Mercury

• The case made by astronomers that Mercury is peculiar is unarguable.

• Mercury is a large ball of iron with a thin layer of rock on top, rather than being mostly made of rock like Earth.

• The metal core is at least partially molten and extends 85% of the way to the surface.

• Caloris Basin: The largest crater on Mercury.

• MESSENGER: MErcury Surface, Space ENvironment, GEochemistry, and Ranging.

Facts about Mercury

• Long winding ridges on Mercury cross-impact craters and other geological formations. The crust of Mercury probably shrank as it cooled from a molten state, which led to the ridges.

• The planet's diameter could have decreased by as much as 8 miles.

• In comparison to the number of large craters, Mercury has fewer small craters than the Moon.

• The gently rolling plains cut through the highlands of Mercury.

• A region of broken terrain can be found on the antipode of the Caloris Basin, directly across from Caloris on the other side of Mercury.

• Strong seismic waves from the collision that created Caloris must have passed through Mercury and around its surface before convergent at the antipode with disastrous results.

• Mercury has a global magnetic field that is produced by a natural dynamo in its molten iron core. However, Earth's magnetic field is 100 times stronger than Mercury's.

• Mercury experiences extreme temperature variations, ranging from 870°F (466°C) during the day to -300°F (-184°C) at night.

• Ice can be found at the bottoms of craters near Mercury's North Pole, which are always in shadow and extremely cold.

Venus

• Venus never experiences a clear day because a layer of concentrated sulfuric acid clouds covering the entire planet, from pole to pole, and is 9 miles thick.

• Venus is the hottest planet in the solar system, with a surface temperature of 870°F (465.5°C) that is relatively constant from the equator to the pole, day and night.

  • Virga: Rain that evaporates before it hits the ground.

• Venus has a high average temperature as a result of an extreme greenhouse effect.

• Venus receives most of its sunlight through its dense atmosphere and clouds, which heats the ground and the air around it.

• The majority of Venus is covered in flat, volcanic lowlands with rilles.

  • Rilles: The winding canyons left by lava flows.

• Baltis Vallis: This region contains the solar system's longest known rille, which spans Venus at a distance of about 4,230 miles.

• Objects capable of creating craters up to 2 miles in diameter are hindered and destroyed by aerodynamic forces in Venus' thick atmosphere.

• Venus's surface is covered in massive mountain ranges and volcanoes.

• Venus Express: The European Space Agency probe that arrived at Venus in April 2006 and orbited it until May 2014. It thoroughly examined the atmosphere of the hot planet, gathered intriguing proof of recent volcanism, and discovered that Venus' rotation might be slowing down.

Mars

• Mars Global Surveyor: A satellite that operated in orbit around Mars from 1997 to 2006.

• Laser Altimeter: An instrument that bounced pulses of light off the Mars surface to measure the altitudes of the surface features that reflected the light.

• Mars Odyssey: NASA’s probe began orbiting Mars in October 2001. It has found caves and evidence of widespread ice and also salt deposits on Mars.

• Mars Express: A satellite from the European Space Agency that began orbiting Mars on December 25, 2003.

• The Northern Hemisphere is generally much lower than the Southern Hemisphere, as seen from the topographic map of Mars.

• Mars is currently cold and dry, but the poles are covered in a lot of ice. According to one estimate, if all the ice on the planet melted, it would flood the entire planet to a depth of 100 feet.

• Some canyons on Mars appear to have been carved out by a massive flood a long time ago.

• Numerous steeply sloping narrow linear features were captured on camera by the Mars Reconnaissance Orbiter.

  • They turn darker in the Martian summer and disappear when the temperature drops.

  • They might be brought on by salty water in the surface layer, which only melts and flows when Mars is sufficiently warm.

• Numerous regions of Mars have soil that was formed by the influence of water, including regions with clay minerals.

• The planet has streamlined islands, pebbles that appear to have been rounded in a torrent, and features that resemble dry riverbeds. The Mars Pathfinder lander probe and its tiny robot, Sojourner, captured images of these pebbles.

• Mars Odyssey discovered evidence of a lot of water, likely frozen, just beneath the surface over a sizable portion of Mars.

• NASA’s Curiosity, the largest rover to traipse around Mars, discovered the remains of what was once a freshwater lake.

• The atmosphere of Mars is mostly carbon dioxide, but it is much thinner than the atmospheres of Earth or Venus.

• Mars also has clouds of water-ice crystals, similar to Earth's cirrus clouds.

• Dry ice is always present on the South Polar Cap.

• A magnetometer on MGS found long parallel stripes of magnetic fields with opposite directions frozen in the Martian surface's rocky crust.

• Olympus Mons: The largest volcano in the solar system. It is roughly five times wider and nearly three times higher than Mount Loa, the largest volcano on Earth, at 370 miles wide and 15 miles high.

• Mars has a large number of canyons, which is 2,490 miles long, the Valles Marineris.

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