Asteroid: Expert explains how ‘Earth defence simulations’ work
The space rock known as 2020 TB12 will fly by Earth on February 1. NASA has revealed the asteroid to be 145 metres long, making it twice as large as a 71 metre Boeing 747. The asteroid is shooting through the solar system at a staggering 8.9 kilometres per second, or more than 32,000 kilometres an hour.
When the asteroid safely passes on Monday, it will be 6.8 lunar distances (LDs) away.
An LD is the distance between the Earth and the Moon, or 384,317 kilometres.
So 6.8 LDs is more than 2.6 million kilometres away.
Nonetheless, it is close enough for NASA to consider it a near Earth object (NEO).
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NASA said on its Jet Propulsion Laboratory (JPL) website: “NEOs are comets and asteroids that have been nudged by the gravitational attraction of nearby planets into orbits that allow them to enter the Earth’s neighbourhood.
“The scientific interest in comets and asteroids is due largely to their status as the relatively unchanged remnant debris from the solar system formation process some 4.6 billion years ago.
“The giant outer planets (Jupiter, Saturn, Uranus, and Neptune) formed from an agglomeration of billions of comets and the left over bits and pieces from this formation process are the comets we see today.”
The space rock has also been deemed to be “potentially hazardous” by NASA.
However, it’s important to note that this asteroid is not expected to hit our Earth during the swing by. But in fact, there are processes by which asteroids and comets can be shifted from their orbits towards us.
NASA said: “Occasionally, asteroids’ orbital paths are influenced by the gravitational tug of planets, which cause their paths to alter.
“Scientists believe stray asteroids or fragments from earlier collisions have slammed into Earth in the past, playing a major role in the evolution of our planet.”
A force known as the Yarkovsky effect can also cause an asteroid to veer off-course. The effect occurs when a space rock is heated in direct sunlight and cools down to release radiation from its surface.
NASA said: “This radiation exerts a force on the asteroid, acting as a sort of mini-thruster that can slowly change the asteroid’s direction over time.”
However, this asteroid is deemed safe and NASA’s tracking systems have ruled out all possibility of danger.
The term ‘potentially hazardous’ does not mean that an asteroid poses an imminent threat to Earth.
Rather, it refers to the sentiment that somewhere down the line in the solar system’s future, an asteroid could collide with Earth.
There are several unknown factors which could influence the future path of the asteroid, including the gravitational pull of other celestial bodies in the solar system.
NASA said: “Potentially Hazardous Asteroids (PHAs) are currently defined based on parameters that measure the asteroid’s potential to make threatening close approaches to the Earth.
“Specifically, all asteroids with a minimum orbit intersection distance (MOID) of 0.05 au or less are considered PHAs.”
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