NASA ScienceCasts: Observing Change Over Time

1. 0:02These pictures depict the magnificent wonders of our planet, yet, they weren't taken anywhere on Earth.
2. 0:11Instead, they were captured by astronauts aboard the International Space Station
3. 0:17to chronicle the fragile beauty and ever-changing landscape of our collective home.
4. 0:27To date, over 4 million photos taken by humans from space have been collected,
5. 0:34from the earliest days of the Mercury and Gemini missions
6. 0:37to the ones taken aboard the Space Station, and all are freely available to researchers, scientists and the public worldwide.
7. 0:46These photographs are taken for many purposes, from artistic to the scientific, and have proven to have a wide range of uses.
8. 0:54A powerful use of crew photography is to study changes to our planet over long periods of time.
9. 1:01The Toshka Lakes and Lake Nasser in Egypt, for example,
10. 1:04have been photographed on a regular basis from the station over the past 20 years.
11. 1:09This is partially because the water levels in these lakes change dramatically on a month-to-month basis,
12. 1:16constantly affecting agriculture in the region.
13. 1:19Researchers, able to observe these bodies of water over a long period of time
14. 1:24using crew photography, can ask: Is their volume more or less stable over time?
15. 1:30Or, are they slowly losing their water?
16. 1:33Andrea Wenzel is a geoscientist for the Earth Science and Remote Sensing unit, who manage requests for crew photography.
17. 1:41She notes the flexibility that a crew member offers when taking a picture of Earth.
18. 1:46"A satellite generally takes the same photos over the same locations in the same orientation over and over.
19. 1:53Astronauts on the other hand can use different lenses
20. 1:56to take photos with different fields of view, from close up to wide shots.
21. 2:02The Cupola on the bottom of the Space Station allows for a panoramic view straight down,
22. 2:07or the crew member can elect to photograph an image that includes the horizon.
23. 2:11And, because the Space Station flies an asynchronous orbit around Earth, it can capture images at any time of day or night".
24. 2:20Wenzel notes that the Viedma Glacier at the southern end of South America
25. 2:24is a good example of a moving Earth feature being observed by crew photography over time.
26. 2:30There's been a significant decrease in the glacier's length over the years
27. 2:34and the photos allow researchers to observe the path the glacier is taking and correlate that to climate change data.
28. 2:43The crew can also be asked to capture an event, like a hurricane, wildfire, flood or volcanic eruption.
29. 2:51This image shows flooding in Columbia.
30. 2:54Wenzel says, "It was one of a series of photos that was used by international first responders to update their flood maps.
31. 3:01As a result, they launched an operation to rescue the inhabitants of local villages
32. 3:06who were stuck in place due to rising water"
33. 3:10Astronauts often say the most remarkable thing about seeing Earth from the Space Station
34. 3:15is viewing our planet across climate zones and continents, without borders drawn on a map.
35. 3:21Fortunately for those of us still on the ground, their photographic skills allow us to see what they see,
36. 3:28now and over decades of time, benefiting all of us in multiple ways.

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