As Nasa's Juno spacecraft edges ever closer to Jupiter, "spectacular" images of the gas giant have been released showing the planet's atmosphere. The infrared images were taken with the European Southern Observatory's Very Large Telescope (VLT) and reveal cloud movement in the months before Juno arrives.
Observations will be used as part of an effort to create high-resolution maps of Jupiter and provide a better insight into the atmosphere – one of the key questions of the Juno mission and one that will help scientists work out how giant planets form.
Team leader Leigh Fletcher, from the University of Leicester, said: "These maps will help set the scene for what Juno will witness in the coming months. Observations at different wavelengths across the infrared spectrum allow us to piece together a three-dimensional picture of how energy and material are transported upwards through the atmosphere."
The images were created from thousands of individual frames. Those least affected by the atmosphere's turbulence, known as "lucky frames", were selected. These frames were combined to produce the resulting images.
The false-colour images were created from observations taken in February and March. Blue areas are cold and free of clouds, while orange areas are cloudy and warm. The bright, colourless areas are warm and cloud-free, while dark regions and cold and cloudy.
Juno will arrive at Jupiter on 4 July when it will be manoeuvred into the planet's orbit. Over the course of the mission, the spacecraft will orbit Jupiter for 20 months before burning up in its atmosphere in February 2018.
Glenn Orton, leader of the ground-based campaign to map Jupiter, said data from the VLT and other ground-based telescopes has and will provide an "incredibly rich dataset" allowing researchers to "characterise Jupiter's global thermal structure, cloud cover and distribution of gaseous species".
Juno is now 5.5 million miles from Jupiter. Ahead of the spacecraft's imminent arrival, Rick Nybakken, Juno project manager said: "It is a great feeling to put all the interplanetary space in the rearview mirror and have the biggest planet in the solar system in our windshield."
Nasa plans to start releasing images returned from Juno from August/September. Scott Bolton, principal investigator, said: "This image is the start of something great. In the future we will see Jupiter's polar auroras from a new perspective. We will see details in rolling bands of orange and white clouds like never before, and even the Great Red Spot."