Interesting talk by Richard Feynman on Light:
(The following is an YouTube video embed)

Very interesting - Dyson Spheres

This is in continuation of my previous post on LHC (Large Hadron Collider).

For many reasons this is an amazing moment in the history of science (many which have probably been repeated on this blog before).

There are roughly 75 countries with at least one institution (university or lab) which has contributed to the construction of this machine. The list includes strange bedfellows: India and Pakistan, Israel and Iran and the United States, Greece and Turkey, Russia and Georgia, all of western Europe, most of eastern Europe, some of northern Africa and south America, Japan, China, S. Korea, etc. This unlikely team has constructed the biggest single machine in the history of the planet after over 20 years since the first plans were laid. At 10,000 scientists, this project represents the modern day pyramids.

This is the kinda stuff that makes this one of the biggest scientific experiments ever conducted by mankind! To give you a scale of the things involved, the LRC Homepage has listed out a series of facts about the experiment:

- The vacuum in the LHC is comparable to outer space, if it were a car tyre with a leak, there are so few gas molecules that it would take 10 000 years to go flat.
- When protons arrive in the LHC they are travelling at 0.999997828 times the speed of light. Each proton goes around the 27km ring over 11 000 times a second.
- The Large Hadron Collider at CERN could be the most ambitious scientific undertaking ever. The results of LHC experiments will probably change our fundamental knowledge of the universe.
- A nominal proton beam in the LHC will have an energy equivalent to a person in a Subaru driving at 1700 kph.

Check out all the other facts here.

Man has now succeeded to set up one of his biggest experiments ever to understand the fundamentals of our universe and its creation. 

“Particle physics is the unbelievable in pursuit of the unimaginable. To pinpoint the smallest fragments of the universe you have to build the biggest machine in the world. To recreate the first millionths of a second of creation you have to focus energy on an awesome scale.”

Young’s double slit experiment is the one that started all the confusion about light’s wave nature vs. particle nature.

Any relatively simple discussions on quantum physics starts off with this insightful experiment conducted by Thomas Young. Till now, I had found Gary Zukav’s Dancing Wu Li Masters as one of the better write-ups on explaining the significance of this experiment.

However, this particular post at Cocktail Party Physics goes one step ahead and makes the whole concept refreshingly clear for people looking to get a glimpse on what quantum physics is all about. I particularly like the analogy of Paris Hilton used here in order to explain the idea that the outcome of a quantum experiment depends on the observer:

There was exciting news from the Lawrence Berkeley National Laboratory last week, as researchers announced that they had performed the world’s smallest double-slit experiment and determined that quantum (subatomic) particles will start behaving in accordance with classical (macroscale) physics at the size scale of a single hydrogen molecule. Quantum physicists are no doubt excitedly discussing these marvelous results with a passion most people reserve for Super Bowl Sunday. But the average reader’s eyes probably just glaze over with incomprehension, leaving him/her to wonder what all the fuss is about. Truthfully? It’s tough to grasp the significance of this latest quantum wrinkle without a bit of background about Thomas Young’s original 1802 experiment (now the poster child of the quantum concept of particle/wave duality), as well as the historical scientific debate that raged around the nature of light. Hence today’s Monster Post.

Read the entire article here.

Currently reading: Isaac Asimov’s The Subatomic Monster: Essays on Science.

The first chapter focuses on the topic of magnetic monopoles. Before we get into that, let us talk about the fundamental difference between electricity and magnetism.

Electric charges can exist in isolation, which means that we can have a single negative charge or a single positive charge.
However, magnetic charges – north pole or south pole have not been found to exist in isolation. This was touched famously in all your physics books in the fact that when you cut a magnet into half, you instantly get another magnet with both the north and the south poles on it.

Theoretical physics, partly to adhere to a grand unified theory, concludes that magnetic monopoles (only a north pole or only a south pole) should exist in this universe.

As per calculations, there is an understanding that such monopoles came into existence exactly 10 to the power -34 seconds after the Big Bang. Beyond this, many of them were annihilated as they came into existence with monopoles of opposite polarity. However, the general belief is that there continued to exist a certain number of monopoles that escaped destruction and are now floating around in the universe. Owing to their unique nature, these as of now hypothetical particles carry with them huge amounts of energy and hence are limited in number (else their gravitational force would have started collapsing the universe by now).

There have been many physicists who have tried to detect monopoles, but there has been no conclusive evidence as yet. As per early calculations, the probability of detecting a monopole, if it exists, is roughly once in 6000 years.

To read more about Magnetic Monopoles, click here. (Wikipedia does seem a not-so-serious link for a topic like this, but it provides good references which you can navigate to).

Time may not exist, writes Tim Folger in the Discover Magazine.

This is an interesting article that probes deep into the concept of time and the perception that we hold of this supposedly omnipresent entity.

Excerpts:

Krausz uses ultraviolet laser pulses to track the absurdly brief quantum leaps of electrons within atoms. The events he probes last for about 100 attoseconds, or 100 quintillionths of a second. For a little perspective, 100 attoseconds is to one second as a second is to 300 million years. But even Krausz works far from the frontier of time. There is a temporal realm called the Planck scale, where even attoseconds drag by like eons. It marks the edge of known physics, a region where distances and intervals are so short that the very concepts of time and space start to break down.

Efforts to understand time below the Planck scale have led to an exceedingly strange juncture in physics. The problem, in brief, is that time may not exist at the most fundamental level of physical reality. If so, then what is time?

Rovelli, the advocate of a timeless universe, says the NIST timekeepers have it right. Moreover, their point of view is consistent with the Wheeler-DeWitt equation. “We never really see time,” he says. “We see only clocks. If you say this object moves, what you really mean is that this object is here when the hand of your clock is here, and so on. We say we measure time with clocks, but we see only the hands of the clocks, not time itself. And the hands of a clock are a physical variable like any other. So in a sense we cheat because what we really observe are physical variables as a function of other physical variables, but we represent that as if everything is evolving in time.

Another important and strange fact that the article refers to is that time always points towards the future:

All the laws—whether Newton’s, Einstein’s, or the quirky quantum rules—would work equally well if time ran backward. As far as we can tell, though, time is a one-way process; it never reverses, even though no laws restrict it.

People busy building time-machines might just want to visit these revised theories of time.

Article link.