A fireball less than one metre in diameter was seen above Ontario, Canada, on November 19, and is the sixth object to be detected in space before impact with Earth, the European Space Agency (ESA) has said. The global asteroid warning systems saw the fireball before it struck Earth, and altered planetary defence experts. The fireball soaring in the skies was a beautiful sight to behold, as evident from a video shared by ESA.
Professional and amateur astronomers started discussing in the early hours of Saturday (local time) that a meteor was on its way. They also said that observers should set up their telescopes and cameras to view the spectacle.
When and where was the meteor spotted?
The meteor entered Earth's atmosphere at approximately 3:27 am EST (1:57 pm IST) on Saturday, over Brantford, Ontario, the Minor Planet Center, which tracks objects in the solar system, said, according to a New York Times (NYT) report.
The Minor Planet Center said that the fast-moving object, which has the temporary designation of #C8FF042, was detected in pictures taken at Mount Lemmon Survey near Tucson, Arizona.
According to the NYT report, Mike Hankey, the operations manager for the American Meteor Society, said he got a call about the meteor around 4 am EST from someone in Germany. Hankey, who was in Maine at that time, said messages about the meteor had started circulating about three hours earlier.
Quoting Hankey, the report said when these things happen, the astronomy community wants to know where the impact took place, and if meteorites survive, they want to recover them as soon as possible.
What is a fireball?
A fireball is a very bright meteor, generally brighter than Venus in the morning or evening sky, according to the American Meteor Society. As of Saturday afternoon, the American Meteor Society had received 33 reports of a fireball from people in Maryland, New York, Ohio, Pennu and Ontario, the report said.
Using reports on social media by people living in and near Hamilton, Ontario, and radar readings, astronomers determined where the meteorites were likely to have hit Earth.
Hankey said there is a chance if there are meteorites that survived that they might be recoverable near Grimsby, Ontario or St. Catherines, Ontario, near the Niagara Falls area.
According to ESA, it is estimated that between 40 and 100 tonnes of space material strike Earth every day, mostly in the form of very small particles.
Difference between meteors, meteorites and meteoroids
Astronomers did not know the size of the meteor on Saturday, Hankey said. Asteroids, comets and meteors are planetary objects in the solar system orbiting the Sun. Asteroids are sometimes called minor planets, and are rocky remnants left over from the early formation of the solar system 4.6 billion years ago. Comets are cosmic snowballs of frozen gases, rock and dust that orbit the Sun. Meteors, also known as shooting stars, are pieces of dust and debris from space that burn up in Earth's atmosphere. A meteoroid is a small place of asteroid that is typically pebble-sized, and could be a little smaller or a little larger, and is often created from a collision.
When a meteoroid gets close to Earth, and enters Earth's atmosphere, it is called a meteor. Since a meteor enters Earth's atmosphere at a very high speed, it burns up and produces a streak of light called a shooting star. When a meteoroid hits the ground, it is called a meteorite.
The fifth space object detected before striking Earth
According to ESA, astronomer Krisztián Sárneckzy discovered a bright and fast-moving new object in the sky using a telescope at the Piszkéstető observatory in Hungary, on March 11, 2022. Sárneckzy collected four observations in quick succession, and 15 minutes later, he reported his findings to the Minor Planet Center. He initially designated the object 'Sar2593'.
Automatic impact assessment systems around the world used the results to estimate the possibility of an impact. At that time, an impact seemed unlikely, with the probability being less than one per cent.
Soon after the discovery, Sárneckzy continued to observe the object, made a further 10 observations, and submitted them to the Minor Planet Center.
The object was detected at 20:25 UTC. Almost exactly an hour later, ESA's "Meerkat" monitoring system triggered an alert to the space agency's Near-Earth Object Coordination Centre (NEOCC), based on the accumulated observations.
This implied that the chance of impact was 100 per cent, and would happen in less than an hour. Scientists had predicted the space object's impact location to the nearest thousand kilometres, expected just a few hundred kilometres north of Iceland. The Minor Planet Center designated the asteroid the title "2022 EB5", shortly after the expected time of impact. Roughly a metre in diameter, 2022 EB5 posed no threat to Earth, as at this size, it likely burnt up in the planet's atmosphere.
Why have only six space objects been detected above Earth so far?
Between 40 and 100 tonnes of space material is expected to strike Earth every day, most in the form of very small particles, and larger objects are expected to strike roughly ten times per year. Yet, only six asteroids have been detected before impact with Earth.
According to ESA, large asteroids, kilometres in diameter, are easier to spot, and are relatively rare. Astronomers know where the vast majority of these are, and are sure that they are safe, at least for the next hundred years.
While smaller asteroids are far more common and strike Earth much more frequently, their impact is small and they are much harder to spot. All the six asteroids, spotted before impact, were found since 2008. Thus illustrates how much asteroid observation technologies have improved in the last years.
According to Detlef Koschny, ESA's acting Head of Planetary Defence, the extremely wide field of the agency's new telescopes, including the Flyeye telescope, will allow the coverage of a large area of the sky in just one night. This will reduce the chance of missing any interesting object.