Researchers are preparing to make one of science’s most unusual journeys. They are planning to transport a container of antimatter in a lorry across Europe.
Antimatter is the most expensive material on Earth – it’s estimated it would cost several trillion dollars to make a gram – and it can only be manufactured in particle physics laboratories such as the Cern research centre near Geneva.
It is also extremely tricky to handle. If antimatter makes contact with normal matter, both are annihilated, releasing a powerful burst of electromagnetic radiation. Only by carefully combining sets of powerful electrical and magnetic fields in special devices can antimatter be stored safely.
“That makes moving it around very difficult, though we are now close to making our first journey,” said Prof Stefan Ulmer, a scientist at Cern. “Antimatter has so much to tell us. That is why we are doing this.”
Moving the antimatter will be a scientific first, though it has a fictional precursor. In Dan Brown’s thriller Angels & Demons – made into a film starring Tom Hanks in 2009 – terrorists steal a canister of antimatter from Cern and try to obliterate the Vatican with it.
The prospect of a similar blast happening in real life is remote, scientists insist – the quantities of antimatter carried will be insufficient to make an explosion of any recognisable nature.
Scientists want to study the particles as they believe they may hold the solution to a fundamental mystery. “We believe the big bang produced the same amounts of matter and antimatter,” said Ulmer. “These should have annihilated each other, leaving a universe made of electromagnetic radiation and not much else.”
That the cosmos seems to be filled with galaxies, stars, planets and living beings made of matter shows this notion must be wrong. There is a basic asymmetry that has favoured matter and stopped the universe from becoming a simmering, empty void.
For this reason, physicists want to study the differences between the particles that make up matter and antimatter. These might provide clues about why the former has come to dominate the universe.
As the Cern scientist Barbara Maria Latacz told Nature: “We are trying to understand why we exist.”
Matter is made up of subatomic particles such as protons and electrons, while antimatter consists of particles that include antiprotons and positrons (as antielectrons are also known). A key source of the latter type of particle is based at Cern in a device known as the Antiproton Decelerator, where antiprotons are generated, collected and studied.
The aim is to measure precisely the properties of antiprotons and compare them with protons. Known as the Base experiment, it could reveal tiny hidden differences that would explain why matter has thrived at the expense of antimatter.
Background magnetic fields near the device are limiting this work, and scientists want to transport samples to other labs. “By moving them to a new location, we can make measurements that are 100 times more accurate and get a deeper understanding of antiprotons,” said Ulmer.
To achieve this goal, Cern scientists have built transportable devices containing superconducting magnets, cryogenic cooling systems and vacuum chambers where antiprotons can be trapped, avoiding contact with normal matter, and carried on seven-tonne lorries.
Initially, antiprotons will be transported within Cern. Over the next year, containers will be moved further afield to a dedicated precision lab at the Heinrich Heine University Düsseldorf.
“In the long term, we want to transport it to any lab in Europe,” said Christian Smorra, leader of the transport project. In this way, scientists hope to find why antimatter all but vanished from the universe. “This could be a gamechanger,” said Ulmer.