[meteorite-list] Fantastic Phobos (Mars Express)

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Mon, 20 Aug 2012 10:00:33 -0700 (PDT)
Message-ID: <201208201700.q7KH0YKm019254_at_zagami.jpl.nasa.gov>

http://www.esa.int/esaSC/SEMDAB1YZ5H_index_0.html

Fantastic Phobos
European Space Agency
20 August 2012
 
Some 135 years after its discovery, Mars' largest moon Phobos is seen in
fantastic detail - and in 3D - in an image taken by ESA's Mars Express
spacecraft as it passed just 100 km by.

This view is much different to the faint object that astronomer Asaph
Hall would have just been able to make out as he observed the Red Planet
through the United States Naval Observatory's 66 cm telescope in 1877.
Through this telescope he discovered Mars' smaller, outermost moon
Deimos on 12 August and the larger, innermost moon Phobos on 18 August.

More than a century later later, spacecraft in orbit around Mars are
studying Phobos in unprecedented detail.

In this image, a bite-sized chunk appears to be missing from the right
edge of the irregular shaped moon - this is a side-on view of the rim of
large impact crater Stickney, so-called after the maiden name of the
discoverer's wife.

Families of grooves appear to emanate from Stickney, carving channels
across the approximately 27 km length of the moon. Initially thought to
be associated with the Stickney impact crater, one recent theory
suggests that they were instead formed when Phobos passed through debris
clouds thrown up from the surface of Mars by asteroid impacts onto the
planet's surface.

Orbiting Mars at just 6000 km from the planet's surface, it is closer to
its parent planet than any other known moon in our Solar System. The
moon's proximity means that it hurtles around Mars faster than the
planet rotates: for an observer on the surface of Mars, Phobos would
appear to rise and set twice a day.

The moon's orbit is decreasing and in some 50 million years time it will
likely break up to form a debris ring around Mars, before colliding with
the planet's surface.
 
Received on Mon 20 Aug 2012 01:00:33 PM PDT