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Could a concentrated light beam from earth reach another planet ?

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  • 2 months ago
    Favorite Answer

    Yes.

    The key is power. A 1 Watt laser uses 1 Joule per second. But if that laser fired a 1 Joule pulse in 1 nanosecond, that works out to be 1 Gigawatts of power. We can already build lasers that, for a brief instant, generate a pulse of light brighter than the surface of the sun ... and not just a little bit brighter than the sun ... 1 billion times brighter is the record at the moment.

    If we pointed that towards a distant star, any aliens would eventually (given the time it would take for light to get there) see these pulses outshine our sun if they had telescopes capable of detecting such short bursts of light. That's one of the things we are now looking for in our hunt for alien civilisations. Maybe they are announcing their existence with pulsed lasers ...

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  • 1 month ago

    We can see sunlight reflected off of the other planets.

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  • goring
    Lv 6
    1 month ago

    only if space was a vacuum=it is not, hence the beam would get absorbed before it got there.

    A radio wave would have no problem

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  • Anonymous
    2 months ago

    As long as something doesn't obstruct it or absorb it, yes.

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  • 2 months ago

    Yes, laser beams have been bounced off of a corner cube placed on mars.

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  • Zirp
    Lv 7
    2 months ago

    Sure

    but to the nearest planet in our own solar-system it would take a fraction of an hour, and to the nearest planet around another star that our sun would take years.

    So no matter how concentrated it is (think laser), there wouldn't be much of a signal to detect at the other end

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  • 2 months ago

    Yes, the light could reach another planet. But ...  the light from reflectors on the moon is barely detectable after traveling (round trip) 800,000 km. Mars is at about 70 times further (one way), so the light would be 4900 times harder to detect.

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  • 2 months ago

    easily. It has been done to the moon, where special reflectors gave us a return signal.

    I doubt it has been done to other planets, but It's easily possible. The problem is, there is no way to detect that it happened, so no reason to spend the money.

    But we could land special reflectors on, say, mars, and hit it with a laser.

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  • Kieth
    Lv 7
    2 months ago

    After the moon landings, scientists here on earth were able to fire a laser at a mirror on the moon and reflect it back.

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  • Anonymous
    2 months ago

    Yes.  Absolutely. 

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