Content:
For the first time, scientists have observed antimatter particles falling downwards due to the effect of gravity, Europe’s physics lab CERN announced.
About antimatter:
- Matter consists of subatomic particles that give matter its mass and volume. These particles include protons and neutrons (also known as baryons), electrons and neutrinos (also known as leptons), and a variety of other particles in the Standard Model of Particle Physics.
- Protons and neutrons are themselves made up of particles known as quarks and gluons.
- But matter can have an opposite in the form of antimatter – reversed charge, parity, and time (CPT Reversal)
- All the subatomic particles in matter either have their own anti-twins (antiquarks, antiprotons, antineutrons, and antileptons such as antielectrons)
A collision between any particle and its anti-particle partner leads to their mutual annihilation
- These anti-particles can combine to form anti-atoms and, in principle, could even form anti-matter regions of our universe.
- Scientists believe that these anti-matter regions would have the same physics, chemistry, and other properties.
- Scientists haven’t observed anti-matter regions in our universe till now.
- But have created antiparticles in particle accelerators and even created anti-elements and anti-atoms.
Physics Mystery:
- Approximately 13.8 billion years ago, the Big Bang is thought to have generated an equal quantity of matter, which comprises everything we can observe, and antimatter, its corresponding but opposite counterpart.
- There is an almost complete absence of antimatter in the universe, giving rise to one of the most profound mysteries in physics: what happened to all the antimatter?
- Physicists believe that matter and antimatter did meet and almost entirely destroyed each other after the Big Bang.
- Matter now makes up nearly 5 % of the universe — the rest is even less understood dark matter and dark energy — while antimatter vanished
Previous year question
Consider the following statements:
1. Light is affected by gravity.
2. The Universe is constantly expanding.
3. Matter warps its surrounding space-time.
Which of the above is/are the prediction/predictions of Albert Einstein’s General Theory of Relativity, often discussed in media?
[UPSC Civil Services Exam – 2018 Prelims]
(a) 1 and 2 only
(b) 3 only
(c) 1 and 3 only
(d) 1, 2 and 3
Answer: (d)
Explanation: The bending of light by gravity can lead to the phenomenon of gravitational lensing, in which multiple images of the same distant astronomical object are visible in the sky. Gravity, Einstein asserted, is caused by a warping of space and time. Gravity is the curvature of spacetime caused by massive objects. In 1917, Einstein applied the general theory of relativity to the structure of the universe as a whole. He found that the general field equations predicted a universe that was dynamic, either contracting or expanding. Since observational evidence for a dynamic universe was not known at the time, Einstein introduced a new term, the cosmological constant, for the field equations to allow him to predict a static universe.
