The closest planet to the Sun, and the smallest in our solar system, Mercury often appears as a bright star-like object in our sky during the early evening or early morning. With a cratered surface, and little atmosphere, the planet’s appearance is incredibly similar to Earth’s Moon. A molten iron core sits at the centre of the planet, accounting for around 40% of its total volume.
Venus’ thick atmosphere traps UV radiation from the Sun creating an extreme greenhouse gas effect and making it the hottest planet in our solar system at a scorching 462ºC (864ºF). Spinning incredibly slowly, almost upright on its axis, Venus has the longest rotation of the planets and experiences almost no seasonal effects. This means one day on Venus is equivalent to 243 days here on Earth!
The planet we call home. The only planet in our solar system that can support such complex life systems. Water from vast oceans, winding rivers and great lakes covers 71% of its surface and gave way to life some 3.5 billion years ago. Orbiting the Sun in 365 days, our planet’s atmosphere hangs in a fragile balance, allowing ecosystems to thrive and species to constantly evolve.
About half the size of Earth, Mars is a cold, rocky, dusty, planet with a thin atmosphere and temperature highs of 20ºC (68ºF). Affectionately coined ‘The Red Planet’, Mars was named by the Romans after their god of war, as its reddish colour is reminiscent of blood. Thanks to its proximity to Earth, Mars is one of the most explored planets in our solar system. Its surface conditions and the past presence of water make it arguably the most hospitable planet after our own. Could Mars be our new home in the future?
The largest planet in the solar system (more than 2.5 times the mass of all other planets combined), Jupiter is the fifth planet from our Sun. While beautiful, its stripes and swirls are actually cold, windy clouds of ammonia and water, floating in an atmosphere of hydrogen and helium. For hundreds of years, Jupiter’s iconic Great Red Spot has been observed (a giant storm bigger than Earth) and we are yet to discover whether this raging storm is deeply rooted in Jupiter’s interior.
The farthest planet from Earth discovered by the unaided human eye, Saturn has been known since ancient times and is named for the Roman god of agriculture and wealth. Recognised for its rings, made of chunks of ice, Saturn has no surface to speak of. Rather, it is mostly swirling gases and liquids, inhospitable to human life and the spacecrafts trying to fly into the planet. For its many moons, however, the story could be different. Could life exist on Titan, whose terrain resembles that of Earth?
Uranus is one of just two planets, alongside Venus, that rotates in the opposite direction to most of the planets, from east to west. Some of the most extreme seasons in the solar system occur here on Uranus. For nearly a quarter of each Uranian year, the Sun shines directly over each pole, plunging the other half of the planet into a 21-year-long, dark winter.
It’s impossible to view Neptune with the naked human eye. More than 30 times as far from the Sun as Earth, its orbit takes a massive 165 years to complete, experiencing seasons lasting 40 years at a time. 80-90% of Neptune is made up of a hot dense fluid of “ices”, making it one of two ice giants in the solar system alongside Uranus. While not as impressive as Saturn’s, Neptune is the proud owner of its own planetary ring system, made up of ice particles coated with silicates or carbon-based material.