how can you see an infared beam with the naked eye?
484806
infa-red is before the red part of the spectrum meaning you can't see it and you can only feel it if it is of the right set of frequencies.
985833
I think I understand your experiment.  I'm standing at the anulus observing.  I see the light from the lighthouse.  Exactly one second later, I see the next flash of light from the lighthouse, no matter the radius of the anulus.  To satisfy (1) the perimeter of the anulus must be 186,000 miles, the diameter 186,000 miles / pi or 59,206 miles, and the radius d/2 = 29,603 miles.  That's about 7.47 times the earth's radius.  For (2), if you double the radius, you double the circumference.  Keeping the time the same, that doubles the speed.  You already knew that.\n\nFor (3), at the lighthouse you see the reflection of the lighthouse beam.  To reduce confusion, you could do what real lighthouses or bouys sometimes do:  alternating rotations are a different color.  But what you would see is the reflection, but delayed by 1/pi seconds, or 318 milliseconds.\n\nI'm guessing at your response.  At z=2D, this 'intersection' is travelling at twice the speed of light.  There's no physics problem with that.  It's not conveying either matter or information faster than the speed of light.  You have just contrived two events closer in time to each other than the time light would take to go between them.
988345
Almost any light can be seen from space. It just depends on what kind of telescope you have.\n-Brandon Everett Spurgeon
265230
dust\nDon't use a mirror to look at a laser. don't use anything to look at a laser unless you know what you are doing. not even one of those 'meeting pointers'. it could very easily damage your eye and cause blindness. don't even shine a laser at an object that is not intended to receive laser energy. you could crash a plane or hurt or kill someone else.
329395
Well, first, you have to be specific about what energy.\n\nIf you are standing in a room where your body tempature is greater than the surrounding air, then you are radiating heat, which the naked eye cannot see. However, you can transfer this energy: for example, in the cold, a herd of animals will draw in close and rub against each other to share body heat and reduce exposure to the elements.\n\nThe human body does not emit light, however it does reflect it (otherwise you couldn't see someone). Your eye, obviously, can see light reflected from objects. You cannot transfer light to someone else, in the sense you're probably thinking of.
313864
Use a plasma beam... God havent you seen ghostbuster.
762620
What you see are particles of dust in the air, illuminated by the projector's beam.
617356
Something about beam misalignment\n\nhttp://www.reference.com/search?db=web&q=jogged%20beam
1110039
Yes, you need a carefully set up arrangement with coherent monchromatic light to see it clearly.\n\nAbsurdly, the Poisson spot was named because Poisson said it was plainly absurd and could not occur. He claimed this predictions of Fresnel's theory of light basically proved Fresnel completely wrong. But it was Poisson who was wrong. Yet Poisson who was remembered.\n\nThere is a lesson there. Just not a good one.
1127088
You should watch the episode of mythbusters where they try to build a death ray with mirrors and need a focal point, they make a mirrior in a contact sorta shape and the light focases on it. if you could make a solar cell like that maybe it would work. The episode was on all weekend, it might be helpful for some other things too!
1066323
u see darkness because light isn't present. Not whether is it possible to look at nothing.
322915
No.  A laser beam, for example, can pass right through another laser beam as if it weren't there.  Light does not block other light.  You can easily see through a beam of light, unless there is a lot of particles in the air which scatter the light and dazzle you.  When you look at something you don't normally see the light in the room crossing your line of sight, only the light which goes directly into your eyes.\n\nThose laser beams you see in space in the movies?  That's just Hollywood.  In reality you couldn't see the beam from the side - light is completely transparent.
455121
I think the other answerers have a few misconceptions.\n\nThe problem with your question is the use of the word "seen."\nSo I will answer your question in two parts.\n\n1) The best visible wavelength (optical) microscopes cannot see atoms. The best they can probably do, is see some of the fine detail of biological cells, nothing more.\n\n2) Using the term loosely, electron microscopes or atomic force microscopes can "see" atoms, and even electron clouds, but one should not take the word "see" too literally.\n\nAn atomic force microscope works by moving a very fine tip  over a sample. Without going into the specifics of it, a computer can build up a model of the shape and dimensions of atoms in the sample by measuring the forces that the atoms exert on the tip.\n\nSo I will state the answer to your question as this:\n\nWe CAN OBSERVE computer images of atoms; by this i mean that we can view computer images of atoms - but these are more like graphs of interatomic forces than actually viewing atoms.\nThe highest precision that can currently be achieved is viewing the electron clouds of various atoms. We cannot directly observe anything smaller than this.\n\nSo, you might ask, how do we know about the existence of particles like electrons, protons, neutrons, or even quarks?\nWell, that's because their existences can be inferred from various experiments.\n\nE.G. Rutherford's Alpha Scattering experiment showed that atoms consist of mostly empty space (in support of our massive nucleus and electron clouds model)\n\nAnd particle physicists can use devices a bit like cloud chambers to "observe" fundamental particles like quarks by accelerating e.g. protons high speeds and then making them crash into each other. This liberates particles smaller than protons, giving evidence for the existence of quarks.\n\nHowever, these particles are "observed" by the effect that they have on the surrounding medium, not by direct observation.\n\n\nSo to sum up, the atomic force microscope is the best microscope for "viewing" atoms, but don't take this literally. It's resolution allows us to examine the electron clouds of individual atoms.\n\n\nAlso note that "Electron clouds" is also not to be taken too literally, as anyone who knows anything about quantum mechanics will tell you.
993183
First you will need to know when it will pass over. You can see where it is now at this website.\n\nhttp://spaceflight1.nasa.gov/realdata/tracking/\n\nAt night, when the sun hits it at the right angle, the station appears as a fairly bright bluish white light. It does not flash like an airplane, and takes roughly three minutes or so to traverse the sky.\n\nIf it's bright enough you can see it with the naked eye. You may also use binoculars but you may not be able to make out any detail without a telescope (which wouldn't be easy to get a lock on the station with because it moves so fast).
833030
Actually, a light beam is invisible as well, unless it's shined directly into our eyes.  A light beam is visible in a dusty room, and a magnetic field is also visible when loose iron filings are present.  The reason why magnetic fields seem invisible to us is merely because our eyes aren't tuned to pick up magnetic fields, but that does not say that it's impossible to devise an artificial eye that can "see" such magnetic fields.
293728
At the speed of light you gain infinite mass so the light beam from a headlight must go faster than light to escape the headlight it's self.If the beam could be a higher energy of light like gamma rays and if you could see a gamma ray which human eyes can't then maybe you'd see something. The question is will they come on,yes because\nthe electricity will flow through the filament of the bulb so it's on but can you tell by eye?No,because it would take forever for the light to reach your eye at equal speeds.
115588
look at a really really bright light