Here's a little behind-the-scenes detail for you. For this week's videos with Chris Hadfield (you've seen them by now, right?), Chris actually played cameraman himself for all the footage shot on the ISS. This was likely the case for his now-famous Space Oddity music video, which makes the feat that much more impressive. The video clips the Canadian Space Agency relayed to us were 720p video shot from on a Nikon DSLR, and while we were reviewing the footage, we noticed speckles of static white pixels throughout the video. It looked like dead pixels on our monitors, but they were actually damaged pixels on the ISS cameras!

The prosumer-grade cameras used on the International Space Station aren't heavily modified for use in space (they are certified through a rigorous testing process), so they actually aren't shielded from the cosmic radiation that exists both outside and inside the station. So when video is being recorded and the DSLR's mirror is flipped up, high-energy particles slam into the digital sensor and damage it permanently. According to astronaut Rex Walheim of STS-135, cameras that are taken on space walks may suffer severe radiation damage on sensor pixels. NASA evaluates the damage and decides whether or not to retire that camera for use.

Cosmic radiation (primarily gamma rays) are a well-known phenomenon for NASA and its astronauts. Some astronauts, including Neil Armstrong and Buzz Aldrin, have even reported seeing streaks of light that were determined to be cosmic rays zipping past their eyes. The most prolific astronaut photographer, Don Pettit, described the rays' effects on ISS equipment on his blog:

"Free from the protection offered by the atmosphere, cosmic rays bombard us within Space Station, penetrating the hull almost as if it was not there. They zap everything inside, causing such mischief as locking up our laptop computers and knocking pixels out of whack in our cameras. The computers recover with a reboot; the cameras suffer permanent damage. After about a year, the images they produce look like they are covered with electronic snow. Cosmic rays contribute most of the radiation dose received by Space Station crews. We have defined lifetime limits, after which you fly a desk for the rest of your career. No one has reached that dose level yet."

So rewatch our videos with Chris Hadfield and see if you can catch those speckles of damaged pixels--it's just another consideration that astronauts have to be mindful about when living on orbit!

GeoGuesser is my favorite kind of mash up. It shows you a random street corner somewhere in the world using Google Street View images. Your goal is to figure out where you are, using only the cues in the Street View images. Then place your guess on a map. The closer you are to the actual location, the higher you score.

The most difficult guesses for me have been long, desolate stretches of country roads, like the one pictured above. Give it a try, then let me know what your best tips for sussing out the right spots in the comments below. (via Kottke)

We all know that life on Earth, in the grand scheme of the universe, is a pretty lucky deal. Our planet is just the right distance from the sun, with just the right atmospheric conditions, to support life. That's so rare, we obviously haven't found another planet with similar conditions. If we had, our sci-fi depictions of alien races would probably be a lot different.

For as unique as Earth is, though, scientists have typically considered our solar system to be, structurally, unremarkable. As NPR writes, we thought our solar system was normal. A star sits in the center. Small(ish) rocky planets, formed from dust melted by the star, orbit fairly close to that star. Beyond a certain point, called the frost line, larger, gaseous planets like Saturn and Jupiter hold much wider orbits. Their formative dust never got close enough to the sun to melt and condense into a rocky planet.

Photo credit: NPS.gov

That was the theory for years. It makes sense. But it's wrong. By peering at other solar systems, astronomers have discovered systems with gigantic, Jupiter-size gas planets nestled closely to their stars, with orbits of only a few Earth days. Mercury, the closest planet to our sun, takes 88 Earth days to make its orbit. Many systems even have twin gas planets in close orbit to their stars.

Given the proximity, these planets are obviously hot, not like the cold gaseous planets we expected. Other systems have rocky planets close, like ours--except not like ours, because they're also orbiting extremely close to their stars.

"As of this month, we've discovered 884 planets, 692 planetary systems, 132 of them with more than one planet and, strange to tell, almost none of them look like us...Though it will take a while to discover smaller planets, right now there's only one planetary system that looks a lot like our own" writes NPR's Robert Krulwich. According to an astronomer from the University of California, Santa Cruz, these solar systems are changing how we view the universe. That systems with very tightly clustered planets are more common than not.

All this makes our own solar system even more unique, but it raises questions, too. How did gaseous planets form so close to stars? One theory is that they form beyond the frost line, like our own gaseous planets, but then move closer to the star. Will that happen in our solar system? DId we have other planets in our system at one point that have been absorbed by the sun?

We don't have the answers, yet, but the questions are interesting all by themselves.

Few things in science fiction look as straight up fantasy as solar sails. The solar sail in fiction essentially mimics the surfboard-plus-sail combo used in windsurfing here on Earth. Except where windsurfers catch gusts of air to carve their way through waves, solar sails would harness radiation pressure--the light and gases emitted by a star--to surf through the blackness of space. Well, turns out that solar sails aren't that fantastical--in fact, NASA plans to launch one as early as 2014.

Photo credit: NASA

NASA's solar sail project couldn't have a more perfect name. It's called Sunjammer, after a 1963 Arthur C. Clarke which coined the term solar sail. According to NASA, the in-development solar sail will measure approximately 124 feet to a side for a total surface area of about 13,000 square feet. But "when collapsed, it's the size of a dishwasher and weighs just 70 pounds. Attached to a 175-pound disposable support module, the Sunjammer is easily packed into a secondary payload on a rocket bound for low-Earth orbit."

Solar sails could offer an alternative to heavy and costly rocket fuels, but they don't exactly offer the same degree of thrust. The maximum thrust would amount to less than a Newton of force, but because the surface area of NASA's sail is so large, it will still be able to move. A solar sail wiki writes:

"Solar pressure is very weak - about 9 millionths of a Newton (micro-Newtons) or 2 millionths of a pound (micro-pounds) of force on a square meter at Earth's distance from the sun. This is far too little pressure to have any effect on Earth, because other forces are much larger, like air drag and gravity driving us into the ground. In space there is no air and objects fall freely under the influence of gravity without the ground to constrain them. Sunlight can have a significant effect on objects, depending on how lightweight they are. Large and lightweight objects are affected more. Dust given off by comets is pushed into brilliant tails millions of kilometers long. Sunlight causes small errors to accumulate over time in spacecraft orbits and spin. Even asteroids gradually change their spin over millions of years. This gentle force is enough for a solar sail that is sufficiently large and light weight to travel between planets or change the behavior of its orbit around a planet or the sun - without consuming any propellant."

Monolith Magazine writes that "When held in orbit, Sunjammer will act as a type of forward observatory for both NASA and the UK Space Agency, with British scientists developing two instruments on board to study solar wind." Sails could eventually be used to clear debris from Earth's orbit or even deflect dangerous asteroids, though it's hard to predict what kind of thrust would be required for that.

Clarke's vision of ships racing under the power of the sun won't come true anytime soon, but NASA launching a real solar sail? That's a good first step.

Fourteen billion years ago, when one tiny, dense point became an unfathomable explosion creating all the matter in the universe, no one was around to witness the spectacle. We may not have first hand accounts of just how hot the blast or just how fast the matter traveled, but that also doesn’t mean that our knowledge of the universe’s early years are blank pages. There is a record of what happened, and from it, you can make music—the big bang’s original sound track, in fact.

In 2003, the mother of an 11-year old contacted John Cramer, a physicist at the University of Washington, with a question about the big bang. She was helping her son on a school project, and she wondered if anyone had been able to record what the explosion sounded like. The answer, of course, was no, but he kept returning to the question.

Image credit: Flickr user altemark via Creative Commons.

Cramer was a frequent contributor to the magazine, Analog Science Fiction & Fact, and just two years earlier he had written enthusiastically about how recent research projects looking at the cosmic wave background allowed scientists to hear “the sound of a Big Bang from a distance of 14 billion light years!” Cramer’s linguistic flourish actually meant that the data gathered could be used to understand what the big bang sounded like over a period of hundreds of thousands of years as the universe rapidly expanded. But scientists hadn’t actually heard the sound with their ears. Cramer had access to enough information. Why not recreate the sound?

Staging a revival of a very, very old explosion took Cramer just 16 lines to program, and an one hour on a Saturday morning. He constructed the sound in the software Mathematica, which gives users the option to render mathematical functions as sound. For all his interest in the subject, Cramer explains now ten years later, “I didn’t know what I was going to get.”

Photo credit: Seattle P-I file

The sound (embedded below), compressed to cover the first 760,000 years of the universe’s life, shoots up and then drops into a chest-vibrating hum that sounds like an airplane landing mixed with the static of the television. What came out of the speakers shocked more than just the physicist. Cramer’s two Shetland Sheepdogs came running into the room to inspect what in the world was going on. It was something bigger.

Every discussion of a manned mission to Mars inevitably touches on the practicality of a one-way, no-comin'-back trip. Sending a lone astronaut, or a small team, on a trip to a planet roughly 50 million miles away (when the orbits of Earth and Mars are relatively aligned) becomes much more viable when you don't have the carry all of the fuel they'd need to get back. Private spaceflight project Mars One is now moving forward with this idea, and hopes to establish a settlement on Mars in the year 2023.

NASA doesn't currently support the idea of a one-way trip to Mars, but The Atlantic wrote a great feature on a similar plan, from way back in 1962, that NASA probably thought long and hard about before going with the Apollo program. It was named the Cord/Seale plan after two engineers at Bell Aerosystems. After John F. Kennedy charged NASA with reaching the moon by the end of the decade, Cord and Seale proposed a way to make that trip by 1965: Send one astronaut, alone, with no way to get back.

Image credit: Bell Aerosystems Company.

Writes The Atlantic's Megan Garber:

"The pair formulated a plan to build a one-man spacecraft, ten feet wide and seven feet tall, that would be large enough to house a single human occupant. It would be half the weight of John Glenn's Mercury capsule. It would include tools and medical supplies and a battery-powered spacesuit. It would be equipped with enough oxygen for 30 days of space travel and enough water for 12. It would also include a nuclear reactor that would generate electrical power.

As Mary Roach outlines in her book Packing for Mars, a series of nine subsequent launches would head to the moon to provide this ultimate lone ranger with a better living module, better communications equipment, and the nearly 10,000 pounds of the food, water, and oxygen he would need to survive away from Earth. During which time, Cord and Seale figured, NASA would have had time to determine the details of another mission -- a rescue mission, essentially -- that would come to pick him up and bring him home."

Unlike the proposed trips to Mars, the astronaut in Cord and Seale's proposal would, after a few years, make it back to Earth. The political reasoning behind their idea is especially interesting. It was partially based on practicality, but it was also the only way they predicted being able to beat the Russians to the moon. At the time, their reserach suggested Russia could put a man on the moon as early as 1965, and there was no way NASA could launch a two-way trip that quickly.

By 1969, the two engineers predicted a three-man ship could carry two more astronauts to the moon and bring the lone explorer back to Earth with them. Assuming, of course, that he survived his time on the moon. It's not hard to see why NASA passed on the plan and decided on the roundtrip that eventually took place in 1969. As much of a political black eye as it would've been to have the Russians land on the moon first, having an astronaut die, stranded, on the moon, would be both tragic and a PR disaster.

That no doubt plays a role in NASA's hesitance to send astronauts on a one-way trip to Mars, as well, but there are many space experts who support the idea. Read the rest of The Atlantic's piece for more on our plans for Mars; and if you're really into the idea, check out the 99% Invisible podcast episode devoted to the subject.