Earthset from the Lunar Reconnaissance Orbiter
Explanation:
On the Moon, the Earth never rises -- or sets.
If you were to sit on the surface of the Moon, you would see the Earth just hang
in the sky.
This is because the Moon always keeps the
same side toward
the Earth.
Curiously, the
featured image does
picture the Earth setting over a lunar edge.
This was possible because the image was taken from a spacecraft
orbiting
the Moon - specifically the
Lunar Reconnaissance
Orbiter (LRO).
In fact, LRO orbits the Moon so fast that, from the spacecraft, the
Earth appears to
set anew about every two
hours.
The featured
image
captured one such Earthset about three months ago.
By contrast, from the surface of the Earth, the
Moon sets about once a day -- with the
primary cause being the rotation of the Earth.
LRO was
launched in 2009 and,
while creating a detailed three dimensional map of the
Moon's surface,
is also
surveying the Moon for
water and possible good landing spots for
future astronauts.
Free APOD Lectures: Editor to speak this coming weekend in
Philadelphia
and
New York City
Authors & editors:
Robert Nemiroff
(MTU) &
Jerry Bonnell
(USRA)
NASA Web Site Statements, Warnings,
and Disclaimers
NASA Official: Jay Norris.
Specific
rights apply.
A service of:
LHEA at
NASA /
GSFC
& Michigan Tech. U.
