Physics rocks ??? :)

Monday, December 4, 2006

5th POST !!! wahaha ...

well, this webbie is abt how things works ...

http://www.howstuffworks.com/

blah ...

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saw this post ... INTERESTING ! lolx ...

Build Your Own Universe
NPR ^ | 11/27/06 | Robert Krulwich

Posted on 11/29/2006 4:19:47 PM PST by LibWhacker

Is this a joke? No, say a bunch of physicists. One day, it may be possible for a person to create a universe!

This is not going to happen tomorrow. Not even close. But according to Columbia University physics professor Brian Greene, it is theoretically not impossible (which is his way of saying the possibilities are not zero) that one day, a person could build a universe.

The very idea is so startling it's hard to know what this means.

Think about it this way: One day (far off, no doubt), it may be possible to go into a laboratory on Earth, create a "seed" -- a device that could grow into a universe -- and then there would have to be a way to get that seed, on command, to safely expand into a separate, infinite, unexplorable but very real alternate universe.

Got that?

This isn't Greene's notion. But he was willing to describe, in very broad outline, how it might work.

The seed, he suggests, could be a black hole. Not the big black holes that sit near the centers of so many galaxies, but what he calls a "mini black hole." Black holes, he says, don't have to be big. They can, in theory, be very small.

I asked him how small, and together we conducted an imaginary (very imaginary) experiment. If you listen to my interview, you will hear us build a mini black hole from an ordinary watermelon.

It's a fanciful experiment done with imaginary sound effects, but it playfully suggests these mini black holes might be manufactured one day. There may even be a real-life attempt. Plans are afoot to detect mini black holes at the new Large Hadron Collider in Switzerland.

Greene also describes a kind of energy, called a "repulsive force," that might be capable of turning that seed into a new universe. The problem is, no one is yet sure how this force works or why. But Eduardo Guendelman, a physicist at Ben Gurion University in Beer Sheva, Israel, and Nobuyuki Sakai and his team at Yamagata University in Japan are working on the problem right now.

But suppose it is possible to create something that grows infinitely and becomes a universe somewhere else, why do it if you can't go and visit your creation? If you can't pop in, take a look and come back, why bother?

In the July 8, 2006 issue, New Scientist writer Zeeya Merali put that question to Stanford cosmologist Andre Linde.

"I sat down and really thought about why we should even care about creating a universe in the laboratory, " he told New Scientist, "We don't seem to be able to communicate with it at all."

Once it's formed, the inventor couldn't meet its inhabitants, mine its minerals, collect souvenirs or judge his or her success. The biblical god who many believe created our universe inspected us on the first through sixth day and decided that what He'd done "was good."

That's not an option for the human scientist who creates.

So why do it? Well, Greene says given the chance to make a universe of his own, "I might have a little trouble resisting this possibility. Just because it's so curious, this idea that because of your volitional act, you are creating a universe that could give rise, perhaps, to things we see around us."

Linde seconded that in his New Scientist interview.

"Just imagine if it's true and there's even a small chance it really could work," he said. "In this perspective, each of us can become a god."

Oh, the vanity of it all!

source ~ http://www.freerepublic.com/focus/f-news/1746101/posts

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Sunday, December 3, 2006

How much radiation do we get?

The average person in the United States receives about 360 mrem every year whole body equivalent dose. This is mostly from natural sources of radiation, such as radon.
In 1992, the average dose received by nuclear power workers in the United States was 300 mrem whole body equivalent in addition to their background dose.

What is the effect of radiation?

Radiation causes ionizations in the molecules of living cells. These ionizations result in the removal of electrons from the atoms, forming ions or charged atoms. The ions formed then can go on to react with other atoms in the cell, causing damage. An example of this would be if a gamma ray passes through a cell, the water molecules near the DNA might be ionized and the ions might react with the DNA causing it to break.
If someone receives a whole body dose more than 1,000 rem, they will suffer vascular damage of vital blood providing systems for nervous tissue, such as the brain. It is likely at doses this high, 100% of the people will die, from a combination of all the reasons associated with lower doses and the vascular damage.

source ~ http://www.physics.isu.edu/radinf/risk.htm

{2:58 PM}

HOW DOES A MICROWAVE OVEN WORKS ???

A microwave oven works by passing microwave radiation, usually at a frequency of 2.45 GHz (a wavelength of 12.24 cm), through the food. Water, fat, and sugar molecules in the food absorb energy from the microwave beam in a process called dielectric heating. Many molecules (such as those of water) are electric dipoles, meaning that they have a positive charge at one end and a negative charge at the other, and therefore rotate as they try to align themselves with the alternating electric field induced by the microwave beam. This molecular movement creates heat as the rotating molecules hit other molecules and put them into motion. Microwave heating is most efficient on liquid water, and much less so on fats and sugars (which have less molecular dipole moment), and frozen water (where the molecules are not free to rotate). Microwave heating is sometimes explained as a rotational resonance of water molecules, but this is INCORRECT: such resonance only occurs in water vapour at much higher frequencies, at about 20 gigahertz. Moreover, large industrial/commercial microwave ovens operating at 915 MHz also heat water and food perfectly well.

source ~ en.wikipedia.org

{12:59 AM}

new blog !!!
stay tune !!
=))

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