Tag Archives: volcanism

A new analysis of data from Messenger suggests that violent explosive volcanism occurred throughout much of Mercury’s history.

A new analysis of data from Messenger suggests that violent explosive volcanism occurred throughout much of Mercury’s history.

What is interesting about this result is that previously it was believed that explosive volcanism didn’t happen at all on Mercury.

On Earth, volcanic explosions like the one that tore the lid off Mount St. Helens happen because our planet’s interior is rich in volatiles — water, carbon dioxide and other compounds with relatively low boiling points. As lava rises from the depths toward the surface, volatiles dissolved within it change phase from liquid to gas, expanding in the process. The pressure of that expansion can cause the crust above to burst like an overinflated balloon.

Mercury, however, was long thought to be bone dry when it comes to volatiles, and without volatiles there can’t be explosive volcanism. But that view started to change in 2008, after NASA’s MESSENGER spacecraft made its first flybys of Mercury. Those glimpses of the surface revealed deposits of pyroclastic ash — the telltale signs of volcanic explosions — peppering the planet’s surface. It was a clue that at some point in its history Mercury’s interior wasn’t as bereft of volatiles as had been assumed.

The new conclusions have not only found evidence of explosive volcanism, it found a wide range of ages for these deposits, indicating that the explosive volcanism took place across an extended period of time.

New data suggesting the presence of granite on Mars also suggests that the planet is more geologically complex than previously believed.

The uncertainty of science: New data suggesting the presence of granite on Mars also suggests that the planet is more geologically complex than previously believed.

In my years of science writing, I can’t count the number of times I’ve written the phrase “more complex than previously believed.” For some reason, modern scientists seem to always assume that things will be simple, with one straight-forward answer. From gamma ray bursts to supernovae to planetary formation to whatever, the first example found and the first theory developed from that first example has repeatedly been expected to explain everything.

But that’s not how things work. Instead, the closer scientists have looked, the more complex and interesting things have always become. Many different things can cause gamma ray bursts. Supernovae come in many types. Solar systems don’t have to resemble ours. Everything is always more complex than you first believe.

Scientists would get things wrong less often if they simply kept this thought in mind, at all times.

The location of the volcanoes on Titan are not where scientists had expected them to be.

The uncertainty of science: The location of the volcanoes on Titan are not where scientists had expected them to be.

As Io moves closer to Jupiter, the planet’s powerful gravity pulls hard on the moon, deforming it. This force decreases as Io retreats, and the moon bounces back. This cycle of flexing creates friction in Io’s interior, which in turn generates enormous amounts of volcano-driving tidal heat. Common sense suggests that Io’s volcanoes would be located above the spots with the most dramatic internal heating. But Hamilton and his colleagues found that the volcanoes are significantly farther to the east than expected.

Many of the news headlines, including the article above, have trumpeted how the volcanoes on Io are in the wrong place. (See also this article.) Not. The theories were wrong, not the volcanoes. Nature does what it wants to do. It is our job to figure out why.