> and can be viewed using a microscope capable of 1000x magnification—a technology that has been available for hundreds of years.
I don't think so; maybe 100 years. To achieve 1,000x magnification with an optical microscope, you need oil (or some other fluid with a refractive index similar to that of the lens) between the objective lens and the subject.
I believe the maximum theoretical magnification you can achieve with an optical microscope is about 1,400x. The limit is imposed by the minimum wavelength of visible light.
You can go higher but it won't help you because you won't see more.
https://physics.stackexchange.com/questions/38146/optical-mi...
> ...
> So for violet light λ=405nm, and good lens with oil immersion (NA=1.25), you can have resolution 197nm.
> So, in conclusion, optical microscopes are limited to ~x1500 because going any further does not resolve smaller details.
The comments below the answer add additional details.
Related Wikipedia article (Diffraction-limited system): https://en.wikipedia.org/wiki/Diffraction-limited_system
There are various "tricks" to achieve more -- "Super-resolution microscopy" - https://en.wikipedia.org/wiki/Super-resolution_microscopy
> Super-resolution microscopy is a series of techniques in optical microscopy that allow such images to have resolutions higher than those imposed by the diffraction limit.
According to random online articles, Antonie van Leeuwenhoek (1632-1723) achieved 275x and a few of his instruments have survived until today, in museums, I presume.
You can, of course, magnify as much as you want; but you won't see more detail.
"Junior" microscopes often brag of a 1000x magnification; but that only works if the lenses are really good, and in that kind of microscope, they aren't.
You need 1000x to see bacteria. Bacteria are really boring to look at; they appear as undifferentiated spheres or rods. And even then you can't see them at all without fixing and staining.
Single-lens microscopes suffer from spherical abberation (only the centre of the image is in focus) and chromatic abberation (everything has rainbow fringes around it). These problems are worse with greater magnification.
As far as I can tell, the best "mass-market" compound lenses these days are made in China.
Source: I bought my son a microscope a few months ago; he said he wanted to see bacteria. I hoped a "junior" 'scope would get me off the hook, but I consulted suppliers, and they warned me off, and told me quite a lot about how to choose a 'scope. I also bought him a set of stains and solvents, including a gram-staining kit. I did a fair bit of research before I spent money.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9186497/
https://www.nsf.gov/news/speeches/colwell/rc01_anatlesson/ts...
The idea we can move so far away with such complicated processes without any contamination is just a dream, no matter the precautions we take. We can just limit it to the minimum, which is already quite amazing.
So the israeli ones are just the one we know about.
wikipedia:
They have been found in diverse regions of Earth's biosphere – mountaintops, the deep sea, tropical rainforests, and the Antarctic. Tardigrades are among the most resilient animals known, with individual species able to survive extreme conditions – such as exposure to extreme temperatures, extreme pressures (both high and low), air deprivation, radiation, dehydration, and starvation – that would quickly kill most other known forms of life. Tardigrades have survived exposure to outer space.
We don’t have to leave this hanging as if tardigrades can survive anything; they’re robust but not immortal. The very same article discusses what that sentence about space really means. In the most direct experiment done so far, after 10 days of exposure to the vacuum of space but not solar radiation, a third weren’t able to reanimate, and after that “subsequent mortality was high”. For tardigrades that were exposed to the vacuum and solar radiation “had significantly reduced survival, with only three subjects of Milnesium tardigradum surviving.” Of the Israeli Lunar Lander, Wikipedia says “in May 2021 it was reported that they were unlikely to have survived the impact.” It might be reasonable to speculate and extrapolate based on the 10 day experiment that even if any did survive impact they probably haven’t by now with three and a half years of vacuum, even if they did land in the shadows, right?
https://en.wikipedia.org/wiki/Tardigrade#Survival_after_expo...
Missions to Mars and other planets have much much stricter cleanliness requirements, so much so that it becomes a real barrier to work and cost.
I quite enjoy the idea that some of my DNA is now on the moon.
I'd be interested to know whether that tardigrade image is actually a photo.
Interesting why this comes up now, then.
> I'd be interested to know whether that tardigrade image is actually a photo.
I'd imagine so. This is exactly what they do look like. Though this is the most detailed image I think that I've ever seen, it is not far beyond other images that I know for certain are not renders.
Tardigrades, sure. But they're out there!
;)
In any case, the alleged tardigrades were actually in the “tun state” (dehydrated) and on a 1 cm square piece of tape that was embedded in epoxy resin. Therefore if they were not vaporized by the impact of the crash they would be preserved but unable to reanimate…
This is why NATO has sent several secret resupply missions with solvent, tiny water bottles, and pita bread, in recent years. But so far all attempts to rehydrate the tardigrades have also crashed.
