"FTL" light trick may lead to much better astronomy

originally posted by: Bedlam

originally posted by: stormbringer1701
i said nothing about the speed of the beam itself.

The spot isn't a tangible object, it's where the photons from the beam hit. Sweeping the beam doesn't move anything faster than light, even if the location of the spot is changing in a way that appears to be moving faster than c.

i didn't say it was tangible.

But isn't the "thing" that you're proposing can move FTL just a designation, description, concept, or something like that? It's not a thing, is it? It's just something that is actually nothing, but we can CHOOSE to comprehend it as "something," as is the case here, as far as I understand... But really nothing... Maybe...

For consideration:
1. The point at which the scissors touch, isn't actually touching, with electricity and atoms and stuff. Even if it were touching, it's not really a thing... I'm not sure how to say exactly what I want, but I bet you know what I mean... Hmm... It's something we equate to meaning or being something we mentally invent;
2. A beam of light, or a laser, if swept across the heavens, theoretically would reach a point, and further (farther?), at which the light particles, or whatever they are, would spread out to where they are no longer as adjacent as we know them to be. Before long, if someone were far enough out there to intercept the light, they could only get one of the particles, and that's if they're lucky, or good. Could you say the same thing? I think not. If yes, then what about something like this:
The "thing" I'm choosing to designate as going faster than light is... "the planet I'm thinking of." Right now, it's Earth. Earth. Earth. NOW it's Jupiter!!! Wow! The "THING" moved SOOOO quick!

Sorry for the run-ons, and if any of this is condescending sounding. Not intentional. It sounded possibly condescending, but it was meant to be discussionful. (new word)

originally posted by: japhrimu
But isn't the "thing" that you're proposing can move FTL just a designation, description, concept, or something like that? It's not a thing, is it? It's just something that is actually nothing, but we can CHOOSE to comprehend it as "something," as is the case here, as far as I understand... But really nothing... Maybe...

nothing is also a thing because you can name it.

but time for an excerpt of the article:

The physics that creates the photonic boom is tied to the faster-than-light sweep speeds of the illuminating spots and cast shadows. Specifically, a flash is seen by an observer when the speed of the scattered spot toward the observer drops from above the speed of light to below the speed of light. The phenomenon is possible only because the spots contain no mass and so cannot only move faster than light, but decelerate past the speed of light without violating Einstein's theory of special relativity.

Details of the effect hinge on the interplay between the time it takes for a sweeping light beam to cross an object, and the time it takes for the light beam to traverse the depth of the object. Therefore, measuring photonic booms gives information about the depth of the scatterer. Were the Moon just a flat disk on the sky, for example, no photonics boom would occur.


Read more at: phys.org...

Kiri-kin-tha's First Law of Metaphysics: "Nothing unreal exists."

originally posted by: stormbringer1701
the key thing is the illumination must sweep the intervening objects at greater than light speed.

You mean like the famous light echo of V838 Mon? www.nasa.gov...
Light echo

~~~

And wow, most replies here seem more concerned with semantics rather than the actual topic.

thats a very beautiful picture. i don't see enough info to determine if that effect was due to this phenomenon but it could be.

originally posted by: stormbringer1701
thats a very beautiful picture. i don't see enough info to determine if that effect was due to this phenomenon but it could be.

Yes, it was light echo, revealing the structure of the surrounding gas and dust clouds.

www.youtube.com...


The light from the outburst appeared to travel faster than the speed of light.

excellent! i wonder why they didn't use this as an example The graphic and video would have got them a lot more views.