Ever since Google Earth was first released, people have been asking how they can access the "live" version. My standard answer is that it's 10-20 years away, and that's still likely the case.
However, a company called UrtheCast is trying to make it a bit more of a reality. They'll be mounting two cameras on the International Space Station that will stream live content for people to view.
Of course, they'll only be capturing a very small area of earth at any given time, so it's certainly quite a long way from being "Google Earth live", but it's interesting nonetheless. That said, there are a few other problems to consider that they've hopefully researched.
The biggest problem is that you can't just point the camera on a particular location and expect to get a good shot. Problems with that are not limited to:
1) For any particular orbit, you may not be able to view the desired location (too far over the horizon, too much of an angle). You might a have to wait dozens of orbits to get over that spot.
2) Daylight - you have to be over the location at the right time of day.
3) Weather - too many variables to count a) clouds b) haze c) pollution.
4) time of year can be a factor - sun angle too low, and weather.
5) Conflicting opportunities. How do you decide which place to have your camera aimed at when there are 100 different places to aim and you're moving at 17,500 mph?
This leads back to the main article we wrote on how Google Earth imagery is processed. Even for static imagery it's quite a long process. To properly put live video into Google Earth would be amazingly difficult. As far as I know, UrtheCast has no plans to integrate their data with Google Earth, but there's still quite a lot to consider.
All of that said, this looks like a pretty neat project!
(via +Google Creative Sandbox)