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Астронет: Астрономическая картинка дня Следы звезд для Красной планеты http://variable-stars.ru/db/msg/1555979/eng |
Credit & Copyright: Dengyi Huang
Explanation:
Does
Mars have a north star?
In long exposures of
Earth's night sky,
star trails make concentric arcs
around the north celestial pole, the direction of our
fair planet's axis of rotation.
Bright star Polaris
is presently the Earth's North Star, close on the sky to
Earth's north celestial pole.
But long exposures on
Mars
show star trails too,
concentric arcs about a celestial pole determined by Mars' axis of
rotation.
Tilted like planet Earth's, the martian axis of rotation points
in a different direction in space though.
It
points to a place on the sky between stars in Cygnus and Cepheus
with no bright star comparable to Earth's north star Polaris nearby.
So even though this ruddy, weathered landscape is
remarkably
reminiscent of terrain in images from the
martian surface, the view must be from planet Earth,
with north star Polaris near the center of concentric star trails.
The landforms in the foreground are found in
Qinghai Province in
northwestern China.
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.