The Exoplanets Contain Active Volcanoes

Out of all the more recent discoveries reported lately, on worlds outside our own solar system, one new discovery could potentially be the most extraordinary we’ve seen to date: A new world known by scientists as 55 Cancri e, residing a mere 40 light-years away from Earth, could have volcanic activity.

“It’s super exciting,” said the Cambridge University astrophysicist Nikku Madhusudhan, who co-authored a new paper recently published online at arXiv.org about the discovery .

When astronomers began uncovering these exoplanets way back in the 1990s, they thought they would require a much bigger, and more powerful successor following the Hubble in order to study them with any depth. They were fortunately wrong. Although the launching of the James Webb Space Telescope would still take place several years in the near future, exoplanet experts have still been successful with probing the atmospheres from these distant worlds, in order to determine whether or they’re still gaseous, like giants in our own solar system such as Jupiter, or more of a rocky, like Earth or Mars; and determine the nature of the storms that currently appear to be whipping across the sands.

It isn’t so much that these volcanoes on their own have the astronomers excited; it’s that modern technology is now allowing us to have a better view of how these exoplanets may actually be. Their ultimate goal remains to uncover a planet which supports life, opening up the possibilities of deep space exploration. The more in depth that scientists are able to describe the physical conditions as they appear on individual planets, then the better they are able to narrow down their searches. Think of it as just another bound to cross while going down that road. According to Madhusudhan, “In our wildest imaginations, we couldn’t have guessed we’d be making discoveries like this as early as 2015.” Think of this as an early surprise that might speed up the rest of the journey.

The discovery isn’t officially one for the books just yet, however, warns Madhusudhan. “We don’t want to jump to conclusions,” he says. What he and his colleagues actually see with the Spitzer Space Telescope is a dramatic variation in the planet’s temperature—from about 1880°F at the “cooler” end to nearly 5,000°F at the hotter. “It’s the first time we’ve seen such a huge level of variability,” said Brice-Olivier Demory, also of Cambridge and the paper’s lead author.

Even at the cooler hemisphere of the planet, the 55 Cancri e, which has been measured as approximately twice the size of Earth, while containing nearly eight times the mass, it’s far too hot to support any lifeforms as we know of them. If the planet’s surface contains solid rock, as astronomers believe it does, then the surface may either be partially or completely molten. But the wide swings of temperature as reported — from the lower temperature back in 2012 to the higher ranges they discovered in 2013 — are a pretty clear indication that there’s something unusual at play here. It may be that the planet is reacting against variations made by the star itself, such as solar storms which interact with the Earth’s magnetic field at home, suggest the scientists, but then these would typically be allocated to random times, with no steady trends of increase. It may be that this is all just an illusion of sorts. Perhaps it could be that the planet ends up becoming eclipsed once every several years due to a cloud of gas or from dust that orbits the parent star. This activity could cause the 55 Cancri e to show up dimmer, and consequently would make the planet appear to be cooler in the telescopes.

Volcanic activity, however, may also lead to a dimming effect on the planet, so the astronomers suspect that this scenario is much more likely. “We know it happens all over our own solar system,” says Madhusudhan. “We see evidence for it on Venus, Mars, [Jupiter’s moon] Io, all kinds of solid bodies. That’s the natural explanation.”

The new theory suggests that enough of these powerful eruptions would release gas and dust in its massive plumes into the planet’s atmosphere, therefore covering the hot surface from telescope visibility, while giving these planets the illusion that they are much cooler. To be seen the eruptions would have to be exceptionally violent, but there is always the likelihood of that happening. The 55 Cancri e orbits near enough to its parent star that a “year” there is only a mere 18 hours, and so it may be flexing against some intensive tidal forces produced by the star’s gravity. The heat created by that flexing could then keep a molten inner core of the planet, providing constant source material for the eruptions.

There’s a heavy emphasis here on the word “Could.”

“We’ll need more data to be able to tell for sure whether the variability is due to volcanoes,” said Laura Kreidberg, an expert on exoplanet atmospheres at the University of Chicago, who did not partake in the new research. “But it’s still really exciting. This is a prototype of the kinds of observations we can use to search for volcanic activity on other planets.”

Heather Knutson, a Caltech astronomer who is also involved in the study of exoplanet atmospheres, calls the new findings “a very provocative result.”

“I think we will have to wait for the launch of the James Webb Space Telescope in order to obtain a definitive picture of the state of this boiling hot planet’s surface and atmosphere,” Knutson says.

This is Madhusudhan’s approach to the situation. “This is all done with the Spitzer telescope,” he says, “which is on its last legs. One can only imagine what we can do with the [Webb telescope].”