Yesterday, NASA announced that the Hubble Space Telescope (HST) has imaged what appear to be plumes of water vapour erupting from the surface of one of Jupiter’s moons, Europa.

Beneath its thick icy surface, Europa is known to harbour an extensive ocean of liquid water. This has caused it to become one of the favourite candidates of hosting extra-terrestrial life within our Solar System. If the HST has indeed observed plumes erupting from the icy moon’s surface, this will offer a way of sampling Europa’s ocean without having to drill through kilometres of ice that make up its surface.

Images of Europa were taken as it passed between the HST’s line of sight and across the face of Jupiter. During the transit, some of Jupiter’s light was blocked out by what appear to be plumes of water vapour rising to an estimated 200 kilometres, before desciending back down to the moon’s surface.

A team at the Space Telescope Science Institute in Baltimore, US, observed Europa transit Jupiter on 10 separate occasions over a period of 15 months. These plume-like structures were noticeable on 3 of these ocassions. The figure to the left shows on of the observations where the plumes can be seen towards the bottom right of the image. The image of Europa itself is a composite of images from the Galileo and Voyager missions and has been superimposed on top of the HST data.

These new observations lend evidence to support the findings from the Southwest Research Institute in San Antonia. Using a different technique, a team detected evidence for water vapour erupting from a region surrounding Europa’s south pole back in 2012.

It is hopes that the James Webb Space Telescope, scheduled to launch in 2018, will allow scientists to make observations in the infrared range that will confirm these plumes. So stay tuned!

Image credit: NASA, ESA, W. Sparks (STScl) and the USGS Astrogeology Science Centre

Classroom Activity

You can identify Europa and the other three Galileon moons of Jupiter using images from the Faulkes Telescopes. The activity below can be done in the classroom with your students and makes a great short investigation activity.

1.  Search the LCOGT data archive (http://lcogt.net/observations/) for an image of a planet with the moons visible in the image – you can do this by typing in the name of the planet in the search box.

2. Once you have found a suitable image, click on the thumbnail image and a full page view of the object will be shown, with observation information on the right hand side. Note down the date and time that the image was taken along with the telescope location.

3. Using Stellarium (freely downloadable here), set the time and date to match the time and date of your image and set the location to the location of the telescope that was used to observe the object.

4. Search for your object in Stellarium and zoom in on it.

5. If you have set your time, date and location correctly, you should be able to identify the moons of the planet as they are automatically labelled in Stellarium when you zoom in far enough.

6. Using ‘Paint’ or another similar software, you can add text to your image to label the moons. When you’re done you should have something similar to the image below.