After researchers analysed samples from its surface, the asteroid Bennu has been the talk of the scientific community of late. However, while the focus has been on what the space rock could tell us about life's origins, a new study has introduced a concerning possibility: it could hit Earth.
It is an outside chance, to say the least, though. Based on modelling estimates, scientists believe that Bennu has a 1-in-2700 chance of colliding with our planet. While the rock is far smaller than the asteroid that originally wiped out the dinosaurs, Bennu could still pose serious dangers to the world.
According to the study, its impact could launch 400 million tons of dust, aerosol, debris and ash injections into the atmosphere.
With this blocking out the Sun, Earth could cool by 4°C, triggering a global winter. Less sunlight would also spell disaster for our plants and – in turn – other forms of life. The water cycle would also be disrupted, resulting in a reduction of rainfall by 15 per cent.
In short, experts think Bennu could have a profound effect on humanity. “Asteroid impacts have taken place many times in Earth’s history. Our early human ancestors may have experienced some of these planet-shifting events before with potential impacts on human evolution and even our own genetic makeup,” co-corresponding author Dr Lan Dai said.
However, there is a shimmer of hope here. Even if those 1-in-2700 odds do line up, Bennu wouldn’t be hitting Earth for another 157 years with the estimates placing its date of impact at 2182. In fact, the researchers put the chance of the collision at 0.037 per cent.
Earth has remained relatively unscathed from asteroid impacts throughout its history, with one notable exception: the dinosaur-killing event that created the Chicxulub crater.
Earlier this month, scientists revealed that samples collected from asteroid Bennu by NASA's OSIRIS-REx mission contain key building blocks of life. These include 14 of the 20 protein amino acids found in Earth’s lifeforms, as well as essential chemicals that form our genetic code.
On top of this, scientists discovered a variety of salt minerals formed by the evaporation of brine from Bennu's parent body. This suggests the presence of water – another key indicator of life.
Together, these findings suggest that the key ingredients for life may be widespread across the Universe, which greatly increases our chances of discovering aliens in the future – assuming we avoid a full-scale collision with Bennu, of course.
Read more:
