51–60 of 88 posts
This makes me think of Voyager 1's pale blue dot photograph. https://upload.wikimedia.org/wikipedia/commons/7/73/Pale_Blu... I find the parallel awesome.
This makes me think of Voyager 1's pale blue dot photograph. https://upload.wikimedia.org/wikipedia/commons/7/73/Pale_Blu... I find the parallel awesome.
How do they know it's a single atom?
View it here in actual life size on your display. http://beta.lifesizer.com/view?user=5&ref=_59&h=1080&w=1920 Edit: based on seeing it in actual size, I would say it would be hard to see it with the naked eye, that said as pointed out in other comments, I suppose not impossible if a human eye can detect a single photon.
View it here in actual life size on your display. http://beta.lifesizer.com/view?user=5&ref=_59&h=1080&w=1920 Edit: based on seeing it in actual size, I would say it would be hard to see it with the naked eye, that said as pointed out in other comments, I suppose not impossible if a human eye can detect a single photon.
Is the light refracting to make the atom appear bigger than it actually is?
A scanning electron microscope, or an x-ray crystallography based machine, uses items with much smaller wavelengths, .01 - 10 nm in the case of x-rays and so they're able to peer inside an atomic structure.
I'm imaging that the process of "magnifying" objects through photography has to degrade the true representation of the object. Kind of like expanding 1 pixel to cover a 500x500px space. In that sense I wonder how clearly we can ever hope to see an atom. Obviously the technology and intent is impressive, but will we ever be able to see an atom more clearly or is it simply too small to be seen without Photoshopping in…
The problem is that of scale: visible light has a wavelength of 380-750 nm (10^-9 meters) while the atomic radius of even large atoms are still in the ~200 pm (10^-12m) which means that visible light still has a wavelength 1000 times that of an atomic radius. To peer more closely at an atom, you would need to be able to use something moving at a much smaller wavelength, like an x-ray or a focused beam of electrons.
Earlier quoted context omitted.
> Even if the exposure were for a year, if the amount of light being emitted is less than the hardware can perceive, it wouldn't register That is not true. It might be noisy, but it would show up. In point of comparison the human eye can see a single photon. A single atom can emit a single photon, ergo you can see a single atom. You won't get any detail out of it obviously, but you'll see it as a dot of light. That's…
If we're seeing the single photon emitted by a single atom, then how much larger is the spot of light in the image compared to the atom that emitted it? Why isn't there a ruler somewhere in the picture? My brain is absolutely failing to make sense of the scales and sizes in this image.
The atom is about 255 picometers, the light is around 400 nanometers. That makes the light around 1500 times larger than the atom.
(Which also helps explain why visible light can not distinguish atoms placed close together - it's so much larger than them.)
> Why isn't there a ruler somewhere in the picture? My brain is absolutely failing to make sense of the scales and sizes in this image.
The two electrodes are about 2mm apart. About the width (not length) of a sesame seed. It's really small. The photo was taken through a microscope.
Another point of reference: the width between the electrodes is about 5,000 times the wavelength of the light being emitted.
In theory, if you had a good enough camera, the dot of light would be around 1/5000 of the width. (However the diffraction limit of your lens might enter into play, blurring the image.)
And finally, the width between the electrodes is about 8,000,000 times the size of the atom.
Earlier quoted context omitted.
No, that's not it. Just because it is small, doesn't make it invisible. You can't see single atoms because they normally don't send any light toward you. But if they did, and this one is, you would see that light. You aren't seeing the atom exactly, you are seeing what it sends toward you, and the human eye can see single photons. (And so can cameras.)
> No, that's not it. That has to be at least partially it for the rest of your comment to be right (which it is!). To say the atom was "held nearly motionless" is to say it moved a little during the exposure. It sent the light toward the sensor from all of its positions.
No, not at all. The wavelength of the light is about 1,500 times larger than the atom emitting it. So the atom would need to move at least 1,500 diameters to make any difference in the light.
It doesn't move that much.
I'm assuming the two ball-pen nib shaped structures on both sides of the spec in the picture are "two metal electrodes placed about 2mm (0.078in) apart". So, the space between the left tip of the electrode and left edge of the spec is about 1 mm. Based on some "visual calculation" (zooming in the picture and doing some approximation), the spec seems to be closer to about 0.03 mm across, which is orders of magnitude larger than 438 pm that it should be. What gives?