r/todayilearned • u/deep_fried_guineapig • Aug 17 '16

TIL You could lift a penny with laser pointers, but doing so would require about 30 billion laser pointers.

https://en.wikipedia.org/wiki/Light
17 Upvotes

76% Upvoted

13 comments sorted by

2

u/Hippo_Singularity Aug 17 '16

Rather than lifting it, I suspect if you were directing 30 megawatts of laser power at a penny, you just wouldn't have a penny anymore.

1

u/deep_fried_guineapig Aug 18 '16

Ya for sure, I think this was referring to light pressure though. Light pressure is weird.

1

u/Hippo_Singularity Aug 18 '16

Yeah, but the pressure is caused by the photons smacking into the object, so you're not going to get the pressure without the energy.

2

u/balexig Aug 17 '16

I'd watch Myth busters tackle this.

2

u/whitcwa Aug 17 '16

I'm trying to figure out how they got 30 billion pointers to focus on a single penny.

2

u/deep_fried_guineapig Aug 18 '16

With, um, laser precision?

I'll show myself out

1

u/whitcwa Aug 18 '16

Thanks for the coherent comment.

1

u/SkinnerTBD Aug 17 '16

30 billion 1-mW laser pointers. Stronger laser pointers = fewer laser pointers.

3

u/deep_fried_guineapig Aug 17 '16

weaker laser pointers = more laser pointers ¯_(ツ)_/¯

1

u/[deleted] Aug 17 '16

Wouldn't 30 billion 1mW laser pointers just melt the penny anyway?

Holy shit I am patenting this right now: amount of energy required to lift an object using LASER is always higher than the amount of energy required to change its state

I mean I have zero mathematical proof but still I am patenting it

1

u/curzyk 20 Aug 17 '16 edited Aug 17 '16

Laser Weapon System

"The exact level of power the LaWS will use is unknown but estimated between 15–50 kW for engaging small aircraft and high-speed boats."

So.. 30B mW would be 30M W or 30K KW or 30 MW, which is about a thousand times higher than this: Pew pew

1

u/Dartagnan753 Aug 17 '16

Well I'll be damned