December 11, 2023

Galileo put gravitational theory to the test by dropping balls from the Leaning Tower of Pisa. Four hundred years on, scientists have performed a higher tech version of the experiment to demonstrate for the first time that antimatter also falls downwards.

The study, by scientists at Cern, showed conclusively that gravity pulls antihydrogen downwards and that, at least for antimatter, antigravity does not exist.

“Broadly speaking, we’re making antimatter and we’re doing a Leaning Tower of Pisa kind of experiment,” said Prof Jonathan Wurtele, a theoretical physicist at the University of California, Berkeley. “We’re letting the antimatter go, and we’re seeing if it goes up or down.”

Antimatter is a mirror version of ordinary matter, with some basic properties like electrical charge reversed. Antiprotons have the same mass, but a negative charge, while antielectrons (also called positrons) are positively charged.

When matter and antimatter meet, they annihilate each other and produce energy, meaning that in a matter-dominated world like our own, antimatter only fleetingly comes into existence. But most theories predict that equal amounts of matter and antimatter should have been produced during the big bang, and the mystery of what happened to all the antimatter is a central question in fundamental physics.

For some, the concept of antigravity has been an enticing potential explanation to this conundrum. This could have led to the spatial separation of matter and antimatter in the early universe, meaning that we only see a small amount of antimatter in the local universe. There are other theoretical reasons that make this idea unlikely, but as the question had never been put to the test, it had remained a fringe possibility.

“Until you measure it, you just don’t know. That’s science,” said Jeffrey Hangst, a particle physicist at Aarhus University, Denmark, and spokesperson of the Antihydrogen Laser Physics Apparatus (Alpha) collaboration at Cern.

The Alpha apparatus at Cern.
The Alpha apparatus at Cern. Photograph: Cern/AFP/Getty Images

A direct measurement of antimatter falling is hugely challenging because the gravitational force is so weak compared with the other three known forces of nature and scientists have struggled to preserve antimatter for long enough to carry out experiments. The latest study, published in Nature, used antihydrogen atoms cooled to half a degree above absolute zero (-273.15C). About 100 of the antimatter atoms were confined in a 25cm-long magnetic bottle with an opening at the top and bottom. Meticulous measurements showed that the atoms were more likely to escape, and meet their annihilation, at the bottom of the bottle due to gravitational forces.

The gravitational acceleration was found to be within 25% of normal gravity, meaning that it could be identical to the gravitational force experienced by ordinary matter – or at least, similar.

“It has taken us 30 years to learn how to make this anti-atom, to hold on to it, and to control it well enough that we could actually drop it in a way that it would be sensitive to the force of gravity,” said Hangst. “The next step is to measure the acceleration as precisely as we can.”

مولدي العملات TikTok: الأمان والمخاطر
TikTok Coin Hacks for Rapid Growth
The Secret Sauce to TikTok Coin Generation
استراتيجيات النجاح في جمع العملات TikTok بفعالية
TikTok Coin Generators: Fact vs. Fiction
The Secret Sauce to TikTok Coin Generation
Aprovechando al Máximo los Regalos de Monedas TikTok
Get Free Coins for TikTok: Top Methods
Are TikTok Coin Generators Worth It?
Entsperren Sie Kostenlose TikTok-Münzen: Ihr Ultimativer Leitfaden
Get Free TikTok Coins: The Ultimate Guide
A Deep Dive into TikTok Coin Generation
Primero la Seguridad: Protegiendo tu Cuenta al Ganar Monedas
Free TikTok Coins: Your Ticket to Stardom
How to Get TikTok Coins Legally and Quickly
Maximiza tus Ganancias de Monedas TikTok con Estos Consejos
The Future of TikTok Coins: Trends and Predictions
Free TikTok Coins: The Future of Social Media
Consigli per la Sicurezza nel Guadagnare Monete TikTok Gratis
Free Coins on TikTok: Tips and Tricks
How to Earn TikTok Coins: Step-by-Step Tutorial
العملات TikTok المجانية: مستقبل محتوى TikTok
Legit Ways to Get TikTok Coins for Free
How to Earn TikTok Coins: Step-by-Step Tutorial
Die Auswirkungen von TikTok-Münzen auf Ihr Profil

Leave a Reply

Your email address will not be published. Required fields are marked *