569 views

3:06

Watch
- Search Videos
  
  Advanced search »
- Submit a New Video
Discuss
About
- Try clicking on the various channels to see videos posted to that channel - if you're into music you can click the Music channel to get more music sifts - go on and explore! Use the "hotness" when you have opened the channel link to get videos that have gotten a lot of votes, or use "newness" to have a look at the new sifts.
  When browsing sifts you like, have a look at the Related Posts list to see other related videos, click the tags under the video title to see more sifts tagged with the same tags or have a look at other sifts from the same user in the More Posts By list. If the sifted video is in a play list, have a look at the play list to see other interesting videos the Sift users have linked together.
  Enter the Sift Lounge to chat with online sifters about anything and everything, or read interesting posts in the Sift Talk forum.
  The Top New Videos list is always full of interesting, current videos. It is always recommended that you have a look through the Top New Videos, but also have a look at these:
  - Upcoming Unsifted Videos - active video submissions that neither are published to the front page nor archived to the submitter's personal queue
- Have you seen a really funny, surprising, scary, interesting, cute or in any other way extra good quality video?
  Post and share it here - VideoSift is the best video aggregator on the Web, where we share, discuss, promote, and interact with the best videos out there on the web. Post it here, and share it with the large community of video-interested users. And - you are guaranteed to find more very good videos here already!
  Mind you, we only share videos you discover that someone else has made; if you "self link," by posting a video you have made, have posted or have interests in, you risk the ban hammer - read the posting guidelines before posting. The sift is NOT for promoting your own videos - it is for sharing videos others have made.
  Submit a Video Now »
Login

What Can Frogs See That We Can't?

submitted by Aard Vark

(oritteropo)
1 decade 1 year 8 months 2 weeks ago

YouTube Description:

What would you see if you were drifting through space, looking back at the sun? Well its light intensity would decrease as the inverse square of distance from the sun. And you would imagine the intensity would decrease smoothly, asymptotically approaching zero.

But this is not what happens.

If you had sensitive enough eyes, like frogs' eyes, you would find that at some point the sun would start to flicker. You would see flashes of light separated by complete darkness. And as you drift further from the sun, what's strange is that these flashes do not decrease in brightness, but they do become less frequent. That's because light comes in lumps, called quanta or photons, which are indivisible. So if you try to spread light out very thinly, you reach a point where there are only single bits of light reaching an observer's eye at any given time.

I should acknowledge the book "The Fabric of Reality" by David Deutsch, which contains a similar story about a frog and a torch. It inspired me to make this film. Thanks also to MinutePhysics for reviewing earlier drafts and suggesting I make it more ridiculous.