Ancient Roman Shipwreck's Cargo Used to Investigate Dark Matter

When a 2,000-year-old Roman shipwreck was discovered off the Sardinian coast, it captured the interest of both archaeologists and physicists. Among these scientists was Ettore Fiorini, a particle physicist from Italy's Institute for Nuclear Physics, who saw potential in the ship's cargo: hundreds of lead bars, each weighing 33 kilograms.

Fiorini proposed a collaboration with cultural heritage officials, aiming to recover the lead for scientific research while promising to fund the recovery efforts. This ancient lead is sought after for its stability, having lost the radioactivity that complicates sensitive physics experiments.

As physicist Paolo Gorla explains, any background noise can disrupt the detection of elementary particles, necessitating deep underground experiments to achieve 'cosmic silence.' Freshly mined lead contains trace amounts of unstable isotopes that can interfere with observations, making ancient lead ideal for use as a shield against both cosmic rays and internal radioactivity.

While the scientific community sees the potential in using ancient artifacts, there is heated debate over the ethics of removing historical items from their context. Critics argue that extracting lead without proper archaeological documentation results in an irreversible loss of historical information.

Dr. Elena Perez-Alvaro highlights the dilemma, emphasizing the importance of understanding the past while also acknowledging the scientific advancements that could arise from using ancient materials. The primary goal of retrieving this Roman lead is to shield experiments searching for dark matter, a mysterious substance thought to constitute 85 percent of the universe's mass.

Dark matter does not interact with light but influences gravity, as first proposed by astronomer Fritz Zwicky in the 1930s. Current efforts, like the CUORE experiment under Italy's Gran Sasso mountain, aim to detect dark matter interactions using detectors shielded with this ancient lead.

Since its inception, CUORE has yet to make significant discoveries, but upgrades are planned to enhance its capabilities. Meanwhile, other experiments are underway globally, including the upcoming SABRE South detector in Australia, aimed at confirming controversial dark matter signals previously detected.

The quest to uncover the secrets of dark matter not only enhances our understanding of the universe but also sparks a fascinating intersection between archaeology and modern physics.