As the Earth revolves around the sun, it plows up dust and debris left by comets and asteroids. This wreck Give birth to meteor showers – which can be one of the most beautiful views of nature.
Most meteor showers Predictable, and repeated annually as the Earth crosses a particular debris path.
However, the Earth occasionally passes through a narrow, dense mass of debris. This results in a meteor storm, sending Thousands of stars falling across the sky every hour.
A slight downpour called Tau Herculids may cause a meteor storm to watchers in the Americas next week. But while some websites promise “the most powerful meteor storm in generations,” astronomers are more cautious.
Introducing Comet SW3
The story begins with a comet called 73P / Schwassmann-Wachmann 3 (Comet SW3 for short). First observed in 1930, it is responsible for a faint meteor shower called Tau Herculids, which nowadays appears to be radiating from a point about ten degrees from the bright star Arcturus.
In 1995, comet SW3 Suddenly and unexpectedly brightened. A number of eruptions were observed over a period of a few months. was the culprit catastrophically fragmentedreleasing huge amounts of dust, gas and debris.
By 2006 (two orbits later), comet SW3 has disintegrated further, to Several shiny shards accompanied by many smaller pieces.
Is Earth on a collision course?
This year, Earth will cross the orbit of Comet SW3 at the end of May.
Detailed computer modeling indicated that the debris was scattered along the comet’s orbit like enormous thin tentacles in space.
Has the debris spread far enough to meet Earth? It depends on how much debris was ejected in 1995 and how quickly that debris was ejected out as the comet crashed. But bits of dust and debris are so small that we can’t see them until we hit them. So how do we get insight into what might happen next week?
Can history repeat itself?
Our current understanding of meteor showers began 150 years ago with an event very similar to the SW3 story.
Guilty called Comet 3D / Biella It was discovered in 1772. It was a short-lived comet, like SW3, that returns every 6.6 years.
In 1846, the comet began to act strangely. Observers saw his head split in two, and some described a “passage of comet matter” between the pieces.
In the comet’s next return, in 1852, the two parts were clearly separated and both were fluctuating unexpectedly in brightness.
The comet was never seen again.
But in late November of 1872, an unexpected meteor storm hit the northern sky, astounding observers at rates of more than 3,000 meteors per hour.
The meteor storm occurred when Earth crossed a 3D orbit/Bella’s orbit: where the comet itself should have been two months ago. A second storm, weaker than the first, occurred in 1885, when Earth once again encountered the remnants of a comet.
3D/Biela shattered into rubble, but the two large meteor storms they created were a fitting wake-up.
A comet is dying, collapsing before our eyes, and a meteor shower attached to it, usually barely imperceptible against background noise. Are we about to see history repeat itself with Comet SW3?
What does this suggest to Tao Hercules?
The main difference between the events of 1872 and those of this year’s Tau Hercules is due to the timing of the Earth’s transit of cometary orbits. In 1872, the Earth crossed the Biella orbit for several months after, after The comet was due, passing through the material left over from where the comet was.
By contrast, the confrontation between Earth’s debris stream and SW3 next week will take place several months Before The comet is scheduled to reach the crossing point. So the debris must spread Before From the culprit to a meteor storm.
Could debris have spread far enough to meet Earth? Some models suggest we’ll see a strong showing from the shower, while others suggest debris will shorten.
Do not count your meteors before they flash!
Whatever happens, observations of showers next week will greatly improve our understanding of how comet fragmentation events occur.
Calculations show that the Earth will Transiting SW3’s orbit at about 3 p.m., May 31 (AEST). If the wreck gets far enough ahead for Earth to encounter, it will likely erupt from Tau Herculids, but it will only last an hour or two.
From Australia, the show (if there ever was one) will end before it’s dark enough to see what happens.
However, North and South American observers will have a ringside seat.
They are more likely to see a moderate display of slow-moving meteors than a massive storm. This would be a great result, but it might be a little disappointing.
However, there is a chance to take a shower in a truly amazing show. Astronomers travel across the world, in anticipation.
What about the Australian observers?
There is also a small chance that any activity will last longer than expected, or may arrive a little later. Even if you’re in Australia, it’s worth looking up on the evening of May 31st, just in case you can get a glimpse of a part of a dying comet!
The debris stream in 1995 is just one of many debris laid down by a comet in the past decades.
During the early morning of May 31, around 4 a.m. (AEST), Earth will pass debris from Comet 1892’s path around the sun. Later that evening, around 8 p.m., May 31 (AEST), Earth will cross debris laid by a comet in 1897.
However, the debris from those hits will spread over time, so we only expect a few meteors to grace our skies from those streams. But, as always, we can be wrong – the only way to know is to get out and look!