Professor Don Pollacco, Department of Physics, University of Warwick:

“Planetary alignments have always occurred; they are times when the planets in the solar system are all roughly positioned in the same direction when viewed from Earth. Given that we understand the orbits of the planets we can predict when these ‘alignments’ will occur. While the planets may look relatively close together in the sky they are of course separated by many millions of miles. Historically, some people proposed that alignments could trigger earthquakes due to the increased gravitational tug, however, even a quick look at the numbers shows that this is not correct as the force is absolutely tiny compared to the tidal forces originating in the Moon and Sun. So astronomically these alignments are of no relevance, visually they can be quite striking – the June 17 alignment will consist of Mercury, Uranus, Jupiter, Neptune and Saturn, visible before sunrise.

"While Jupiter and Saturn will be easy to spot by eye, Mercury will be more challenging as its proximity to the sun means that it is only just above the horizon and visible about an hour before sunrise (and sky could be brightening then). Neptune and Uranus need binoculars to be sure of seeing them (although some keen-sighted people can see Uranus unaided). Jupiter and Saturn will be bright objects that have a yellowy colour, Mercury often looks pink, and Uranus and Neptune pale white/green. Overall, it will be pretty to look at but not astronomically relevant (but supposedly astrologically important – but then as a scientist I wouldn't endorse that!).”