You should try out the brave browser. Using it on my laptop, I actually thought this was a fine site until I saw the comments, that's how effective it is at blocking some of these anti-consumer patterns.
Huh. I was saved from the ads, but the XSS to Stripe creeps me. Maybe it's an exploit, checking whether I have an account, or am logged in. Or maybe not. But still creepy.
Not necessarily; cameras in general tend to have much worse low light performance than our eyes.
Take, for example, the night sky. You can easily see the stars with the naked eye, but try getting them to show up in a photo. You’ll almost certainly need a long exposure.
He didn't say he saw it with his naked eye though.
However, at least by some metrics, the human eye can detect even a single photon. So if he shut off all other sources of visible light in the room, and sat there for a bit, he should start seeing the light (assuming he's young, red light perception decreases the older you get).
But then, for this to work, the only detail you need on your side is proof that only one atom is emitting light.
It is true that naked eyes can't do long exposures. It is not true that you can't do a long exposure of something that is also visible to the naked eye.
In theory, at least, the atom could be emitting enough light and oscillating over a large enough area that persistence of vision could result in a visible dot to the naked eye.
People can detect (though not very reliably) single photons hitting a photoreceptor or ~7 of them entering the eye once they're totally dark-adapted, so that almost has to be true.
There is a number of trapping techniques for ions (Paul trap, Penning trap) and for neutral atoms (magneto-optical trap, optical tweezer, optical lattice).
In the case of trapped ions, their mutual repulsion keeps them tens of micrometers apart, so one can easily resolve the individual ions on a camera image with modest magnification. This is an image of 9 ions taken by the same group that made the artistic image in the article: https://www2.physics.ox.ac.uk/sites/default/files/imce/248/c...
For neutral atoms one can for example have a tweezer whose trapping region is so small that only a single atom fits inside.
IANAPhysicist, but my guess would be, you set up your atom trap in such a way that conditions/forces/solutions to wave equation/whatever exclude any states except "no atom" and "a single atom".
meta: this is one of those achievements where unsubstantial comment policy is really going against human nature. my initial instinct is to just type 'holy shit' and a line of exclamation marks.
As far as my limited understanding goes, the atom does not strictly have an enclosure like a marble. It's a probabilistic space with nucleus at the centre. So here, are we looking at the nucleus itself?
You are probably thinking of the electron orbitals which describe the spatial distribution of where the electrons are located. Their characteristic length scale is thousands of times smaller than the wavelength of light, so there is absolutely no way of resolving this structure. From an optical perspective an atom simply looks like an infinitely small radiating dipole.
The nucleus itself is again tens of thousands of times smaller than the orbitals. Due to this small size and very high resonance energies, nuclei don't interact with visible light at all.
I don't think nuclei emit any light except when they're either fusing or breaking apart. The light is probably coming from a cloud of excited electrons, a certain number of which have an extremely high probability of existing near each Strontium nucleus.
What does anything have to do the origin of the atom? If it is a single atom, it doesn't have the properties of its molecule. The following sentence makes me think all the article is BS, or the reporter confused a molecule with an atom ---> "Strontium is a soft, silvery metal that burns in air and reacts with water. It's best known for giving fireworks and flares their brilliant red glow, and for being one of the key ingredients in 'glow-in-the-dark' paints and plastics, as it can absorb light and re-emit it slowly. Which is exactly what happened in this photograph."
The choice of atoms in these experiments have a lot to do with the way they interact with light. This is very much related to their behavior in chemistry and paints. Sure, not all properties are the same as for the bulk material, especially if we are talking about metals, but many do carry over.
Small objects are usually hard to see because they scatter small amounts of light. In this case, the ion is illuminated with a laser close to a strong resonance which makes it emit a surprisingly large amount of light (tens of million photons per second). This makes it relatively easy for the camera to detect.
Atoms are about three orders of magnitude smaller than the wavelength of visible light. So for any optical microscope they are just point sources. The finite size spot a camera sees is only due to diffraction from the finite size of the objective. This is also why stars don't appear infinitely small in images.
For those wondering about the word “objective” as it is used above;
> In optical engineering, the objective is the optical element that gathers light from the object being observed and focuses the light rays to produce a real image. [1]
I found this [2] article to be pretty approachable without the jargon overload like Wikipedia often suffers from.
FTA: "The Strontium atom appears larger than its true size because it was emitting light, and was oscillating slightly, over the course of the long exposure."
I believe the journalist misunderstood this point. Trapped ions do oscillate somewhat, but the amplitude should be way below the resolution of this imaging system. Most likely the finite spot size is due to the finite resolution and maybe some blooming from over-exposure.
It's a very accurate way of doing it though. You know exactly where the point source is and ... that it is as close to a point as you're going to get. I wonder if this has an application in optics?
Hehe yeah, but probably hideously expensive, and there are cheaper ways to get real point sources.
Quantum dots are a few nanometers in size (so << the wavelength that they emit) and you can get a solution of them from Sigma Aldrich for ~$500. People mix them into their samples and then use that to deconvolve the image/volume that they acquire.
Thanks for that, (I missed the comment in the article), because my skeptic-o-meter was maxing out. You can see the machining marks on the electrodes. There's even screws to be seen in the photo, which makes the 'atom' about the size of a largish dust particle, using a rough guess.
Advanced microscopes can distinguish individual atoms. This is relatively trivial if you have the correct setup. Search atomic force microscope and HOPG (highly ordered pyrolytic graphene).
This wasn’t the correct setup though to do that. Presumably the reason you can see a single atom is because there is only one present, ie if there was a second one next to it you wouldn’t necessarily be able to see the difference in the photograph.
What does this atom look like? Do you see an atom or do you see light? Of course, all pictures are pictures of light. But there’s a difference between taking a picture of the light coming from a light bulb and a picture of a light bulb, as I am sure you’re aware.
Look at a light bulb when the filament is heated and is emitting light. Then look at it when it is not. The only people who can’t see the difference are blind, literally.
When the filament is cold, you can see it because of light that comes from it after having been reflected off of it, rather than having been emitted from it originally; or, if it's dark on a light background, because of light that comes from other parts of the lightbulb after being transmitted through it from behind. In all of these cases, what you see in the photo is light that came from the lightbulb, and all of them are equally legitimately "pictures of the lightbulb", although they might display more or less detail.
You're looking for the word "glow". People are (somewhat rightfully) piling up on you because all pictures indeed are pictures of light, whether that light is reflected by an inactive lightbulb or is from its powered, glowing filament.
Despite the haters, this is pretty much on the money. This is the light scattered from a single atom that came through the lens and hit exactly just one pixel on the sensor. That dot is (guessing) millions of times larger than an actual single atom.
This is no different in principle than a photo of a starry night sky, where the size of the pixel is far greater than the actual angular size of the object from our vantage point.
This is the most pedantic thing I've ever seen posted on HN.
If an object is illuminated by the sun or by a flashlight, you see the light. When you illuminate a single strontium atom with a laser while it's suspended in an ion trap, you see the light.
Edit: I mean it’s called BigThink; does the flashing adverts (on mobile) between every sentence not make that name a little ironic?