|
|
Thread Tools | Display Modes |
#1
|
|||
|
|||
could we shine a laser on this new solar system and detect something in 180 years?
"Tony Rusi" wrote in the subject line for some reason "could we shine a laser on
this new solar system and detect something in 180 years?" http://news.independent.co.uk/world/...p?story=421468 Hmm, let's try it out ... *shines laser* Waits ... ... ... ... ... ... ... Aha! Something's coming back ... "Oi! Turn that light off, some of us are trying to sleep over here, you know!" |
#2
|
|||
|
|||
could we shine a laser on this new solar system and detect something in 180 years?
Tony Rusi wrote:
http://news.independent.co.uk/world/...p?story=421468 No. The brightest lasers around would be detectable only with sensitive instruments at this distance. The reflection would be so dim that I'd be surprised if a photon a second would pass through our solar system. -- http://inquisitor.i.am/ | | Ian Stirling. ---------------------------+-------------------------+-------------------------- Get off a shot FAST, this upsets him long enough to let you make your second shot perfect. -- Robert A Heinlein. |
#4
|
|||
|
|||
could we shine a laser on this new solar system and detect something in 180 years?
We can't even shine a laser on Pluto from Earth and get
a return. This Solar System is roughly a kajillion (to use a technical term) times farther away. So no. |
#5
|
|||
|
|||
could we shine a laser on this new solar system and detect something in 180 years?
Gordon D. Pusch wrote:
(Tony Rusi) writes: could we shine a laser on this new solar system and detect something in 180 years? http://news.independent.co.uk/world/...p?story=421468 No, unless a technological civilization MUCH more advanced than ours happens to live there, is looking for laser light, and happens to have a MUCH bigger laser system than we can currently build properly positioned to shine a beam back at us. Lasers still obey the inverse sqaure law beyond the diffraction-limiting distance of their focusing aperture. It would take a HUGE lens system thousands of kilometers in diameter stationed at the edge of the solar system to hold a laser beam reasonable tight over interstellar distances, and a VERY powerful laser before it will be easily noticed against the much brighter background light that the Sun produces. Not quite that big. I suspect you've read (or calculated) the needs for a laser pushed sail. Talking near-term, and assuming you are using an OWL class 100m mirror scope for the transmitter. Say 100 light years. This is 3*10^9 light seconds away. The above scope will produce a beam with a divergance of around 1*10^-8 radians. This will produce a beam with a diameter of 30 light seconds at the target star, so you will need to point it at a planet. The sun produces around 1400W into 1m^2 at around 500 light seconds. This will be (6*10^7)^2 dimmer at the target star, or 4*10^15 times dimmer, for a power of 6*10^-12W/m^2. The beam area is around 1*10^20m^2, to equal the suns power into this area needs a laser with power of 600Mw. The largest current continuous wave lasers are around a megawatt or so, which would be trivially detectable by even primitive spectroscopy. To get something naked-eye visible needs a bit more (assuming for the sake of argument the naked eyes are similar to ours) It'd be a large engineering project, but something that could be done essentially now, given funding, without much development of much actual new stuff. It does not for example require the large space-based manufacturing industry, that laser-pushed sails probably do. As to data transmission, that gets lots easier once someone is actually pointing a large dish your way. -- http://inquisitor.i.am/ | | Ian Stirling. ---------------------------+-------------------------+-------------------------- "I am the Emperor, and I want dumplings." - Austrian Emperor, Ferdinand I. |
#6
|
|||
|
|||
could we shine a laser on this new solar system and detect something in 180 years?
"Christopher M. Jones" wrote in message ...
We can't even shine a laser on Pluto from Earth and get a return. This Solar System is roughly a kajillion (to use a technical term) times farther away. So no. Has anyone else tried Gunter Nimtz's method over a longer distance? Yet last month an extraordinary development in this tale unfolded at a special colloquium organised in Snowbird, Utah. Attending the meeting were some of the leading researchers in this field of faster-than-light quantum phenomena. To an astonished audience, Nimtz announced that his team at Cologne had not only measured superluminal speeds for their microwaves, but had actually sent a signal faster than light. The signal in question was Mozart's 40th Symphony. What they did was frequency modulate their microwave source with the music and then measure how quickly the music arrived after traversing the forbidden zone in a waveguide. According to Nimtz, Mozart's 40th hopped across 12 centimetres of space at 4.7 times the speed of light. What's more, Nimtz actually had a recording to prove it. To his now bemused audience, he played a tape in which among the background hiss strains of Mozart could be heard. This was the "signal" that had travelled faster than light. But that very word "signal" triggered heated discussion, with some participants claiming that the symphony could not be regarded as a signal. Among them was Chiao. "It's not a signal in Einstein's sense because of the timescales involved. I agree that when the music crosses the barrier it is shifted forward in time, compared with music that travels by a conventional path, but only by a very small amount. It is so small that you can predict what will happen to the music simply by looking at how the original audio waveform is changing. There is no threat to causality." Nimtz is not so sure. "I don't have an opinion on whether this violates causality. However, I do not accept that Mozart's symphony isn't a signal. In principle, I could extend the path over much longer distances and then it would not be possible to predict the course of the music. Then you really would have a signal travelling faster than light." Nimtz clearly believes he is onto something important. By contrast, Chiao and his colleagues, while happy to peer beyond the normal confines of scientific orthodoxy, are determined not to be lured over the edge. Their collective view remains firmly grounded in the sanctity of causality and Einstein's special theory of relativity. "Einstein causality," Chiao says, "rules out the propagation of any signal faster than light, but it does not limit the group velocity of electromagnetic propagation." Chiao's colleague Steinberg puts it another way: "What stops you from sending a signal faster than light is that the calculation only works for smoothly varying pulses. If a smoothly varying pulse shows up at noon, it may have been possible to predict its shape from the shape of the pulse at 8 am. If at noon you suddenly have an important message and decide to change the shape of the pulse in order to convey this message, that change will not travel any faster than the speed of light." Despite such reassurances, many physicists admit to being more than a little troubled by these faster than light phenomena. While few are prepared to accept Nimtz's more extravagant claims, many will doubtless want to see how much further theory and experiment can fly in the face of common sense. |
#7
|
|||
|
|||
could we shine a laser on this new solar system and detect something in 180 years?
|
#8
|
|||
|
|||
could we shine a laser on this new solar system and detect something in 180 years?
In article ,
Tony Rusi wrote: Has anyone else tried Gunter Nimtz's method over a longer distance? While the distance can be extended in principle, it's nothing so simple as just buying a longer pipe. Moreover, as I understand it -- with the caution that this is an area I *don't* keep up with -- Nimtz et al did *not* actually measure the speed of propagation, in any sense that physicists in general acknowledge as measurement. Rather, he demonstrated transmission of a signal through a path whose speed, given certain assumptions, is *calculated* to be faster than light. But the path is very noisy and the difference between the speed of light and the calculated speed is a fraction of a nanosecond, so actually confirming the calculation is exceedingly difficult, and he is currently pretty much alone in believing it. Note that in any case, this trick only works within a waveguide -- it is not something you could use to signal across open space. -- MOST launched 1015 EDT 30 June, separated 1046, | Henry Spencer first ground-station pass 1651, all nominal! | |
#9
|
|||
|
|||
could we shine a laser on this new solar system and detect something in 180 years?
|
#10
|
|||
|
|||
could we shine a laser on this new solar system and detect something in 180 years?
|
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
System to monitor heat panels could safeguard future spacecraft (Forwarded) | Andrew Yee | Space Shuttle | 0 | July 15th 04 06:14 PM |
Scientists Develop Cheap Method for Solar System Hunt | Ron Baalke | Science | 0 | November 20th 03 03:55 PM |
ESA Sees Stardust Storms Heading For Solar System | Ron Baalke | Science | 0 | August 20th 03 08:10 PM |