Astronomers are using the NASA/ESA Hubble
Space Telescope to study auroras — stunning light shows in a planet’s
atmosphere — on the poles of the largest planet in the Solar System,
Jupiter. This observation programme is supported by measurements made by
NASA’s Juno spacecraft, currently on its way to Jupiter.
Jupiter, the largest planet in the Solar System, is best known for its colourful storms, the most famous being the Great Red Spot.
Now astronomers have focused on another beautiful feature of the
planet, using the ultraviolet capabilities of the NASA/ESA Hubble Space
Telescope.
The extraordinary vivid glows shown in the new observations are known as auroras [1].
They are created when high energy particles enter a planet’s atmosphere
near its magnetic poles and collide with atoms of gas. As well as
producing beautiful images, this programme aims to determine how various
components of Jupiter’s auroras respond to different conditions in the solar wind, a stream of charged particles ejected from the Sun.
This observation programme is perfectly timed as NASA’s Juno
spacecraft is currently in the solar wind near Jupiter and will enter
the orbit of the planet in early July 2016. While Hubble is observing
and measuring the auroras on Jupiter, Juno is measuring the properties
of the solar wind itself; a perfect collaboration between a telescope
and a space probe [2].
“These auroras are very dramatic and among the most active I have ever seen”, says Jonathan Nichols from the University of Leicester, UK, and principal investigator of the study. “It almost seems as if Jupiter is throwing a firework party for the imminent arrival of Juno.”
To highlight changes in the auroras Hubble is observing Jupiter daily
for around one month. Using this series of images it is possible for
scientists to create videos that demonstrate the movement of the vivid
auroras, which cover areas bigger than the Earth.
Not only are the auroras huge, they are also hundreds of times more
energetic than auroras on Earth. And, unlike those on Earth, they never
cease. Whilst on Earth the most intense auroras are caused by solar
storms — when charged particles rain down on the upper atmosphere,
excite gases, and cause them to glow red, green and purple — Jupiter has
an additional source for its auroras.
The strong magnetic field of the gas giant grabs charged particles
from its surroundings. This includes not only the charged particles
within the solar wind but also the particles thrown into space by its
orbiting moon Io, known for its numerous and large volcanos.
The new observations and measurements made with Hubble and Juno will
help to better understand how the Sun and other sources influence
auroras. While the observations with Hubble are still ongoing and the
analysis of the data will take several more months, the first images and
videos are already available and show the auroras on Jupiter’s north
pole in their full beauty.
Notes
[1] Jupiter’s auroras were first discovered by the Voyager 1
spacecraft in 1979. A thin ring of light on Jupiter's nightside looked
like a stretched-out version of our own auroras on Earth. Only later on
was it discovered that the auroras were best visible in the
ultraviolet.
[2] This is not the first time
astronomers have used Hubble to observe the auroras on Jupiter, nor is
it the first time that Hubble has cooperated with space probes to do so.
In 2000 the NASA/ESA/ASI Cassini
spacecraft made its closest approach to Jupiter and scientists used
this opportunity to gather data and images about the auroras
simultaneously from Cassini and Hubble (heic0009). In 2007 Hubble obtained images in support of its sister NASA Mission New Horizons which used Jupiter's gravity for a manoeuvre on its way to Pluto (opo0714a).
More Information
The Hubble Space Telescope is a project of international cooperation between ESA and NASA.
Image credit: NASA, ESA
Links
Contacts
Jonathan Nichols
University of Leicester
United Kingdom
Tel: +44 116 252 5049
Email: jdn4@leicester.ac.uk
Mathias Jäger
ESA/Hubble, Public Information Officer
Garching bei München, Germany
Cell: +49 176 62397500
Email: mjaeger@partner.eso.org
