Hubble captures rare triple moon transit of Jupiter
These new NASA/ESA Hubble Space Telescope images capture a rare occurrence as three of Jupiter’s largest moons parade across the giant gas planet’s banded face. Hubble took a string of images of the event which show the three satellites — Europa, Callisto and Io — in action.
There are four Galilean satellites — named after the 17th century scientist Galileo Galilei who discovered them . They complete orbits around Jupiter ranging from two to seventeen days in duration. The moons can commonly be seen transiting the face of Jupiter and casting shadows onto its layers of cloud. However, seeing three of them transiting the face of Jupiter at the same time is rare, occurring only once or twice a decade.
The image on the left shows the Hubble observation at the beginning of the event. On the left is the moon Callisto and on the right, Io. The shadows from Callisto, Io and Europa are strung out from left to right. Europa itself cannot be seen in the image.
The image on the right shows the end of the event, just over 40 minutes later. Europa has entered the frame at lower left with slower-moving Callisto above and to the right of it. Meanwhile Io — which orbits significantly closer to Jupiter and so moves much more quickly — is approaching the eastern limb of the planet. Whilst Callisto’s shadow seems hardly to have moved, Io’s has set over the planet’s eastern edge and Europa’s has risen further in the west. The event is also shown from start to finish in a video.
Missing from this sequence is the Galilean moon Ganymede which was outside Hubble’s field of view.
The moons of Jupiter have very distinctive colours. The smooth icy surface of Europa is yellow-white, the volcanic sulphur surface of Io is orange and the surface of Callisto, which is one of the oldest and most cratered surfaces known in the Solar System, is a brownish colour.
The images were taken with Hubble’s Wide Field Camera 3 in visible light on 23 January 2015. Whilst Hubble captures these moons in great clarity they can also be seen with a small telescope or even a decent pair of binoculars. Why not try it at home?
 These were among the first observations ever made using a telescope. They revolutionised our understanding of the Universe, and finally laid to rest the theory that the Earth is the centre of the Solar System.
Notes for editors
The Hubble Space Telescope is a project of international cooperation between ESA and NASA.
ESA/Hubble Public Information Officer
Garching bei München, Germany
Tel: +44 7816291261
Georgia Bladon | ESA/Hubble Media Newsletter
Researchers create artificial materials atom-by-atom
28.03.2017 | Aalto University
Astronomers probe swirling particles in halo of starburst galaxy
28.03.2017 | International Centre for Radio Astronomy Research
The Institute of Semiconductor Technology and the Institute of Physical and Theoretical Chemistry, both members of the Laboratory for Emerging Nanometrology (LENA), at Technische Universität Braunschweig are partners in a new European research project entitled ChipScope, which aims to develop a completely new and extremely small optical microscope capable of observing the interior of living cells in real time. A consortium of 7 partners from 5 countries will tackle this issue with very ambitious objectives during a four-year research program.
To demonstrate the usefulness of this new scientific tool, at the end of the project the developed chip-sized microscope will be used to observe in real-time...
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
20.03.2017 | Event News
14.03.2017 | Event News
07.03.2017 | Event News
28.03.2017 | Physics and Astronomy
28.03.2017 | Health and Medicine
28.03.2017 | Life Sciences