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Why don't we have HD video of Earth rotating in space?
January 1, 2014 8:13 AM   Subscribe

Why don't we have HD video of Earth rotating in space? You know, relatively close-up, as if the Enterprise had just dropped out of warp and the planet was being majestically introduced to the cinema audience. An extended, multiple pass/rotation exposure, so that it could be watched by appreciative viewers wanting to get a bit of perspective/peace. I imagine I would sit and gaze at this for extended periods. What are the technical limitations which have prevented this?
posted by paleyellowwithorange to Technology (23 answers total) 10 users marked this as a favorite
 
As I understand it, there are no technical limitations. It just hasn't been done. See also Deep Space Climate Observatory which might provide what you are looking for and has been delayed for political, not technical reasons.
posted by vacapinta at 8:19 AM on January 1


There is plenty of HD video taken from the ISS of the Earth below. I'm not sure there is one continuous video spanning multiple orbits. This video is digital these days so downloading it from the ISS to Earth takes considerable bandwidth.

The recent Russian spacewalk on the ISS installed two cameras that will eventually provide real-time photos (and video, I think) of the Earth from the ISS. They had trouble getting them on-line but they should eventually provide anyone with the ability to see home from space. Possibly for a fee, as they are commercial endeavors.

There are also amazing videos of the Earth and the Moon dancing from far away. Perhaps not what you're looking for but certainly providing appreciative viewers with perspective and peace.
posted by bondcliff at 8:21 AM on January 1


Not exactly what you're looking for, but pretty nonetheless:

View from the ISS at Night
Time-Lapse | Earth
posted by bluecore at 8:26 AM on January 1


Why don't we have HD video of Earth rotating in space?

There's all kinds of video of the Earth from space, some in HD. I think it's less a question of "Why hasn't this been done?" as whether the shot you've got in your head has been taken or not. If it hasn't, the answer is probably something along the lines of "Because there are a practically infinite number of shots to be taken, and the people responsible haven't gotten to your specific one yet."
posted by valkyryn at 8:29 AM on January 1 [1 favorite]


The problem with the specific shot you're thinking of is placing a camera platform in a position and leaving it there. Orbitally that's difficult. About the only way it could be done is in the L1 point, which is directly between the Earth and the Sun.

Why hasn't it been done? Because it would be expensive, and because it wouldn't actually yield any interesting information to justify the expense.
posted by Chocolate Pickle at 8:37 AM on January 1 [4 favorites]


And from what I've seen and read (still need to go up and check for myself), a straight shot of 24 hours would be quite boring, mostly cloud cover and ocean. A composite of shots in the aspect of a desk globe would be pretty cool, I think it could be generated via a google earth spin and a screen capture?
posted by sammyo at 9:11 AM on January 1


Here's a sequence of the moon from an entire lunar month condensed into 24 seconds. Clouds would muck up doing the same trick with images of Earth. Almost there, NASA has compiled cloudless images of Earth.
posted by tinker at 9:18 AM on January 1


Tinker -- that was rendered.
posted by Chocolate Pickle at 9:20 AM on January 1


I've wondered the same thing about the sun myself. Real time seems to be the important bit.
posted by odinsdream at 9:23 AM on January 1 [1 favorite]


Until recently, Dish Network had a camera pointing at the earth on one if their satellites. If you had Dish you could tube in and get a (non-HD) view of the earth at any time. Unfortunately they decommissioned the camera. Maybe some day if they launch a new satellite they will resurrect the channel, and in HD.

There has been live HD footage of the earth taken from the ISS before, and it looks like this company is gearing up to provide such video soon. But the view is much closer and you won't get a whole-hemisphere "blue marble" type view.
posted by zsazsa at 10:43 AM on January 1 [1 favorite]


The problem with the specific shot you're thinking of is placing a camera platform in a position and leaving it there. Orbitally that's difficult. About the only way it could be done is in the L1 point, which is directly between the Earth and the Sun. Why hasn't it been done? Because it would be expensive, and because it wouldn't actually yield any interesting information to justify the expense.

To expand on that orbital difficulty ...

Low earth orbit (LEO) satellites (like ISS) are whizzing over the earth at relatively low altitude, so you get the close view seen in the videos linked above, not a global view.

If you get all the way up to geosynchronous orbit (GEO), then you do indeed get a global view -- the Earth subtends 18 degrees in the view from up there (it's 18 deg wide). However, the satellites are orbiting at the same rate that the earth turns, and so the satellite always sees the same side of earth (e.g. western hemisphere), so no apparent rotation.

A satellite orbiting somewhat above or below GEO would indeed see a slowly rotating Earth below, although much slower than realtime, meaning a full rotation would take far more than 24 hours. The farther you get from GEO, the faster it would appear to rotate, until you got to "normal" once-per-day rotation seen from an extreme distance like the L1 point that Chocolate Pickle mentioned.
posted by intermod at 1:07 PM on January 1 [6 favorites]


This is about as close as you're going to get to what you're asking for.

To get Galileo out to Jupiter it was necessary to make a couple of slingshots around inner system planets, including the Earth. Galileo's camera had a good telescope, and they shot telephoto pictures of Earth as they were leaving and stitched them together into a movie.
posted by Chocolate Pickle at 6:06 PM on January 1


A satellite orbiting somewhat above or below GEO would indeed see a slowly rotating Earth below, although much slower than realtime, meaning a full rotation would take far more than 24 hours. The farther you get from GEO, the faster it would appear to rotate, until you got to "normal" once-per-day rotation seen from an extreme distance like the L1 point that Chocolate Pickle mentioned.

Must be something I'm missing here: why would how far I am change the perceived duration of a full revolution? Surely that only changes if I'm not stationary with respect to Earth's rotation - or not?
posted by progosk at 9:55 PM on January 1


A satellite in the L1 point doesn't orbit the Earth. It's in Solar orbit, with the same orbital period as the Earth.
posted by Chocolate Pickle at 10:17 PM on January 1


Yes, but is there a reason why there couldn't be a satellite at or near the typical GEO distance, stationary with respect to the sun (and thus witness to a 24-hour Earth rotation)?
posted by progosk at 1:06 AM on January 2


Must be something I'm missing here: why would how far I am change the perceived duration of a full revolution? Surely that only changes if I'm not stationary with respect to Earth's rotation - or not?

If you're closer than geosynchronous orbit, you're orbiting faster than the Earth turns- e.g. The Space Station, which moves over our heads every ~90 min. If you're further, you're orbiting slower than the Earth turns. What intermod is saying, I think, is that the viewpoint of an observer slightly below GEO will move slowly ahead of the Earth's rotation, and one above GEO will slowly slip behind.

A satellite in the L1 point doesn't orbit the Earth. It's in Solar orbit, with the same orbital period as the Earth.

That's the Sun-Earth L1. There's also the Earth-Moon L1, which requires halo/Lissajous shenanigans to stay around.

Really, what we need is to send James Cameron on a Moon mission.
posted by zamboni at 4:01 AM on January 2


Yes, but is there a reason why there couldn't be a satellite at or near the typical GEO distance, stationary with respect to the sun (and thus witness to a 24-hour Earth rotation)?

The reason is "gravity". To do that would require thrusters to be firing constantly to hold it in place, and it would soon run out of fuel. The position you're describing isn't a stable orbit.
posted by Chocolate Pickle at 6:42 AM on January 2 [1 favorite]


Basically there is no stable orbit that would provide the image you're looking for. Putting something in a non-stable orbit and keeping it there would be incredibly expensive.
posted by blue_beetle at 9:25 AM on January 2


To expand on my link in the first comment in this post:

-The DSCOVR satellite is scheduled to go up
-It will be in a Lissajous orbit around L1
-It will likely have an imaging camera which is described as:
"Global spectral images of the sunlit side of the Earth. Wavelength spans ultraviolet and near infrared. 4 megapixel CCD sensitive over entire wavelength with 8-14 km resolution."

More info on that here (PDF)

Here's a good explanation of Lagrangians and Lagrangian orbits.
posted by vacapinta at 10:19 AM on January 2


Thanks, Chocolate Pickle & blue_beetle, got it now - it was the orbit stability part of the issue that I was missing: so it's not that the imaging is impossible at closer orbits, it's that it's so impractical/expensive as to be unfeasible. And now I know about L1, 2, 3, 4 and 5, too!
posted by progosk at 11:23 AM on January 2


This is about as close as you're going to get to what you're asking for.

Thanks, Chocolate Pickle, that certainly is the sort of thing I am after. Ideally, I would like it to be higher quality, and slightly closer.
posted by paleyellowwithorange at 4:30 PM on January 2


If you pay attention to that video, you'll notice that the apparent size of the Earth gets smaller as the movie proceeds. That's because the satellite was moving away.

If the movie were shot when the satellite was closer, that effect would be more pronounced.
posted by Chocolate Pickle at 11:25 PM on January 2


Check out this post from the blue about the HD camera delivered to the ISS by SpaceX.
posted by lharmon at 5:23 AM on June 13


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