Start your Tuesday the way your forefathers did, with an amazing time-lapse video of the International Space Station passing over a storm-struck African continent with the Milky Way popping in to say hello in the background. Also visible is Comet Lovejoy, two weeks after its near-fatal sunburn. Please, go look. You’ll feel better about being up.

‘Lights in the Dark’ has some information about the video, recorded over a 20-minute period on December 29, 2011:

1. How fast is the ISS traveling? A: 17,500 mph (28,160 km/hr). This footage is faster than real time.

2. What are those bright streaks on the right? A: Reflections in the window of the ISS from its lit interior and the light from outside.

3. Are those moving specks of light UFOs seen along Earth’s limb on the right side? A: Unidentified as in, I can’t specifically identify them, perhaps. But they are most likely satellites, of which there are 974 operational ones in orbit at the present time – and lots more inoperative as well as bits and pieces of old ones.

4. Why can we see stars? A: This is a time-lapse of individual photos, assembled by the team at Johnson Space Center. That said, the camera that took the photos was set to expose for nighttime viewing of Earth, making it much more sensitive to starlight. When imaging on the day side, the setting is much less sensitive so the scene isn’t overexposed, thus making stars not able to show up on digital film. That’s photography basics… film speed (ISO) plus shutter speed plus aperture (f-stop) equals a correctly-exposed photo…same thing in space.

5. What’s the glow around Earth? Pollution? A: No, it’s airglow. Ions in the upper atmosphere get charged up by sunlight and release that stored energy as light, which is easily seen at night by astronauts.

6. Why not higher resolution? A: The resolution uploaded by JSC is not full HD, and YouTube compresses it even further. Check out a more “HD” version on my Flickr page here.

[Source: LightsintheDark]