# Smallest thing we can see. **URL:** \ **Category:** Factual Questions\ **Created:** [March 12, 2004, 4:13am UTC](https://boards.straightdope.com/t/smallest-thing-we-can-see/233847 "2004-03-12T04:13:17Z")\ **Posts on this page:** 11\ **Page:** 1
**Author:** ![cmonidareya](https://avatars.discourse-cdn.com/v4/letter/c/ecd19e/32.png) [@cmonidareya](https://boards.straightdope.com/u/cmonidareya)\ **Post date:** [March 12, 2004, 4:13am UTC](https://boards.straightdope.com/t/smallest-thing-we-can-see/233847/1 "2004-03-12T04:13:17Z")
What would be the smallest thing we could physically possible magnify in order to see? I am asking theoretically. Not what we are capable of now, unless that is as far as we can go. ---
**Author:** ![Q.E.D](https://avatars.discourse-cdn.com/v4/letter/q/51bf81/32.png) [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)\ **Post date:** [March 12, 2004, 4:22am UTC](https://boards.straightdope.com/t/smallest-thing-we-can-see/233847/2 "2004-03-12T04:22:48Z")
If you mean the smallest things we can see optically, that would probably be the smaller bacteria, since optical microscopes are limitied to a useful magnification of around 1200x. That would be “seeing” in the traditional sense. If you count electrom microscopes, then we can “see” individual atoms. ---
**Author:** ![cmonidareya](https://avatars.discourse-cdn.com/v4/letter/c/ecd19e/32.png) [@cmonidareya](https://boards.straightdope.com/u/cmonidareya)\ **Post date:** [March 12, 2004, 4:46am UTC](https://boards.straightdope.com/t/smallest-thing-we-can-see/233847/3 "2004-03-12T04:46:33Z")
Well, I meant not just optically, but magnifying the image to view on a screen ( a la an electron microscope). Could we develop technology to see something smaller than an individual atom? What would the technology involve? I know there is probably a physical limit to what we can achieve, have we achieved it? ---
**Author:** ![Bob55](https://avatars.discourse-cdn.com/v4/letter/b/e9c0ed/32.png) [@Bob55](https://boards.straightdope.com/u/Bob55)\ **Post date:** [March 12, 2004, 5:04am UTC](https://boards.straightdope.com/t/smallest-thing-we-can-see/233847/4 "2004-03-12T05:04:46Z")
Well like QED said it depends on what you mean. Optically you can see a spec of dust which is probably about .01 millimeters (or 10,000 nanometers for comparison below). Below that we are limited by the wavelength of light used. Resolving power of a microscope is half of the wavelength of the light used, so a light microscope, using visible light, is restricted to 400 nm / 2 = 200 nm resolving power, which is the size of the smallest bacteria. Human cells are ~1000 nm so even some of their intracellular pieces are resolved, but viruses are usually 30 - 100 nanometers which is just too tiny. The electron microscopes QED mentioned, using electrons with short wavelengths, have excellent resolving power and can evidently see individual atoms in some materials. The ones I’ve used only went up to ~60,000 magnificiation which allowed us to see slight detail on a 30 nanometer virus, but that was it. You can of course combine 1000 of these images to improve resolution. The field I work in, X-ray crystallography, uses X-rays to determine atom placement in molecules and proteins. The X-ray wavelength used is usually 0.97 to 1.54 angstroms, so I guess theoretically the resolution limit is 0.5 angstroms, but you rarely see protein structures published below 2 angstroms. But this is enough to resolve individual atoms and place water molecules. ---
**Author:** ![Starving\_Artist](https://avatars.discourse-cdn.com/v4/letter/s/aeb1de/32.png) [@Starving\_Artist](https://boards.straightdope.com/u/Starving_Artist)\ **Post date:** [March 12, 2004, 5:09am UTC](https://boards.straightdope.com/t/smallest-thing-we-can-see/233847/5 "2004-03-12T05:09:11Z")
What do atoms look like in an electron microscope? Do you only see the nucleus as the electrons are whizzing around too quickly to see. I’ve seen photos on occasion where the caption says I’m looking at atoms (or maybe molecules), but what I see is something that looks like a group of blurry globes. ---
**Author:** ![Joe\_Random](https://avatars.discourse-cdn.com/v4/letter/j/e8c25b/32.png) [@Joe\_Random](https://boards.straightdope.com/u/Joe_Random)\ **Post date:** [March 12, 2004, 5:33am UTC](https://boards.straightdope.com/t/smallest-thing-we-can-see/233847/6 "2004-03-12T05:33:57Z")
> [@cmonidareya](#): > > Well, I meant not just optically, but magnifying the image to view on a screen ( a la an electron microscope). The thing is, you’re not magnifying an image at all. Electron microscopes probe the specimen with an electron beam and display the obtained data in a visible format. > [@Starving Artist](#): > > What do atoms look like in an electron microscope? Do you only see the nucleus as the electrons are whizzing around too quickly to see. Nope. Electrons don’t “whizz around the nucleus”. In fact, electrons do not exist as distinct objects in the classical sense, instead existing as a sort of probability wave. > [@Starving Artist](#): > > I’ve seen photos on occasion where the caption says I’m looking at atoms (or maybe molecules), but what I see is something that looks like a group of blurry globes. Which is exactly what you’d expect. Electron microscopes work by bombarding the atoms with (surprise!) electrons. Since like charges repel, the electron “shell” of the atoms under observation reflects the incoming electron beam. ---
**Author:** ![Squink](https://avatars.discourse-cdn.com/v4/letter/s/b5e925/32.png) [@Squink](https://boards.straightdope.com/u/Squink)\ **Post date:** [March 12, 2004, 5:40am UTC](https://boards.straightdope.com/t/smallest-thing-we-can-see/233847/7 "2004-03-12T05:40:29Z")
Here’s a nice picture of [carbon atoms in graphite](http://www.physics.purdue.edu/nanophys/stm.html) taken with a scanning tunneling microscope. Purdue’s [Pictures of Small Things](http://www.physics.purdue.edu/nanophys/pictures.html) has many pictures of small things taken with various sorts of microscopes. ---
**Author:** ![Bob55](https://avatars.discourse-cdn.com/v4/letter/b/e9c0ed/32.png) [@Bob55](https://boards.straightdope.com/u/Bob55)\ **Post date:** [March 12, 2004, 5:50am UTC](https://boards.straightdope.com/t/smallest-thing-we-can-see/233847/8 "2004-03-12T05:50:28Z")
> [@Starving Artist](#): > > What do atoms look like in an electron microscope? Do you only see the nucleus as the electrons are whizzing around too quickly to see. I’ve seen photos on occasion where the caption says I’m looking at atoms (or maybe molecules), but what I see is something that looks like a group of blurry globes. I know what you’re talking about, I’ve seen similar pictures. One that comes to mind resembles that egg crate thing I sleep on. Well [here](http://www-structure.llnl.gov/Xray/tutorial/Maps/tyr_mit.gif) is what atoms look like to an X-ray Crystollogropher. The blue is the electron density map (where the X-rays struck an electron) and the stick model was of course inserted via computer. ---
**Author:** ![Bob55](https://avatars.discourse-cdn.com/v4/letter/b/e9c0ed/32.png) [@Bob55](https://boards.straightdope.com/u/Bob55)\ **Post date:** [March 12, 2004, 5:51am UTC](https://boards.straightdope.com/t/smallest-thing-we-can-see/233847/9 "2004-03-12T05:51:50Z")
> [@Squink](#): > > Here’s a nice picture of [carbon atoms in graphite](http://www.physics.purdue.edu/nanophys/stm.html) taken with a scanning tunneling microscope. **Squink** found that picture of the [egg crate](http://www.physics.purdue.edu/nanophys/images/hopg3d-1.jpg) I mentioned. Thanks! ---
**Author:** ![Starving\_Artist](https://avatars.discourse-cdn.com/v4/letter/s/aeb1de/32.png) [@Starving\_Artist](https://boards.straightdope.com/u/Starving_Artist)\ **Post date:** [March 12, 2004, 5:52am UTC](https://boards.straightdope.com/t/smallest-thing-we-can-see/233847/10 "2004-03-12T05:52:22Z")
Joe Random, thank you for the explanation, and Squink, thanks for taking the trouble to supply the picture links. Damn, I love this board. It’s like you can find out…you know…_anything_! ---
**Author:** ![Starving\_Artist](https://avatars.discourse-cdn.com/v4/letter/s/aeb1de/32.png) [@Starving\_Artist](https://boards.straightdope.com/u/Starving_Artist)\ **Post date:** [March 12, 2004, 5:55am UTC](https://boards.straightdope.com/t/smallest-thing-we-can-see/233847/11 "2004-03-12T05:55:11Z")
Oh, and thanks, too, Bob55. Your post came in while I was answering the other two. Thanks also for the very interesting link.