Tuesday, April 24, 2012

Planet Earth

In anticipation of Planet Earth's return to BBC America, this video was released featuring young fans reading scripts and voicing over action on the screen. These are supposed to be narrator auditions for the Planet Earth series, and some of their youngest fans decide to try their hand at relaying wilderness scenes. However, Sir David Attenborough - the regular narrator - is a tough act to follow, even for kids. The results are hysterical.

Sunday, April 22, 2012

28th National Space Symposium

Last week was the 28th National Space Symposium attended by over 3,000 space professionals. The keynote speech was given by Dr. Neil deGrasse Tyson, director of the Hayden Planetarium and the host of COSMOS. It is an inspiring forty minutes of speech by Dr. Tyson, followed by twenty minutes of Q&A. It is definitely worth listening to, especially in a time when NASA is quickly losing all of its funding. Enjoy!

Thursday, April 19, 2012

The Retirement of Discovery

The space shuttle Discovery took one last flight leaving from NASA's Florida spaceport this past Tuesday (April 17). After thirty years of service, it is going on permanent display at the Smithsonian Institution's National Air and Space Museum just outside Washington, D.C. Discovery was the leader of NASA's space shuttle fleet and, having launched in 1984, the oldest of the three shuttles remaining. Both Columbia and Challenger debuted earlier, but were lost along with their crews in tragic accidents.

Discovery is known as the world's most often flown spacecraft, having flown thirty-nine space missions and traveling a distance that is the equivalent of over 300 flights to the moon and back. Even more impressively perhaps is that it is the shuttle responsible for deploying the Hubble Space Station in April, 1990.

Eager viewers were able to snap photos on Tuesday as Discovery made its last flight, seen here on top a modified Boeing 747 jet.

Wednesday, April 4, 2012

Scientists develop ultra-thin solar cells

Today, Austrian and Japanese scientists have unveiled solar cells thinner than a thread of spider silk. These cells are still flexible enough to be wrapped around a single human hair. In the article on Physorg, Sekitani, from the University of Tokyo and one of the lead researchers, said the team hoped to increase the rate at which the device converts sunlight into electricity and put it to practical use in around five years.

So, what impact does this have on solar energy powered cars? Couldn't a car store the energy saved all day to charge the battery for later use?

Ignoring clouds, the daily average irradiance for the Earth is approximately 250 W/m2 . A Toyota Camry is 4.805m long and 1.820m wide, for a total top area of ~8.75m2 . That means every hour in the sun absorbs 2188W. Eight hours in the sun would get you 17,504 Wh.

But we have to take inefficiency in solar tech into account, which is currently around 10-20% efficient for most commercially available types. So we're only getting at most 3500Wh or 3.5kWh. Also that assumes no clouds and direct overhead sunlight, which is not often available, but for the purpose of the calculation we'll comply with. The Tesla Model S gets about 3.5 miles/kWh from it's battery back.

So covering your entire car with solar cells and leaving it in the sun for an entire day would get you at most 12.25 miles, but probably a lot less as not all the cells would be lit at the same time, the sun wouldn't be directly overhead, and there could be inclement weather, etc.

Now we just need to get the battery tech up to spec with the solar cell tech. It's no accident that the Oil & Gas giants have been scooping up patents to improved battery technology for years now. E.g. Chevron owning the large format NiMH patents. The truth is that while there is lots of anticompetitive and borderline illegal behavior in the industry. After all, it's a fiercely competitive industry so not unexpected. However, generally things are improving.

Plenty of technology has been developed over the last 10 years that is well outside the grasp of the Oil conglomerates and the $/kWh (cost per kilowatt hour) of renewables is steadily declining as the non-renewables costs are steadily increasing. Renewables will probably reach price parity with non-renewables for large-scale energy generation in the next 5 years or so and forward thinking countries like Canada, Germany, Denmark, etc... are certainly speeding up the process with their generous renewables subsidies too. So fret not, renewables are here to stay.

Sunday, April 1, 2012

Wind Map

Earlier today I came across something incredibly cool: a US Wind Map. It is an interactive map of the US with forecast winds shown across the country. These near-term forecasts are updated once per hour, with data from the National Digital Forecast Database. The website describes it as a "living portrait."

There are handy keys detailing the wind speeds on the side bar, along with a note of the top and average speeds. It's unfortunate that it isn't shown where the top speed occurs.

The site proudly states that it is not associated with any corporation and is, in fact, a personal art project. A disclaimer expounds, "We've done our best to make this as accurate as possible, but can't make any guarantees about the correctness of the data or our software. Please do not use the map or its data to fly a plane, pilot a boat, or fight wildfires." So while the map may be fun to look at, don't use it for anything serious!