Study tracking asteroids for next 1,000 years finds rock with ‘greatest chance of collision’ with Earth

At least 28 out of 2,000 asteroids found having non-zero probability of ‘deep encounter’ with Earth

Astronomers have mapped the trajectories of over 2,000 potentially hazardous asteroids for the next 1,000 years and found those with the closest possible encounters with Earth in this period.

While none of these near-Earth asteroids (NEO), over a kilometre in size, pose a significant risk over the next century, the yet-to-be peer-reviewed study narrowed down on one posing the greatest collision threat in the next 1,000 years.

Predicting the impact risk over such long-time scales has been a challenge as small changes in orbit may lead to large uncertainties in the paths of asteroids.

To overcome this limitation, researchers, including those from Nasa’s Jet Propulsion Laboratory, simulated as many trajectories as possible for this catalogue of asteroids, given some uncertainties in their current paths and velocities.

Based on this simulation, they could determine the closest possible encounter known hazardous asteroids may have with Earth.

They found one particular NEO – Asteroid 7482 – to be particularly hazardous.

“The asteroid with the largest estimated probability of a deep close encounter is 7482,” researchers wrote in the study.

This space rock, scientists said, will spend a significant amount of time near Earth for the next 1,000 years.

While this may not inherently mean it would lead to a collision with Earth, it still has the greatest chance of collision among all the observed NEOs in the next 1,000 years.

In these large time scales, even a small difference in the force experienced by an asteroid, such as from the pull of Jupiter, may lead it on an uncertain, yet potential, collision path with Earth.

Researchers also flagged another NEO – Asteroid 143651 – with a chaotic orbit that made it impossible to predict its position after a few decades, highlighting the need for further analysis of this space object.

Of the nearly 2,200 NEOs analysed, scientists found a total 28 candidates with a “non-zero” probability of a “deep encounter”.

This means these rocks could come in close proximity to Earth at a distance less than that from the planet to the moon.

“The present work provides a list of asteroids and dates in which impact monitoring tools can be used to more accurately determine impact probabilities far beyond the default dates reported by impact monitoring systems,” scientists concluded.