Orbit

• Now it’s our turn, as comet 12P/Pons–Brooks is creeping into view for the southern hemisphere.
• Comet Pons–Brooks is visible to the naked eye, but only if you know where to look.

Why do people call it the ‘devil comet’?

• 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.

• 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.
• The solar wind pushed the resulting dust, gas and debris away from the Sun, giving the comet an unusual appearance.

Where (and when) should I look?

• 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.
• The comet’s tails point away from the Sun – so will rise upwards from the western horizon in the evening sky.

But wait… there’s more!

• 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.

Jonti Horner does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.