The Smallest ever seen

Originally posted by @sonhouse
Besides that, the light that enters your eye is delayed in time so even that is not in the strictest sense 'direct'. For instance, to take an unlikely case, suppose we aim a telescope at Mars, we are seeing it a few minutes in the past so if a giant asteroid hit it we wouldn't even know for that few minutes so is that a 'direct' observation?

One could argue we NEVER 'directly' observe anything in the external world (meaning external from one's own mind) in the present because it takes time for light to reach our eyes and time for sound to reach our ears and time for electrical nerve signals from any sense organ to reach our brain and even then, after the signals have entered the brain, it takes time for those signals to be deciphered and processed by the brain so that we then can perceive anything from it.
Only partly because of the finite speed of light (c), we can only observe the physical external world or anything in it as it was in the past and never how it is in the present.
We see only the past, never the present.

Things are even stranger in the Quantum Universe:

YouTube

If light is bounced of off something, then the smallest 'thing' which could be resolved is determined by whatever the smallest unit of light is (namely, the photon); anything smaller than a photon cannot be resolved (by light). If you want to 'see' something smaller than a photon, then you have to bounce something smaller than a photon off of it.

Originally posted by @moonbus
anything smaller than a photon cannot be resolved (by light).

(1) I think that should be more like; "anything shorter in diameter than half a wavelength of a photon cannot be resolved (by light)."

(2) perhaps surprisingly, there is a loophole in the (1) law of physics (which I will explain on request) that may one day be exploited to make an optical microscope see things of lower diameter than half the wavelength of the photons the microscope uses to illuminate the specimen.
That hasn't happened yet but I hope it will.

Originally posted by @humy
(1) I think that should be more like; "anything shorter in diameter than half a wavelength of a photon cannot be resolved (by light)."

(2) perhaps surprisingly, there is a loophole in the (1) law of physics (which I will explain on request) that may one day be exploited to make an optical microscope see things of lower diameter than half the wavelength of t ...[text shortened]... ns the microscope uses to illuminate the specimen.
That hasn't happened yet but I hope it will.

Here is a photo of a single atom, just a dot of light but it is there:

http://bgr.com/2018/02/14/single-atom-photo-strontium-picture-image/

At the very smallest levels, sub-atomic particles do not exist as things anymore; quarks and leptons are not like miniature billiard balls of hard material. They exist as clouds of probability. What we 'see' at this level is only metaphorically related to what someone would see if he looked through a conventional light-microscope at a fly's wing.

Originally posted by @sonhouse
[b]Besides that, the light that enters your eye is delayed in time so even that is not in the strictest sense 'direct'.

Sonhouse is on to something really important. In Quantum non-locality, (the slit theory, etc) the photons can't ever be observed because it would be an "indirect" observation. The light would be reflected off something BEFORE it hits the observers eyes. ! Good job Sonhouse !!

Originally posted by @ogb
Sonhouse is on to something really important. In Quantum non-locality, (the slit theory, etc) the photons can't ever be observed because it would be an "indirect" observation. The light would be reflected off something BEFORE it hits the observers eyes. ! Good job Sonhouse !!

Your profile says you are retired, what was your field of work when you were playing that game?

Originally posted by @kazetnagorra
A photon enters your eye. A neuron goes PING.

Ah, so that explains it... that pinging sound in my head.

Originally posted by @lemon-lime
Ah, so that explains it... that pinging sound in my head.

for me, after 3 beers the Ping starts to diminish..

Originally posted by @ogb
for me, after 3 beers the Ping starts to diminish..

I worked with magnetics, sometimes I was out standing in my field🙂 What was your line of work?

Originally posted by @ogb
I know there must be very powerful microscopes now..but what is the smallest thing ever seen..An atom ? proton ? etc..

When it happens, I fully expect to see someone in that atom with a powerful microscope trying to visualize us.

Originally posted by @whodey
When it happens, I fully expect to see someone in that atom with a powerful microscope trying to visualize us.

We would be too big to see under a microscope.

But even looking through a powerful telescope we might be too big to see. The atom dweller could postulate our existence (and what we are) based on what he is able to see, but I doubt he would be able see us in the same way we are able to see each other.

But if he is indeed able to see us under a microscope, then reality is not what we think it is... such as size being (literally) irrelevant.