Explanation:
Two days ago, the MESSENGER spacecraft became only the
second spacecraft in human history to swoop past Mercury.
The last spacecraft to visit the Sun's closest planet was
Mariner 10 over
35 years ago.
Mariner 10 was not able to
photograph Mercury's entire
surface, and the
images it did send back raised many questions.
Therefore, much about
planet Mercury
remains unknown.
This week's flyby of
MESSENGER
was only the first of three flybys.
Over the next few years MESSENGER will swing past twice more and finally enter Mercury's orbit in 2011.
MESSENGER is currently moving too fast to enter orbit around Mercury now.
The above image was taken two days ago during MESSENGER's flyby and shows part of Mercury's surface that has
never been imaged
in detail before.
Many more detailed images of Mercury
are expected to be sent back over the next few days.
The data acquired by
MESSENGER
will hopefully help scientists
better understand how Mercury's surface was formed, and why it is so dense.
Note:
Today's APOD image has been updated.
The latest MESSENGER images are here.
