Vision and Voyages for Planetary Science in the - Solar System ...

FIGURE 1.8 The mirror for the Large Synoptic Survey Telescope prior to polishing and grinding.
SOURCE: Howard Lester / LSST Corporation.
RECENT ACHIEVEMENTS IN PLANETARY SCIENCE
Twelve discoveries made since the publication of the last planetary decadal survey illustrate the
vitality and diversity of planetary science. These discoveries represent just a small fraction of the
advances in planetary sciences over the last decade (see Chapters 4-8 for additional achievements).
• An explosion in the number of known exoplanets. Confirmed examples have grown from a
few dozen at the beginning of this decade to many hundreds, including numerous multi-planet systems.
Multiple lines of evidence suggest that the majority are Uranus- and Neptune-size bodies including
microlensing surveys that seem to account for selection effects.
• The Moon is less dry than once thought. Evidence is mounting that the lunar surface and
interior is not completely dry as previously believed. Apollo samples now show the Moon’s interior to
hold more water than thought. Observations from Lunar Prospector, LRO, LCROSS, Cassini, and
Chandrayaan-1 also suggest small, but significant, quantities of water on the Moon: including exospheric
and exogenic water generated by solar wind proton reduction and cometary deposits in the extremely cold
regions of the lunar poles.
• Minerals that must have formed in a diverse set of aqueous environments throughout martian
history. Observations from multiple orbiters and rovers have identified a broad suite of water-related
minerals including sulfates, phyllosilicates, iron oxides and oxyhydroxides, chlorides, iron and
magnesium clays, carbonates, and hydrated amorphous silica.
• Extensive deposits of near-surface ice on Mars. These deposits are a major reservoir of
martian water, and because of oscillating climate conditions, potentially lead to geologically brief periods
of locally available liquid water.
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