Look out for the first major display of shooting stars in more than three months with the return of the Lyrid meteor shower in April. Observers will have to contend with bright moonlight in 2021, but you may still spot the brighter “shooting stars” in clear skies.
The Lyrid meteor shower, also simply known as the Lyrids, is active from April 16th to 25th, according to the International Meteor Organization (IMO). It is made up of dust shed by Comet Thatcher.
The Lyrids reach their peak on the night of April 21st-22nd in 2021, according to the IMO. The number of meteors visible to an observer under perfect conditions (the Zenithal Hourly Rate, or ZHR) is forecast to be 18. Moonlight will seriously reduce this number, with a gibbous phase, just past First Quarter.
In practice, you are always likely to see fewer meteors than the ZHR figure because of factors such as the height of the meteor shower’s radiant above the horizon and the darkness of the sky. But if you find a place to watch, away from light-polluted cities, street lights and house lights, you may be lucky and see a few. Look in a direction away from the Moon so that it does not dazzle you.
For mid-northern latitudes such as in the UK, Europe and much of the USA, the Lyrids’ radiant will rise early in the evening. The Moon will already be high in the sky in Leo at maximum, and will not set until twilight is beginning.
Unlike January’s Quadrantids, which have a short peak, the Lyrids generally offer good rates of meteors for three nights around the night of maximum activity. The meteors appear fairly swift, entering the atmosphere at about 48 km per second (30 miles per second).
Don’t expect to see something as soon as you start looking! Meteor watching requires plenty of patience, particularly with a medium-strength shower such as the Lyrids. So don’t be fooled by some of the wilder promises of dramatic firework displays from popular general news sites that offer plenty of clickbait but have no astronomical expertise.
Different meteor showers have different characteristics. According to IMO, the Lyrids lack persistent trains, but the shower can produce fireballs, so be ready for an unexpected treat.
The shower is named the Lyrids because the meteors appear to radiate from a point in the constellation of Lyra, the lyre. This point is known as the radiant. However, the meteors themselves can appear anywhere in the sky. By tracing their paths back, you will find they intersect at the radiant.
You may also see other meteors which do not radiate from Lyra. These are unrelated to the stream of debris left by the comet. They are known as sporadic meteors, or simply sporadics, and are random bits of background meteoric debris that can be seen all year round.
Lyra is a northerly constellation and so the Lyrids are better seen from the northern hemisphere, where the radiant climbs high in the sky after midnight.
However, some meteors can be seen from anywhere in the world as long as Lyra is above the local horizon, so southern hemisphere observers can see the shower, even as far south as Australia and New Zealand.
The parent comet, which takes about 415 years to make one orbit of the Sun, is named after amateur astronomer Professor A. E. Thatcher, of New York, who discovered it on April 4, 1861. Professor Thatcher, who found several comets, spotted this one on 5 April, 1861, at magnitude 7.5. Within a month, it had become a bright naked-eye object with a tail. Its full title is C/1861 G1 (Thatcher).
Though we won’t see the comet again until the year 2276, the Lyrids are a regular sample of its debris delivered to our skies. In fact the shower is one of the oldest known and has been seen for 2,700 years, with the first recorded sighting being made by the Chinese in 687 BC.
So if you spot one or more Lyrids suddenly shoot across the sky, you will be sharing an experience from history, enjoyed by some of the earliest people to gaze at the stars in wonder.
