How far can the human eye actually see into space, considering areas of utter darkness and other areas that are iluminated by stars. What is the finite distance most people can see before they are blind by distance?
The eye isn't "blinded by distance" as such... An object bright enough at the CMBR surface (13? billion light years away) would be visible to the naked eye (if there was nothing in the way). Is the Andromeda galaxy the furthest visible object? It's 2 million light years away. There may be more distant visible things - I'm not sure.
Range of sight is not actually determined by distance, but by the brightness of whatever it is you're looking at. The unaided human eye can see a few thousand stars - in other words, not very many at all. Using an optical instrument such as binoculars or a telescope allows you to see more not because the instrument magnifies things, but because it collects more light than the unaided eye. I'm not sure what the furthest object is which is visible with the naked eye. We can see, faintly, neighbouring galaxies in our local group, which are perhaps a million light years away.
I just checked. M31 (the Andromeda galaxy) and M33 (another spiral galaxy) are the most distant things visible to the naked eye, both at about 2 million light years. That's almost 20 thousand million billion kilometers.
Humans can actually descern a single photon under the right circumstances thus giving us infinte range.
Really? I've heard that a single photon can trigger a lab-detectable response in a rod cell, but I don't think that counts as "seeing".
It comes from my introduction to psychology book and states that it is a conscious response in human test subjects under specific test conditions and a large error range.. Ill have to lookup the reference (which box was that book in)...
That's impressive. I'll file it in my "it could be true" compartment. Don't worry about the reference, it's not critical knowledge for me Please Register or Log in to view the hidden image!
even though andromeda is so far away, it is actually one of the closest messier objects and is our galaxy neighbor so to speak
Pedantry of the week Please Register or Log in to view the hidden image! While Andromeda is one of our closest neighbouring galaxies, most Messier objects are nebulas and clusters within our own galaxy. Less than 40 of the 110 objects in the Messier catalog are more distant than Andromeda.
