Ammon News - The rocky object called Bennu is classified as a near-Earth asteroid, currently making its closest approach to Earth every six years at about 186,000 miles (299,000 km) away. It might come even closer in the future, with scientists estimating a one-in-2,700 chance of a collision with Earth in September 2182.

So what would happen should Bennu strike our planet? Well, it would not be pretty, according to new research based on computer simulations of an impact by an asteroid with a diameter of roughly three-tenths of a mile (500 meters) like Bennu.

Aside from the immediate devastation, it estimated that such an impact would inject 100-400 million tons of dust into the atmosphere, causing disruptions in climate, atmospheric chemistry and global photosynthesis lasting three to four years.

"The solar dimming due to dust would cause an abrupt global 'impact winter' characterized by reduced sunlight, cold temperature and decreased precipitation at the surface," said Lan Dai, a postdoctoral research fellow at the IBS Center for Climate Physics (ICCP) at Pusan National University in South Korea and lead author of the study published this week in the journal Science Advances.

In the worst-case scenario, the researchers found that Earth's average surface temperature would decrease by about 7 degrees Fahrenheit (4 degrees Celsius), average rainfall would fall by 15%, there would be a reduction of up to 20-30% in plant photosynthesis and a 32% depletion in the planet's ozone layer that protects against harmful solar ultraviolet radiation.

The impact of a Bennu-sized object - a medium-sized asteroid - on Earth's land surface would generate a powerful shockwave, earthquakes, wildfires and thermal radiation, leave a gaping crater and eject huge amounts of debris upward, the researchers said. Reuters