Written by Arshiya Sangar, a grade 11 student
On Sunday, August 16, at 12:08 am EST (9:38 am Indian Time), an asteroid the size of an SUV passed by Earth. This asteroid, flying above the southern Indian Ocean, about 2950 kilometers (1830 miles) away, was the closest recorded asteroid to pass by Earth without impacting the surface.
The asteroid was approximately 3 – 6 meters (10 – 20 feet) in diameter.
What is an Asteroid?
NASA (the National Aeronautics and Space Administration in America) defines asteroids as relatively small, inactive rocky bodies orbiting the Sun. If parts of asteroids break off from their main body and enter the atmosphere of the Earth (known as meteors), because of the velocity they travel with, and the resistance they experience in the atmosphere, they burn up, forming what we recognise as shooting stars in the sky.
Do Asteroids Come By Often?
This asteroid, earlier referred to as ZTF0DxQ, is now formally called 2020 QG by astronomers. Asteroids of similar size pass by Earth this closely only a few times a year. Asteroids mainly populate the asteroid belt (which is a belt of asteroids orbiting the Sun, located between Mars and Jupiter), and these asteroids pose no threat to Earth.
Was this asteroid dangerous? Not particularly. Objects large enough to cause catastrophic damage to the level of destroying civilizations only come by once every few million years. Space rocks which are about 25 meters (about 82 feet) in diameter will most likely burn up as they enter Earth’s atmosphere, causing little or no damage.
Did We Expect This Asteroid?
Scientists have said that they did not expect the arrival of this asteroid. The reason for this is that 2020 QG came from the direction of the Sun. The telescopes used by scientists to observe these asteroids can best detect them in the dark of the night sky, making it extremely difficult to detect asteroids and other objects coming from the direction of the Sun.
Owing to this, the Palomar Observatory in California first detected the presence of 2020 QG only six hours after it had flown by Earth.
What is Being Done to Detect More Such Asteroids?
Scientists consider the fact that we could detect the presence of this asteroid an achievement in itself. NASA has been working extensively to try and predict when asteroids will come close to the Earth, and when there is a possibility of impact. NASA has established a Planetary Defense Coordination Office (PDCO), which ensures early detection of potentially hazardous objects. They deal with tracking and classification of these objects on the basis of any potential threat of impact, providing timely and accurate information.
There is also a protocol when it comes to asteroids that are coming from the direction of the Sun. When scientists discover them on their prior passages by Earth, they perform calculations in order to make predictions years, sometimes decades in advance, whether there is a chance of impact.