Amazing Solar System Facts

If you could take a spin through the solar system, these are the sights you shouldn't miss—including the possibility of life on an ocean moon.

Tired of all the usual travel spots this year? Wish you could go somewhere new, but airfare is through the roof? Well, we’ve got your ultimate out-of-this-world summer travel guide, with five breathtaking destinations that each have something for the whole family. From the lead-melting heart of Venus to the mysterious ocean worlds of the outer solar system, you can't go wrong when you leave the Earth. How you get there is up to you.

For those of you who like it hot, nothing can beat Venus, the hottest planet in the solar system. Even though Venus sits farther away from the Sun than Mercury, it still manages to achieve hotter surface temperatures. The average temperature across Venus is about 850 degrees Fahrenheit, with the lowland valleys reaching over 900 degrees Fahrenheit. That's hot enough to melt lead, and the reason that the only spacecraft to reach the surface have only survived about 15 minutes.

Venus achieves this remarkable feat thanks to its sweltering, oppressively thick atmosphere. The air pressure on the surface is almost one hundred times greater than on the Earth. And that atmosphere is composed of almost entirely poisonous carbon dioxide. If that's not enough, this hellscape of a world features perpetual sulfuric acid rain.

Long ago, Venus had a normal atmosphere and liquid water oceans. But its proximity to the Sun triggered a runaway greenhouse effect that released uncontrolled amounts of carbon dioxide into the atmosphere, choking the planet off from anything resembling a reasonable existence. So not only do you get to enjoy the heat, you also get to appreciate a cautionary tale about global warming.

There's gold in them thar’ asteroids! Discovered 1852, Psyche is the 16th largest asteroid in the solar system, stretching roughly 200 kilometers on a side. Psyche is what's known as an "M-type" asteroid. Unlike other asteroids, which are mostly made of boring old rock, Psyche is very rich in heavy metals, like gold, nickel, and iron. Astronomers believe that Psyche may be the leftover core of a planet that either never fully formed, or one that got smashed to pieces in the early days of the solar system.

If you were to somehow chop up Psyche, bring the pieces back to Earth, and sell the metals at their current prices, you would earn somewhere around $10,000 quadrillion dollars. That's… a lot of money. But of course economics doesn't work out that cleanly, as flooding the Earth with more gold, nickel, and iron than we’ve ever mined throughout the entirety of human history might drop the prices a tad. Plus, you have to factor in the cost of getting to Psyche in the first place and devising a scheme to a haul it back to the Earth, neither of which is exactly cheap.

But if you’re looking for a speculative adventure this summer, you know where to go.

Love scuba diving? Sick of all the coral reefs, sunken shipwrecks, and all the other same-old same-old dive sights? Then you need to try Europa, the ultimate dive spot in the solar system.

Europa is the second moon of Jupiter, and from a distance it may not look all that appetizing. Water ice covers the entire world, and save for a network of cracks and crevasses that crisscross its surface, there's not all that much going on. However, the real fun of Europa isn't on the surface, but below it. Under that thick shell of ice stretching 100 miles deep sits a globe-spanning liquid water ocean.

That's right: water engulfs the entire interior of Europa. There's more liquid water on Europa than there is on the Earth. The ocean itself is probably hundreds of miles deep. The moon is warmed by gravitational interactions with Jupiter, which stretches and squeezes its core, making it molten. That warmth heats the interior ocean, but not enough that the whole world turns into lava (which is what happened to the innermost moon of Jupiter, Io).

Astronomers are currently preparing missions to orbit Europa and search for signs of life, but why wait for them when you could jump straight to your ultimate dive destination. One tip: you’ll need to pack a flashlight, because no sunlight can penetrate that 100 miles of surface ice.

I know you’re probably thinking: I need a beach vacation, but all the resorts are just so crowded. Well then I’ve got the place for you. Imagine sipping your favorite cocktail, reading your favorite book, hearing your kids splashing away in the methane.

That's right, methane. Why don't you give Titan a try this summer? It's the largest moon of Saturn, and the only rocky world in the solar system other than the Earth and Venus to host a substantial atmosphere. And it shares something else in common with our planet: it's the only other world to host liquids on its surface, which is quite a remarkable feat, especially considering given its incredible distance from the Sun, it boasts an average surface temperature of only minus 290 degrees Fahrenheit.

That's far too cold for water to exist as a liquid, but Titan has a trick up its sleeve. It has a hazy, thick atmosphere. It rains. There are streams, rivers, lakes, and even possible oceans. But none are made of water—instead, liquid hydrocarbons like methane are the building blocks.

Scientists are enormously interested in Titan because it too might be another home for life. But any life here would be exotic indeed, as it would need to use methane as a solvent, rather than water. If that's not weird enough for you, then dig through Titan's crust and you just might find yet another globe-spanning liquid water ocean, just like Europa. There's something for everybody on Titan.

Ah, Pluto. It was once a weird little planet, and then the astronomical community decided that it was a littletoo weird and kicked it out of the planet club. But it still has something to offer. If you’d rather get away to somewhere mountainous and hit the slopes, you can't beat this strange world.

Pluto features perhaps the best skiing and snowboarding opportunities in the solar system. The tallest mountains on Pluto rise higher than Everest, and yet they’re not made of rock. At these distances from the Sun, water ice can become rock-hard and able to support such massive mountains (the relatively weak gravity of the diminutive word makes it easier, too).

It snows here, too, but the fresh powder on the slopes is made from frozen nitrogen condensing out of the atmosphere. This is a rare occurrence! Pluto takes 248 years to circle the Sun in a wide ellipse, meaning that it sometimes it comes closer than the planet Neptune. As it moves farther from the Sun, as it's doing now, the nitrogen freezes onto the ground. Once the atmosphere is cleaned out there will be no more snow.

And there are more visual treats on Pluto to delight the adventurous explorer. The giant heart-shaped region is actually a huge nitrogen glacier field, with giant boulders of water ice drifting through in slow-motion. And don't forget the romance! At this distance from the Sun, Pluto is locked in permanent twilight, so you never have to hurry to catch the perfect evening mood.

Paul M. Sutter is a science educator and a theoretical cosmologist at the Institute for Advanced Computational Science at Stony Brook University and the author of How to Die in Space: A Journey Through Dangerous Astrophysical Phenomena and Your Place in the Universe: Understanding Our Big, Messy Existence. Sutter is also the host of various science programs, and he's on social media. Check out his Ask a Spaceman podcast and his YouTube page.

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