Explanation:
The planet Mercury has been known since history has been recorded, but parts of the Solar System's innermost planet have never been seen like this before.
Two days ago the robotic
MESSENGER spacecraft buzzed past
Mercury
for the second time and imaged terrain mapped previously only by
comparatively crude radar.
The above image was recorded as
MESSENGER looked back 90 minutes after passing,
from an altitude of about 27,000 kilometers.
Visible in the
above image, among many other newly imaged features,
are unusually long
rays that appear to run like
meridians of
longitude
out from a young crater near the northern limb.
MESSENGER is scheduled to fly past
Mercury
once more before firing its thrusters to enter orbit in 2011.
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