Study finds one of Europa's plumes may not exist

Study finds one of Europa's plumes may not exist



Concealed beneath a shell of ice, Jupiter’s moon Europa is known to host an ocean of liquid water, leading scientists to believe it may be among their best shots at finding alien life.

While accessing this subsurface ocean would be a great hurdle, recent Hubble observations suggest there may be active water vapour plumes on the icy moon, which could allow for direct study.

Findings from a new study, however, suggest that one of these suspected plumes may not exist at all – instead, the region may just be home to warm rocks.



The absence of plumes wouldn’t kill chances for life on Europa, but it would make the hunt for such organisms far more difficult.

Using the Atacama Large Millimeter Array, researchers from the California Institute of Technology captured a daytime thermal image of the moon, including a region near Pwyll Crater, which has been linked to two possible plume detections.

In this spot, NASA’s Galileo instrument previously detected excess night-time heat, suggesting it could be a plume site.

The team examined something known as thermal inertia, which explains how quickly a material absorbs and loses heat, according to New Scientist.

By comparing the new ALMA observations with old data, however, the researchers found the behaviour in the area doesn’t line up with the model.

‘If thermal excess were due to an endogenic hot spot, then it could support the idea that the region northwest of Pwyll exhibits modern geologic activity,’ the authors wrote in a study published to arXiv.



‘Using a global one-dimensional thermal diffusion model, we fit both the ALMA and PPR observations.

‘However, while the location in question does appear hot relative to our model at night, it appears colder in our ALMA daytime image than the model predicts.’

According to the researchers, this could be a sign of elevated thermal inertia, meaning that particular area may be made up of rocks that gradually heat all day, and stay warm into the night.

This could also mean that the area does not contain a plume, as previously thought.



But, it’s too early to know for sure.

‘All we can say is that our data are not consistent with a current subsurface heat source,’ lead researcher Samantha Trumbo told New Scientist.

‘That doesn’t necessarily mean there’s no plume there.’

Upcoming missions to Europa will help scientists get a much better idea of the activity at the surface, and find out if these plumes really do exist.