Asteroid Bennu, a near-Earth object first identified in 1999, is now playing a crucial role in the quest for a potential fifth fundamental force of nature, which could alter our understanding of the universe.
In October 2020, NASA's OSIRIS-REx spacecraft collected samples from Bennu, a 500-meter-wide asteroid believed to contain primordial materials dating back over 4.5 billion years. The samples may include organic compounds that contributed to life's emergence on Earth.
Recent analyses by a team led by physicist Yu-Dai Tsai from Los Alamos National Laboratory suggest that subtle deviations in Bennu's orbit could indicate the presence of a fifth force, potentially linked to dark matter, which constitutes approximately 85% of the universe’s mass but remains undetectable.
Historically, physicists have pursued the idea of a fifth force since the 1980s, theorizing various forms it might take. The unique motion of Bennu provides a controlled environment to test these hypotheses.
Using data from OSIRIS-REx and prior observations, Tsai's team explored anomalies in Bennu’s trajectory. They sought to identify any unexplained influences affecting the asteroid's path.
The study yielded no direct evidence of a fifth force but established stringent limits on its potential strength and reach, ruling out certain models involving ultralight bosons, particles that some theorists believe could explain dark matter.
Although Bennu has not yet provided definitive answers, it has set the stage for future investigations. The team plans to examine Apophis, another near-Earth asteroid, during its close approach to Earth in 2029, hoping to gather more data that could further illuminate the search for this elusive force.
As research continues, Bennu exemplifies how asteroids can be pivotal in uncovering fundamental truths about the universe.