What are those two stars in the west? Millions of people have asked this question in the past few days. The answer: the planets Jupiter and Venus. During late February and early March 2023 they are set to provide a beautiful sight in the evening sky.
Each evening the two planets will be in different positions as Venus climbs higher in the sky. On 22 February the crescent Moon will join the pair to make a spectacular photo-opportunity. Jupiter is the fainter of the two planets, and during the last week of February is uppermost.
Then on 1 March the two planets are side by side, less than a degree apart – a close approach known as a conjunction.
Following that, Venus gets higher in the sky each night and Jupiter sinks into the evening twilight, becoming hard to see by mid March.
The planets only appear close through a line-of sight effect. Venus is the closer to Earth, but still 205 million km away on 1 March. Jupiter is over four times more distant, at 864 million km.
Although Venus is moving closer to Earth throughout the spring and summer, it remains about the same height in the evening sky all the time. This is because the angle of the ecliptic – the track that the planets follow in the sky – is changing all the time. Currently it’s at a steep angle to the horizon, but throughout the spring it dips, taking Venus with it. By early June, when Venus is at its greatest angular distance from the Sun, it will only be about as high in the sky at twilight as it is now. By July it will be too low in the evening sky to see easily, as viewed from the UK.