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Imagine Laser Stars
Extending to Space?
I thought of this question suddenly when I was bored.
Imagine having a very long metal rod, so long that it's about the diameter of the Earth. If I place the metal rod in front of me, parallel to Earth's surface, wouldn't it be like a tangent to a circle, and the rod would extend beyond the Earth's atmosphere and to space?
Some might say that the rod will bend downwards and never extend to space.
But what if I had a extremely powerful laser, of which its beam is very visible (think the Death Star laser), and shine it parallel to the Earth's surface? Would it extend to space? If it bends, then it contradicts the fact that light cannot bend (yes I know it can bend under certain circumstances, but definitely not now).
Just a few thoughts.
Darren -
If I understand your question, then you are correct. The rod is deceiving, because the weight of the rod itself would cause the rod to bend severely before it got to the next block, much less outer space. However, if you assume a rod with infinite stiffness and no mass, then you could extend it along the surface of the earth in any direction. As the surface of the earth falls away due to its curvature, the rod would extend in a straight line out into space. If it was long enough, you could reach out and touch the moon as it rises or sets.
The laser has its own set of complications. Sure, it would reach outer space - but it would not be perfectly straight. It would bend slightly due to refraction as it leaves the denser atmosphere, and it would also bend slightly due to the earth's gravitational field. These are small effects, but not zero.
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Laser Stars
Laser Teeth Whitening Like Superstars
These days you cannot through a magazine or view a TV show with smiling people with sparkling teeth. This can put a lot of pressure on us to aspire to looking great as we want to look like the stars and get the superstar image but without the budget.
The smiles are simply beautiful. As we get older, our teeth begin losing the whiteness of youth. It can occur from the use of medications, tobacco products and drinks, such as coffee, tea, curry, blackcurrant and even Fruits like Blackberries.
As the effects become more obvious, people begin to lose self-confidence in their smile and in their body image. A feeling of growing old begins to creep up and you find yourself reacting less attractive and youthful. There is hope. The laser teeth whitening system is a way to reinstate that beautiful smile and have you feeling young again.
The laser tooth system is done in a professional's office or in the comfort of your home. The patient has a whitening mixture applied to the teeth. A special ultraviolet lamp is then directed at them to speed up the procedure.
The whitening mixture as a bleaching agent and has long been acknowledged as a safe method for removing superficial stains from them. The process takes about an hour and the effects are immediately obvious.
There are a few things to keep in mind when electing to use the laser teeth method. The first is that patients should have their teeth cleaned by a professional before undergoing the whitening treatment. This ensures that they are free from plaque.
The second is that there may be some side effects. People who have severe tooth decay, have a serious gag reflex and sensitive gums may not be suitable for this treatment. Only your dentist can make the determination, so it is wise to talk with your regular dentist before going in for a laser teeth consultation.
Laser teeth whitening is more expensive than the at home kits, which are comprised of whitening trays, gels or whitening strips. It does require a trip to a expert, but if you consider the cost of the treatment in comparison to the effects and the cost of at home kits, then you may be surprised to see that it is affordable.
Those strips you apply to your teeth can take up to thirty days to show an advance of only a few shades. Laser yields immediate results and can produce six shades difference.
Imagine walking into a Laser teeth whitening specialist's office or a whitening clinic and walking out with a brand new smile. A whiter smile is a thing that most people remember as it catches their eye.
Before spending money on costly whitening trays or strips, at least visit a Laser whitening specialist. He or she can give you an estimate of the total cost of the procedure, and can even show you how many shades whiter your teeth will be after just one session.
About the Author
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The star pattern is caused by the beam diverging in a non uniform manner. You could calculate what that divergence is and it comes out to around 700 milliradians. That is not good, typical divergences on a solid-state laser like that should be less than 1 milliradian. The fact that is is non-uniform and a star pattern is also instructive. It sounds like you've cracked the output coupling mirror or misaligned the laser cavity. There is no fix for that, which is bad news. The good news is that unless the output coupler is so badly cracked it shatters and falls into pieces, it won't get any worse. The bad news is that your laser pointer is essentially useless as a laser pointer.