I find the sky endlessly fascinating, but only get to see it from underneath. Satellites, of course, have the job of sending useful data, yet the images can also be stunning. And apparently, Earth-watching is a favorite past-time of astronauts on the International Space Station. ESA astronaut Alexander Gerst tweeted this picture a few days ago. Isn't it beautiful? Really, it could be a painting.

Here is another superb image of Earth taken by an astronaut aboard the International Space Station. The Australian Outback was photographed in multicolor glory by Canadian astronaut Chris Hadfield.

Lava flows from Mt Etna, imaged in February 2013. This is a false color image that's coded to emphasize different features. The red, for example, is fresh lava flow. The blue-green color - fortunately for the people nearby - is just snow. The picture was taken by NASA's Earth Observing-1 satellite.

Here is the latest photo from ESA astronaut Alexander Gerst: Dunes in the Sahara Desert. Another great picture from the International Space Station.

Barringer Crater in Arizona is a pretty big hole in the ground. You can certainly see it from space, as Alexander Gerst tweeted this picture today.

This is a strange image. I certainly couldn't have guessed what it is. It's Frozen Lake Sharpe, South Dakota which would be an ox bow lake cut off from the Missouri River, but it's maintained as a reservoir. The circles in the center are agricultural fields. The picture was taken last year from the International Space Station.

Here is the San Francisco Bay Area from space in a photo taken by Canadian astronaut Chris Hadfield when he was on the International Space Station. You can see the Gold Gate Bridge and a few others.

It could be an abstract painting. It could be a Martian landscape. But it's a photo that ESA astronaut Alexander Gerst took from the ISS over northern Africa. I'm running out of superlatives to describe the pictures he's tweeting back to Earth.

This is an unusual view of California's Napa Valley. It's not a photo, but an interferogram gernerated by using two radar images from the Sentinel-1A satellite.

The two round shapes visible in the central part of the image show how the ground moved during the quake. Deformation on the ground appear as rainbow-coloured patterns. The maximum deformation is more than 10 cm, and an area of about 30x30 km was affected significantly.

The image also shows that the fault slip continues further north than is obvious from a surface examination. Sharp lines in the interferogram show minor movements on other faults, such as the part of the West Napa Fault system that crosses Napa airport.

September 2, 2014. From the International Space Station NASA astronaut Reid Wiseman tweeted this wonderful picture of the ocean with the glow of the newly-risen Sun on it. It's quite magical.