What are planet killer asteroids?
"Planet killer" asteroids are space rocks that are big enough to cause a global mass extinction event, through the chucking up of dust into the upper atmosphere and the blotting out of the sun's light, if they were to smash into Earth.
A team of astronomers has discovered three massive near-Earth asteroids hiding in the glare of the Sun. Of these, one called 2022 AP7 is believed to be the largest planet killer-sized asteroid to be spotted in nearly a decade, and is “potentially hazardous” to Earth.
The asteroid 2022 AP7 is no exception. “Over time, this asteroid will get brighter and brighter in the sky as it starts crossing Earth's orbit closer and closer to where the Earth actually is,” Dr. Sheppard said.
“Any asteroid over 1km in size is considered a planet killer,” said Sheppard, adding that should such an object strike Earth, the impact would be devastating to life as we know it, with dust and pollutants kicked up into the atmosphere, where they would linger for years.
The term “planet killer” may sound scary but as far as 2022 AP7 goes, it will be staying “well away” from Earth for now, according to Sheppard. “It has no chance to hit the Earth currently,” he told Euronews Next in an email. As things stand, 2022 AP7 crosses Earth's orbit.
The Chicxulub Event
65 million years ago an asteroid roughly 10 to 15 kilometers (6 to 9 miles) in diameter hit Earth in what is now Mexico. The impact killed 70% of all species on Earth, including the dinosaurs.
Rocks that explode can provide a powerful light show. If the exploding rocks are large enough, their fragments can still plummet down like smaller stones. Experts estimate that between 10 and 50 meteorites fall every day, according to the American Meteor Society.
Will Apophis hit Earth? Not anytime soon. It definitely will miss Earth in 2029 and 2036, and radar observations of Apophis during the asteroid's flyby in March 2021 ruled out an impact for at least the next 100 years.
The Earth is in danger not only from asteroid strikes but also from their icy equivalents, comets. They could wreak havoc if they were to collide with our world. These objects usually live far away beyond even Pluto but can be jolted from their usual orbits by passing stars or gigantic gas clouds.
While space rocks of this magnitude are likely to hit Earth only every hundred million years or so, NEOs 50 to 100 meters (164 to 328 feet) across can strike much faster, roughly every thousand years, and can destroy a large city or level similarly large areas, and also lead to ecological destruction.
When did an asteroid last hit Earth?
What Happened in Brief. According to abundant geological evidence, an asteroid roughly 10 km (6 miles) across hit Earth about 65 million years ago.
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99942 Apophis.
| Discovery | |
|---|---|
| Semi-major axis | 0.9227 AU (138.03 Gm) |
| Eccentricity | 0.1914 |
| Orbital period (sidereal) | 0.89 yr (323.7 d) |
| Average orbital speed | 30.73 km/s |
Luckily for us 2022 AP7 “has no chance to hit the Earth currently”, according to Scott Sheppard at the Carnegie Institution for Science. He and his international team of colleagues observed 2022 AP7 in a trio of “rather large” asteroids obscured by the Sun's glare (the other two don't pose a risk).
Kinetic impactor
Kinetic impactors are one way by which we might be able to alter an asteroid's path. In principle, this technique requires smacking an asteroid to change its orbit around the sun so it no longer is a threat to Earth.
The threat from asteroids and comets
If a celestial body of this size crashed into Earth, it could destroy an entire city and cause extreme regional devastation. Larger objects - 0.6 miles (1 km) or more - could have global effects and even cause mass extinctions.
Only our two nearest neighbours Venus and Mars have been landed on. Landing on another planet is technically challenging and many attempted landings have failed. Mars is the most explored of the planets.
Shoot The Asteroid With Lasers
Space agencies would use solar-powered lasers to vaporize some of the asteroid and break of pieces. As these pieces break off, that force would cause the NEO to change speed and trajectory, ideally enough so that it doesn't impact Earth and destroy life as we know it.
Earth is estimated to be 4.54 billion years old, plus or minus about 50 million years. Scientists have scoured the Earth searching for the oldest rocks to radiometrically date. In northwestern Canada, they discovered rocks about 4.03 billion years old.
"There are about 100 pingpong-ball-sized meteoroids hitting the moon per day," Cooke said. That adds up to roughly 33,000 meteoroids per year. Despite their small size, each of these pingpong-ball-size rocks impacts the surface with the force of 7 pounds (3.2 kilograms) of dynamite.
Before entry in Earth's atmosphere, the meteoroid probably had an absolute magnitude (H) of roughly 31. The meteoroid entered at a record speed of 64,000 ± 1,600 mph (28.6 ± 0.7 km/s), the fastest fireball on record from which meteorites were later recovered.
How long is Earth safe from asteroids?
Calculations in recent years have proven the asteroid will safely glide past Earth in both 2029 and 2036. Thanks to additional observations of the near-Earth object (NEO), the risk of an impact in 2029 was later ruled out, as was the potential impact risk posed by another close approach in 2036.
Its center is offshore near the community of Chicxulub, after which it is named. It was formed slightly over 66 million years ago when a large asteroid, about ten kilometers (six miles) in diameter, struck Earth. The crater is estimated to be 180 kilometers (110 miles) in diameter and 20 kilometers (12 miles) in depth.
Asteroid 2002 RM4 has been estimated by astronomers to be between 360-809 yards/330-740 meters wide. So at it's very largest it could be as wide as the world's tallest building is tall. Astronomers at the Pan-STARRS 2 telescope in Haleakala, Hawaii on September 12, 2022, discovered 2022 RM4.
An asteroid, named "2019 PDC", was discovered that will come dangerously close to the earth 8 years from now, on April 29, 2027. The space rock is between 330 and 1000 feet in size, somewhere in between the length of 6.5 school buses to the height of two Washington Monuments stacked on top of each other.
On April 13, 2029 (which happens to be Friday the 13th), something unsettling will happen. A decent-sized asteroid, the 1,100-foot-wide Apophis, will pass so close to Earth it'll be visible in the sky from certain places.