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One of the latest uploads to the Gateway to Astronaut Photography of Earth site, this short-but-oh-so-sweet video shows the view from the Space Station as it passes over Africa, Madagascar and the southern Indian Ocean at night on December 29, 2011. Multiple lightning storms flash over Africa while the Milky Way rises majestically behind the thin line of Earth’s atmosphere, capped by a greenish layer of airglow. Also making an appearance is Comet Lovejoy, at the time two weeks after its near-fatal sunburn. It can be made out rising near the Milky Way’s right side, its faint tail vertical.
This video has made the rounds on the ‘net over the past couple of days, appearing on several news sites and gathering quite a few hits on my YouTube channel (at the time of this writing, about 160,000!)
Some of the common questions I’ve fielded on YouTube in regards to this have been:
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.
7. Is this CGI, fake and/or “gay”? A: Nope. None of the above. (To those of you unfamiliar with the world of YouTube comments, these are sadly some of the more common ones.)
Anyway, it’s awesome to see people so excited about a view of our planet from space. I hope it gets spread all over the place, because everyone should get to enjoy it! If it makes even just a few people more supportive of our space industry, it’s well worth it.
Video courtesy of the Image Science & Analysis Laboratory, NASA Johnson Space Center