I Color and appearance of a "pile" of biological viruses

[Skaperen]

TL;DR Summary

If there is a "pile" of biological viruses where the pile is way large enough to be seen, optically, what color might this "pile" have?

Normally, an electron microscope would be needed to "see" a biological virus or other objects of this size scale because they are so much smaller than wavelengths of light we can see with our red/green/blue sensitive eyes (700 nm down to 400 nm) at any magnification of an optical microscope. What I have been wondering about is a "pile" of viruses (under a vacuum to avoid any "floating" away) of size, perhaps 1 cm by 1 cm is what the "pile" might look like. would it absorb light and thus look black or would it reflect light and look white? could it have color?

 

[Baluncore]

A thin film of viruses, with thickness similar to the wavelength of light, would have a colour determined by the thickness of the film and the spectrum of the illumination.

If the film was thick, you would see the colour of the virus coat, or the hydroxides that would bond to it in air, so I guess a creamy yellow.

 

[A.T.]

I guess a creamy yellow.

MailOnline went with olive oil style, while The Sun prefered sugar like:

 

[sophiecentaur]

TL;DR Summary: If there is a "pile" of biological viruses where the pile is way large enough to be seen, optically, what color might this "pile" have?

would it absorb light and thus look black or would it reflect light and look white? could it have color?

Just how you'd get hold of a teaspoonfull of 'viruses' could be a serious practical problem and require some degree of expertise. But optical spectroscopy is a way of detecting various chemical compounds. The visibe colour would probably (as with beef stock) be pretty non-descript, once the emerging light is passed through a spectrometer, there will probably be recognisable bands of absorbed wavelengths corresponding to common compounds.

 

[256bits]

TL;DR Summary: If there is a "pile" of biological viruses where the pile is way large enough to be seen, optically, what color might this "pile" have?

what the "pile" might look like. would it absorb light and thus look black or would it reflect light and look white? could it have color?

Depends upon if the virus clump is crystalized or not.
For example, sugar, salt are clear when crystalized, but white when seen as a powder.
In geology, the test for certain minerals is the color of the streak test, which is the color of the powder form, as opposed to the crystalized form.

The above are 'simple' compounds compared to the chemical nature of viruses, so it isn't clear what one would see of the viruses - a much more complex makeup of chemicals - in crystalized form, where transmission, absorption, and reflection ( internal from inside the body, as well as external from the surface ), or in powder form where the light coming back to your eyes is scattered. The terms are specular and diffuse lighting from a flat or rough surface.
Also important is the location of the lighting source. For a comparison, clouds normally look white or dark, but at a particular location of the light source, internal reflections of the light within the water droplet produces many colours known as a rainbow.

Nonetheless, viruses have been grouped together and studied for quite some time.
Some virus groupings can form crystals, while others not.

I take you to Wiki for more info.
The site does show a picture of the tobacco virus crystal in two forms. Both crystals appear metallic, with one having a more gold appearance, and the other more steel like in my opinion.
https://en.wikipedia.org/wiki/Virus_crystallisation
Although, it should be said, the technique for study is uses X-ray crystallography, not visable light.
Even so, the pictures are of a virus crystal through a compound microscope.

Size of crystal.
Here they say up to 0.5 mm, and they all look similar to the salt crystals.
https://www.researchgate.net/figure...he-presence-of-either-a-high-PEG_fig2_6362485
I imagine some crystalizing solution to be be entrained within.

 

[DaveC426913]

Nonetheless, viruses have been groped together and studied for quite some time.

The scientists responsible have been sacked.

 

[256bits]

The scientists responsible have been sacked.

Not sure what you mean.

 

[Ibix]

Not sure what you mean.

There's a typo in the sentence of yours that Dave quoted.

 

[256bits]

There's a typo in the sentence of yours that Dave quoted.

Fixed,
A new batch of scientists hired replacing that nasty bunch.

 

[tech99]

TL;DR Summary: If there is a "pile" of biological viruses where the pile is way large enough to be seen, optically, what color might this "pile" have?

Normally, an electron microscope would be needed to "see" a biological virus or other objects of this size scale because they are so much smaller than wavelengths of light we can see with our red/green/blue sensitive eyes (700 nm down to 400 nm) at any magnification of an optical microscope. What I have been wondering about is a "pile" of viruses (under a vacuum to avoid any "floating" away) of size, perhaps 1 cm by 1 cm is what the "pile" might look like. would it absorb light and thus look black or would it reflect light and look white? could it have color?

I think that the strongly coloured crystals are of ionic compounds, such as Copper, Iron and Cobalt. This seems to be because the ions are electrically charged and so will respond to a passing EM wave, which can induce electron resonances. On the other hand, co-valent compounds are often not coloured, and their response to an EM wave would then be due to asymmetry, such as with the water molecule, or CO2. Some metals are coloured, due to electron resonances. As a virus is a piece of DNA, and DNA is, so far as I know, a co-valent compound, I would expect it to be largely colourless. Of course it will disturb a passing light ray because its permittivity will differ from that of free space, but I would not expect to find significant resonance effects to create colour.

 

[256bits]

The coloured images are made with polarized light apparatus, so that could the reason also, besides impurities.

See
http://www.hyperphysics.phy-astr.gsu.edu/hbase/phyopt/polint.html