DISTORTIONS

YouTube FanFest with HP in Mumbai: http://www.youtubefanfest.com/india/
Follow me: https://twitter.com/tweetsauce SOURCES BELOW

Guy (editor/production): https://twitter.com/guylar

music from: http://www.youtube.com/JakeChudnow and http://www.audionetwork.com

Celestia 3D space software: http://sourceforge.net/projects/celestia/

Another great visualization of star locations in 3D space: http://moebio.com/exomap/viewsofthesky/2/

minutephysics video about why it's dark at night: http://www.youtube.com/watch?v=gxJ4M7tyLRE

my video on moving illusions: http://www.youtube.com/watch?v=Iw8idyw_N6Q

rolling shutter effect: http://www.diyphotography.net/everything-you-wanted-to-know-about-rolling-shutter

Rolling shutter media:

guitar strings: http://www.youtube.com/watch?v=TKF6nFzpHBU
http://boingboing.net/2010/08/20/explain-this-photo.html
http://imgur.com/YQrBF
http://upload.wikimedia.org/wikipedia/commons/1/15/Rolling_shutter_effect_animation.gif
http://en.wikipedia.org/wiki/Rolling_shutter
http://www.youtube.com/watch?v=Fg9Ph53ka2I

Big Dipper 3D: http://upload.wikimedia.org/wikipedia/commons/b/b9/Astro_4D_uma_rg_anim.gif

Voyager: http://voyager.jpl.nasa.gov/where/

angular diameter of celestial objects:

http://danbliss.blogspot.co.uk/2011/07/deep-space-to-scale.html
http://apod.nasa.gov/apod/ap061228.html
http://mikkolaine.blogspot.co.uk/2014/01/size-of-deep-sky-objects-compared-to.html
http://www.slate.com/blogs/bad_astronomy/2014/01/01/moon_and_andromeda_relative_size_in_the_sky.html

rolling shutter effect and galaxies:

http://www.madsci.org/posts/archives/2007-05/1179062966.As.r.html
http://physics.stackexchange.com/questions/45255/how-distorted-does-the-andromeda-galaxy-appear-to-us-due-to-the-speed-of-light

good passage about light-nanoseconds: http://books.google.co.uk/books?id=rKFhqlzjv-IC&pg=PA22&redir_esc=y#v=onepage&q&f=false

galactic year: http://en.wikipedia.org/wiki/Galactic_year

wiki pages on light dimming causes:

http://en.wikipedia.org/wiki/Inverse-square_law
http://bit.ly/1g2Suuh
http://en.wikipedia.org/wiki/Red_shift

Hey, Vsauce!

Michael here.

I am distorted.

The pixels you are watching
have been time displaced.

They've been mapped onto a gradient

and the darker the region they're mapped to,

the further behind they lag.

The effect is really fun, but
it's certainly not realistic...

Or is it?

Many, many popular digital cameras
suffer from lag-induced distortion,

like what you just saw, though
much, much more subtle.

Usually completely unnoticeable.
It's called a rolling shutter.

Instead of snapping a full exposure at once,

they quickly scan strips of each frame.

It's usually undetectable, but
when the subject changes

faster than the camera scans,
you get the faintest jello-y,

wobbly rolling shutter effect. Really fast things,

like vibrating guitar strings
and airplane propellers

are famous victims, but people can be too.

Luke Mandel submitted
this photo to Boing Boing.

His camera scans left to
right and, in this instance,

managed to capture a blink,
eyes closed, when the scan

began and then opened in the reflection,

scanned a fraction of a second later.

But the rolling shutter effect
is not just a neat curiosity.

It represents a fundamental
and inescapable distortion

that affects everything we see,
rolling shutter or not.

First things first, let's talk about distortions.

A hallucination is a distortion of reality

when there is no apparent stimulus.

If you are merely misinterpreting an actual stimulus,

that is an illusion. But some distortions occur

before our sense organs and minds get in the way.

They are called optical phenomena.

They are not the result of sensation
or perception gone wrong.

Instead, optical phenomena
are distortions caused

by the mere properties of light
and matter in and of themselves.

If you look up at the sky and see
a giant, vivid drinking gourd,

you are hallucinating. But if you
see a flat, two-dimensional,

connect-the-dots Big Dipper,
you are seeing an illusion.

It's an illusion because those dots merely appear

to be on the same plane, like holes
poked in the dark roof of the sky.

In reality, those dots are stars, light years apart

from one another in three dimensions.

As Celestia's brilliant, free,
real-time, 3D visualization

of space shows, from different
perspectives, besides our own,

they look a lot less like a dipper or plow.

In fact, all constellations and asterisms
are geocentric illusions.

From a wider perspective, their outlines
point inward to the single,

lowly point in space that gave them
their names. But you can't blame us!

I mean, Earth is the only perspective
any human has ever had.

And even Voyager One, the most
distant man-made object,

is still not even close to
being far enough away

for the constellations to look even

remotely different than they do here on Earth.

It's also not our fault, our eyes and brains fault,

that distant, distant stars weren't included

in our early cosmic connect-the-dot game.

Sure, our eyesight could be better,

but optical phenomena are also to blame.

If it weren't for redshifting
and the Inverse-square Law

and light extinction, distant things
could be seen in all their glory.

The night sky would look phenomenal.
Many structures up there are huge.

They're just too dim for their
hugeness to be appreciated.

When we see Hubble telescope
images of distance objects

like the Helix Nebula, it's easy to think that without

a telescope to zoom in, the object must

just be a tiny point in the sky. But, in reality,

even though the Helix Nebula
is 700 light years away,

it's three light years across.

If we could make the Helix Nebula less dim,

if our eyes could take
a really long exposure of it,

we would see the Helix Nebula as it really is,

nearly 70% the apparent diameter of our moon.

This is a serious picture.

That is how large the Helix Nebula
would appear in the night sky

from Earth if it just wasn't so dim.

Our moon is tiny in the sky, by the way.

It's easy to think of the moon
as this huge, baseball sized thing

up there in the sky, but that's an illusion.

Try this the next time you see the moon.

Grab a sheet of notebook
paper and you will notice

the angular diameter of the moon is the same size

as a hole punched in a sheet of notebook paper,

held an arms length away.
Seriously, try it sometime.

It shows just how cute and tiny our little moon is.

The Orion Nebula would appear
even larger if we saw all of its light.

And the Andromeda Galaxy--just
a smudge in the sky to our eyes--

but if our eyes were better at collecting dim light,

we would see Andromeda's true extent in our sky.

Of course, our night sky doesn't look like that.

Distant objects are dimmer.

That's a bummer.

But light still wins when it comes to speed.

Light travels at the fastest speed, in fact.

In a vacuum, light travels
300,000 kilometers a second.

That's fast.

But not really.

I mean, not compared to how far
apart things are in the universe.

Sydney, Australia, is 1/14th of a light second

away from London.

But the Andromeda galaxy is two and half million

light years away from London.
To put that in perspective,

let's take a light speed journey
from London to Sydney.

It would look like this. Ready? Three, two, one...go!

Nice. Alright, alright. Here's
the Andromeda galaxy, okay?

Now, relativistic effects
aside, let's take a look at

what it would look like to travel toward

the Andromeda galaxy at the speed of light.

Are you ready? Alright. Three...two...one...go!

(sighs in annoyance)

Yeah. I mean, seriously, it's pretty lame.

Even at the speed of light,
the fastest speed possible,

a year from now, we won't even
be a millionth of the way there.

That's how far away Andromeda is.

It's almost sad in a way.

But this brings us back to
the rolling shutter effect.

The Andromeda galaxy is huge.

It's more than a hundred thousand light years across

and our view of it is tilted,
which means that on the plane

we view it in, light from the back represents

what Andromeda looked like
thousands and thousands of years

before what light from the front represents.

Changes in its appearance reach
us sooner from the front

than from the back. Andromeda is rotating,

spinning at hundreds of kilometers
per second in some places.

Now, a lag between light coming
from near and far points

on a spinning object results in a skewed image.

The rolling shutter effect on
a cosmic scale applied, to say,

a Chess board, seeing the front ahead

of the back is pretty trippy and dramatic.

So does that mean we see
wobbly, funhouse mirror,

rolling shutter effect versions of Andromeda

and other distant galaxies?
Well, technically, yeah.

But the distortion is negligible.

It may as well be ignored. Why?

Well, the speeds used in these
visualizations are not to scale.

On average, yes, matter within galaxies
orbits the galactic center at hundreds

of kilometers per second,
but galaxies are so huge,

it takes them hundreds of millions of years

to complete just one rotation. In other words,

the lag between light reaching
you from near and far points

on a galaxy is nothing compared
to how much time it takes

matter in the galaxy to travel that same distance.

In the case of Andromeda,
if you insisted on seeing

Andromeda as it really is,
that is, corrected for any lag

caused by the fact that the speed of light is finite,

the most extreme points on
the galaxy would only need

to be adjusted by about a ten-thousandth
of the width of any image.

In this case, less than a pixel.

So it's not a big deal.

But it's not a nothing deal. It's real.

In fact, everything we look at is, in some way,

distorted by the fact that
the speed of light is finite.

Your own feet are about five
to six light nanoseconds

away from your eyes,

which means, when you look at your feet,
you're seeing where they were,

5-6 nanoseconds ago,

5-6 nanoseconds in the past.

Of course, a delay that brief
is pretty much undetectable,

but it is calculatable. If it makes
you feel a little sad to know that,

even with the sharpest mind
or the best instruments,

appearances still depend on where you are,

that optical phenomena ensure
appearances are always relative...

don't feel bad. We call the people
closest to us our relatives.

We're really just a family.

A big family of reference frames that, like a family,

don't always agree, but do have
plenty of cool things to look at.

I'd like to think my editor, Guy, for help with

the rolling shutter effect in this video.

And I'd like to thank you because, as always,

thanks for watching.

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