#space collection

Mars

The Red Planet

Named after the Roman god of war, Mars is half the diameter of Earth and has a year that’s almost twice as long as Earth’s. Its atmosphere is made from 95.97% carbon dioxide, but the air pressure at sea level is only 0.6% that of Earth’s. It is home to the Olympus Mons, the tallest mountain in the Solar System at 27 km (88,600 ft) high, and Valles Marineris, one of the largest canyons in the Solar System at 4,000 km (2,500 miles) long, 200 km (120 miles) wide, and 7 km (23,000 ft) deep. 

Just like Earth, Mars has seasons and polar ice caps. In 2012, the Curiosity rover discovered an ancient riverbed in the Gale Crater; further analysis concluded that the water ran at hip-depth at 3.3 km/h (0.92 m/s). Water still exists on the planet in its ice caps and in small amounts of vapor in the atmosphere. Many believe that Mars was once inhabited by life, but although there is some evidence pointing in that direction, there is not enough to make a solid conclusion yet. Any life that was on Mars would’ve had to deal with the radiation.

Jupiter

The Gas Giant

Well, its nickname is the Gas Giant, but it is only the first of the four outer gas giants outside the asteroid belt. It is the biggest planet in the Solar System with a diameter of 143,000 km (88,856 miles), and it can fit more than 1,300 Earths. Its thick atmosphere is made up of mostly hydrogen and helium and has thick lines of clouds that swirl around at wind speeds between 309 km/hr to more than 644 km/hr (192 mph to more than 400 mph). 

Venus

Earth’s evil twin.

This planet is just about the size of Earth, but it’s the polar opposite to Earth in every other way. Instead of having a reasonable surface temperature, Venus is the hottest planet in the Solar System at 462°C (863°F), hot enough to melt lead. This is due to its very thick atmosphere that is 96.5% carbon dioxide, guaranteeing a planet-wide greenhouse effect that traps the Sun’s heat in its surface. 

The atmosphere is also 93 times the mass of Earth’s, making the surface pressure 92 times that of on Earth’s. This would be like being under 900m (3,000 ft) of water.

Ganymede

Not only Jupiter’s largest moon but also the largest moon in the Solar System, with a 5,268 km (3,273 mile) diameter. Its crust is made of silicate rock and water ice, and it’s covered in both dark regions of craters and light regions of grooves that might come from tectonic movement.

Most likely because of the liquid convection in its iron core, Ganymede is the only moon in the Solar System with a magnetic field. This field makes beautiful rings of aurorae circle around the poles like the ones on Earth. 

Callisto

Jupiter’s second-largest moon and the third-largest moon in the Solar System.

Callisto’s surface is the oldest in the Solar System and, consequently, the most cratered. There is no evidence of tectonic or volcanic activity on it, so meteorites are the only thing affecting its surface (especially when the only thing in a meteorite’s way is a really thin carbon dioxide/maybe-oxygen-too atmosphere).