According to a new study by Chinese astronomers, up to a million asteroids could collide with the Earth over the next century.
While the risk of collision is low, and the majority of asteroids are less than 100 meters (328 feet) in diameter – small in comparison to the asteroid that wiped out the dinosaurs – each one contains more kinetic energy than an atomic bomb, and we know very little about them.
The small size and a large number of these short-term hazardous asteroids (SHA) made tracking them extremely difficult, according to Professor Gan Qingbo and colleagues at the China National Space Administration’s Space Debris Observation and Data Application Centre.
Accurate identification of impact threat targets and early warning capabilities necessitate more precise orbit determination and impact risk assessment algorithms,” they wrote in a paper published Thursday in the Chinese peer-reviewed journal Acta Astronomica Sinica.
Astronomers have concentrated their efforts on larger asteroids that could collide with the Earth.
Asteroids with a diameter of tens of meters have not been regarded as a severe threat, and there has been little interest in the number of SHAs out there or when they will arrive.
However, the Chinese researchers warn that ignoring the threat could prove costly.
In 2013, an asteroid exploded over Chelyabinsk, Russia. Although the asteroid was only 19 meters (62 feet) wide, it generated an explosion roughly 30 times as powerful as Hiroshima’s nuclear blast.
Over 7,200 buildings were damaged by the shock waves, which spread across a large area. Although no one was killed, approximately 1,500 people required medical treatment for various injuries, most of which were caused by the shattered windows.
The Chelyabinsk incident demonstrated that a 10-meter-scale asteroid is capable of wreaking havoc,” Gan and colleagues wrote.
They analyzed data from a global asteroid database, calculated the orbits of the small objects, and discovered that over 700 of them could collide with the Earth within a century.
Five of those had a one-in-a-thousand chance of colliding, a probability that could change due to the constant variations in their orbits.
Additionally, the researchers calculated that the total number of SHAs could range between 100,000 and a million using physical models of asteroid formation.
They concluded that these previously overlooked asteroids were probably concentrated in specific solar system regions and moved similarly.
The researcher stated that the discovery “is critical for the development of near-Earth asteroid search and monitoring strategies.”
Professor Chen Ping, a Chinese Academy of Sciences geologist based in Guangzhou who discovered two impact craters in China, said there was no reason to panic.
These minor asteroids were “an intriguing subject for academic research and public debate,” he said, but that should be the extent of it. Due to their small size, the majority of SHAs are expected to burn up in the atmosphere.
Chen stated that China’s asteroid research was accelerating.
“Recently, the government made a significant investment in this field of research,” he explained.
China intends to launch a spacecraft to collect samples from an asteroid and construct the world’s largest planetary defense radar network.
According to a recent report by the Shanghai Aerospace System Engineering Institute, which is involved in the national asteroid defense program, monitoring asteroids was about science and China’s national security in space.
Other countries, such as the United States, were developing their space forces, and China could not afford to fall behind.
Because it is difficult to reach agreement on the control of space forces, the space situation will inevitably devolve into conflict,” the report stated.
The network of planetary defenses would be fully integrated with military programs such as missile defense systems.