Our solar system is big. Way big. In fact, if Earth were the size of a marble, the solar system out to Neptune would cover an area the size of San Francisco.
Within this vastness lies an array of celestial wonders: the sun with its surface of plasma, the Earth with its abundance of life and massive oceans, the mesmerizing clouds of Jupiter, to name a few.
For this particular list, we've decided to highlight some well-known celestial wonders, as well as a few you might not know about. With new discoveries happening all the time, and so much left to explore, the cosmos is never short on beauty and astonishment.
Below are just a few of the scattered jewels of our solar system.
The impact crater of Utopia Planitia, Mars
The largest recognized impact basin in the solar system, Utopia Planitia features a crater that stretches more than 2,000 miles (about 3,300 kilometers) across Mars' northern plains. Because the impact is believed to have occurred early in Mars' history, it's likely that Utopia may have at one time hosted an ancient ocean.
In 2016, an instrument on NASA's Mars Reconnaissance Orbiter added weight to this theory after detecting large deposits of subsurface water ice beneath the impact basin. It's estimated as much water as the volume of Lake Superior may lie in deposits located 3 to 33 feet (1 to 10 meters) below the surface. Such an easily accessible resource could prove enormously beneficial for future human-based missions to the red planet.
"This deposit is probably more accessible than most water ice on Mars, because it is at a relatively low latitude and it lies in a flat, smooth area where landing a spacecraft would be easier than at some of the other areas with buried ice," Jack Holt of the University of Texas said in a 2016 statement.
The solar system's tallest mountain on Vesta
Despite its diameter of about 330 miles (530 km), the asteroid Vesta is home to our solar system's tallest mountain. Centered within an impact crater called Rheasilvia, this 14-mile-high (23 km) unnamed peak could easily fit two stacked Mount Everests.
This mega-mountain is believed to have formed 1 billion years ago after an impact with an object at least 30 miles (48 km) across. The resulting force carved out a huge amount of material, some 1 percent of Vesta, that was ejected into space and scattered across the solar system. In fact, it's estimated that some 5 percent of all space rocks on Earth originated from Vesta, which thus joins only a handful of solar-system objects beyond Earth (including Mars and the moon) from which scientists have a sample.
The vast canyon of Valles Marineris, Mars
To put the scale of Mars' immense Valles Marineris into perspective, just imagine the Grand Canyon four times deeper and stretching from New York City to Los Angeles. As you might expect, this vast canyon is the largest in the solar system, spanning more than 2,500 miles (4,000 km) and diving up to 23,000 feet (7,000 meters) into the red planet's surface.
According to NASA, Valles Marineris is likely a tectonic crack in Mars' crust that formed as the planet cooled. Another theory suggests it was a channel created by lava flowing from a nearby shield volcano. Regardless, its varied geography and likely role in channeling water during Mars' wet years will make it an attractive target for human-based missions to the red planet. We imagine the view from the rim of one of the canyon cliffs will be pretty spectacular as well.
The icy geysers of Enceladus
Enceladus, Saturn's second-largest moon, is a geologically active world covered in thick ice, and home to a large subsurface ocean of liquid water estimated to be about 6 miles (10 km) deep. Some of its most distinctive features, however, are its spectacular geysers — more than 100 discovered so far — that erupt from cracks in its surface and send dramatic plumes into space.
In 2015, NASA sent its Cassini spacecraft cruising through one of these plumes, revealing saltwater rich in organic molecules. In particular, Cassini detected the presence of molecular hydrogen, a chemical characteristic of hydrothermal activity.
"For a microbiologist thinking about energy for microbes, hydrogen is like the gold coin of energy currency," Peter Girguis, a deep-sea biologist at Harvard University, told the Washington Post in 2017. "If you had to have one thing, one chemical compound, coming out of a vent that would lead you to think there’s energy to support microbial life, hydrogen is at the top of that list."
As such, Enceladus' beautiful geysers may point the way to the most habitable spot for life in our solar system beyond Earth.
The 'Peaks of Eternal Light' on Earth's moon
While the so-called "Peaks of Eternal Light" on Earth's moon are a misnomer, they're nonetheless impressive. First postulated by a pair of astronomers in the late 19th century, the term applies to specific points on a celestial body almost perpetually bathed in sunlight. While detailed lunar topography collected by NASA's Lunar Reconnaissance Orbiter did not discover any points on the moon where light shines unabated, it did find four peaks where it occurs more than 80 to 90 percent of the time.
Should humans one day colonize the moon, it's likely the first bases will be founded on one of these peaks to take advantage of the abundant solar energy.
Because this phenomenon only occurs on bodies in the solar system with a slight axial tilt and regions of high altitude, it is thought that only the planet Mercury shares this characteristic with our moon.
Jupiter's Red Spot
Believed to be several hundred years old, the Great Red Spot of Jupiter is an anticyclonic storm (rotating counter-clockwise) roughly 1.3 times as wide as Earth.
While there's no definitive answer as to what caused the Great Red Spot, we do know one thing: It's shrinking. Recorded observations taken in the 1800s measured the storm at about 35,000 miles (56,000 km), or about four times the diameter of Earth. When Voyager 2 flew by Jupiter in 1979, it had reduced to a little over twice the size of our planet.
In fact, it's possible that perhaps over the next 20 to 30 years, the Great Red Spot (or GRS) will disappear completely.
"The GRS will in a decade or two become the GRC (Great Red Circle)," Glenn Orton, a planetary scientist at NASA JPL, recently told Business Insider. "Maybe sometime after that the GRM — the Great Red Memory."
Total solar eclipse from Earth
Nowhere in our solar system are total solar eclipses so perfectly experienced as from our own Earth. As witnessed across North America in August 2017, this phenomenon occurs when the moon passes between the Earth and the sun. During totality, the lunar disk appears to perfectly shield the sun's entire surface, leaving only its fiery atmosphere exposed.
The fact that these two different celestial objects appear to line up perfectly at all boils down to both math and a bit of luck. While the moon’s diameter is about 400 times smaller than the sun’s, it also is about 400 times closer. This creates the illusion in the sky of both objects being the same size. The moon, however, is not static in its orbit around the Earth. A billion years ago, when it was about 10 percent closer, it would have blocked the entirety of the sun. But 600 million years from now, at a rate of 1.6 inches (4 centimeters) per year, the moon will have drifted far enough away so that it will no longer cover the sun's shell.
In other words, we're lucky to have evolved when we did to view this temporary wonder of the solar system. You can catch the next one from North America in April 2024.
The ice spires of Callisto
Callisto, the second-largest moon of Jupiter, features the oldest and most heavily cratered surface in the solar system. For a long time, astronomers also assumed the planet was geologically dead. In 2001, however, that all changed after NASA's Galileo spacecraft passed a mere 85 miles (137 km) above Callisto's surface and captured something strange: ice-covered spires, some as high as 330 feet (100 meters), jutting from the surface.
Researchers believe the spires were likely formed by material ejected from impacts by meteors, with their distinctive jagged shapes the result of "erosion" from sublimation.
Like Jupiter's Great Red Spot or Earth's total solar eclipses, this is one wonder that is temporary in nature. "They are continuing to erode and will eventually disappear," James E. Klemaszewski of NASA's Galileo mission said in a 2001 statement.
We'll get our next shot at studying these bizarre ice spires when the European Space Agency's JUICE (JUpiter ICy moons Explorer) spacecraft visits three of Jupiter's Galilean moons (Ganymede, Callisto and Europa) in 2033.
Saturn's rings, spanning an estimated 240,000 miles (386,000 km) wide, are composed of 99.9 percent pure water ice, dust and rock. Despite their size, they are extremely thin, with thickness ranging from only 30 to 300 feet (9 to 90 meters).
The rings are believed to be very old, dating back to the formation of the planet itself 4.5 billion years ago. While some believe they are leftover material from Saturn's birth, still others theorize they may be the remains of an ancient moon that was ripped apart by the immense planet's tidal forces.
While Saturn's rings are gorgeous, they're also something of a mystery. For instance, before NASA's Cassini spacecraft burned up in September 2017, it collected data showing the planet's closest D-ring was "raining" 10 tons of material into its upper atmosphere every second. Even stranger, the material was made of organic molecules, not the expected mix of ice, dust and rock.
"What was a surprise was the mass spectrometer saw methane — no one expected that," Thomas Cravens, a member of Cassini's Ion and Neutral Mass Spectrometer team, said in a 2018 news release from the University of Kansas. "Also, it saw some carbon dioxide, which was unexpected. The rings were thought to be entirely water. But the innermost rings are fairly contaminated, as it turns out, with organic material caught up in ice."
The vertigo-inducing cliff face of Verona Rupes on the moon Miranda
On the moon of Miranda, the smallest of Uranus's satellites, there exists the largest known cliff in the solar system. Called Verona Rupes, the cliff face was captured during a flyby of Voyager 2 in 1986 and is believed to feature a vertical drop of as much as 12 miles (19 km), or 63,360 feet.
For comparison, the tallest cliff face on Earth, located on Mount Thor in Canada, has a relatively paltry vertical drop of about 4,100 feet (1,250 meters).
For those wondering, io9 crunched the numbers and discovered that, due to Miranda's low gravity, an astronaut jumping off the top of Verona Rupes would essentially free-fall for about 12 minutes. Even better? You might live to tell the tale.
"You wouldn't even need to worry about a parachute — even something as basic as an airbag would be enough to cushion the fall and let you live," io9 adds.