IN the world of "Star Trek," the starship Enterprise zips through space using a warp drive that harnesses antimatter. Suffice it to say, such technology remains in the realm of science fiction.
But scientists are making important strides toward better understanding antimatter. Researchers said they have demonstrated for the first time that antimatter responds to gravity the same way matter does - by falling, as one might expect - in an experiment that once again buttressed physicist Albert Einstein's bedrock theory of general relativity.
All the stuff with which we are familiar - planets, stars, poodles and lollipops - is made of ordinary matter.
Antimatter is the enigmatic twin of ordinary matter, possessing the same mass but with an opposite electrical charge. Almost all subatomic particles, such as electrons and protons, have an antimatter counterpart. While electrons are negatively charged, antielectrons, also called positrons, are positively charged. Likewise, while protons are positively charged, antiprotons are negatively charged.
Under current theory, the Big Bang explosion that initiated the universe should have produced equal amounts of matter and antimatter. This, however, does not seem to be the case. There appears to be very little antimatter - and on Earth almost none. What's more, matter and antimatter are incompatible. If they touch, they blow up, a phenomenon called annihilation.
The experiment was conducted at the European Center for Nuclear Research (CERN) in Switzerland by researchers from the international Antihydrogen Laser Physics Apparatus (ALPHA) collaboration. It involved the antimatter counterpart of hydrogen, the lightest of the elements.
"On Earth, most antimatter that occurs naturally is produced from cosmic rays - energetic particles from space - that collide with atoms in the air and create antimatter-matter pairs," said physicist Jonathan Wurtele of the University of California, Berkeley, co-author of the study published in the journal Nature.
This newly created antimatter lasts only until it hits a normal matter atom in the lower atmosphere. However, antimatter can be synthesized under controlled conditions, as in the ALPHA experiment, which used antihydrogen created at CERN.
The antihydrogen was contained within a cylindrical vacuum chamber and trapped with magnetic fields at the top and bottom. The researchers reduced the magnetic fields to set the antimatter free in order to observe whether or not it would fall once the influence of gravity became apparent. It did, behaving as hydrogen would in the same conditions.
"This result was predicted by theory, and indirect experiments that relied on subtle phenomena. But no group had ever done a direct experiment in which antimatter was simply dropped to see which way it would fall," UC Berkeley physicist and study co-author Joel Fajans said.
"Our experiment rules out other theories that require antimatter to rise - 'anti-gravity' - in the Earth's gravitational field," Wurtele added.
While Einstein devised his theory of general relativity - a comprehensive explanation of gravity - before antimatter was discovered in 1932, he treated all matter with equivalence, meaning that antimatter would be expected to respond the same way to gravitational forces as matter.
But what if antimatter had defied expectations?
"This would have been an enormous surprise, as it would be in significant contradiction with many theories," said physicist and study co-author William Bertsche of the University of Manchester in England, who conducts experiments at CERN and serves as a deputy spokesperson for the ALPHA collaboration.
"I think this is a testament to the strength of general relativity and its equivalence principles," Bertsche added.
Scientists remain puzzled by antimatter's scarcity in the observable universe. For instance, there is no indication of galaxies made of antimatter.
"The nearly complete absence of naturally occurring antimatter is one of the great questions facing physics," Wurtele said.
In showing that antimatter and matter are gravitationally attracted, the experiment ruled out one possible explanation for antimatter's scarcity - that it was gravitationally repelled by matter during the Big Bang.
"No matter how pretty the theory, physics is an experimental science," Fajans said.
Reuters
Fri Sep 29 2023
An artist's conceptual rendering of antihydrogen atoms falling out the bottom of the magnetic trap of the ALPHA-g apparatus, a tall cylindrical vacuum chamber used in an antimatter experiment. - REUTERS
AWANI Pagi: Hari sedunia bagi keselamatan & kesihatan di tempat kerja 2024
Memahami kaitan perubahan iklim kepada isu keselamatan dan kesihatan pekerjaan, yang diangkat sebagai tema Hari Sedunia bagi Keselamatan dan Kesihatan di Tempat Kerja tahun ini. Diskusi bersama Ts Mohd Soffian Osman, Perunding Keselamatan & Kesihatan Awam, Safety Management Academy 7.30 pagi nanti
Jualan kediaman kekal memberangsangkan - TA Global
Kenaikan harga hartanah akibat tekanan inflasi ke atas harga bahan binaan tidak menghalang hasrat rakyat Malaysia untuk memiliki rumah idaman.
Rakyat Israel desak kerajaan bawa pulang tebusan yang tinggal
Ribuan berkumpul di Tel Aviv pada Sabtu malam bagi mendesak kerajaan Israel mencapai perjanjian gencatan senjata dengan Hamas dan membawa pulang tebusan yang tinggal
Hamas keluarkan video dua tebusan Israel
Kumpulan pejuang Hamas mengedarkan video menampilkan dua tahanan Israel yang menyeru kepada Perdana Menteri Israel, Benjamin Netanyahu, untuk memenuhi perjanjian pembebasan mereka.
Israel sedia tangguh serangan ke atas Rafah
Israel bersedia menangguhkan serangan ke Rafah jika perjanjian pembebasan tahanan Hamas tercapai. Menteri Luar Israel, Israel Katz, menegaskan keutamaan pembebasan tahanan.
Restoran nasi kandar dibaling cat, polis kesan tiga lelaki
Cat merah tersebut terkena papan tanda dan pintu hadapan restoran yang mula beroperasi pada Sabtu.
Kawasan Beris Lalang terbakar lagi
Cuaca panas melampau di Kelantan menyebabkan kebakaran ladang dan semak di kawasan Beris Lalang. Penduduk dan pekebun mengalami kerugian
Ringgit dijangka diniaga dalam jajaran kecil
Ringgit Malaysia dijangka berada di sekitar 4.77 berbanding Dolar AS minggu depan, bergantung kepada keputusan FOMC dan data ekonomi AS
Bursa Malaysia dijangka diniagakan dalam jajaran kecil
Analisis terkini menunjukkan Bursa Malaysia berpotensi naik dalam jajaran kecil minggu depan, dengan pandangan positif terhadap kembalinya dana asing. Paras sokongan dan konsolidasi disebutkan.
PM tiba di Riyadh untuk hadiri mesyuarat WEF
Datuk Seri Anwar Ibrahim tiba di Riyadh bagi menghadiri Mesyuarat Khas Forum Ekonomi Sedunia. Beliau dijadual terlibat dalam dialog strategik, panel, dan pertemuan bersama pemimpin serantau
Filem Shah Rukh Khan buat kemunculan di China
Filem 'Zero' akan ditayangkan pada majlis penutup Festival Filem Beijing yang akan berlangsung dari 13 hingga 20 April depan.
12 Years A Slave diangkat Filem Terbaik BAFTA
Filem Gravity mendominasi Anugerah BAFTA apabila membawa pulang enam trofi termasuk Pengarah Terbaik untuk Alfonso Cuaron.
Gravity, American Hustle dahului senarai pencalonan Anugerah Akademi
Mengekori rapat ialah filem 12 Years of Slave yang telah memenangi Filem Terbaik di Anugerah Golden Globe pada Isnin, dengan 9 pencalonan.
Gravity terima 11 pencalonan BAFTA
Gravity mendahului saingan lain apabila mendapat 11 pencalonan untuk Anugerah BAFTA.
Apa kata kunci Google Search yang paling dicari bulan Oktober?
Apa yang dicari rakyat Malaysia di laman web Google Malaysia. Artis dan filem mengungguli carta carian Google Malaysia pada bulan Oktober 2013.