Meteor showers are not an exclusive show on our planet. Every world in the solar system can at times receive the debris left by comets in outer space, even in spectacular fashion with spectacular light shows. This year, it might be the turn of Venus to be pummeled by interplanetary material.
On December 18, the recently discovered comet C/2021 A1 (Leonard) will pass just 4.34 million kilometers (2.6 million miles) from Venus. Two days later the planet will be in a position such that Comet Leonard's dust trail will graze it. A new paper, submitted to The Astronomical Journal and posted to the preprint server arXIV.org, looked at the possibility of meteors falling on Venus and being visible from Earth.
Meteor showers here on Earth take place when our planet crosses the path of debris leftover by a comet’s multiple passages over the centuries. Some of these showers are bigger and richer than others depending on the debris. Some in the past have been incredible, like the Leonids meteor shower of 1833, when 100,000 meteors per hour were seen falling from the heavens.
That is the biggest recorded one on Earth but not in the Solar System. Back in 2014, a close encounter between Mars and comet C/2013 A1 (Siding Spring), led to an incredible 108,000 meteors per hour raining down on the Red Planet. But this was only seen indirectly, causing the meteors to produce a layer of metallic material in the Martian atmosphere.
The Siding Spring encounter was a less common type of shower, when a long-period comet, one that only rarely enters the inner solar system passes incredibly close to a planet. In this case, it flew 140,000 kilometers (87,000 miles) from Mars. This is a similar scenario to what will happen to Venus, so the comet’s orbit is not rich in debris from years past. It’s all about what the comet is bringing in its wake.
The paper shows that the possibility that we will see meteors striking the atmosphere of Venus is very low but not impossible. The main factor for such a show will depend on when the comet has become active. The further away from the Sun, the better. The comet will have to be rich in extremely volatile ice that begins sublimating from further away than Neptune. Again not impossible but also not very likely.
The paper still calls for observations of the encounter as there could be events visible from Earth, and also it could be an opportunity to study a cometary tail in detail. The unlikely scenario of rain of sizable debris also means that Akatsuki, the only spacecraft currently around Venus, should be in no danger. Actually, the Japanese Space Agency’s orbiter might capture some meteors hitting the atmosphere or reveal the aftermath like orbiters around Mars did when it was the Red Planet’s turn.
While meteors on Venus might not be visible this time. Comet Leonard could become bright enough to be visible from Earth by the naked eye or a simple binocular. The closest passage to our planet is on December 12.