Where common sense and the film divide is just how best to dodge an oncoming meteor. I wrote a while back on the idea of painting one side of the asteroid black while beaming heat onto it, causing the asteroid to shift course. It’s a neat idea, but not nearly as neat as the gravity tractor, not just because this approach is more elegant, but because there’s a British company called EADS Astrium that announced last week that they could actually build one if it were needed.

The idea for the tug first proposed by NASA scientists Edward Lu and Stanley Love in a paper in Nature in 2005. The pair realized that sure, we could change an asteroid’s course by docking a rocket onto the asteroid and pushing it, but landing on an asteroid is really hard: The asteroid is an extremely fast-moving target, and often it rotates asymmetrically around its axis, meaning that a lumpy part of the asteroid could smash a relatively teeny rocket in its rotational path. But, the scientists argued, the spaceship could hover 200 meters or more above the asteroid and use their mutual gravitational attraction to form a “towline” between the two. Then ship could use its own propulsion to slowly pull the asteroid to another course. It would have to push very gently to avoid breaking the bond and flying away, but over the course of 15 to 20 years, the asteroid could be persuaded to miss our planet.

The idea of a gravity tractor has been refined (PDF) by scientist Bong Wie, working at Arizona State University, who proposed the use of solar sails to eliminate the problem of fuel capacity on the satellite. (Love and Lu’s proposal relied on nuclear energy generators for power in their design.) Solar sails capture the momentum from photons of solar radiation to provide propulsion. By properly angling the sail (Wie proposes 35 degrees), the body of the space ship can be moved in the desired direction. The sail can take months to build up significant velocity, but since it has a long time to accomplish its tugboat-like task, this isn’t inherently a showstopper. That said, solar sail technology is still in its infancy—it’s only been tested on a very small scale by American and Japanese scientists in space—so it’s not ready for large-scale deployment just yet.

EADS Astrium’s design uses four ion thrusters of the sort used on Deep Space 1.  Each is aligned to keep the device hovering above the asteroid while gently pulling the asteroid via it’s gravitation “towline” off course. The ship will be 30 meters (about 98 feet) across and weigh about 10 tons. In news articles, Astrium representatives say they haven’t even built a prototype yet, but they’re convinced they can bang one out if necessary.

All of which puts us back to the question of whether there’s enough capacity to provide the necessary early warning to build and launch a gravity tractor in time to have it work. Since NASA currently tracks about 6,000 asteroids, of the 100,000 out there, I’m going to go with no.

It’s been worth the wait.

Since the probes started sending data back to Earth, scientists from JPL have been helping Kloor’s team turn it into the most accurate visual renderings of first few planets of the solar system anyone has ever seen. These reputedly amazing visuals will form the bread and butter of Quantum Quest, an animated, science-fiction, large-format film film that’s now been 12 years in the making.

Each rendering will be founded on contours developed from radar data, and then surfaced over with visual data, all merged together through CGI. And although the plot will feature a crew of talking neutrinos and photons taking a “solar safari” from the sun to Saturn’s moon Titan, all the space visuals, Kloor swears, will be real.

But unlike the real solar system, in Quantum Quest, there will be sound in space.

Naturally, this isn’t the sort of explosions and lasers we heard in Star Wars or Serenity. Quantum Quest aims for a more exacting standard of scientific precision (aside from the talking particles). I had a chance to talk to Kloor and his composer, Shawn Clement, in the midst of the madness of Comic-Con. First, he explained that the Huygens Probe did actually record sound (while it was in Titan’s atmosphere) and transmit it back to Earth.

But more of the film’s score is inspired by radio signals Cassini detected coming off the rings of Saturn, rather than actual sound. Of course, the human ear does not, as a rule, “hear” radio signals. To get around that, sound engineers “frequency shifted” the signals down into the audible range. Another challenge was that the sounds were also very long; they didn’t modulate quickly. So to get them into a format that could be used in a film, engineers compressed the signals into smaller packages. Kloor said these manipulations were necessary, but don’t alter the fundamental shape of the sound.

Clement never had to deal with any of this himself. He and the sound magicians at Skywalker Ranch, who are handling the background folio for the film,  got the samples already in audible form. To write the music, Clement started mucking around with the sounds in his synthesizer, but found that it wasn’t really working. So instead he went old-school and busted out a guitar and a violin.

“What I did with those was mimic those sounds a lot,” he said. “But I was able to manipulate that and do what I wanted to do. It worked out really, really well. You’re hearing those sounds and hearing them shift and change and eventually, by the end, you get the full orchestra.” Clement sent me a couple of clips of his music:

Neat-o space sounds inspired by radio waves from Saturn’s rings

After all these years, the film is finally due out in February 2010.

If you don’t have  time to watch the video you can read recaps and quotes from the panel here, here, here, here and here.

Big thanks to Jennifer at SEE, to all of our panelists, and to the Bad Astronomer, who found time to moderate our panel while he wasn’t partying with Hollywood starlets (Phil – we kid because we love).

For any curious readers of the Loom, we’re already checking with Yturralde if he wouldn’t mind if we submit a pic of his tattoo to Carl’s Science Tattoo Emporium.

“I think of Shrapnel as the anti-Star Trek,” says Sagan, who wrote several episodes for the franchise. “Instead of putting aside our differences to boldly go and do great things, I’m not sure that’s the way it’s going to actually happen. Shrapnel is based on the idea that we do colonize the solar system, but it’s not clean and optimistic. The haves are putting the screws to the have-nots. The story is about the last stand of the last free colony in the solar system.”

But moreover it reflects about man’s battle with himself—pitting the thin veneer of civilization against millions of years of evolutionary programming. “Higher levels of technology allow fewer people to do more damage,” says Sagan. “That’s going to be a real challenge for us. There’s a belief that if we branch out into the solar system, if something goes terribly wrong on Earth, we have an escape route. That’s a hopeful idea, but we tend to take our problems with us wherever we go. As a science-fiction writer, I feel my responsibility is to look ahead and see the dangers of what might happen, and try to warn people of the potential pitfalls.

“It’s an understandable criticism that with so much to fix on earth, why are we going off into space? But space exploration brings an appeal to the spirit and sense of wonder, not to mention opportunities to bring enemies together in a joint effort.”

Sagan—actually his voice—is already representing Earth to the universe: His father included his six-year-old voice saying, “Hello from the children of planet Earth,” on a record aboard NASA’s Voyager (aka V’ger).

“Years later high school friends would tell me that because I sent a message to the stars, my family would be spared by invading aliens,” he said. “They asked if I could put them on the list. I’d say, ‘Suuuurre… how much do you have on you?’”

—Guest-blogger Susan Karlin

Quantum Quest: A Cassini Space Odyssey is an animated film that makes use of data from NASA’s Cassini mission.  The movie tells the story of Dave, a solar surfing photo who battles his way through the solar system to save the Cassini probe from evil aliens.

Twelve years in the making, Quantum Quest has cycled through at least a couple of voice casts.  At last year’s Comic Con Quantum Quest panel, producer Harry “Doc” Kloor, a scientist and veteran science fiction writer, announced that he had lined up Digimax Inc., a Taiwanese animation studio, as his partner to finish the film.

At this year’s panel, featuring Bob Picardo, Doug Jones andJanina Gavankar, Kloor announced that the movie will see wide release in February 2010 and will include actual Cassini images, including Enceladus and Titan.

This morning, io9 demonstrated that in addition to putting out an awe-inspiring blog every day, they could also put on a mind-expanding Comic Con panel.  With no Hollywood celebrities and just a couple of special guests, our favorite sci-fi bloggers ran through the TV shows, movies, comics and books of the past year that “blew our minds without blowing up any giant robots.”

Here are a few of their recommendations:

Moon -Duncan Jones’s new movie topped the list for both Annalee Newitz and Meredith Woerner.  Like a lot of the works recommended by the panel, Moon explores what it means to be human in a rapidly approaching era where humanity can be technologically upgraded or artificially created (note: this is not a spoiler, the lead character realizes very early in the film that he is a clone).

Julian Comstock – In this novel, Robert Charles Wilson depicts a 22nd century American that has sunk into barbarism and theocracy.  In response, the hero undermines the regime in part through trying to popularize ideas about Darwin in a world that has forgotten about science.

Rest -  What if someone invented a pill that meant no one would ever have to sleep, with no adverse side effects?  Panel guest Bonnie Burton from StarWars.com picked the Devil’s Due comic Rest, which explores this idea and its implications on society, the environment and mental health.

Wonton Soup – James Stokoe’s comic, recommended by Graeme McMillan, investigates what humans would do if they had to be out in space for a really long time.  Apparently the answers are get high and cook alien recipes.

Infoquake – io9 editor Charlie Jane Anders picked a series of novels by David Louis Edelman.   In Edelman’s future, people can hack and upgrade their own bodies and brains, impacting human relations in both the literal and business senses of the phrase.

Given the awesomeness of science non-fiction that year, I might almost expect it to be a down year for science fiction. Not so. 1969 had some good sci-fi—maybe not as good as landing on the moon, but damn good nonetheless.

It was, for example, the year Billy Pilgrim came unstuck in time. In Slaughterhouse-Five, Kurt Vonnegut challenged the idea that sci-fi wasn’t an appropriate genre for high-brow “literary-fiction” writers, tradition that has carried forward to become the “counter factual” fiction (sci-fi by any other name…) of writers like Margaret Atwood and Michael Chabon. It was also the year Ursula K. LeGuin explored gender and identity in Left Hand of Darkness, and Michael Crichton scared the bejesus out of everyone with his  mutated virus in The Andromeda Strain. Ray Bradbury published a collection of short stories in I Sing the Body Electric (the title story of which became The Electric Grandmother), and Isaac Asimov collected some of his best stories in Nightfall and other Stories.

In June of that year, TV watching geeks saw Captain Kirk set his phaser on stun for what they thought might be the last time (oh, what they didn’t know!) when Star Trek went off the air. Perhaps in mourning, ardent fans held the first Star Trek convention before the show was even canceled, in March 1969 at the Newark public library. The Doctor (you know Who) regenerated for just the second time as Patrick Troughton made way for the 1970 arrival of Jon Pertwee.

In movieland, sci-fi screenwriters would have a hard time following up Barbarella, 2001: A Space Odyssey, and Planet of the Apes, all of which came out in 1968. Gregory Peck struggled to rescue stranded astronauts Gene Hackman, Richard Crenna, and James Franciscus in Marooned, which came out four months after the moon landing. The novel that provided the basis for the movie actually used the single-occupant Mercury capsule, but Hollywood updated it for the Apollo era. The space station in the film is based on NASA’s early drawings for SkyLab. In some ways the movie was ahead of its time, as producers decided not to include a regular score and instead use a series of beeps and hums to evoke the isolation of space. (Turner Classic Movies will be airing Marooned at 1:30 a.m. EDT Tuesday, July 21. Check local listings and set your Tivos!).

Tough to compete with actual space travel when you’re a science-fiction writer or producer, but still, not a bad year to be a nerd.

If a nanoparticle field emission thruster (the aforementioned NanoFET) has been a subject of investigation for University of Michigan electrical engineer Brian Gilchrist for several years now. Gilchrist, joined by a team of scientists, has published and presented papers (pdf) at conferences (pdf) around the country, trying to show the theory of how electronically charged nanotubes could enable a spaceship to achieve astonishing speeds.

As Gilchrist envisions it, a nanoFET engine would be installed as a series of flat plates around our spaceship—let’s say the Millennium Falcon. So instead of the white glare of rockets pointed off the back of the Falcon as it flees TIE fighters, there would be a series of flat panels that resemble the silicon wafers that go into microchips (the MEMS production process would be very similar). Each panel would be covered in round discs, each 10 centimeters in diameter, which in turn would be comprised of thousands of emitters, each roughly 100 micrometers in diameter.

Each emitter works a bit like an tiny particle accelerator: The anode of the emitter charges the nanoparticles, which are then accelerated and then shot out a tube by a strong magnetic field generated by a stack of microchip-like components. “In that a particle accelerator uses an electrical field to propel charged particles to high speeds — that’s exactly what we’re doing,” Gilchrist told MSNBC. Thanks to Newton’s third law, as the ship ejects particles in one direction, the ship moves in the opposite direction. Eject long, thin nanotubes for high-efficiency, slow acceleration; use short, thick nanotubes for better acceleration at greater cost of energy. The NanoFet could potentially eject nearly any type of nanoparticle that would take a charge.

The nanoFET is also remarkable flexible and scalable. A plate of nearly any size could be placed more or less anywhere on the object to be propelled, and each plate could be nearly any size. So instead of the Millennium Falcon merely being the fastest hunk of junk in the galaxy, it could also be astonishingly maneuverable, with smaller plates on different parts of the hull to establish tight turns and sudden changes in direction.

The only real downside is that nanoFETs are not imagined to provide the kind of high acceleration needed to break Earth’s gravity and escape orbit. But once in space, a ship equipped with nanoFET would have an extremely thin and lightweight engine with a commensurately compact fuel source. The nanoFET would be able achieve nearly constant acceleration. Do that for long enough, and speeds of 90 percent of light speed might become possible. Just think, if the Americans in Armageddon had a nanoFET powered space ship available to get out and intercept that asteroid, that whole Affleck-Armageddon fiasco could have been avoided. And wouldn’t we all want that?

DISCOVER: What kind of realistic technology could we use to get to nearby stars? Which stars would be feasibly reachable by such technologies?

Kevin Grazier: It’s a saying plastered on T-shirts and bumper stickers—the kind sold at both science-fiction conventions and physics departments nationwide:

186,000 miles per second:
It’s not just a good idea, it’s the law.

The speed of light, of all electromagnetic energy, in a vacuum is the ultimate speed limit in the universe. Nothing that has mass or carries information can travel faster.

This universal speed limit is a direct fallout from Albert Einstein’s special theory of relativity. Special relativity implies that the speed of light in a vacuum is a universal constant, but values that we tend to think of as constant in our daily experience—mass, length, and the rate of the passage of time—are not. Depending upon the relative velocity of two observers, these values will “adjust” so that both observers see the speed of light as a constant. Two observers travelling at high speeds relative to each other will find themselves in strong disagreement about measurements like the length of each other’s spacecraft and the rate of the passage of time.

Another consequence of special relativity is that, as an object travels increasingly faster, it behaves as if it has increasingly more mass. Therefore the amount of thrust it takes for an incremental change in velocity (known in the space program as a delta-V) is vastly greater at high speeds than at low. This effect is also highly nonlinear: It takes almost an order of magnitude more thrust to accelerate from .9c (nine-tenths of the speed of light) to .99c than it does to accelerate from .5c to .7c. An object travelling at the speed of light would act as if it had an infinite amount of mass and it would, therefore, require an infinite amount of energy (read: an infinite amount of thrust/fuel) to attain it.

This is, of course, a shame for civilizations (like ours) who want to explore planetary systems around other stars first hand. The distances involved are, well, astronomical. Just within the Solar System, it typically takes NASA probes 6 months to a year to reach Mars; it took Cassini 6 years, 9 months to reach Saturn. The (currently) fastest object created by humankind, the Voyager 1 spacecraft, will take 40,000 years, give or take a few thousand years, before it makes its closest encounter with its first star: AC+79 3888—currently located in the constellation Ursa Minor. At that speed few Time Lords, and even fewer humans, would survive the journey to even “nearby” star systems.

Current chemical rockets, and even the more efficient ion drives, cannot propel humanity to the stars at a reasonable speed, but there are concepts for interstellar spacecraft drives that are promising, that could be constructed in a practical sense, and you may be surprised how long the designs have been around. Stanisław Ulam, a Polish mathematician who participated in the Manhattan Project, proposed nuclear pulse propulsion back in 1947.

The idea is simple: explode a series of nuclear bombs behind a spacecraft. The explosions are directed against a thick steel “pusher plate”. The pusher plate is, in turn, connected to the spacecraft by a huge shock absorber to lessen the high G forces from the impulsive accelerations. In the straightforward terminology of Jimmy Johnson, the engineer on the Phaeton:

Basically, we gonna blow us up a bunch of big ass bombs off the ass-end of this here ship. Big ass bombs gonna vaporize some big ass alloy plates, and the translation of all that big ass energy’ll make us go real fast. Real fast. Yippe kai-ay, m…

The practical attempt to design and develop nuclear-pulse propulsion was performed by General Atomics in San Diego in the 1950s and 1960s. Ultimately the Nuclear Test Ban Treaty between the Unites States and Soviet Union made the testing for such a drive illegal, nevertheless over 50 years ago the design seemed practical and could be implemented within the bounds of existing technology. For more information, NASA and Star Trek designer Mike Okuda provided still more details on Project Orion, the U.S. government’s investigation into a nuclear-pulse spacecraft.

An Orion-style drive powered by thermonuclear explosions could theoretically reach speeds of .08c to .10c. That could get a spacecraft to the nearest stars within a human lifetime, but not within Phaeton’s 10-year mission. Virtuality is set in the mid-21st century, and it’s reasonable to assume some technological advances in the intervening time. Phaeton does not use thermonuclear explosions for propulsion, the charges dropped out the back are matter/antimatter charges (yes the thrust for Phaeton is, in essence, provided by photon torpedoes). The obvious assumption is that by the mid-21st Century, science has solved problems regarding the generation and containment of antimatter. One estimate has shown that Orion-style drive propelled by matter/antimatter explosions could attain speeds of .5c to .8c.

If Phaeton’s Orion Drive (named after the real-life nuclear concept) could propel it to 80 percent the speed of light, it could get to Sol’s nearest neighbor, Alpha Centauri (4.4 light-years away) in just 5 years, 6 months. That’s certainly a vast improvement, and shortens the round-trip mission time to several nearby stars to less than a human lifetime.

Only, it gets better.

Special relativity, which bit us in the asteroid when it comes to top-end velocity, does our crew a favor as our spacecraft attains speeds that are a high fraction of the speed of light. Recall that for objects travelling at relativistic speeds, values like mass, time, and length appear to “adjust” to keep the speed of light a constant. At high speeds, distances that we measure at “rest”, or at low speeds compared to c, appear to be shortened. This effect is called Lorentz contraction or Lorentz-Fitzgerald contraction.

Moving at a snappy .5c, the distance to Alpha Centauri is only 3.8 light-years (down from 4.4), and the apparent travel time is a bit over 7 years, 6 months. At 80 percent light speed, the distance is 2.6 light-years, and the travel time is 3 years, 3 months—less elapsed time for the crew than it would take for light to make the same journey.

Travelling at a speed of 0.7c is the “break even” point, where the combination of spacecraft velocity and Lorentz Contraction means you are travelling at “functional light speed” (the distance to Alpha Centauri in that frame would be 3.1 light-years and the travel time 4 years, 5 months). Of course time passes at different rates based upon their relative speeds as well, a phenomena called relativistic time dilation, so if Phaeton were travelling at a speed of .7c, for every year that passes for the crew, a year and five months would pass for The Edge of Never viewers back on Earth. Billie Kashmiri alludes to this in her confessional near the end.

With the phenomena of Lorentz Contraction as an aid, many more star systems become potential targets of a 10-year mission. There are sound scientific arguments why astronomers believe that any star that could potentially have a planet with life, in particular intelligent life, must be similar to our Sol: from mid-F range on the Herzsprung-Russell Diagram to mid-K. There are several stars in that size/temperature range in Sol’s neighborhood. Below is a screen capture of a spreadsheet that the producers of Virtuality used to select the target star for Phaeton’s mission (text color corresponds to the star’s color):

On the spreadsheet are the stars’ distances at rest, and at various fractions of light speed—with the corresponding travel time.

Click image to embiggen.

Epsilon Eridani, the nearby star that the Phaeton is sent to explore, has one, perhaps two planets orbiting it, as well as at least three asteroid/planetesimal belts. If we assume that Phaeton’s Orion Drive can get her up to .8c, or 80 percent the speed of light, then because of Lorentz contraction the journey (normally 10.5 light-years) is only 6.3 light-years, and it takes just under 7 years, 11 months. So if the Orion Drive can reasonably get a spacecraft up to .8c, then Phaeton’s mission is actually closer to 16 years. If, however, the Orion Drive was capable of propelling Phaeton to .9c, or 90 percent the speed of light, then the distance to Epsilon Eridani is only 4.6 light-years, and the one-way flight time is 5.1 years.

So in order for Phaeton to get to Epsilon Eridani and back within the stated 10-year mission duration, we clearly see that the ship’s Orion Drive would have to propel her to over 90 percent the speed of light (.9c). For all the elements of Phaeton’s mission that might be practically attainable by the mid-21st Century, this is where a little science fiction enters the picture.

Thank you to Steve Cooperman, Doug Creel, and John Weiss for their helpful input and comments.

So, without further ado, here is what it would have looked like if a large object hit the Earth, during the 70’s, and many, many movie stars from that era (including Malden, Sean Connery, Natalie Wood, Brian Keith from Family Affair and a presidential Henry Fonda) had to run around reacting to it.

Question: How big an asteroid would be needed to completely destroy a planet?
That’s easy. It would have to be really, really big or moving very, very fast (or both for a real whopper of an impact), but there are some subtleties that are worth explaining.

First off, let’s admit that we’re really concerned with how big an asteroid would destroy planet Earth, especially life on Earth. I’m a bit more worried about my home planet than Mars, Jupiter, or even Pluto and even more worried about all the life we see around us (not to mention ourselves!). Earth is far more important from the human perspective, so let’s tackle that question.

Frighteningly, many large objects have hit Earth. Real whoppers. That’s a bit scary to think about. The good news is that the Earth is still here, so apparently large impacts of the planet-destruction kind rarely happen. We do know that smaller impacts have happened, such as the meteorite that hit the high Arizona desert just east of Flagstaff, at the site known as Meteor Crater. If we could count the impacts, we could gauge how frequently and when the impacts took place.

However, it is hard for us to find evidence of all the impact craters on Earth today. This is mainly due to erosion, which washes away the evidence by slowly filling in the craters, but looking at the Moon, where erosion is for all intents and purposes non-existent, we see that our nearest companion has been pummeled a lot, though mainly in the distant past. It, too, is still here and in one piece. The far side of the Moon, which always points away from the Earth, has a lot more craters than the side facing the Earth, which makes sense because the far side is more likely to be hit—it’s a bit harder for asteroids to sneak by the Earth and hit the shielded side of the Moon (though some have) than to hit the exposed side.

In fact, the Moon itself holds the key to what was probably the largest impact that the Earth has experienced (and hopefully will ever experience). Before I explain what we know about this biggest of all collisions, it is important to understand what we currently know about the formation of the solar system.

Stars form when dense and cold gas and dust that is prevalent in galaxies like the Milky Way slowly collapses under the influence of gravity. Astronomers see these forming stars just about everywhere we look—from regions practically next door, like the Orion Nebula, to the most distant galaxies we can see with the Hubble Space Telescope. As the star forms, a disk of leftover material takes shape through the combined effects of angular momentum and the force of gravity. These disks become fairly violent places as small particles of material slowly accumulate to form specks of dust, then pebbles, boulders, and ultimately planets. Astronomers have seen such disks in various stages of evolution with powerful telescopes.

Current models of planet formation gauge the time to go from a disk of gas and dust to a fully formed planetary system at about a million years, depending on the mass of gas and dust available and some other factors. Astronomers are not entirely sure how the process proceeds, but they have developed telescopes designed to peer through the material surrounding these forming stars to try and pin down the details. A prime example is the Spitzer Space Telescope, which observes in the infrared portion of the spectrum. Radio telescopes like the Very Large Array or the Atacama Large Millimeter Array (now under construction in Northern Chile) can also be used to effectively study the star- and planet-formation process, because the long-radio wavelengths they receive can escape the dense molecular clouds, unlike visible light.

It is now generally accepted that the Moon formed when a large, Mars-sized object crashed into the Earth very soon after the Earth itself formed. This collision dug deep into the Earth’s crust and threw off material from as deep as the Earth’s mantle into orbit where it was pulled together by its own gravity to form the Moon. This explains why rocks brought back from the Moon are composed of fairly lightweight minerals and rocks, containing little to no iron or nickel (metals found at the core of the Earth rather than the mantle). It also explains why the orbital plane of the Moon doesn’t line up with the orbital plane of the Earth itself (the impactor came from a different orbital plane). From dating the ages of rocks, geologists know the Earth is 4.65 billion years old, while the Moon is a bit younger, about 4.6 billion years old, evidently created in a subsequent massive collision.

So, in some sense, Earth wasn’t “destroyed” by an impact of an object the size of Mars that hit the Earth a somewhat glancing blow, but a more direct impact of an even more massive object could easily have had enough energy to seriously disrupt the Earth. Even so, in this case some kind of residual object would have formed, perhaps even two, and if life had taken hold after the planet and its companion cooled down, we might live in a true double planet system. Imagine looking up each night and seeing a blue companion planet in place of the Moon, with its own continents, weather, and oceans. That would be quite a sight.

What about life-ending impacts?
By studying the fossil record, geologists have identified sudden mass extinctions of species. They count the type and number of species in different layers of rock and can see when the number of species changes significantly. Two of the most significant extinction events are called the K-Pg boundary (a.k.a. the Cretaceous-Paleogene event) and the Permian-Triassic event.

The Permian-Triassic event took place about 251 million years ago. Although it is not entirely clear that major impacts caused this extinction, it is clear that the Earth’s life suffered an extreme setback. This extinction event led to the loss of 96% of marine species and 70% of terrestrial vertebrate species. Ponder this for a minute: This means that nearly all marine life was completely wiped out. More than two-thirds of all terrestrial animal species disappeared. Even many insect species—among the best survivors on the planet—were wiped out as well. This event is commonly referred to as the “Great Dying”—suffice to say it would not have been pleasant time to be alive. Although multiple impacts by large asteroids is a likely explanation for the Permian-Triassic event, there are other possibilities and research continues.

The K-Pg event took place 65.5 million years ago and is fairly clearly caused by the impact of a large asteroid. A thin layer of sediment with a high concentration of iridium was laid down around the world in a very short period of time. Iridium is very rare in the Earth’s crust, because it sank along with iron to the Earth’s core, but it’s often found in asteroids. There is also evidence of significant geologic activity around the time of this extinction event, which led to the loss of about 75% of all extant species, but most geologists believe it was caused by a giant impact near today’s Yucatan peninsula, forming the so-called Chicxulub crater. It is still not clear if the impact and its debris cloud (and tsunamis) were the sole cause of the extinctions or if secondary causes (chemical changes in the atmosphere or oceans) had a role to play. Again, research continues.

What can we take away from these extinction events? Life is both pretty tough and pretty disposable. Although life as a whole goes on, your species may not get a golden ticket. Impacts happen that can destroy most life on Earth. The good news is that life managed to survive and ultimately re-conquer the ocean and land, just not in the same forms that existed before. It is one of the amazing things about life on our planet that evolution guides both the long-term survival of life generally and the development (and extinction) of individual species. Life goes on, but any individual species may not.

Astronomers have begun multiple projects to scan the solar system and identify potential asteroids that might impact the Earth. Hopefully by identifying possible life-threatening objects, we could come together worldwide to somehow save ourselves (and all the other life on the planet). Right now, destroying or nudging an asteroid on a collision course would be a tremendous challenge, but it seems that impacts are few and far between, so we probably have enough time to develop the technology necessary for planetary protection.

Meta-conspiracy: Does the government want you to believe in UFO’s? [via Futurismic]

Real-life Terminator robots here, here and here.  [via Technovelgy]

Video of low-altitude flight over the lunar surface by the Japanese KAGUYA explorer [via Pink Tentacle]

Recently released scenes of the upcoming remake of V combine two of our favorite things: creepy aliens and Party of Five! [via thrfeed]

The GQ layout, “The Rock Stars of Science,” introduces a public service campaign that matches musicians with leading researchers in different medical fields to highlight the need for additional research funding.  The featured scientists include Francis Collins,  Harold Varmus and Anthony Fauci, all of whom have been mentioned in DISCOVER recently, so we can’t quarrel with the science cast or the cause.

My beef is with the rock stars.  Joe Perry?  Sheryl Crow?  Seal?  It’ s beyond me why GQ couldn’t find anyone who had produced a meaningful hit in the last ten years.  How about Tunde Adebimpe from TV on the Radio (bonus: album is called “Dear Science“)?

The Louis Vuitton campaign features astronauts Sally Ride, Buzz Aldrin and Jim Lovell promoting a $1500 handbag called the “Icare” (presumably as in Icarus as opposed to caring about space or handbags).  What does the space program have to do with Louis Vuitton?  Beats the heck out of me.  Just enjoy the video and hope that LV dug deep to pay these guys to participate.

Until recently, there was no need for us to try and engage with this sort of water recycling technology. In general, water has been plentiful in this world, and if it wasn’t we just piped it in. (I just re-saw Chinatown, so I’m feeling up on all this.) But increasingly short supplies of water in the American southwest and elsewhere have turned eyes to water recyling as at least a part of the long-term water supply solution. But to take a more extreme situation, let’s look at the final frontier, where there’s really no water at all. In fact, to transport water up to the International Space Station costs $15,000 a pint if we let the Russians do it, more if we send it up on Endeavor or Atlantis.

But today we got the marvelous news that instead of having to truck tons of water of space, the astronauts can just drink their own pee! (Yay?) Today marked  a successful test of the International Space Station’s water recycling system. The astronauts marked the occasion by raising a baggie (no glass in space) of recycled water (née urine) in a toast,  and taking it a sip. They deemed it delicious, and, after taking a few questions from reporters, went about their day.

The system is actually surprisingly basic. Most of the water comes from the toilets, though dehumidifiers in the oxygen regeneration system remove three liters of water a day from the atmosphere. For the moment the atmospheric water is being hydrolyzed to provide oxygen for the workers, but eventually it will be put into the recycling system with everything else.

The wastewater goes through a seven-step filtration system. First, they strain out the solids. Yes, this includes poop, which is 75% water to begin with, and thus cannot be flung out with the trash. Then the water is boiled, and the steam trapped in a system that behaves remarkably like a still. As the steam runs through the pipes, it cools and condenses until it’s pumped through a series of filters that are similar to water treatment down here on Earth. NASA says the water would pass muster in most municipal water systems.

In the end, though, they only recapture 93% of the water, no where close to the Fremen’s skill. Of course, the actual stillsuit would have some pretty serious technical barriers to actually working, as detailed by NASA scientist John C. Smith in his stillsuit chapter of The Science of Dune (edited by SciNoFi pal Kevin Grazier). Among other problems, it would be unpleasantly warm, especially after a day in the desert; the human body doesn’t provide enough kinetic energy to power the thing as author Frank Herbert suggested; and there would be great difficulties in cooling the evaporated water back into liquid. But, as Smith points out, Dune is set 13,000 years in the future. If today we can already make a unit the size of two-refrigerators for a space station, perhaps in 13 millenia we’ll have a real, wearable stillsuit up and running.

Image courtesy of NASA