Almost everyone has trouble visualizing the very large and the very small. Adding zeroes or exponential notation or 'order of magnitude' doesn't really help for visual learners. So here's a nice description of relative size.
In this perspective, aliens who want to find Earth have to scour Manhattan Island, looking for...nope, not just a quarter. Not just the O on the quarter, because that's the stars we can see, about 2000 light years in diameter. No, they need to find the tiny dot (perspective: about the size of a red blood cell), inside the O, that represents our solar system. And then...
...they need to find the tiny dot that is Earth, within the system.
[Note: the planets' sizes are to scale, and the distances from the Sun are to scale, but the two scales are not the same. On the 'distance' scale, the Sun would be smaller than a pinhole. The planets....nope.]
Worth noting: given that the speed of light is limiting, finding Earth would be a trifle difficult because the evidence of intelligent life---our radio signals---only go out about 200 light years. On the Manhattan Island/quarter scale of the universe that's another pinhole. A small pinhole.
"General Glyzztx, we have found intelligent life! it's on a planet that the inhabitants call Earth!"
"Well done, Colonel Prrnsaa-AH, but how did you find it?"
"Absolute random luck, sir. We just happened to pass through a volume of space through which radio signals were being emitted."
In this perspective, aliens who want to find Earth have to scour Manhattan Island, looking for...nope, not just a quarter. Not just the O on the quarter, because that's the stars we can see, about 2000 light years in diameter. No, they need to find the tiny dot (perspective: about the size of a red blood cell), inside the O, that represents our solar system. And then...
...they need to find the tiny dot that is Earth, within the system.
[Note: the planets' sizes are to scale, and the distances from the Sun are to scale, but the two scales are not the same. On the 'distance' scale, the Sun would be smaller than a pinhole. The planets....nope.]
Worth noting: given that the speed of light is limiting, finding Earth would be a trifle difficult because the evidence of intelligent life---our radio signals---only go out about 200 light years. On the Manhattan Island/quarter scale of the universe that's another pinhole. A small pinhole.
"General Glyzztx, we have found intelligent life! it's on a planet that the inhabitants call Earth!"
"Well done, Colonel Prrnsaa-AH, but how did you find it?"
"Absolute random luck, sir. We just happened to pass through a volume of space through which radio signals were being emitted."
