More on meteor showers<\/strong><\/strong><\/h3> - Autumn’s best meteor showers<\/strong><\/em><\/a><\/li>
- See the next meteor shower<\/strong><\/em><\/a><\/li>
- Shooting stars explained<\/strong><\/em><\/a><\/li> <\/ul> <\/div>
Credit: Tom\u00e1\u0161 Slovinsky <\/figcaption> <\/figure> <\/div> <\/div> Larger meteoroids can penetrate the cabin of crewed space vehicles, and even small impacts can damage satellite components and short-circuit electronics.<\/p>
For example, ESA\u2019s Olympus 1 communications satellite started tumbling out of control and had to be subsequently deactivated during the 1993 Perseids shower.<\/p> ![\"Perseid](\"https:\/\/c02.purpledshub.com\/uploads\/sites\/48\/2023\/08\/perseid-meteor-shower-1.jpg\")
Perseid meteor shower over Haputale, Sri Lanka, 4 August 2024. Thilina Kaluthotage\/NurPhoto via Getty Images <\/figcaption> <\/figure> There is an ever-present background threat of meteoroids, so spacecraft are built with shielding and redundant systems.<\/p>
But during a meteor shower, the risk can jump for a short period, forcing spacewalks to be postponed or satellites to be turned to present a less vulnerable side to the shower radiant.<\/p> ![\"Artist's](\"https:\/\/c02.purpledshub.com\/uploads\/sites\/48\/2024\/06\/shooting-star-over-earth.jpg\")
Meteor showers occur when Earth passes through a stream of debris left behind by a comet or asteroid. Credit: Adastra \/ Getty Images <\/figcaption> <\/figure> Meteor showers explained<\/strong><\/h2> Meteor showers are caused<\/a> when Earth passes through the stream of debris left along the orbital track of a comet, and so they are broadly predictable.<\/p> NASA\u2019s Meteoroid Environment Office, where Althea Moorhead works, issues annual meteor shower forecasts to help mission planners avoid the worst risks.<\/p>
The difficulty is that the intensity of different showers changes over the years or key parameters are unknown, such as the density of particles or their size range.<\/p>
Plus new showers are being reported all the time.<\/p> ![\"Image](\"https:\/\/c02.purpledshub.com\/uploads\/sites\/48\/2024\/10\/space-station-mmod.jpg\")
Image of a small crater on an International Space Station air shield caused by MMOD (micrometeoroids and orbital debris). Credit: NASA <\/figcaption> <\/figure> Gauging how dangerous a meteor shower is<\/strong><\/h2> Moorhead has been working on improving predictive models to make sure that warnings are only issued for the most genuinely hazardous events.\u00a0<\/p>
She started by defining the threshold of what constitutes a potentially hazardous meteor shower.<\/p>
It\u2019s a lengthy definition, but boils down to when the rate of energetic, potentially damaging, meteoroids is at least 5% that of the background level.<\/p>
There are over 100 showers with relatively well measured parameters and Moorhead applied her criteria to pick out those that present the worst risks.\u00a0<\/p> ![\"The](\"https:\/\/c02.purpledshub.com\/uploads\/sites\/48\/2023\/08\/GettyImages-899971840.jpg\")
The Geminid meteor shower is among the most dangerous meteor showers, according to research. Credit: David Hoffmann Photography \/ Getty Images <\/figcaption> <\/figure> Perhaps surprisingly, the meteoroid showers that result in the most impressive displays of shooting stars can pose minimal risk to spacecraft.<\/p>
These are produced by unusually large, high-speed meteoroids, but if there\u2019s not a great number of them, the chance of any hitting a satellite is tiny.<\/p>
The Epsilon Geminids, for example, which occur in late October, are caused by exceptionally fast particles and can produce spectacular fireballs, but pose an utterly insignificant risk to spacecraft.<\/p>
On the other hand, slow-moving showers dominated by smaller particles can act more like a shotgun blast of particles hazardous to satellites.\u00a0<\/p>
The most dangerous meteor showers identified by Moorhead include the Geminids<\/a>, which peak in mid-December, and the Perseids<\/a> in mid-August.<\/p> She also keeps a close watch on variable showers, which are typically low-activity and don\u2019t exceed her danger threshold for most years, but can occasionally surge hundreds of times over during an outburst.<\/p>
Larger meteoroids can penetrate the cabin of crewed space vehicles, and even small impacts can damage satellite components and short-circuit electronics.<\/p>
For example, ESA\u2019s Olympus 1 communications satellite started tumbling out of control and had to be subsequently deactivated during the 1993 Perseids shower.<\/p> There is an ever-present background threat of meteoroids, so spacecraft are built with shielding and redundant systems.<\/p> But during a meteor shower, the risk can jump for a short period, forcing spacewalks to be postponed or satellites to be turned to present a less vulnerable side to the shower radiant.<\/p> Meteor showers are caused<\/a> when Earth passes through the stream of debris left along the orbital track of a comet, and so they are broadly predictable.<\/p> NASA\u2019s Meteoroid Environment Office, where Althea Moorhead works, issues annual meteor shower forecasts to help mission planners avoid the worst risks.<\/p> The difficulty is that the intensity of different showers changes over the years or key parameters are unknown, such as the density of particles or their size range.<\/p> Plus new showers are being reported all the time.<\/p> Moorhead has been working on improving predictive models to make sure that warnings are only issued for the most genuinely hazardous events.\u00a0<\/p> She started by defining the threshold of what constitutes a potentially hazardous meteor shower.<\/p> It\u2019s a lengthy definition, but boils down to when the rate of energetic, potentially damaging, meteoroids is at least 5% that of the background level.<\/p> There are over 100 showers with relatively well measured parameters and Moorhead applied her criteria to pick out those that present the worst risks.\u00a0<\/p> Perhaps surprisingly, the meteoroid showers that result in the most impressive displays of shooting stars can pose minimal risk to spacecraft.<\/p> These are produced by unusually large, high-speed meteoroids, but if there\u2019s not a great number of them, the chance of any hitting a satellite is tiny.<\/p> The Epsilon Geminids, for example, which occur in late October, are caused by exceptionally fast particles and can produce spectacular fireballs, but pose an utterly insignificant risk to spacecraft.<\/p> On the other hand, slow-moving showers dominated by smaller particles can act more like a shotgun blast of particles hazardous to satellites.\u00a0<\/p> The most dangerous meteor showers identified by Moorhead include the Geminids<\/a>, which peak in mid-December, and the Perseids<\/a> in mid-August.<\/p> She also keeps a close watch on variable showers, which are typically low-activity and don\u2019t exceed her danger threshold for most years, but can occasionally surge hundreds of times over during an outburst.<\/p> Meteor showers explained<\/strong><\/h2>
Gauging how dangerous a meteor shower is<\/strong><\/h2>