Even at a glance, the planets in our solar system are extremely diverse. Huge and small, airless and densely packed with atmosphere, they have a wide range of characteristics that set them apart. But if I were stuck, which one would I choose as the strangest of all?
Easy: Venus is the strangest planet in the solar system.
There’s a reason we call it Earth’s evil twin. For reasons that are still unclear, long ago it suffered a massive, uncontrollable greenhouse effect, filling its atmosphere with heat-trapping carbon dioxide. The result is a planet with a surface pressure 90 times that of Earth, a temperature above 460 degrees Celsius (860 degrees Fahrenheit), and clouds made of sulfuric acid.
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Yet in its troposphere, at an altitude of about 50 to 60 kilometers, Venus’ pressure and temperature are similar to those of Earth at sea level. Acidic clouds and poisonous air would remain a problem, but in theory it is possible that humans could one day live in floating habitats high up. Cytherean skies – truly strange.
Jupiter is the strangest planet in the solar system. With a width of 11 Earths and a mass more than 300 times that of our planet, it is a gas giant – a colossal bag of hydrogen and helium that turns into a strange liquid mixture lower in its atmosphere and eventually turns metallic even deeper. As best we can tell, Jupiter has a core of metal and rock, but it’s fuzzy and mushy, not at all like the obvious demarcated layers we enjoy on our homeworld. And it has a powerful magnetic field that spreads in the solar wind to extend hundreds of millions of kilometers, making it the largest continuous structure in the solar system after the sun’s heliosphere. If our eyes could see it, Jupiter’s magnetosphere would appear larger than the full moon in the sky!
Mercury is the strangest planet in our solar system. Burnt by the sun, it’s locked in a tug-of-war gravitational struggle with our star which, over time, has forced the planet to rotate three times for every two times it orbits the sun. Coupled with its elliptical orbit, this has strange effects; there are places on the surface where, in the morning, you could watch the sun rise for a while, then set and then rise again, all near the same spot in the sky. And despite Mercury’s intense irradiation, there are deep, cold craters near its poles that never see sunlight and harbor water ice. It is a planet of paradoxes.
Neptune is the strangest planet in the solar system. The furthest major planet from the Sun and the last stop before interstellar space, Neptune is only dimly illuminated by our star, receiving only 0.1% as much light as Earth. It was not discovered by direct observation but with gravitational effect on Uranusalthough it was spotted, little known at the time, by Galileo centuries earlier. Its internal heat powers the fastest winds in our solar system, measured at an incredible 2,200 kilometers per hour, faster than the speed of sound. Never try to fly a kite on Neptune. It’ll rip your arms off.
Mars is the strangest planet in the solar system. At one-tenth the mass of Earth, it nevertheless has the highest mountain and the largest canyon in the solar system. It is covered with a fine dust composed of various kinds of iron oxide: rust. The atmosphere is ugly, tinting the air a butterscotch color, except near the sun in the sky, where the scattering of light creates a blue aura that is best seen at sunset. This makes it the opposite of Earthwith its blue sky and red sunsets.
Uranus is the strangest planet in the solar system. Eons ago, a catastrophic event toppled the enormous ice giant, which now orbits the sun with an axial tilt of 98 degrees. This gives it extreme seasons, each lasting 21 Earth years. At its north pole, for example, it takes about four decades after sunrise for our star to set again. And for years, at the height of summer, the sun is almost directly overhead. Additionally, the axis of Uranus’s magnetic field is offset by about 8,000 km from the center of the planet. This may have the same cause as the tilt of the world; perhaps it was hit by another massive planet shortly after its formation, toppling Uranus catawampus. On top of all that, it can also rain diamonds there.
Saturn is the strangest planet in the solar system. Its density is actually lower than that of water; The oldest joke in astronomy is that if you threw Saturn in a bathtub, it would float, but it would leave a ring. Its magnificent ring system is the most spectacular thing in our planetary neighborhood.yet if you put all the particles in the ice ring together, they would only form a small moon less than 400 km wide – one more satellite to add to Saturn’s horde of known moons, some 285 in all. And as impressive as its rings are, the planet also has a huge hexagonal vortex almost 30,000 km in diameter at its north pole, which allows the immense Earth to pass comfortably through one of its sides. It’s actually a natural atmospheric feature that still looks a lot like an alien portal to another place in time and space.
Unsurprisingly, I could go on and on about the strangeness of any given planet in the solar system – not to mention smaller objects such as Pluto, as well as moons, asteroids, comets, Kuiper Belt objects and the Oort Cloud – but it is our own biases that color our view.
Ultimately, Earth is by far the strangest planet in the solar system. For one thing, it has plate tectonics – the sliding and buckling of large plates of rock that constantly reshape its surface – a feature found nowhere else around the sun. Earth also has an unusually large moon relative to its size, a much larger ratio than any other moon around a major planet.
Even stranger, Earth’s distance from the Sun, combined with its inherent atmospheric greenhouse effect, gives our planet a surface temperature where water can coexist in three phases: solid, liquid, and gas. This situation is unique among the solar planets and is essential to Earth’s exceptional status; water is an excellent medium for life to arise and evolve. It can dissolve and mix important prebiotic minerals, and its water cycle – in which water evaporates over oceans, rains in a different location and then returns to the sea – transports these materials to places where they can concentrate and generate complexity.
Over time – billions of years – these simpler materials bumped, crushed, collapsed and reformed, taking advantage of the chemistry around them and the energy of the sun to become the astonishing, dazzling biological variety we see all around us.
Do you want something weird? Of the hundreds of worlds in our solar system, only one is known to contain life, and you live on it.
Strangeness East relative, however. We continue to probe these other places, searching and sniffing for life, existing or not. Perhaps we will find him again, several times. And if we do, Earth might not be so strange after all.
