Scientists Raise Alarm Over a Potential Risk in Venus’s Orbital Zone

Scientists Raise Alarm Over a Potential Risk in Venus’s Orbital Zone

Two decades ago, the U.S. Congress tasked NASA with locating 90% of near-Earth asteroids large enough to pose a threat. Significant progress has been made in identifying those that orbit the Sun and come within 1.3 astronomical units of our planet.

However, new research suggests scientists may need to widen their search — as potentially dangerous asteroids sharing Venus’s orbit have recently come into focus.

A recent study explores how many of these Venus co-orbital asteroids might exist and how difficult they are to detect. These objects often remain hidden in the Sun’s glare, making them especially challenging to spot. Their visibility depends on observation windows and how their brightness changes over time.

Titled “The invisible threat: assessing the collisional hazard posed by the undiscovered Venus co-orbital asteroids,” the paper has been submitted to Astronomy & Astrophysics and is currently available on arXiv. It is led by Valerio Carruba, an assistant professor at São Paulo State University in Brazil.

Currently, 20 co-orbital asteroids around Venus have been identified. While their shared orbit with Venus usually prevents close encounters with the planet, it doesn’t rule out potential Earth crossings.

These asteroids are classified as potentially hazardous if they are at least 140 meters wide and come within 0.05 astronomical units of Earth’s orbit.

The key question remains: could these asteroids threaten Earth?

The researchers aim to assess the risk posed by the yet-undiscovered population of Venus co-orbiters — and determine whether current observatories, both ground-based and in space, are capable of detecting them.

So far, only one of the known 20 has an orbital eccentricity below 0.38. This suggests that detection is likely skewed toward those with more Earth-crossing paths — meaning many smaller, less eccentric orbits may still be hiding undetected.

One major challenge in assessing the risk posed by Venus co-orbital asteroids is their chaotic behavior.
“These asteroids are highly unpredictable, with orbital stability lasting only about 150 years before becoming completely unstable,” the researchers explain. This timespan, known as the Lyapunov time, means that long-term predictions of their paths are extremely difficult.

To better understand the potential danger, scientists ran simulations using a statistical approach. They created 26 “clone” asteroids with different orbital properties and tracked their paths over 36,000 simulated years alongside the planets of the solar system. The results showed that certain orbits — particularly those with eccentricity below 0.38 and low inclination — could eventually bring these asteroids close to Earth.

Next, the team tested whether such objects could be detected from Earth using the upcoming Vera Rubin Observatory. They found that visibility is limited due to the Sun’s glare, with observation windows opening mainly when the asteroids are near Earth.

“Observations are constrained by how far these objects appear from the Sun in the sky and by elevation limits — meaning we can only spot them during specific times of the year,” the authors note.

The study highlights the difficulty in tracking this hidden asteroid population. One proposed solution? Sending a spacecraft into orbit around Venus to observe from a better vantage point. Missions to stable points like the Sun-Earth or Sun-Venus L1/L2 halo orbits have already been suggested.

Some of these asteroids are large enough to cause catastrophic damage if they were to strike Earth. A rock just 150 meters across could hit with the force of hundreds of megatons — thousands of times more powerful than the atomic bombs used in World War II.

“Low-inclination Venus co-orbitals represent a unique hazard,” the researchers conclude, “not only because of their potential to collide with Earth, but also because they remain nearly invisible from our current observatories.”