Here’s something we don’t see very often: a meteoroid grazing the Earth.
On September 22, 2020, a small cosmic rock jumped over the Earth’s atmosphere and bounced back into space. The meteoroid was spotted by a camera from the Global Meteor Network, seen in the sky over northern Germany and the Netherlands. It reached an altitude of 91 km (56 miles) – far below any orbital satellites – before jumping back into space.
Denis Vida, a postdoc in physics at Western University in Ontario, Canada, who runs GMN, said they tracked the rock to the orbit of the Jupiter family, but no convincing matches were found when searching for potential parent bodies.
As the ESA explains, a meteoroid is usually a fragment of a comet or asteroid that turns into a meteor ̵
Scientists estimate that meteoroids with earth grazing appear only a few times a year. But every day, hundreds of tons of small interplanetary objects enter the Earth’s atmosphere. The most common effect that these small objects produce when interacting with the Earth’s atmosphere are meteors – often called shooting stars. A small percentage of the largest rocks reach the earth as meteorites.
There is no estimate for the size of Earthgrazer as of September 22, but it is probably quite small. And while tens of thousands of meteorites have been discovered on Earth, only about 40 can be traced to a parent asteroid or asteroid source.
In order for the rock to “bounce” off the Earth’s atmosphere, it must enter the atmosphere at a fairly small angle. And like a rock “jumping” over a lake, the meteor also briefly enters the atmosphere before coming out again.
The global meteor network – whose slogan is “No Meteor Unobserved” – works to cover the globe with meteor cameras to provide the public with real-time warnings, as well as to build a picture of the meteorological environment around the Earth.
“The network is basically a decentralized scientific tool made up of amateur astronomers and civilian scientists around the planet, each with their own camera systems,” said Vida, who founded the initiative. “We make all data such as meteorological trajectories and orbits available to the public and the scientific community in order to observe rare meteor showers and increase the number of observed meteorite falls and help understand the mechanisms for delivering meteorites to Earth.”
The GMN station operators whose data are shown in the leading animation are Paul Roggemans, Jürgen Dörr, Martin Breukers, Erwin Harkink, Klaas Jobse, Kees Habraken.