16 A spacecraft orbiting Mars has detected large quantities of water-ice just below the surface of the planet.
17 The magnetosphere is the region of electrically charged particles that are trapped in the magnetic field of the planet.
18 A hydrosphere in physical geography describes the collective mass of water found on, under, and over the surface of a planet.
19 A science-fiction thriller about a planet that is mired in civil war and whose computerized defense system runs amok, threatening everyone.
20 Early astronomers thought that our planet was the centre of the universe.
21 The planet Jupiter radiates twice as much heat from inside as it receives from the Sun.
22 These chemicals could indicate the presence of water on the planet.
23 And although she was probably just an ordinary-looking kid, in my eyes she was the most beautiful child on the face of the planet.
24 Okay, a scientist reports the measurement of the temperature of a new discovered planet to be minus point eight degrees.
25 The total number of species on the planet appears to be growing by leaps and bounds.
26 The planet Jupiter may have no solid surface at all.
27 Pluto is the farthest planet in the solar system.
28 A fuzzy photo released Monday - taken from 1.2 million miles away - appears to show the planet as an elongated blob, not a round space rock.
29 The ozone layer shields the planet from damaging ultra-violet rays, which can cause skin cancer and eye cataracts, and has been recovering after a phase-out of damaging chemicals under the U.N.'s 1987 Montreal Protocol.
30 The new research reinforces that statement from Curiosity's vantage point, and adds the perspective of the Opportunity rover, which has found a different ancient habitable environment on another part of the planet.