There’s no denying it—volcanoes are pretty awesome. But what’s even cooler than the inspiration for Mount Doom? Space volcanoes. And they’re way more explosive, awe-inspiring, and destructive than anything you’ll find on Earth.

1. Olympus Mons Mars

Olympus Mons is the largest volcano in the solar system. The massive Martian mountain towers high above the surrounding plains of the red planet, and may be biding its time until the next eruption.
Found in the Tharsis Montes region near the Martian equator, Olympus Mons is one of a dozen large volcanoes, many of which are ten to a hundred times taller than their terrestrial counterparts.

The tallest of them all towers 16 miles (25 kilometers) above the surrounding plains and stretches across 374 miles (624 km) — roughly the size of the state of Arizona. Olympus Mons rises three times higher than Earth's highest mountain, Mount Everest, whose peak is 5.5 miles above sea level.
Like volcanoes on Earth, Olympus Mons was formed due to cooling lava emerging from hot spots underground. However, unlike Earth, Mars doesn’t have a lot of tectonic motion, so these hot spots never shifted to a different location. The lava just kept building up in the same place until it became the beast of a mountain that is Olympus Mons. In fact, the volcano is so heavy that it actually sinks into the Martian surface, creating a moat around its base.

2. Pancake Domes Venus

Venus has more than 1,600 major volcanoes, and over 85 percent of its surface area is pure volcanic lava plains. However, most of these volcanoes aren’t your standard lava-spewing hills. One unusual structure type is referred to as a pancake dome.

This image shows three of the venusian pancake domes. They lie near the equator on the edge of Eistla Regio. The two larger domes are roughly 65 km (40 miles) wide, and the smaller dome is about 22 km (13 miles) wide. All three are very low, rising less than 1 km above the surrounding plains. The tops are fairly flat to slightly bowl-shaped, and they show clear patterns of small cracks and faults.

Most of these cracks probably formed with the dome, but some may have formed later with the faults in the surrounding plains. Note how some features extend from plains onto the edges of the central and right hand domes (arrows).

3. Tiger Stripes Enceladus (Moon Of Saturn)

Scientists studying the Cassini spacecraft images have observed a series of 120-kilometer (75-mile) long cracks in the south polar region of Enceladus, which were nicknamed "tiger stripes" because they resemble a tiger's distinctive marks. These stripes are actually four huge ridges across the moon’s surface. They span 130 kilometers (80 mi) each and are roughly 2 kilometers (1.2 mi) wide and 500 meters (0.3 mi) deep.

The way the tiger stripes are oriented on the moon's surface when Enceladus is farthest from Saturn pull most of them open, and when Enceladus is closest to Saturn, the stresses force most of them to close, which exposes water vapor to the vacuum of space.

Enceladus' exaggerated elliptical orbit causes the moon's icy crust to flex at these fault lines. As huge pieces of crust rub together, they generate enough heat to evaporate the ice lurking within the faults, in the same way that comets sprout tails when they veer too close to the sun's heat. In addition, Enceladus might have a vast, underground ocean that allows Enceladus to be more easily stretched by tidal forces so that it would produce enough heat to sprout geysers.

4. Pillan Patera Io (Moon Of Jupiter)

These images of Io show the results of a dramatic event that occurred at Pillan Patera during a five-month period. The changes occurred between the time Galileo acquired the left frame, during its seventh orbit of Jupiter, and the right frame, during its tenth orbit.

A new dark spot, 400 kilometers (249 miles) in diameter, which is roughly the size of Arizona, surrounds Pillan Patera. Pele, which produced the larger plume deposit southwest of Pillan, also appears different than it did during the seventh orbit, perhaps due to interaction between the two large plumes. Pillan's plume deposits appear dark at all wavelengths. This color differs from the very red color associated with Pele, but is similar to the deposits of Babbar Patera, the dark feature southwest of Pele.
The Galileo spacecraft indicate that the lava at Pillan Patera exceeded 1,700 degrees kelvin (2,600 degrees Fahrenheit) and may have reached 2,000 degrees kelvin (3,140 degrees Fahrenheit). The hottest eruptions on Earth today reach temperatures of about 1,500 kelvin (2,240 degrees Fahrenheit), but hotter lava erupted billions of years ago.

5. Cryovolcanoes Triton (Moon Of Neptune)

Despite being almost 2.7 billion miles away, we know a surprising amount about Neptune’s largest moon. The Voyager 2 also captured images of streaky formations that were formed by nitrogen geysers and plumes of gas and ice as high as 8 km (about 5 mi) that were erupting from active volcanoes.

Unlike the hot molten lava that we are familiar with here on Earth, the volcanoes of Triton give forth to eruptions of extremely frigid gas and ice spewing from Triton's frozen core. A cryovolcano is an icy volcano that emit plumes of very cold methane, ammonia and/or water. This volcanic activity is a result of melted ices that are caused by tidal friction or another source of heat.

6. Tupan Patera Io

Tupan Patera is a fiery, hellish pit with an island stuck in the middle. At a modest 75 kilometers (46 mi) across and 900 meters deep, it may not be the largest or most destructive volcano on Io, but it is one that offers the most information about the planet’s composition.

The island in the middle of Tupan Patera has a wonderful red margin surrounding it, most probably caused by sulfur deposits. This indicates that Tupan Patera is very active and could well be leading up to a big explosion any day now.

7. Tharsis Montes Mars

Tharsis Montes is the largest volcanic region on Mars. It is approximately 4,000 km across,10 km high, and contains 12 large volcanoes. The largest volcanoes in the Tharsis region are 4 shield volcanoes named Ascraeus Mons, Pavonis Mons, Arsia Mons, and Olympus Mons. The Tharsis Montes (Ascraeus, Pavonis, and Arsia) are located on the crest of the crustal bulge and their summits are about the same elevation as the summit of Olympus Mons, the largest of the Tharsis volcanoes.

While not the largest of the Tharsis volcanoes, Arsia Mons has the largest caldera on Mars, having a diameter of120 km (75 mi)! The main difference between the volcanoes on Mars and Earth is their size; volcanoes in the Tharsis region are up to 100 times larger than those anywhere on Earth.
In a very similar mechanism to one found on the Hawaiian islands, studies have shown that the members Tharsis Montes region have actually lined themselves up over the planet’s history. Further studies also indicate that the region may be lying dormant for now and could erupt again sometime in the future.

8. Culann Patera Io

Culann Patera is a colourful volcanic centre on Io. A dark red, curving line may mark a crusted-over lava tube feeding the dark hot silicate flows to the northwest. Dark red flows to the southeast may be sulphur or silicate flows whose surfaces have been modified. Diffuse red material is perhaps a compound of sulphur deposited from a plume of gas. Culanns caldera and several lava flows extending from the caldera are coated by greenish materials.

Whereas explosion-dominated eruptions are over in a matter of hours or days, flow-dominated eruptions last years—even decades—with a steady outpouring of lava which travels thousands of miles across the surface. Because of this, there are lava plains on Io that are bigger than the largest African countries.

9. ‘An Unusual Volcano’ Venus

This strange volcano lies in Aino Planitia. Its central dome is roughly 100 km across, but it is only about 1 km high. Around the dome are several thick, fan-shaped lava flows and a much larger flow with a banded surface. These flows strongly suggest the eruption of very viscous lavas. First, the fan-shaped flow lobes are very thick. The measured flow heights vary between 120 and 540 m (~400 to 1700 feet). Second, the shape of these flows suggests that the lavas had a hard time flowing away from the volcano. Third, while the larger flow is much thinner, it looks a lot like the banded flows produced by viscous lavas on Earth.

We already have a vague idea about what happened to the water on Venus. Since Venus lacks an ozone layer, ultraviolet light from the Sun was able to penetrate its upper atmosphere, where it broke down water into its individual components—hydrogen and oxygen. Solar wind then stripped away the lighter hydrogen molecules. Somewhere along the line, the planet’s surface heated up and sent most of its water into the air, where it fell victim to this solar stripping.

10. Tvashtar Paterae Io

Tvashtar Catena is one of the most interesting features on Jupiter’s moon Io. It is an active volcanic region located near the moon’s north pole. This ever-changing, extremely active volcanic field consists of a chain of giant volcanic paterae (caldera-like depressions).

During this time, a 25 kilometres (16 mi) long (the size of Manhattan), 1 to 2 kilometres (0.62 to 1.2 mi) high curtain of lava was seen to erupt from one crater, a lake of superheated silicate lava erupted in the largest crater, and finally a plume of gas burst out, rising 385 kilometres (239 mi) above the moon and blanketing areas as far away as 700 kilometres (430 mi).

Therefore scientists expected that the lava flow margins or patera boundaries within Tvashtar would have changed drastically. However, the series of observations revealed little modification of this sort suggesting that the intense eruptions at Tvashtar are topographically confined.