Is the LASER beam visible in space?

[NO4H99]

Just because something is in a vacuum does not mean that it has no mass.

 

[grainde]

I didn't say see a laser BEAM. I mean *see* the laser if you were in a space station and someone was shining it directly at you. You could probably see a faint green if someone was shining it with a beam expander on a clear night with 500-1000mW of power. Probably more.

Theres no "probably" about it. The experiment has been done with only a roughly 800 mW, poorly diverging 445 and with no beam expander. It was clearly seen from the space station. :beer:

 

[hwang21]

Seconded^ yes if the laser is aimed at you, of course you'll see it

 

[zyxwv99]

There's no real naturally occurring vacuum in our galaxy. If you can get into intergalactic space the air will be a lot thinner, but it's still "air" of a sort. Kind of like the Moon's atmosphere, one millionth the pressure of Earth's, but still an atmosphere. Until you get to the heliopause, you're still within the sun's outer atmosphere. In interstaller space, you're just inhaling every other star's second-hand fumes.

Given a powerful enough laser, you should be able to see beam. In low Earth orbit, it wouldn't even have to be that powerful. I can't give you any exact numbers, but maybe 500MW. (That's MW with a capital M.)

 

[Benur]

There's no real naturally occurring vacuum in our galaxy. If you can get into intergalactic space the air will be a lot thinner, but it's still "air" of a sort. Kind of like the Moon's atmosphere, one millionth the pressure of Earth's, but still an atmosphere. Until you get to the heliopause, you're still within the sun's outer atmosphere. In interstaller space, you're just inhaling every other star's second-hand fumes.

Given a powerful enough laser, you should be able to see beam. In low Earth orbit, it wouldn't even have to be that powerful. I can't give you any exact numbers, but maybe 500MW. (That's MW with a capital M.)

Interesting information...
And 500MW, that's pretty impresive

 

[123splat]

NO4H99 is pretty much spot on. And NO, NO, NO,,, The ISS and most sats are NOT in the normal atmospheric envelope..... Jeese,,,
If they were, the drag would make the loose velocity and fall into earth, or more likely burn because of the friction.
There is a lot of dust and other particle out there, so under the right conditions, a beam would/could be visable. What the guys in the ISS saw was the difused beam from the 1W that some austin ameture astronomer was shinning at the ISS during an experiment conducted at the observatory at Canyon of the Eagles. Not the deathray (beam), but just a dim glow.

 

[NO4H99]

Thanks @123splat :beer:

 

[The Lightning Stalker]

But I'm talking about outer space, not about space as in earth orbit. Like the laser of the Death Star in Star Wars.

I don't remember them ever saying in the movie that it was a laser.

 

[NO4H99]

I don't remember them ever saying in the movie that it was a laser.

Nah you're right. Maybe just a few high powered thrower flashlights with green LEDs. They didn't look or in anyway imitate green lasers

:wtf: else would it be? Did you watch the same Star Wars as I did?

 

[Benur]

I don't remember them ever saying in the movie that it was a laser.

Is that necessary? It is clearly a laser, but for some reason, they don't go at the speed of light. :undecided:

 

[NO4H99]

True, they should travel close to the speed of light (slightly less due to being held by gravitational forces). Also it doesn't matter if the observer is moving or not, so that couldn't be it.

 

[Benur]

And the laser should not sound in outer space.

 

[NO4H99]

And the laser should not sound in outer space.

You wouldn't believe how much that annoyed me the first time I watched it . Glad I'm not the only one :crackup: