Neil deGrasse Tyson: There Is No Speed of Dark

Catch up with StarTalk Radio around the web:

[StarTalk]

*In today's Lunch with a "Side Order of Science": Is there a Speed of Dark?*

[godsdonttalk]

“Light thinks it travels faster than anything but it is wrong. No matter how fast light travels, it finds the darkness has always got there first, and is waiting for it.” - Terry Pratchett

[GamerVidz]

"What's the speed of dark?"
Usain Bolt

[StarTalk]

New Video: What is the speed of dark? Watch Neil deGrasse Tyson and Eugene Mirman give this Cosmic Query the answer it deserves: Neil deGrasse Tyson: There Is No Speed of Dark

[stephenkamenar]

If you had a bright room, then turned off the light, the speed of dark would be the speed of light. Because that's how long it takes for the light to leave.

Although I'm not sure, if you had walls, the light might bounce around a few times before it's gone.

[KALAMANAMANAWA]

Is Dark actually the absence of Light?

Or is Light (absorbed) within the Dark?

[shishkbbgaming]

Neil DeGrasse Tyson sept 2013 : There is no speed of dark.

Michael Stevens July 2014 : Hi Vsauce, Michael here. What is the speed of dark !!

[jessicalee]

But what happens if you move slower than the speed of Stop?

[LudwigvanBeethoven]

Dark is absence of light...

Or is it?

[Cues Vsauce Music]

[DeathBringer]

After you turn the lights off in an enclosed room with no windows, how long does it take for it to get dark? Just the speed of light leaving that space again? My dad asked me this question and I wasn't sure how to answer it after he added, "What happens to the photon? Where does it go? Does it go on forever?" He essentially was asking about photon decay, something not fully understood and theoretical, so...

[Plump_Nick]

I can watch Neil all day. I recently had a dream about him. It was awesome lol. Defiantly one of my role models to say the least

[crazygreek]

i love the way he talks and reasons. i would love to look forward and maybe someday meet him

[guitrguy]

I saw NdT speak back in March, and someone asked him this same exact question. He gave pretty much the same exact answer as this.

[violacrb]

The difficulty is that the gravity equations do not allow for a point where the gravity attraction between two objects is truly zero. It can be remarkably small, but not zero. Therefore, you would be testing the change in gravity based on the changing distance between the two celestial objects. We already do this with comets, asteroids, and the other planets. The intensity of the attraction changes predictably with distance, but because gravity is always present, you can't measure its 'speed'.

[nimosx]

I think that the guy asking the question was talking about the Dark Flow. The theory that all matter in our universe is moving towards a specific direction.

[Lacertilian]

Light is a wave when travelling and a particle when it is emitted or absorbed. So when it 'goes somewhere' it is being absorbed by whatever is in the room.

[AdamSmithNES]

What about: How long does light take to dissipate/disappear from a room when the switch is turned from on to off? Where does it go?

[mikeyoung]

It doesn't hurt to ask any question as long as you are prepared for an answer you don't like.

[TacticusPrime]

0 is a useful placeholder for absence, but it is also a number. For instance, anything to the 0th power is 1.

Some physicists reject the concept of "before" space. A plurality, I would say, say that space and time came into existence at once 13.8 billion years ago. Since time did not exist prior to then, it doesn't make sense to say "before". We're certainly at the limits of our knowledge here. Intuition can not serve us.

[arealmench]

Dark does have a speed but it can't be measured because it's too dark. Btw, saying that dark is the absence of light is the same as saying that light is the absence of dark.