Physicists have announced that antimatter falls downward, resolving a long-standing question in the realm of particle physics. The study, conducted by the ALPHA collaboration at the European Organization for Nuclear Research (CERN) in Switzerland, sheds light on the elusive nature of antimatter.
Antimatter is believed to have been created in equal amounts alongside regular matter during the Big Bang, the cosmic event thought to have birthed the universe. While matter consists of particles, antimatter comprises antiparticles, possessing identical mass but opposing properties. Despite this fundamental understanding, much about antimatter remains a mystery.
The ALPHA collaboration’s research reveals that antihydrogen atoms, the antimatter counterpart of hydrogen, obey the same gravitational laws as conventional matter. This observation dispels the notion of repulsive ‘antigravity,’ as detailed in their study published in the journal Nature.
These findings mark a significant milestone in the exploration of antimatter, bringing us closer to unravelling its enigmatic properties. The properties and governing laws of antimatter have long baffled scientists, who are still puzzled by the universe’s apparent lack of antimatter.
A noteworthy achievement in antimatter research occurred in June 2011 when CERN scientists successfully trapped antimatter atoms for over 16 minutes, enabling in-depth studies of their characteristics. The latest study builds upon this progress by capturing groups of approximately 100 antihydrogen atoms, one group at a time, and slowly releasing them over a 20-second period.
While a regular hydrogen atom consists of an electron and a proton, an antihydrogen atom comprises a positron (a positively charged electron) and an antiproton (a negatively charged proton). Creating these antihydrogen particles involved slowing down antiprotons and binding them with positrons.
One challenge in studying antimatter is its propensity to interact with regular matter, resulting in annihilation. To prevent this, the lab-created antimatter was confined within a magnetic trap, maintaining a controlled environment. Subsequently, the antihydrogen particles were released in a vertical setup to observe and measure their response to gravity.
Jeffrey Hangst, spokesperson for ALPHA, stated, “It’s taken us 30 years to learn how to make this anti-atom, hold on to it, and control it well enough that we could actually drop it in a way that it would be sensitive to the force of gravity.”
Antimatter’s interaction with matter leads to annihilation, producing radiant energy in the process. This radiant energy, existing in the absence of matter, has been a subject of intense scientific interest.
“In physics, you don’t really know something until you observe it. This is the first direct experiment to actually observe a gravitational effect on the motion of antimatter,” explained Hangst, an experimental particle physicist at Aarhus University in Denmark.
Timothy Friesen from the University of Calgary, Canada, remarked, “We know there’s a problem somewhere in quantum mechanics and gravity. We just don’t know what it is. There has been a lot of speculation on what happens if you drop antimatter, though it’s never been tested before now because it’s so hard to produce and gravity is very weak.”
William Bertsche of the University of Manchester, UK, and Deputy Spokesperson of ALPHA, noted, “Einstein’s General Theory of Relativity describes how gravity works. Until now, we weren’t entirely sure if this theory applied to antimatter. This experiment proves that it does and affirms one of the most celebrated scientific theories of all time.”
The next phase of research aims to precisely measure antimatter’s acceleration, further investigating whether matter and antimatter indeed experience the same gravitational effects. This discovery represents a significant leap forward in our quest to understand the fundamental properties of the universe.