|
Collection:
|
|
NASA Astronomy Picture of the Day Collection
Collection
NASA Astronomy Picture of the Day Collection
Collection
|
|
Title:
|
|
3-D Mars' North Pole
Title
3-D Mars' North Pole
Title
|
|
Explanation:
|
This dramatic premier [ http://ltpwww.gsfc.…] three-dimensional visualization of Mars' north pole is based on elevation measurements made by an orbiting laser. During the Spring and Summer [ http://ltpwww.gsfc.…] of 1998 the Mars Orbiter Laser Altimeter [ http://ltpwww.gsfc.…] (MOLA) flashed laser pulses toward the Martian surface from the Global Surveyor spacecraft and recorded the time it took to detect the reflection [ http://ltpwww.gsfc.…]. This timing data has now been translated to a detailed topographic map of Mars' north polar terrain [ http://antwrp.gsfc.…]. The map indicates that the ice cap is is about 1,200 kilometers across, a maximum of 3 kilometers thick, and cut by canyons and troughs up to 1 kilometer deep. The measurements also [ http://earth.agu.or…] indicate that the cap is composed primarily of water ice with a total volume of only about four percent of planet Earth's Antarctic ice sheet [ http://antwrp.gsfc.…]. In all it represents at most a tenth of the amount of water some scientists believe once existed on ancient Mars [ http://www.sciam.co…]. Where did all the water [ http://humbabe.arc.…] go?
Explanation
This dramatic premier [ http://ltpwww.gsfc.…] three-dimensional visualization of Mars' north pole is based on elevation measurements made by an orbiting laser. During the Spring and Summer [ http://ltpwww.gsfc.…] of 1998 the Mars Orbiter Laser Altimeter [ http://ltpwww.gsfc.…] (MOLA) flashed laser pulses toward the Martian surface from the Global Surveyor spacecraft and recorded the time it took to detect the reflection [ http://ltpwww.gsfc.…]. This timing data has now been translated to a detailed topographic map of Mars' north polar terrain [ http://antwrp.gsfc.…]. The map indicates that the ice cap is is about 1,200 kilometers across, a maximum of 3 kilometers thick, and cut by canyons and troughs up to 1 kilometer deep. The measurements also [ http://earth.agu.or…] indicate that the cap is composed primarily of water ice with a total volume of only about four percent of planet Earth's Antarctic ice sheet [ http://antwrp.gsfc.…]. In all it represents at most a tenth of the amount of water some scientists believe once existed on ancient Mars [ http://www.sciam.co…]. Where did all the water [ http://humbabe.arc.…] go? Explanation
|
|
Credit and Copyright:
|
Credit_and_Copyright
Credit and Copyright
|
|
keyword:
|
|
mars
|
|
keyword:
|
|
water
|
|
keyword:
|
|
ice
|
|
keyword:
|
|
north pole
keyword
north pole
keyword
|
|
keyword:
|
|
polar cap
keyword
polar cap
keyword
|
|
facet_when:
|
|
1998
facet_when
1998
facet_when
|
|
facet_where:
|
|
Mars
facet_where
Mars
facet_where
|
|
facet_where:
|
|
Goddard Space Flight Center (GSFC)
facet_where
Goddard Space Flight Center (GSFC)
facet_where
|
|
facet_where:
|
|
Jet Propulsion Laboratory (JPL)
facet_where
Jet Propulsion Laboratory (JPL)
facet_where
|
|
facet_what:
|
|
Earth
facet_what
Earth
facet_what
|
|
facet_what:
|
|
Mars
facet_what
Mars
facet_what
|
|
facet_what:
|
|
Surveyor
facet_what
Surveyor
facet_what
|
|
facet_what:
|
|
Altimeter
facet_what
Altimeter
facet_what
|
|
facet_what:
|
|
Polar
facet_what
Polar
facet_what
|
|
facet_what:
|
|
Mars Global Surveyor Orbiter (MGS)
facet_what
Mars Global Surveyor Orbiter (MGS)
facet_what
|
|
facet_what:
|
|
Mars Orbiter Laser Altimeter (MOLA)
facet_what
Mars Orbiter Laser Altimeter (MOLA)
facet_what
|
|
facet_when_year:
|
|
1998
facet_when_year
1998
facet_when_year
|
|
original url:
|
original_url
original url
|
|
UID:
|
|
SPD-APOD-ap981216
UID
SPD-APOD-ap981216
UID
|
