Now two months past opposition, the solar system’s largest planet, Jupiter, is highest in the UK sky before sunset and is already descending in the southwest by the time the sky is dark enough to observe it. However, there is still phenomena of the Galilean moons to see and the planet’s Great Red Spot, so make the most of your Jovian observations while you can during May.
As dusk fades to dark on Sunday, 17 April, observers in the British Isles should look up to the southern sky to see the 10-day-old waxing gibbous Moon and Jupiter just four degrees apart, within the same binocular field of view. Jupiter’s largest moon, Ganymede, and second Galilean moon, Europa, provide some events for telescope owners to view at higher magnifications.
As it orbits Jupiter, the icy surface of Europa heaves and falls with the changing pull of its parent planet’s gravity, creating enough heat to likely support a global ocean beneath the Jovian moon’s solid shell. Experiments by geoscientists suggest that this process, called tidal dissipation, could create far more heat in Europa’s ice than scientists had previously assumed.
The impact of a small comet or asteroid on Jupiter observed by European amateur astronomers on 17 March has heightened interest in the solar system’s largest planet. While such an event is uncommon, Jupiter and its family of four bright Galilean moons provide a wealth of other interesting phenomena to view with small telescopes during April.
Unbeknown to two European amateur astronomers 1000 miles apart capturing video of Jupiter through their telescopes in the early hours of Thursday, 17 March, their digital footage would subsequently show confirmation of a totally unexpected phenomenon — the likely impact of a small comet or asteroid on the edge of the solar system’s largest planet.
As darkness falls, observers in Western Europe and the British Isles fortunate to have clear skies can view a naked-eye conjunction between largest planet Jupiter and the Moon. For telescope owners, Jupiter’s Great Red Spot will be on show, while Galilean moons Io and Europa partake in a close orbital dance.
If you haven’t done so already, now is the time to ensure that your telescope is clean and collimated (aligned) to deliver the sharpest images of planet Jupiter at its best. We tell you the optimal UK times to view the largest planet’s Great Red Spot and multiple shadow transits from its Galilean moons.
In the early evening of Tuesday, 23 February, the rising waning gibbous Moon — one day after full Moon — lies just 3½ degrees from magnitude -2.5 planet Jupiter low in the eastern sky. Jupiter is closest to Earth on Tuesday, 8 March, so now is the time to get acquainted with the solar system’s largest planet.
In the dawn twilight of Friday, 4 December observers in the British Isles and Western Europe can see the 23-day-old waning crescent Moon just 2.5 degrees (half a 10×50 binocular field of view) below largest planet Jupiter in the constellation Leo high in the southern sky. And if you have a telescope, Jupiter’s largest moon plays hide and seek.
The existence of a fifth giant gas planet at the time of the solar system’s formation — in addition to Jupiter, Saturn, Uranus and Neptune that we know of today — was first proposed in 2011. Now astrophysicists at the University of Toronto have found that a close encounter with Jupiter about four billion years ago may have resulted in the fifth giant planet’s ejection from the solar system altogether.