Our planet Earth flies between the sun and the outer planet Jupiter on June 10. That places Jupiter – largest world in our solar system, and a very bright planet in our sky – opposite the sun. In other words, Jupiter is now rising in the east as the sun is setting below the western horizon. Astronomers call this event an opposition of Jupiter.
Opposition marks the middle of the best time of year to see a planet. That’s because it’s when the planet is up all night and generally closest for the year (the exact date of Jupiter at its closest this year is June 12).
Rising in the east around sunset, Jupiter climbs highest in the sky at midnight. (By midnight, we mean midway between sunset and sunrise.) It sets in the west around sunrise. Jupiter is always bright; it’s the largest planet in our solar system. It shines more brightly than any star in the evening sky.
With the exception of the sun and moon, only Venus – the brightest planet, now low in the east before sunrise – outshines Jupiter. Try catching both Venus and Jupiter at morning dawn. Venus will be blazing low in the east while Jupiter will sitting low in the west. You’ll need an unobstructed horizon in both directions to see both Venus and Jupiter before sunrise.
At this 2019 opposition, Jupiter shines in the vicinity of Antares, the brightest star in the constellation Scorpius the Scales. There’s no way to mistake Antares for Jupiter, though, because dazzling Jupiter outshines this 1st-magnitude star by nearly thirty times.
Technically, Jupiter is just north (above) the northern border of Scorpius. Jupiter presently lights up the constellation Ophiuchus the Serpent Holder and will continue to do so till nearly the end of the year. Next year, in 2020, Jupiter will be in front of the constellation Sagittarius the Archer.
Jupiter comes to opposition about every 13 months. That’s how long Earth takes to travel once around the sun relative to Jupiter. As a result – according to our earthly calendars – Jupiter’s opposition comes about a month later each year.
Last year – in 2018 – Jupiter’s opposition date was May 9.
Next year – in 2020 – it’ll be July 14.
Astronomer Guy Ottewell has a great post at his blog on Jupiter’s oppositions in 2017, 2018 and 2019. Note on the charts below (used with Guy’s permission) that Jupiter at opposition shifts one constellation eastward each year:
April 7, 2017 opposition: Virgo
May 9, 2018 opposition: Libra
June 10, 2019 opposition: Ophiuchus
There’s a NASA spacecraft orbiting Jupiter now. The Juno spacecraft’s orbit carries it low over Jupiter’s poles, providing never-before-seen glimpses of the giant planet’s polar regions. Jupiter isn’t a rocky planet like Earth. It’s more like a failed star, not massive enough or hot enough inside to spark thermonuclear fusion reactions, but some 2.5 times more massive than all the other planets in our solar system combined. Jupiter shows us nature magnified! Check out the video below, which provides an infrared view of the massive cyclones at Jupiter’s poles:
— NASA's Juno Mission (@NASAJuno) April 11, 2018
Bottom line: Look for Jupiter on the night of June 10, 2019, as this world comes to opposition, the point opposite the sun in our sky. You’d need some 80 Jupiters – rolled into a ball – to be hot enough inside for thermonuclear reactions … for Jupiter to shine as stars do. Yet on this May night – as Jupiter rises opposite the sun – you can imagine it beaming down on us as a tiny sun all night long.