Reader Picks of NASA Shots

Atafu Atoll, Tokelau, Southern Pacific Ocean (April 6, 2009)

A tiny atoll, part of a New Zealand territory, is seen as photographed from the International Space Station by an astronaut.

The Atafu Atoll is one of four atolls and islands that are part of the Tokelau Islands. Geology suggests that a volcanic island created the atoll. Coral reefs likely formed around the volcano, which then eroded beneath the water, leaving a ring of sand and reefs.

Atafu's main village can be seen to the left as a collection of small grey dots. Around 500 people responded to a 2006 census of the atoll.


Extratropical Cyclones Near Iceland (January 2, 2007)

One cyclone's bad enough. But the Terra imaging satellite managed to find double trouble--two of the spiraling storms, formed simultaneously above Iceland and Scotland.

Though cyclones are usually thought of as tropical events, they do often form at higher latitudes. Cyclones of this type drive much of Earth's weather.

Iceland can be seen at the top-center of the above image, showing through milder skies. Scotland is in the bottom right-hand corner, close to the larger and perhaps stronger cyclone.


STEREO's First View of the Sun (January 3, 2007)

Loops of highly charged particles shoot out from the sun's roiling surface, as seen in ultraviolet by the twin STEREO spacecraft.

The sun's surface regularly pumps out these coronal mass ejections--explosions caused by magnetic stress in the sun's atmosphere, which is shown above at roughly a million Kelvin (1.8 million degrees Fahrenheit). Solar flares surge into space with each eruption, causing auroras on Earth and disrupting communications and radio systems.

The active region at the base of each blast can be seen from Earth as sunspots, but the ultraviolet loops can only be observed from space.


The Southern Lights (January 25, 2006)

The aurora australis, or southern lights, glimmer green over Antarctica in the picture above.

Four days after a massive solar flare, NASA researchers obtained readings from the now-defunct IMAGE satellite, which monitored Earth's magnetic field.

Overlaying the data onto a "Blue Marble" satellite photograph of Earth resulted in both the image above and an animation of the solar storm's effects on Earth's atmosphere.


Ocean Sand, Bahamas (September 13, 2002)

Though viewers would be forgiven for thinking the above picture a work of abstract art, the image is actually a photograph captured by the Earth-orbiting Landsat 7 satellite.

Ocean currents in the Bahamas made the sand-and-seaweed sculpture in much the same way that winds create sand dunes in the Sahara.