July 3, 2016, by Brigitte Nerlich
Jupiter and Juno
Once in a while I write a blog post about space missions – and there have been quite a few recently. I especially enjoyed the Rosetta mission to 67P and the New Horizons mission to Pluto. Now another mission has crossed my horizons, namely the Juno mission to Jupiter. While Pluto was believed to be small and unspectacular but turned out to be spectacular, Jupiter has always been spectacular. Jupiter is, after all, the largest planet in the solar system and it has an intriguing red spot. But obviously there is more to Jupiter than that. So what’s the mission about?
The Juno mission
“The Juno mission is the second spacecraft designed under NASA’s New Frontiers Program. The first is the Pluto New Horizons mission, which flew by the dwarf planet in July 2015 after a nine-and-a-half-year flight.” Juno, a solar powered craft (actually “the most distant solar powered spacecraft”), was launched on August 5, 2011. On Monday 4 July at 11:53 p.m. Eastern time (in the United States that’s Independence Day) Juno will reach Jupiter (in Europe this means it will arrive at 4:18 am BST/5:18 am CEST on the morning of 5th July 2016). As Kenneth Chang said in a nice New York Times article: “After traveling for five years and nearly 1.8 billion miles, NASA’s Juno spacecraft will announce its arrival at Jupiter with the simplest of radio signals: a three-second beep.” After that, if all goes well, Juno will orbit Jupiter for 20 months (37 orbits) and explore it from top to bottom.
“Juno’s goals are to study Jupiter’s gravitational field, inner structure, deep atmospheric composition and magnetic environment in order to understand the origin and evolution of the giant planet” and indeed the origin and evolution of our whole solar system.
I won’t be able to say anything that hasn’t been said better by NASA. And I can’t say anything more poetic than this little video by Dennis Overbye, Jonathan Corum and Jason Drakeford. However, I can bring the mission a bit down to Earth, even down to the East Midlands.
Jupiter, Leicester and Nottingham
Many many years ago I went to the Leicester Space Centre with a bunch of kids. I remember wandering through the ‘Planets’ section with them. One of them piped up and said that Pluto was boring, but she was quite impressed by Jupiter. Lets see how impressive Jupiter will turn out to be when probed by Juno; Pluto certainly changed its ‘image’ after the New Horizons mission. And from what we have seen so far, Jupiter is even more impressive than it already is, having recently been crowned with a spectacular aurora, for example.
But why do I bring up Leicester? Although the Juno mission is led by NASA, it is, like all space missions, a truly international affair, involving many European scientists and amateur astronomers, including, in particular, scientists from the University of Leicester. One of them, Dr Leigh Fletcher presented stunning new images of Jupiter at the National Astronomy Meeting which took place at the University of Nottingham on 27 June. In an interview he said: “We used a technique called ‘lucky imaging’, whereby individual sharp frames are extracted from short movies of Jupiter to ‘freeze’ the turbulent motions of our own atmosphere, to create a stunning new image of Jupiter’s cloud layers,” explained Dr Fletcher. “At this wavelength, Jupiter’s clouds appear in silhouette against the deep internal glows of the planet. Images of this quality will provide the global context for Juno’s close-up views of the planet at the same wavelength.”
Jupiter, Europe and Europa
Fletcher and many other astronomers used ESO’s very large telescope to obtain these images. ESO is “the European Southern Observatory”, which “is the foremost intergovernmental astronomy organisation in Europe and the world’s most productive astronomical observatory.” As ESO pointed out: “Europe has provided instrumentation for the mission and European scientists from Italy, France, Belgium, the UK and Denmark are part of the team of co-investigators that will help analyse data sent back by Juno. Amateur and professional scientists from across Europe are also involved in campaigns using ground- and space-based telescopes that will study Jupiter at a range of wavelengths to put Juno’s close-up observations into context.”
Jupiter (and its four moons Io, Europa, Ganymede, and Callisto) has of course already a very special status in our understanding of the solar system, indeed in changing our understanding of it and of us completely – through the works of Galileo, Kepler and others across Europe. But who came up with the names for the moons, including Europa – an icy moon awaiting its own mission? It seems to have been Kepler.
The story of the names is here told by the 17th century German astronomer Simon Marius (who published Mundus Iovialis in 1614, a book in which he described the planet Jupiter and its moons): “Jupiter is much blamed by the poets on account of his irregular loves. Three maidens are especially mentioned as having been clandestinely courted by Jupiter with success. Io, daughter of the River, Inachus, Callisto of Lycaon, Europa of Agenor. Then there was Ganymede, the handsome son of King Tros, whom Jupiter, having taken the form of an eagle, transported to heaven on his back, as poets fabulously tell . . . . I think, therefore, that I shall not have done amiss if the First is called by me Io, the Second Europa, the Third, on account of its majesty of light, Ganymede, the Fourth Callisto . . . . This fancy, and the particular names given, were suggested to me by Kepler, Imperial Astronomer, when we met at Ratisbon fair in October 1613. So if, as a jest, and in memory of our friendship then begun, I hail him as joint father of these four stars, again I shall not be doing wrong.”
Jupiter and Juno
And what about Juno? Who is Juno, who has given her name to the space probe that is now approaching Jupiter? According to Wikipedia, “ Juno (Latin: Iūno [ˈjuːno]) is an ancient Roman goddess, the protector and special counselor of the state. She is a daughter of Saturn and sister (but also the wife) of the chief god Jupiter and the mother of Mars and Vulcan. Juno also looked after the women of Rome.”
Let’s hope Juno the goddess also looks after Juno the spacecraft. And Good Luck!
Image: Wikimedia commons