Originally posted by FabianFnas
With 'you' I meant all of us posting in this thread. Nothing personal.
Our technological civilasation is newborn. We haven't even known the structures in the atoms for long. The neutron was discovered as late as 1931 (if I remember right). We know very little of universe, yet. We think we are something, but the fact is that we're not, we're quite primi ...[text shortened]... that reason. They're not visiting any governement at all. They just come here look at us.
The range of our astronomy instruments is universal sized, we are measuring events and systems 13 billion light years away and that's with just the relatively puny scopes in orbit and on earth now.
In 30 years, we will know a lot more for sure but already if there was a civilization emitting RF at something like 100 ly away we would have already detected it. So that close in sphere will get much larger as time goes by. A sphere 100 LY in radius encompasses several million stars but that is only 0.01% of the stars even in our own galaxy, not to mention stars in Andromeda and the other galaxies in our local group. It might even be better to scan Andromeda when our scopes become sensitive enough to be able to find an alien signal.
Right now, in our own galaxy, we can't see the trees for the forest. At least with Andromeda we can scan pretty much the whole thing but one has to realize the distance at several million LY away, that means whatever we detect was millions of years in Andromeda's past and a signal would neccessarily be a one way transmission.
But it might give a clue as to how many signals we could expect in our own galaxy. The size of the telescopes would have to be REALLY huge though, arrays of scopes in orbit around the distance of Neptune or better. I thought of a way to utilize the gravitational lens effect of our sun to great effect, the 'solar foci' as it's called, is about 85 billion miles away from the sun. That is a subject I spent quite a bit of time on. So here goes: If we can get a telescope, optical, RF or neutrino or gravity wave, doesn't matter because the gravitational focus effect focusses EVERYTHING.
So suppose we put a probe with whatever kind of energy we are detecting, if Electromagnetic, then whatever wavelength of interest, but the idea is, suppose we want to probe Andromeda. We put the probe on the OTHER SIDE of the sun directly in line with Andromeda.
Then we turn around and block out the radiation from the sun itself, actually, the further away from the sun the better, like 200 billion Km would be better because the focusing effect would be coming from an altitude of better than one Radii from the surface of the sun and so there would be less interferance with solar noise. So suppose we are at 200 billion Km out and we point an antenna directly at the sun.
We are looking therefore at any energy that passes by the sun coming from say, Andromeda, and the effective size of the lens would be a giant ring around the sun at twice the diameter of the sun, so a disk twice the size of the sun but relatively thin, say a few Km, so if we consider a one Km wide disc with a diameter of (the size of the disk that would be focussing at 200 billion Km, approximate of course)
1,400,000 km radius, * 2= 2.8E6 km diameter * PI= approximately 9,000,000 Km circumferance, and 1000 meters wide, so that works out to an effective collection area of about 10 TRILLION square meters.
Lets assume we are looking at a wavelength of 1 meter, 300 Mhz.
That would put the energy from the vacinity of Andromeda in an area of 10 trillion square meters focussed down to something like one square meter. Now of course that is just an algebraic estimate, the real area is extremely complicated to calculate, way beyond my limited math skills, but using those figures, you would be getting a gain of 10 trillion to one. If you know what Decibels are, that works out to using an antenna with a gain of 130 DB!
Now the amateur radio antennae I use at one or two meters, 146 Mhz for instance, the two meter ham band, a decent antenna has a gain of around 20 dbi. Dbi means an isotropic radiator, in other words, if it was transmitting, a gain of 0 Dbi would put radiation equally around a spherical space around the antenna. So the more Db of gain, the smaller the beamwidth and the larger the received and transmitted signal.
So at 20 db, if you have a transmitter of 1 watt, the portion of it hitting that isotropic sphere, would be the same as if the isotropic radiator had a power of 100 watts. In the case of the sun, our 130 db gain means a one watt signal is squeezed down so small in so tight a beam it would equal in the one direction it is aimed, equal to a 10 trillion watt transmitter that went out in all directions equally. Thats the 50 Cent tour of antenna gain.
So from a receive standpoint, it gives a gain of 10 trillion to one or 130 DB and the area scanned at 2 million light years, the size of the circle of detection at the distance of Andromeda works out to about 12 million Km. So you can see you can scan in on an individual solar system and take in signals from individual planets, which of course would be still a lot smaller than that 12 million Km wide circle but what that means is you can scan across a single solar system at that distance and detect ANYTHING our proported alien transmits, neutrinos, RF, IR, UV, visible light, Xray, Gamma, gravity waves, whatever, they ALL get focussed by the lens effect of the sun.
Not a perfect lens by any means because you have to be at an exact distance from the sun to gather energy from an exact distance away from the surface of the sun and the further away you go, the more energy you collect from a distant source, at least up to a point.
I am writing a couple of papers on this and want some help with graphics so I can present the whole idea but you can see where with a single sensor you get one hell of a lot of gain for free, with the cost being you have to get to the distance away from the sun and in the right direction to look back on the sun, through the sun to a distant source and get spectacular gains, whether it's a neutrino detector or RF, everything gets deflected by the lens effect.
All in all, the benefits of that kind of probe outweigh any kind of multi dish array anywhere in the solar system. Due to the vagarities of relativity, my numbers are probably way off because of just using trig and algebra but they won't be like a thousand times off, maybe an order of ten off, still even if you chop off 90% of the signal, you are left with not 130 DB gain but 120 db gain. No antenna on earth or in space would EVER be able to give that kind of gain.
The gain might be it's weak point even. It requires an extremely delicate movement, you can see if you are getting a trillion to one gain, then a movement of 1 km left or right at the sensor means scanning an area 1 trillion Km away from the spot you were just at. So a movement of one METER moves the scan 1 trillion meters, or moving the scan 1 billion Kilometers away from where you were. So moving one MILLIMETER moves the scanned area by 1 million KILOMETERS. Pretty touchy scanner, eh. Kind of boggles the mind though, doesn't it? Thats what I have been working on in my spare time.