If you’re below retirement age, you’ll never have seen it so big or so bright. Amid all the political seismic shocks, the universe is throwing in a stunning natural phenomenon this week, with the appearance of the largest “supermoon” to grace our skies in 68 years.

The moon is coming closer to Earth than is usual on its orbit on Monday, and the side facing us will be fully illuminated by the sun. The combination produces what is known as a “super perigee full moon”, and we will witness one of the most impressive examples as it passes closer to Earth on Monday than at any point since 1948.

It should be around a third brighter than the smallest full moon and will be a mere 225,623 miles away, compared with the 252,088 miles at its furthest point from Earth. The average distance of the moon, which keeps an imperfect 27-day oval orbit, is 238,855 miles.

Full moons always rise around sunset which, cloud cover permitting, will be a good time to spot the “supermoon”, said Dr Chris North, science lecturer at Cardiff University. Writing for the Conversation, he said: “The reason this perigee full moon is quite so ‘super’ is because perigee and full moons happen at almost exactly the same time, so the moon is at its closest possible when it’s also at its fullest. There are a number of other subtle effects that cause the moon’s orbit to vary slightly in size and shape, but this one pips the last few decades’ worth of super perigee full moons by a few hundred kilometres.

“These differences are pretty small, and with the moon rising so high in the sky, as it does in the winter, it’ll be quite hard to notice any difference without comparing photographs. Of course, it might be cloudy – though it can be rather atmospheric to see the bright, full moon through thin cloud,” he said.

“Even if it’s completely overcast, there are plenty of other chances to see the moon as it gradually moves past its full phase over the next few nights, so don’t be disheartened. It rises at different times of day and night as it orbits the Earth ... but it’s not going anywhere.”

At around 11.30am on Monday the moon will reach its closest point to us – the perigee moment – and will then begin moving away, very slowly. By 1.30pm the Earth, sun and moon will be almost perfectly in a line – a phenomenon known as a “syzygy” – with the moon directly opposite the sun. So the best time to see it in the UK will be when the sun sets, when it will only be about 50km further away than in the late morning – not much in the grand scheme of things.

Neil deGrasse Tyson, director of New York’s Hayden Planetarium, thinks “supermoon” is an unsuitable term. “I don’t know who first called it a supermoon,” he said. “I don’t know, but if you have a 16-inch pizza, would you call that a super pizza compared with a 15-inch pizza?”

If it is cloudy on Monday night then fear not. You will be able to see a comparable display again on 25 November 2034.