Study Suggests Hidden Danger May Be Orbiting Alongside Venus

Two decades ago, the U.S. Congress tasked NASA with identifying 90% of near-Earth asteroids that could pose a threat. Since then, the agency has made progress tracking objects that orbit the Sun and pass within 1.3 astronomical units of Earth.

A New Threat Emerging Near Venus

However, a new area of concern is emerging: astronomers are now detecting asteroids that co-orbit with Venus — and despite their distance, these objects might threaten Earth.

Researchers have been exploring how many of these co-orbiting asteroids remain undiscovered and how we might detect them. The challenge lies in the fact that these bodies can remain hidden in the Sun’s glare, making detection difficult. Observing them depends on specific visibility windows and how their brightness fluctuates.

The study, titled “The invisible threat: assessing the collisional hazard posed by the undiscovered Venus co-orbital asteroids”, has been submitted to Astronomy and Astrophysics and is available on arxiv.org. The lead author is Valerio Carruba, an assistant professor at São Paulo University in Brazil.

Currently, 20 asteroids are known to share Venus’s orbit. Although their co-orbital configuration keeps them from getting too close to Venus itself, it doesn’t prevent them from crossing paths with Earth.

What Makes an Asteroid a Potential Hazard?

According to the researchers, these asteroids are classified as potentially hazardous (PHA) if they are at least 140 meters in diameter and come within 0.05 astronomical units of Earth’s orbit.

The central question: do these objects pose a real collision risk to Earth?

The study aims to evaluate the potential danger posed by undetected Venus co-orbitals and to assess whether they can be identified using Earth-based or space-based telescopes.

Of the 20 known asteroids, only one has an orbital eccentricity below 0.38. This suggests an observational bias — objects with wider orbits approach Earth more closely and are easier to detect. Therefore, there could be many more with more circular orbits that have simply gone unnoticed.

A key complication is the chaotic nature of these asteroids’ orbits. The authors explain that their orbits are highly unstable, with Lyapunov times — the point at which predictions become unreliable — of about 150 years.

Using Simulations to Predict Collisions

To overcome this, the researchers created statistical simulations using “clone” asteroids. They modeled a range of orbital inclinations and populated the grid with 26 clones with varying characteristics. These were then integrated with the orbits of the Solar System’s planets over 36,000 simulated years to check for close encounters with Earth.

They found that there is a band of orbits, especially at lower inclinations and with eccentricities under 0.38, where Venus co-orbitals could indeed pose a collision hazard to Earth.

The researchers also tested whether the upcoming Vera Rubin Observatory could observe these objects. Their findings showed that due to the Sun’s interference, these asteroids are only visible during limited times — mostly when near their closest approach to Earth.

“The combination of elevation and solar elongation constraints restricts our ability to observe them to specific periods each year,” the authors wrote. (Solar elongation is the angular distance between the asteroid and the Sun as seen from Earth.)

Proposing a Space-Based Solution

Given how challenging it is to detect these potentially dangerous asteroids from Earth, the study suggests that sending a space-based observatory to Venus’s orbit — facing away from the Sun — might greatly improve detection capabilities. Scientists have already proposed several mission concepts, including placing observatories in Sun-Earth or Sun-Venus L1 or L2 halo orbits.

It’s a known fact that some asteroids have enough energy to cause catastrophic damage. Some are large enough to destroy entire cities. Even a 150-meter-wide asteroid could strike with the force of hundreds of megatons of TNT — thousands of times more powerful than the atomic bombs dropped during World War II.

The researchers emphasize that Venus co-orbitals with low eccentricity are particularly difficult to detect and track, making them a unique and worrisome challenge.

While the Vera Rubin Observatory will likely discover many asteroids through its normal operations, locating the dangerous few that share Venus’s orbit may require a dedicated mission.

“In our view, although upcoming surveys like the Rubin Observatory may detect some of these asteroids, only a focused observational mission near Venus could successfully identify all the still ‘invisible’ potentially hazardous asteroids among Venus’s co-orbitals,” the authors conclude.

Read the original article on: Science Alert

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