A spectacle of three meteors will grace our skies this weekend

Looking for something spectacular to brighten up a cold, dark winter night?

Well, this weekend might just have something in store: not one, not two, but three meteor showers active at the same time—combining to provide a celestial fireworks display for most of the night.

While the best nights to watch are Saturday evening, July 30, until dawn on Sunday morning, all three rains will be nearing their peak levels starting tonight. So you’ll have plenty of opportunities to catch the show while avoiding bad weather or other commitments.

Best of all, there will be a new moon, which means there won’t be a lot of glare ruining the show.

What is a meteor shower?

The solar system is full of debris left behind from the formation of the planets more than 4.5 billion years ago. Some of this debris – comets and asteroids – move in orbits that cross Earth’s path around the sun.

Every time those comets and asteroids swing toward the sun, they release debris. For hundreds or thousands of years, their orbits are shrouded in vast streams of dust.

Earth is constantly passing through this stream of detritus as it moves around the sun, which gives birth to the annual meteor shower. Every year, we return to the same spot in our orbit, encounter the same debris flow, and get another good show as the debris burns harmlessly, 80 kilometers overhead.

In the depths of the Australian winter, Earth moves through a bit of space where three streams of debris intersect with our planet’s orbit. All three streams spawned the show’s stars this weekend: Southern Delta Aquariids, Alpha Capricornids, and Piscis Austrinids.

The International Meteor Organization has a 3D animated visualization of the Southern Aquariid Delta and the Alpha Capricornid meteor stream, showing how debris is distributed in space.

The 3D visualization of the Alpha Capricornid meteor stream allows you to move around the solar system and see the debris stream in action. (Provided: International Meteor Organization )

The story of three rains

So, let’s introduce the star of the show.

The Southern Delta Aquariids are the most active of the three showers, with meteors moving the fastest. Most of the meteors you’ll see this weekend will likely be members of this stream.

The origin of the Southern Delta Aquariids is a topic of debate. They are one of several meteor showers that appear to be linked to a single parent object, as if a large comet had disintegrated long ago, leaving behind a large amount of debris, potentially including fragments large enough to be comets themselves.

For thousands of years, the debris has spread, causing Earth to hit it several times each year. Currently, the Southern Delta Aquariids are tentatively bound to a comet called 96P/Machholtz, which is the most active object in the debris stream.

The Southern Delta Aquariids have been known to deliver some surprises. In 2006, they produced an explosion, with some people observing more than 60 meteors per hour at their peak. No explosions are expected for this year, but you never know what might happen!

The second of our rain triad is Alpha Capricornids. It produces the slowest meteor of the three showers. They also have a reputation for raining “fireballs” – often producing spectacular meteors that outshine the brightest stars.

These are the meteors you’re most likely to catch on film, and provide a great opportunity to practice astrophotography.

The last rain, Piscis Austrinids, is perhaps the least studied of the three. Like the Alpha Capricornids, they are small showers that produce only a few meteors per hour, even at their peak. Their meteors are medium speed.

So where, and when, should I look?

The key for the observer is to know when the shower “beam” will be above the horizon. Radiation is the point in the sky from which all the meteors in the shower appear to radiate.

Meteor showers are named after the location of their emission. Alpha Capricornid, for example, radiates from the near point of the star Alpha Capricorni.

The meteor shower will be high in the eastern sky, around 11 p.m. local time. The planets Jupiter and Saturn, as well as the bright stars Fomalhaut, Altair (in the northeast) and Achernar (in the southeast) will be visible, weather permitting.(Provided: Museum Victoria/Stellarium)

In the case of our midwinter trio, we were quite lucky. All three beams emerge early to mid-night from Australia, and reach reasonable heights around 10pm.

As a result, you will be able to see the meteor any time from midnight onwards. The best rates will be seen from around 10 pm, until dawn.

Once you have settled in a comfortable place to observe, try to avoid looking at your phone. You should allow your eyes to adjust to the darkness so you can see the faintest meteors. Glancing at the screen, even for a second, will return you to square one.

By morning, at around 05.00 local time, on Sunday 31 July, a meteor shower will appear to radiate from the western sky. The planets Saturn, Jupiter, and Mars should also be visible. (Provided: Museum Victoria/Stellarium)

We found the best place to look while watching a meteor shower is about 45 degrees above the horizon, and about 45 degrees to the left or right of the beam.

Therefore, in the afternoon, it would be better to look east or northeast. At midnight, and soon after, looking north is best. And in the hours before dawn, you have to look west or northwest.

And don’t worry when you’re done! While these three showers are poised to put on a decent show, it’s not the best meteoric event of the year. That’s Geminids, coming in December. So there’s still a lot to look forward to!

Jonti Horner is Professor (Astrophysics) at the University of Southern Queensland and Tanya Hill is an honorary fellow at the University of Melbourne and Senior Curator (Astronomy) at Museum Victoria. This work first appeared in The Conversation.

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