Observing the Curve of the Earth

On the USA Science and Engineering Festival blog, astronaut John Grunsfeld describes what it's like to rocket into space. Astronauts first spend two hours strapped in on the launchpad, "flipping switches and thinking about our training and the jobs we have to do." They count down to ignition, mindful of the 4.5 million pounds of explosive in the fuel tanks. After liftoff, the shuttle accelerates out of Earth's atmosphere in less than nine minutes, causing each astronaut to feel like they weigh 700 pounds. An instant later, they are weightless. On Starts With a Bang, Ethan Siegel shares majestic pictures of the Earth from space, including a panoramic image from 1948 that clearly shows the curvature of the planet. Nowadays, MIT students can take a similar shot for only $150. But they still can't compete with pictures of the Earth from the moon, from Voyager, from Mars, from Mercury, and from the rings of Saturn. Whether out the window or merely pixellated, the Earth is a truly beautiful place.

• Astronaut John Grunsfeld Tells What Lifting Off in the Space Shuttle is Really Like! on The USA Science and Engineering Festival Blog
• Happy Earth Day, 2011 Edition! on Starts With a Bang!