Venus, Jupiter and Mars will cross paths in ‘planetary trio’ spectacle
Will not happen again until 2021 because of the planets’ different speeds
The rare phenomenon is best viewed an hour before sunrise, around 5am
It will require an exceptionally early start, but it is so rare this is the last time it will happen until 2021.
Venus, Jupiter and Mars, all pursuing their ordinary orbits around the sun, will be visible from today until Thursday.
The rare phenomenon is best viewed an hour before sunrise via the naked eye or binoculars.
The spectacular meeting will not happen again util 2021 because of the planets’ different speeds. The further they are from the Sun, the slower they travel.
Venus takes only a fraction of one Earth year – 225 days – to orbit the sun once.
Jupiter takes about 12 Earth years – 4,330 days – to go round the sun, while Mars takes 686 days.
As such, this sight – known as the planetary trio – is incredibly rare.
Mars in now just 33.9 million miles from Earth, Venus is just over 56 million miles and Jupiter about 10 times further at 560 million miles (900 million km).
Venus and Jupiter are the brightest planets in the night sky as seen from Earth.
Mars is some 250 times fainter than Venus, the sky’s brightest planet, and some 25 times fainter than Jupiter, the sky’s second-brightest planet.
It may even be possible to see a fourth planet – Mercury – over the horizon as darkness gives way to dawn.
Places with low light pollution, so away from the city and street lights, will give the best views.
Perhaps the best place to watch the rare event is Galloway Forest Park in Scotland, Britain’s first Dark Sky Park – which has as many as 50 times more stars than a major city.
The other best viewing spots include Exmoor, Powys in Wales, Kielder Forest in Northumberland and Romney Marsh in Kent.
Science website EarthSky wrote: ‘You won’t want to miss Venus and the early morning planets.
‘They’ll be like beacons before dawn and the best views should be about an hour before your local sunrise time’.
In June this year, Venus and Jupiter passed so close together they appeared to merge together in the night sky.
The next in August 2016 will be visible only from certain latitudes, while they will not be seen in UK skies like that until November 2019.