Welcome to brain Stuff from How Stuff Works. Hey, brain Stuff, Christian Seger here. Okay, so you have this amazing idea to start your own business, a licorice themed food truck. You got liquorice Ravioli, licorice gumbo. It's genius, right, But the bank turned you down and your Kickstarter campaign failed the fund. Fortunately, you know where you might be able to find a large stash of gold if you can only get to the end of this rainbow you've been
following for six hours. But wait a minute, is it actually possible to get to the end of a rainbow? And if so, what will you find when you get there? Let's start with the bad news. Sorry, everyone, lepre cons are liars. You cannot reach the end of the rainbow. If you were to mark on a map the place where the rainbow seems to meet the land, and then travel to that location, you would not be standing inside
a glorious pillar of colors. There would be nothing there except probably the fresh smell of a recent rain shower. To understand why this is, we need to look at how rainbows form. Rainbows are created when sunlight reflects and refracts through water droplets suspended in the air on the opposite side of you from the sun. Those water droplets act like both a mirror and a prism. Like a mirror, they reflect the sunlight back towards you, but like a prism,
they also bend and disperse the light. This is because rays of light shining through the air change speed when they enter a different medium, for example water. This sudden change in speed bends the trajectory of the light and disperses white light into the whole roy g BIV spectrum. The reason you see a nice ordered gradient of colors within a rainbow, going from red to violet is because this refraction bends each of the different colors of light
at a slightly different angles. So, for example, red light bends at forty two degrees, violet light bends at forty degrees, and all the other colors are somewhere in between. So all right, let's find a rainbow. To do this, you need to locate your anti solar point. That your anti solar point is really just the point in space that's a d eighty degrees or exactly opposite from the sun. A simple way to find this is to go outside
and look for the shadow of your own head. Now imagine drawing a straight line in three dimensions from the sun through your head to the shadow of your head. Now look up. If there is a rainbow to be seen, you will find it by facing away from the sun and looking for an arc forty two degrees above that line from the sun to your anti solar point. Notice that the apparent location of your rainbow depends on three things. Where the sun is, where the water droplets are, and
where your eyes are. Change any one of those variables and you'll see a different rainbow or none at all. So no matter where you see your rainbow, if you try to walk out to meet it, you'll be changing the variable of your own position, and you could be walking forever, or at least until your rainbow disappears. Trying to find the end of a rainbow is sort of like trying to walk to the end of your own shadow. Somebody else could stand at the apparent end of your rainbow,
but you will never ever reach this location yourself. But here's another thing. A rainbow isn't actually a bow. Rainbows are circular. Usually, when you're standing on the ground, most of the rainbow is blocked by the horizon. In rare cases, like if you're in an airplane or something, you'll actually be able to see the entire rainbow as a round, spectacular beauty. But there's an obvious takeaway from this. It doesn't actually meet the ground anywhere. There's just the altitude
where you can't see it anymore. Despite all this science that is quite well understood, you're going to find plenty of people on the Internet swearing up and down that they have found the end of a rainbow. And look, I don't know what to tell you. I'm not sure what's up with that. Check out the brain stuff channel on YouTube, and for more on this and thousands of other topics, visit how stuff works dot com.