I read 2 articles. one from year 2000 other from 2007 On the 1st it says (like if wasa truth) that scientists broke light speed barrier Now, in the 2007 article they are skecptics about such experiments. They need more experiments to get sure. I know that my english is not good lol but i got confused with those artices. So, have we broke LightSpeed barried? Last question, can you explain in a simple english and with simple examples what tunneling is?? thanks oh, almost forgot the articles: http://www.cbc.ca/health/story/2000/07/20/speedlight000720.html http://news.zdnet.com/2424-9595_22-160112.html
Hi Kazbadan, My understanding from what I've read is that the conventional view says some "things" can travel faster than light, but not information itself. Information in this sense is basically anything that can have a determined effect on the outcome of anything else. It's tough to explain without writing out a really boring, long-winded reply. To borrow an analogy I once heard used by Brian Greene, imagine I take a pair of shoes and put each shoe in a single box. I then mail the two boxes out, one to Los Angeles and one to New York city. Obviously if one person gets a left shoe, they know that the other person gets a right shoe. Now imagine we make this into some sort of bizarre quantum system where each shoe is 50% left and 50% right, i.e. when you open either box, the shoe inside has a 50/50 chance of materializing into either a left shoe or a right shoe. If the person in L.A. is the first to open their box (from an Earthbound observer's P.O.V.), and they get a left shoe for instance, then instantaneously, a faster than light "signal" is transmitted to New York turning the other shoe into a right shoe. However, all the person in L.A. will know is that either the recipient in New York already opened their box and got a right shoe, or that they will get a right shoe when they open their box in the future. Hence no actual information is transmitted in the process, and the two recipients will only realize that something bizarre happened when they get together or talk on the phone and compare their results using conventional, slower than light signals. In the case of the experiment from 2000 reported on the CBC site, I had heard that the experimenters themselves never claimed that actual information had been transmitted faster than light. The light pulse is transmitted faster than the speed of light, but its transmission has to first be delayed before this can happen. So it's kind of like if I had a flashlight and shone a beam at Mars, which would take several minutes to reach its destination. In principle, I could delay this beam by a few minutes and then have it zoom over faster than light, so that it reaches Mars just as quickly as if there had never been a delay in the first place. Faster than light travel hasn't been totally ruled out, i.e. you've probably heard of the idea of wormholes and warp drives and all that stuff. However, the existence of a wormhole taking you faster than light to a different place and time in the universe would also place restrictions on what kind of return trips you could take and what kinds of wormholes could be used to go in the opposite direction. Otherwise it may be possible to end up with causality violations where you could travel into your own past and kill your grandfather, etc. As for tunnelling, this refers to the ability of a particle to overcome a barrier it would normally not have enough energy for. For instance, imagine I have a basketball which behaves like an electron, and I have a basketball hoop that's 10 000 feet up in the sky. I myself don't have anywhere near the strength to toss a basketball that high, but if I did it to a "quantum basketball", it would have a small probability of picking up energy from empty space and reaching this height. And if I shot an electron at a target where the electron doesn't have enough energy to penetrate the target (i.e. it should be classically impossible), the electron still has a small probability of penetrating.
hi! thanks a lot for your explanation! I read it carefully and was very elucidative Please Register or Log in to view the hidden image!
