia up in arms….

Such was my reaction when, a few weeks ago, I happened upon the last two minutes of the series premiere of a new television show—the one that involves time-traveling colonists going 85 million years into the past to live among the dinosaurs. (Don’t ask me any more about the plot; I’ve only ever caught the last two minutes of each show when I change the channel to wait for House. All I know is each episode seems to end with people creeping through a jungle at night carrying torches….)

So what irked me so badly? Scene: colonists in settlement in Cretaceous jungle, night time, looking up at the starry, Moon-adorned sky. A child muses, "Is that the Moon?" (never having seen it before). "It’s so big!" Indeed, the Moon aloft in these prehistoric skies was depicted as truly huge—I’d estimate ten or fifteen degrees across, about the width of your hand spread wide at arm’s length (20 to 30 times the size of the Moon we know).

Enter "brainy" teenage girl to explain: The Moon is moving away from the Earth a few centimeters each year, so here, 85 million years in the past, it’s much closer to Earth.

How much closer was the Moon to Earth 85 million years ago? Do the math, brain: The Moon is currently moving away from the Earth at about 3.8 centimeters per year, so 3.8 cm for 85 million years equals 323 million centimeters. Sounds like a lot, right? 323 million of just about anything seems like a lot. 323 million centimeters is 3,230,000 meters, or 3,230 kilometers. Or a little over 2,000 miles—which, coincidentally, is about the diameter of the Moon itself. Since the Moon is presently 240,000 miles from Earth, being 2000 miles closer to us in the past (about 0.8%) would not have made it perceptibly larger—let alone appearing as big as a cantaloupe!

The Moon has been moving away from the Earth since its formation, which took place about four and a half billion years ago. Through tidal interactions with the Earth, the Moon has "stolen" some of Earth’s rotational momentum (spin) to gradually boost itself farther and farther away, slowing the Earth’s spin as a result. Back in the day when the Earth and Moon were young and fresh—and much closer together—the Earth spun much faster: maybe once in 8 hours. (But that was WAY before life existed, so try not to imagine the dinosaurs experiencing much shorter days, please.)

Oh yeah, in that same two minutes of the show premiere, the "brainy" girl (it’s not her fault; it’s the show’s writers, of course) also had an answer for why all the stars in the Cretaceous sky bore no resemblance to the constellations we know today. The Universe is expanding, she said (correctly), and so in 85 million years that expansion has caused the stars to change position" (not so correctly). The Universe is expanding, yes, correct; the stars in Earth’s skies 85 million years ago would have looked completely different, yes. But the two have nothing to do with each other.

The Universe is expanding and carrying all of the galaxies and galaxy clusters farther and farther apart. But this has no effect on the stars gravitationally bound within each galaxy. At the scale of a single galaxy, like our own Milky Way, the gravity binding the stars together in that great spinning spiral overpowers the effect of space expanding.

The stars we see in our skies are all inside of our galaxy, to which they are gravitationally bound. It is merely the motion of those stars within the galaxy as they orbit the center that change their relative positions, and so the patterns of constellations that we perceive. Analogously, continental drift on Earth may move a pair of land masses away from each other, but that large-scale motion won’t cause the trees within either of those lands to move apart.

Nit picking? Yeah, maybe. But I even do it to Star Trek on occasion….