Light-based interstellar communication with star-bright LED's?

[Nuke]

i tend to lean that way myself. alcubierre drive has too many question marks right now to even consider what to do should it be possible to construct one (save it for the realm of science fiction). im more interested in the more physically plausible modes of interstellar travel and communications.

[AngelLestat]

In my humble opinion, we will have to get used to the idea that information can not travel faster than the speed of light. We would need to deal with that.

[YNM]

It's not that weird to have data (or information) sent physically (using hard drives and such). Even this practice is quite common today, when you have a load of datas to be moved...

http://what-if.xkcd.com/31/

[Pixel of Life]

Solution for the FTL problem (although a theoretical one): Wormholes.

1) Open a really tiny wormhole between two places, located several light years apart.

2) Use a laser to transmit data through the wormhole.

3) ???

4) Profit! You now have FTL data transmission. Problem, physics?

[Aethon]

http://what-if.xkcd.com/13/

To outshine the Sun, you'd need something more than giving the YAL-1 to every human in the world. The article did also talk about the NIF, but of course, it assumes everyone has one. The actual single output of NIF lasers is in the orders of terrawats, while the Sun gives three hundred yottawats. Outshined by at least 8 orders of magnitude.

We're talking about two different things here. I'm talking about a very brief pulse of laser light that for a nanosecond is brighter than the sun by four orders of magnitude. You're talking about shining enough light on the moon to make it as bright as the sun. They are two drastically different engineering challenges.

[YNM]

We're talking about two different things here. I'm talking about a very brief pulse of laser light that for a nanosecond is brighter than the sun by four orders of magnitude. You're talking about shining enough light on the moon to make it as bright as the sun. They are two drastically different engineering challenges.

Alright... now, what's precisely 4 magnitudes brighter ? Is it visible magnitude, that haven't been counted for the distance, or the actual output ? I mean, a 3.846*10^(30) Watt laser, which is 10^(4) solar luminosity ? (remember, 10^(4) is 4 magnitude.)

[Aethon]

Read the paper I linked. It explains this much better than I can.

https://www.princeton.edu/~willman/observatory/oseti/oseti_apj_preprint.pdf

"directed laser pulse that outshines the broadband visible light of the Sun by four orders of magnitude"

[YNM]

I see the problem : the paper counts the no. of photons received by observer not by dividing it by the total surface area of the radiation "sphere" but only by the patch of sky (or the radiation sphere) it's going to lit, while my method divides everything by the radiation "sphere's" surface area.

I'm not sure, but even as I've told by my teachers, and even by those who participated once in the IOAA (international astronomy olympiad, to say), every radiating body, no matter whether the beam is directed, have to be calculated as if it radiates the whole sphere of radiation. An application of this is to count the magnitude of Mars at quadrature, or any other bodies that's not seen as illuminated by 100%; I solved it first by dividing the reflected "luminosity" of Mars' projection only by half of the radiation "sphere". Then, they told me that it should always be divided by the whole radiation sphere, no matter where the lit percentation is, or the direction of the beam is.

Anybody to give me some patch of light on this case ?

[dbmorpher]

Um just a short interjection but LEDs, per square meterage, is one of the most expensive electrical layering ever, more than solar panels. So the Laser on order of the ratio of lumens/dollars is more efficient.