Earth could face devastation in 2182 if asteroid Bennu collides

WASHINGTON,— Asteroid Bennu, a near-Earth object currently making its closest pass by our planet, poses a potential risk for collision in the distant future, scientists warned.

Bennu, which orbits the Earth every six years, passes as close as 186,000 miles (299,000 km) to the planet. Experts estimate a slim one-in-2,700 chance of Bennu striking Earth in September 2182, according to recent findings.

New computer simulations of a potential impact by Bennu—a 500-meter asteroid—reveal that the consequences would be severe.

If the asteroid were to strike Earth, it would not only cause immediate destruction but also lead to long-lasting disruptions in global climate and ecosystems. Researchers predict that the impact would throw 100-400 million tons of dust into the atmosphere, which could significantly alter climate patterns for up to four years.

“The dust would block sunlight, triggering a dramatic global ‘impact winter’ marked by colder temperatures, less rainfall, and reduced sunlight,” said Lan Dai, a postdoctoral research fellow at the IBS Center for Climate Physics (ICCP) at Pusan National University in South Korea. Dai, who led the study published in Science Advances, explained that the effects of such an impact would be felt worldwide.

According to the research, the worst-case scenario would result in a drop in Earth’s average surface temperature by about 7°F (4°C) and a 15% reduction in rainfall. Additionally, photosynthesis would decrease by 20-30%, and the ozone layer—critical for protecting life on Earth from harmful ultraviolet radiation—could be depleted by as much as 32%.

In the aftermath of the impact, the Earth would experience a combination of earthquakes, powerful shockwaves, wildfires, and thermal radiation. The collision would also create a massive crater and send debris into the atmosphere, further disrupting climate systems, experts said.

The study also highlighted the differing effects on life on land and in the oceans. While plant growth on land would take years to recover, plankton in the ocean would bounce back much faster, showing an unexpected increase due to iron-rich dust falling into the sea.

However, the general decline in plant life, both on land and in the oceans, could lead to long-term disruptions in food supply and ecosystems.

Severe ozone depletion would occur in the stratosphere, the second layer of the atmosphere, due to warming caused by the absorption of dust particles from the impact. This ozone loss would further harm life on Earth, particularly by increasing exposure to harmful ultraviolet radiation.

The study did not focus on estimating the number of human casualties, but Dai said that the location of the asteroid impact would play a significant role in determining the death toll.

A Bennu-sized asteroid strike would likely cause catastrophic loss of life, with climate and environmental disruptions severely affecting the global population.

Scientists have long studied Bennu, which is considered a “rubble pile” asteroid—a loose collection of rocks rather than a solid body.

Bennu is thought to be a remnant of a larger celestial body that formed early in the solar system’s history about 4.5 billion years ago. In 2020, NASA’s OSIRIS-REx spacecraft visited Bennu and collected rock and dust samples for analysis.

Research on these samples revealed that Bennu contains some of the chemical ingredients necessary for life, supporting the theory that asteroids may have played a role in delivering the building blocks for life to early Earth.

Asteroids have caused significant destruction in Earth’s history. One such asteroid, estimated to be 6-9 miles (10-15 km) wide, struck the Yucatán Peninsula in Mexico 66 million years ago, causing the extinction of nearly three-quarters of Earth’s species, including the dinosaurs.

In response to the growing concern about asteroid impacts, NASA conducted a planetary defense test in 2022, using the DART spacecraft to alter the trajectory of an asteroid, Dimorphos. This test is part of ongoing efforts to develop strategies for deflecting any potential asteroid threat.

Although the chances of Bennu striking Earth are low—only about 0.037%—researchers stress that the potential impact could have catastrophic consequences.

“Even though the probability is small, the impact would likely lead to severe food shortages and climate conditions similar to those following some of the largest volcanic eruptions in recent history,” said Axel Timmermann, ICCP director and senior author of the study. “It’s important to consider the risk,” he added.

(With files from Reuters)