April 14, 2003
Canadarm and the Seven Sisters
Credit: Don Pettit, ISS Expedition
6 Science Officer, NASA
Explanation: Sometimes a picture is worth a thousand
words.
International Space Station (ISS)
science officer Don Pettit took this
one on January 18, 2003. In the foreground is the space station’s
Canadian-built robotic arm, “Canadarm“,
which helps astronauts with construction of the growing ISS.
Just above Canadarm’s elbow are the Pleiades,
also known as the Seven Sisters. These seven stars, arranged
like a little dipper, are just the brightest members of a cluster
of more than 3000 stars lying 400 light years from Earth.
Between Canadarm and the Pleiades
is Earth itself. Below, the cloudy landscape is lit by a nearly-full
Moon (off camera). Above, the edge of Earth’s atmosphere is defined
by a layer of glowing
air–a brownish-yellow band of light stretching all the way
across the image. Airglow
is caused by chemiluminescent
reactions in Earth’s nighttime atmosphere. The reactants are
atoms and molecules broken apart during the day by solar ultraviolet
radiation. And finally, just under Canadarm’s elbow, is a streak
of green–the aurora borealis.
There was no big geomagnetic storm underway when the picture
was taken. Nevertheless, the Northern Lights were there.
Breathtaking… x 1000. |
