Image: Aurora Australis Observed from the International Space Station

Jun 23, 2010
Image credit: NASA.

(PhysOrg.com) -- Among the views of Earth afforded astronauts aboard the International Space Station (ISS), surely one of the most spectacular is of the aurora. These ever-shifting displays of colored ribbons, curtains, rays, and spots are most visible near the North (aurora borealis) and South (aurora australis) Poles as charged particles (ions) streaming from the Sun (the solar wind) interact with Earth’s magnetic field.

While aurora are generally only visible close to the poles, severe magnetic storms impacting the Earth’s magnetic field can shift them towards the equator. This striking aurora image was taken during a that was most likely caused by a coronal mass ejection from the Sun on May 24, 2010. The ISS was located over the Southern Indian Ocean at an altitude of 350 kilometers (220 miles), with the astronaut observer most likely looking towards Antarctica (not visible) and the .

The aurora has a sinuous ribbon shape that separates into discrete spots near the lower right corner of the image. While the dominant coloration of the aurora is green, there are faint suggestions of red left of image center. Dense cloud cover is dimly visible below the aurora. The curvature of the Earth’s horizon (the limb) is clearly visible, as is the faint blue line of the directly above it (at image top center). Several stars appear as bright pinpoints against the blackness of space at image top right.

Auroras happen when ions in the collide with atoms of oxygen and nitrogen in the upper atmosphere. The atoms are excited by these collisions, and they typically emit light as they return to their original energy level. The light creates the aurora that we see. The most commonly observed color of aurora is green, caused by light emitted by excited oxygen atoms at wavelengths centered at 0.558 micrometers, or millionths of a meter. (Visible light is reflected from healthy (green) plant leaves at approximately the same wavelength.) Red are generated by light emitted at a longer wavelength (0.630 micrometers), and other colors such as blue and purple are also sometimes observed.

Explore further: SDO captures images of two mid-level flares

Related Stories

Chandra probes high-voltage auroras on Jupiter

Mar 02, 2005

Scientists have obtained new insight into the unique power source for many of Jupiter's auroras, the most spectacular and active auroras in the Solar System. Extended monitoring of the giant planet with NASA's ...

Halloween Storms of 2003 Still the Scariest

Oct 29, 2008

(PhysOrg.com) -- By the eerie light of a Halloween moon, while a chilly wind blows autumn-dry leaves askitter on bare and fingered branches, scary things can happen. Blood-sucking bats, creepy-crawly spiders, ...

Recommended for you

SDO captures images of two mid-level flares

Dec 19, 2014

The sun emitted a mid-level flare on Dec. 18, 2014, at 4:58 p.m. EST. NASA's Solar Dynamics Observatory, which watches the sun constantly, captured an image of the event. Solar flares are powerful bursts ...

Why is Venus so horrible?

Dec 19, 2014

Venus sucks. Seriously, it's the worst. The global temperature is as hot as an oven, the atmospheric pressure is 90 times Earth, and it rains sulfuric acid. Every part of the surface of Venus would kill you ...

Image: Christmas wrapping the Sentinel-3A antenna

Dec 19, 2014

The moment a team of technicians, gowned like hospital surgeons, wraps the Sentinel-3A radar altimeter in multilayer insulation to protect it from the temperature extremes found in Earth orbit.

Video: Flying over Becquerel

Dec 19, 2014

This latest release from the camera on ESA's Mars Express is a simulated flight over the Becquerel crater, showing large-scale deposits of sedimentary material.

Spinning up a dust devil on Mars

Dec 19, 2014

Spinning up a dust devil in the thin air of Mars requires a stronger updraft than is needed to create a similar vortex on Earth, according to research at The University of Alabama in Huntsville (UAH).

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.