Speaker 1: Welcome to brain Stuff from how Stuff Works, Hey, brain Stuff,
Speaker 1: Lauren Vogel bomb here as far as get rich quick
Speaker 1: schemes go, Stumbling upon gold the end of a rainbow
Speaker 1: sounds pretty delightful, But is it actually possible to get
Speaker 1: to the end of a rainbow? And if so, what
Speaker 1: would you find when you got there. Let's start with
Speaker 1: the bad news. Leprechns are liars. You cannot reach the
Speaker 1: end of a rainbow that appears in the sky. If
Speaker 1: you were to mark on a map the place where
Speaker 1: the rainbow seems to be the land, and then travel
Speaker 1: to that location, you would not be standing inside a
Speaker 1: glorious pillar of colors. There would be nothing there except
Speaker 1: probably the fresh smell of a recent rain shower. To
Speaker 1: understand why this is, we need to look at how
Speaker 1: rainbows form. Rainbows are created when sunlight reflects and refracts
Speaker 1: through water droplets suspended in the air in front of
Speaker 1: you while the sun is behind you. Those water droplets
Speaker 1: act like both a mirror and a prism. A mirror,
Speaker 1: they reflect the sunlight back towards you, but like a prism,
Speaker 1: they also bend and disperse that light. This is because
Speaker 1: rays of light shining through the air change speed when
Speaker 1: they enter a different medium, for example droplets of water.
Speaker 1: This sudden change in speed bends the trajectory of the
Speaker 1: light and disperses white light into the whole roy g
Speaker 1: BIV spectrum. The reason you see a nice ordered gradient
Speaker 1: of colors within a rainbow going from red to violet
Speaker 1: is because this refraction bends each of the different colors
Speaker 1: of light at a slightly different angle. So, for example,
Speaker 1: red light bends at forty two degrees, violet light bends
Speaker 1: at forty degrees, and all the other colors are somewhere
Speaker 1: in between. So, okay, let's find a rainbow. To do this,
Speaker 1: you need to locate your antisolar point. Your anti solar
Speaker 1: point is the point in space that's a hundred and
Speaker 1: eighty degrees or exactly opposite from the sun. A simple
Speaker 1: way to find this is to go outside and look
Speaker 1: for the shadow of your own head. That's your antisolar point.
Speaker 1: Now imagine drawing a line straight from the sun through
Speaker 1: your head to the shadow of your head. Now look up.
Speaker 1: If there is a rainbow to be seen, you will
Speaker 1: find it by facing away from the sun and looking
Speaker 1: forty two degrees above your anti solar point. Notice that
Speaker 1: the apparent location of your rainbow depends on three things.
Speaker 1: Where the sun is, where the water droplets are, and
Speaker 1: where your eyes are. Change any one of those variables
Speaker 1: and you'll see a different rainbow or none at all. So,
Speaker 1: no matter where you see your rainbow, if you try
Speaker 1: to walk out to meet it, you'll be changing the
Speaker 1: variable of your own position, and you couldn't be walking forever,
Speaker 1: or at least until your rainbow disappears. Trying to find
Speaker 1: the end of a rainbow is sort of like trying
Speaker 1: to walk to the end of your own shadow. Somebody
Speaker 1: else could stand at the apparent end of your shadow
Speaker 1: or rainbow, but you will never ever reach this location yourself.
Speaker 1: You can, of course, find earthly rainbows and a waterfall
Speaker 1: or the spray of a sprinkler or hose. You might
Speaker 1: even perceive yourself to be standing right next to one,
Speaker 1: depending on the angle of light coming into the water.
Speaker 1: But here's one more thing. Those rainbows you see in
Speaker 1: the sky aren't actually bows. Rainbows are circular. Usually, when
Speaker 1: you're standing on the ground, most of the rainbow is
Speaker 1: blocked by the horizon. In rare cases, like if you're
Speaker 1: in an airplane, you'll be able to see the entire rainbow,
Speaker 1: rain hoop, rain loop, rain Hole. It's around spectacular beauty,
Speaker 1: but there's an obvious takeaway from this. It doesn't ever
Speaker 1: actually meet the ground anywhere. Today's episode was written by
Speaker 1: Joe McCormick and produced by Tyler Clang. For more on
Speaker 1: this and lots of other light topics, visit our home planet,
Speaker 1: how Stuff Works dot com