Climate and science.
You can see two of the Universe's bright planets in the sky at the right moment on Saturday.
Venus and Jupiter are millions of miles apart, but they will be close to each other.
This year's planetary conjunction will be much closer than usual.
The spectacle will not occur again until 2039.
It should be easy to see it in the sky with the naked eye or binoculars.
The two planets will go their separate ways after Saturday.
It is a great opportunity for people to get out and have a look at the stars, according to space scientist and chief stargazer at the Society for Popular Astronomy Prof Lucie Green.
A conjunction is when two planets are close together.
Venus and Jupiter have been coming together in the sky in the last few days.
The planets are about 430 million miles apart, but their apparent alignment from Earth gives the illusion that they are touching.
You will need to be quick in the UK. The best time to view the sun is before the sun rises.
The view of the planets in the sky will be blocked by hills and buildings. If you can, look for two bright spots very close together.
The planets will have differing brightness. When you see Venus, it will look very bright. Prof Green says that Jupiter will be slightly fainter than Venus.
She suggests that you use an app to navigate the skies.
If you have a telescope, you can see some structure in the atmosphere of Jupiter or some of its largest moons.
The conjunction can be seen from both hemispheres at different times.
Those using a telescope can see a view of Mars and Saturn forming a line of four planets.
Prof Green says she will be up and out of bed to watch it.
If I miss it on Saturday morning, I will be fine.
The two planets will start to get further apart in the coming days, so I will still be able to see them.