Författare: Jonti Horner Professor Astrophysics University of Southern Q

Meteors – commonly known as shooting stars – can be seen on any night of the year. But some nights are better than others.

As Earth moves around the Sun, we encounter streams of dust and debris from comets and asteroids. That debris gives birth to “meteor showers” – times when the number of shooting stars you are likely to see increases dramatically.

Currently, we are passing through the outskirts of one such debris stream, left behind by Halley’s comet. It creates the Eta Aquariid meteor shower, one of the best visible from the southern hemisphere. Every year, when Earth reaches this point in its orbit, you can see the Eta Aquariids in the morning sky.

This year’s display promises to be extra special. The peak coincides with a new Moon, meaning skies will be extra dark in the hours before dawn – perfect conditions to watch fragments of a famous comet rain down. There are even hints the shower might be more “active” than usual.

Fragments of the most famous comet

Halley’s comet (1P/Halley by its official name) orbits the Sun every 76 years or so, and has spent thousands of years on its current path.

Every time it swings through the inner Solar System, the comet sheds dust and gas. This dust has slowly spread through space, shrouding the comet’s orbit in a broad swathe of debris.

Earth runs through that debris twice per year, giving birth to two famous meteor showers. In October, we get the Orionid meteor shower, visible from both hemispheres and relatively well known.

But the better of the two showers from Halley’s debris peaks in early May – the Eta Aquariid meteor shower. Earth begins encountering that debris in mid-April, and then spends approximately six weeks traversing the broad debris stream left behind by the mighty comet.

For much of that time, Earth passes through the outskirts of the stream, and the number of meteors produced remains low. But for around a week centred on May 6, Earth moves through the densest part of the stream, and the Eta Aquariids reach their peak.

How can I watch the meteor shower?

The Eta Aquariids are actually one of the best meteor showers of the year, but are relatively poorly known for a simple reason – they are best seen from the southern hemisphere, and are very hard to observe from locations north of the equator.

The reason is that in northern locations, the Eta Aquariid radiant (the point in the sky from which the meteors appear to radiate) does not rise until it is already morning twilight. As a result, all but the brightest meteors get lost in the rising daylight.

Southern observers are more fortunate. For most Australian locations, the radiant – located in the constellation Aquarius – rises at around 1:30am to 2am local time. This gives us several hours before dawn to observe the spectacle.

A general rule of thumb when observing meteor showers is the higher in the sky the radiant rises, the better the display will be as your location on Earth is turned into facing the oncoming shower of cometary dust.

The first hour after radiant rise will likely not produce many meteors. It is still worth staring skyward though, as the few meteors you do see will be crashing into the atmosphere at a very shallow angle, allowing them to streak from horizon to horizon. These are known as “earthgrazing” meteors.

An Eta Aquariid meteor captured in Wyoming in 2013.
David Kingham/Flickr, CC BY-NC-ND

As the radiant climbs higher, so, too, will the number of meteors you observe. At their peak (on the morning of May 6th), in the hour or two before dawn, the Eta Aquariids could easily produce 20 to 30 meteors per hour. Similar rates should be visible for a couple of mornings either side of the maximum, making the weekend of May 4 and 5 a perfect time to do some morning meteor spotting.

However, meteors don’t come at an even rate. You can wait 15 minutes and see none, then four may come along at once. So remember to wrap up warm, get comfortable and gaze towards the eastern sky as you relax to enjoy the show.

An extra special year?

The Eta Aquariids are always a fabulous autumn treat for observers in Australia, but this year promises to be extra special. First, the skies will be dark thanks to a new Moon, making meteors easier to spot.

But there’s more. Scientists modelling the behaviour of the Eta Aquariids over the past few decades have found tantalising hints that this year could see significantly enhanced rates. In fact, they suggest the 2024 Eta Aquariid meteor shower could prove to be the strongest of the entire 21st century.

Predicting the activity of meteor showers is really hard, however. Other researchers have argued this year might just be “business as usual”.

Even if the latter is true, this is still an excellent meteor shower to try to catch. With perfect conditions, and the peak falling on the morning of May 6 (a public holiday in Queensland and the Northern Territory), it’s the ideal time to plan a weekend trip to the country – to settle down somewhere dark, and wake up to spend a few hours enjoying a display of natural fireworks before watching a beautiful autumn sunrise. What’s not to love? Läs mer…

If you’re a fan of all things space, you’ve doubtless heard about the “devil comet”, which has been captivating keen-eyed observers in the northern hemisphere for the past few weeks. Now it’s our turn, as comet 12P/Pons–Brooks is creeping into view for the southern hemisphere.

Before you get too excited, let me quash your hopes. Comet Pons–Brooks is visible to the naked eye, but only if you know where to look. It will look like a fuzzy glowing patch, but nonetheless promises some amazing photo opportunities for the coming weeks.

Even better, it may serve as a celestial warm-up act for an even more special comet later in the year.

Here’s everything you need to know about Pons–Brooks, and how to get the best view.

Why do people call it the ‘devil comet’?

Named after two astronomers who independently discovered it in the 19th century, Comet 12P/Pons–Brooks (its full, official name) was last visible in 1954.

It takes around 71 years to orbit the Sun, making the comet’s visits to the inner Solar System a rare treat for us here on Earth.

At its heart (its nucleus), Pons–Brooks is a dirty snowball around 34 kilometres in diameter. As the comet came swinging back towards us in its orbit, astronomers spotted it back in 2020. At that time, the comet was almost 1.8 billion kilometres from the Sun, and lay dormant.

As the comet kept falling inwards toward the Sun, its surface temperature began to rise, making it “active”. Exposed ices started to sublime, turning directly from solid to gas. This activity is how a comet gets its tail: the nucleus becomes shrouded in a diaphanous “coma” of dust and debris from its sublimated surface, which is then blown away from the Sun by the solar wind.

Comet C/2020 F3 (NEOWISE) captured in 2020 with a long, blurry tail clearly visible.
Serrgey75/Shutterstock

But comet 12P/Pons–Brooks didn’t activate gently and smoothly. Instead, it produces several large outbursts of activity, each time, emitting vast amounts of gas and dust in a very short period of time before settling down again.

In the first of those significant outbursts, on July 20, 2023, the comet brightened by a factor of a hundred times, shedding an estimated ten million metric tons of dust and ice.

The solar wind pushed the resulting dust, gas and debris away from the Sun, giving the comet an unusual appearance. To some, the comet looked like the Millennium Falcon from Star Wars. To others, it looked vaguely demonic – sporting the cometary equivalent of horns.

The moniker of “devil comet” took hold in media articles and appears to have stuck – even though the comet’s horned appearance is now a thing of the past.

Comet 12P/Pons–Brooks on July 27, 2023, showing the unusual horned appearance that led to its ‘devil comet’ nickname.
Juan Iacruz/Wikipedia, CC BY-SA

Where (and when) should I look?

Over the last few days, the first confirmed sightings of 12P/Pons–Brooks have come in from around Australia. It is currently visible low in the western sky after sunset, albeit almost lost in the glow of twilight.

In the next few weeks, the comet will slowly climb higher in the evening sky. The two videos below show the location of the comet’s head at 6:30pm from mid-April through to mid-June, as seen from Toowoomba and Melbourne.

Visibility of comet 12P/Pons–Brooks, as seen from Toowoomba, from mid-April to mid-June 2024.

Visibility of comet 12P/Pons–Brooks, as seen from Melbourne, from mid-April to mid-June 2024.

Remember, the comet is a diffuse object, rather than a single point of light. The head is where the comet is brightest (centred on its nucleus). The comet’s tails point away from the Sun – so will rise upwards from the western horizon in the evening sky.

While the comet is visible with the naked eye, you really need to know where to look. The best bet is to search with binoculars. Make sure to wait until the Sun is well below the horizon. Once you find the telltale blur of the comet, you will know where to look, and can switch to see if you can spot it with the naked eye.

For me, the most exciting time with Pons–Brooks will come during the first two weeks of May. At that point, the comet will be passing underneath the constellation Orion, which will serve as a signpost.

That period will be prime astrophotography season, so I expect to see many spectacular images of the comet’s tails cutting through the celestial hunter, shining next to the spectacular nebulae dotted throughout Orion’s body.

Read more:
Want to get into stargazing? A professional astronomer explains where to start

But wait… there’s more!

While comet 12P/Pons–Brooks currently basks in the limelight, a potentially great comet is currently moving sunward, promising a spectacular show later this year.

That comet, C/2023 A3 (Tsuchinshan-ATLAS), was discovered in January 2023, and astronomers soon realised it has the potential to become truly dazzling.

Comet behaviour is hard to predict, so take the following with a pinch of salt, but things still look really promising.

Current predictions suggest Tsuchinshan-ATLAS will be at least as bright as the brightest stars in late September and early October this year. During that time, it will pass almost directly between Earth and the Sun. It might even briefly become visible in broad daylight at that time.

In the days following that chance alignment, the comet will gradually become visible in the evening sky and could be an incredible sight, up to a hundred times brighter than Pons–Brooks at its best.

So, with any luck, the current apparition of 12P/Pons–Brooks is merely the warm-up act, with an even greater spectacle to come later this year. Fingers crossed! Läs mer…