Is Mercury volcanically active?

Is Mercury volcanically active?

"While all of the lava flows we observe are quite old—Mercury stopped being volcanically active 3.5 billion years ago—you will see that the most recent signs of volcanic activity happened mainly in regions where there are impact craters, places where the shell is thin or fractured," Byrne explains. "These observations suggest that beneath Mercury's surface is a layer of solid rock which may be deep enough to contain a reservoir of heat from which it could erupt with sudden force."

He continues: "We know that asteroids and comets can deliver their cargo of dust, water, and biological material to Earth, but could also have played a role in shaping the surfaces we see today from Mercury to Neptune?"

The answer is yes, Mercury is volcanically active. Data from NASA's MESSENGER spacecraft has revealed that the planet's interior is still hot, with a molten core likely surrounded by a rigid shell about the thickness of a water film. The presence of a substantial amount of iron inside Mercury has been confirmed by measurements made by MESSENGER's Magnetometer/Rotation Sensor (MGR). This instrument showed that Mercury has a strong magnetic field, which means that its entire outer shell is wrapped around an inner core of metal.

You can read more about Mercury's surface features in our article on Mercury's Top 10 Facts.

When was the last time Mercury had a volcano?

However, other scientists have discovered evidence from a massive impact crater that looks to be more recent, leading them to assume that Mercury may have seen volcanic activity as recently as 1 to 2 billion years ago. In either scenario, Mercury's volcanic stage has long ago gone.

Volcanism is a major part of Earth's history and has played an important role in shaping our planet's surface. The eruption of large amounts of lava or steam, accompanied by sulfur dioxide (SO2) and hydrogen fluoride (HF), can destroy life at the surface. However, some species of bacteria and archaea are able to survive such events due to their ability to close their pores against harmful gases. Other organisms deep within the crust would be killed by the heat or gas released but later re-emerged from depth due to deeper layers of rock collapsing causing fissures through which they could grow back.

The first evidence of volcanism on Mercury comes from data collected by Mariner 10 during its closest approach in 1973. The spacecraft found no active volcanoes but did detect many linear features on the surface that were estimated to be about 50 miles (80 km) long. Scientists think that these might be dried up lakes filled with basaltic lava. Indeed, similar structures have been observed on Venus and Io.

What is the evidence of volcanic activity on Mercury? What was the origin of that activity?

The MESSENGER spacecraft imaged most of Mercury's surface and discovered signs of volcanic activity changing the planet's surface. Some of the lava flows date back one to two billion years. Other areas show features that are unique to more recent activity, including 20-40 km wide depressions called calderas. These results provide strong evidence that volcanism has been a major force on shaping Mercury for at least the last two billion years.

The new images from MESSENGER reveal a highly active planet with many large volcanoes. The spacecraft found several regions where lava appears to have recently drained into shallow valleys rather than spreading out over the surface like in true volcanoes on Earth. Scientists think some of these features may be dormant rather than inactive volcanoes that have not spread lava across the surface for some time.

MESSENGER's close-up views of the planet's surface showed that volcanic activity has altered much of Mercury. Large parts of its surface appear bright due to deposits of sulfur caused by volcanic eruptions millions of years ago. Other areas are dark because they are composed of iron ore formed as molten rock deep within the planet cooled and hardened.

The discovery of volcanic activity on Mercury helps scientists understand how planets around other stars are shaped by their environments.

Why are there valleys on the surface of mercury?

The MESSENGER team scientists believe that these canyons on Mercury's surface developed as a result of mechanical and thermal erosion of the planet's surface by hot, low-viscosity, quickly-flowing lavas. Is there a volcano on Mercury? There are volcanoes on Mercury. However, they're not like terrestrial volcanoes because they don't emit lava flows or volcanic ash like Earth's volcanoes do. Instead, they form small peaks called mesa that rise about 100 feet (30 meters) above the surrounding terrain.

Volcanism on Mercury was first suggested based on similarities between some of its features and those on Venus, which has a very similar atmosphere and environment. Later studies showed that the same processes may be responsible for creating canyons on both planets.

Venus and Mercury have almost identical orbits around the Sun, making their orientation with respect to the solar wind dynamic rather than seasonal. As a result, they experience large scale geologic changes as a result of impact events from outer space and intense heat flow from their interiors that cause major tectonic activity.

However, while there are many areas on Venus where evidence has been found that points toward past water availability, no such evidence has been discovered on Mercury. Scientists think this might be because the water would have been lost to radiation before it had a chance to evaporate or be trapped as ice.

Why was the lava on Mercury so violent?

Although much of Mercury's volcanism occurred in the form of slow-moving lava, some of it was rather violent. "When magma reaches the lower-pressure conditions of the planet's surface, gases that were initially dissolved in it break it apart," Thomas explained. The gas bubbles expand, causing the rock to shatter and melt away.

Mercury is always hot because its thin veneer of air causes it to heat up rapidly. The volcanic activity we see today was probably common when the planet was more heavily forested with plants taking up space that have since died out or been consumed by lava flows.

These explosions would have blown away most of the soil and exposed fresh rock, which would have absorbed much of the heat from the sun that was previously contained by the vegetation.

The presence of these large deposits of explosive volcanic material indicates that Mercury has experienced many more such events than Earth has over its long history. It may be that this state of affairs is typical for small planets near their stars: they tend to lose their atmospheres quickly due to radiation from the sun and experience high temperatures during the day as a result.

This may also explain why the solar system's smallest planet is also one of its hottest: without an atmosphere to protect it, it experiences direct exposure to sunlight all day every day.

About Article Author

Lupe Laguire

Lupe Laguire has lived in Bali for the last 7 years and she is a yoga instructor, entrepreneur, and writer. She loves to travel through-out Indonesia and exploring new cultures. Lupe teaches meditation as an alternative therapy that helps with stress relief.

Related posts