Alrighty then... time for an introduction to another topic in physics - gravity.
I am not going to start with the story of the apple falling on Newton's head. The previous statement should not have been the first!
So, Newton explored the concept of gravity and explained it as a force that attracts two bodies to each other. He also provided a mathematical relationship between this gravitational force and the distance between the bodies in question. For most non-relativistic physics, Newton's theory of gravity seems to suffice. For example, the orbits of almost all planets in the solar system seemed to follow the trajectory Newton's equations predicted. Almost! Mercury's orbit seemed to deviate slightly from Newton's predicted trajectory. There really was no explanation for this discrepancy for a while.
Then came Einstein with his theory of general relativity. In this theory, he postulated the concept of the curvature of spacetime - a concept I wish I could visualize. As per this theory, Einstein stated that the planets and stars are just following straight paths along the curvature of spacetime. So, they are not moving due to a force of attraction/repulsion, but due to inertial motion. These straight paths are called 'geodesics'. The theory of general relativity successfully accounted for the deviation of Mercury from Newton's predicted orbit.
Check out this video to get a glimpse into how gravity is a consequence of spacetime curvature - gravity in terms of space-time .
Friday, January 21, 2011
Thursday, January 13, 2011
Antimatter
I must first say that the original intent of this blog seems outdated - I have grown (or shrunk) from that mindset. I want to just use this space to put down anything I find interesting which I feel is worth the public's time.
The concept of antimatter has come up a few times in the last few days. There was an article on BBC's website stating that thunderstorms generate antimatter. A photograph showed magical arc-shaped yellow beams above the swirling clouds of a thunderstorm. An antimatter halo, almost. And then, Ed Witten brought antimatter up while discussing the history of string theory. So, what really is this antimatter?? It definitely seems to have caught the interest of all physicists around the world.
The first sentence in Wikipedia's definition of antimatter explains that antimatter is the 'antiparticle' to matter. That raises two questions really - what is the antiparticle? what is matter? A common way of defining matter is anything that has mass and volume. The antiparticle consists of the same mass and OPPOSITE electric charge of a particle. Alright, sounds good.
So, what happens when matter meets antimatter? KABOOM. Both matter and antimatter are annihilated, giving rise to either gamma rays or other particle - antiparticle pairs. This brings up another interesting idea - that radiation, matter and antimatter are three forms of 'existence' of particles. You can get matter and antimatter from radiation and vice versa. With absolutely no idea of experimental observations made on this front, the idea of antimatter is very much like science-fiction to me. Apparently, we have mainly observed just matter - we do not see much antimatter around. As nature seems to like symmetry, there is considerable aversion to the idea that there is so much more matter than antimatter. So... physicists are out to find antimatter.
The Large Hadron Collider was able to generate some antimatter. Stunning project, the LHC. It was able to create antihydrogen - the antiparticle to hydrogen. Understandably, it is very difficult to set up experiments with antimatter as 'explosive annihilation' occurs once they meet matter.
Some scientists propose that there might have been a slight asymmetry between matter and antimatter at the time of the Big Bang with the amount of matter being greater than that of antimatter. Imagine - we are talking about an event close to 14 BILLION YEARS AGO. And we, little specks of mass with life, having an average individual life span of 50 years, are trying to understand the universe. This is exciting. Of course, without sufficient impetus of our species to understand it all in the first place, we are reaching this understanding at a snail's pace.
The concept of antimatter has come up a few times in the last few days. There was an article on BBC's website stating that thunderstorms generate antimatter. A photograph showed magical arc-shaped yellow beams above the swirling clouds of a thunderstorm. An antimatter halo, almost. And then, Ed Witten brought antimatter up while discussing the history of string theory. So, what really is this antimatter?? It definitely seems to have caught the interest of all physicists around the world.
The first sentence in Wikipedia's definition of antimatter explains that antimatter is the 'antiparticle' to matter. That raises two questions really - what is the antiparticle? what is matter? A common way of defining matter is anything that has mass and volume. The antiparticle consists of the same mass and OPPOSITE electric charge of a particle. Alright, sounds good.
So, what happens when matter meets antimatter? KABOOM. Both matter and antimatter are annihilated, giving rise to either gamma rays or other particle - antiparticle pairs. This brings up another interesting idea - that radiation, matter and antimatter are three forms of 'existence' of particles. You can get matter and antimatter from radiation and vice versa. With absolutely no idea of experimental observations made on this front, the idea of antimatter is very much like science-fiction to me. Apparently, we have mainly observed just matter - we do not see much antimatter around. As nature seems to like symmetry, there is considerable aversion to the idea that there is so much more matter than antimatter. So... physicists are out to find antimatter.
The Large Hadron Collider was able to generate some antimatter. Stunning project, the LHC. It was able to create antihydrogen - the antiparticle to hydrogen. Understandably, it is very difficult to set up experiments with antimatter as 'explosive annihilation' occurs once they meet matter.
Some scientists propose that there might have been a slight asymmetry between matter and antimatter at the time of the Big Bang with the amount of matter being greater than that of antimatter. Imagine - we are talking about an event close to 14 BILLION YEARS AGO. And we, little specks of mass with life, having an average individual life span of 50 years, are trying to understand the universe. This is exciting. Of course, without sufficient impetus of our species to understand it all in the first place, we are reaching this understanding at a snail's pace.
Subscribe to:
Posts (Atom)