Physics/Can aliens see what we upload to internet?
when I upload something to internet it gets transmitted by the microwaves right from my computer to the telecommunications pole and then to satellite and then to a telephone pole and to another computer. So if I take a picture of myself and upload it to internet the uploading microwaves emanate from my computer and telephone poles and satellite as microwave radiation and then the microwaves because of their wave function start traveling to outer space. So does that mean if I take a picture of myself and upload it to internet and let's say that 4.3 years from now on an alien living in Alpha Centauri system could intercept the microwave containing the information about my picture and then convert the information to a picture and see me?
> let's say that 4.3 years from now on an alien living in Alpha Centauri system
> could intercept the microwave containing the information
Three problems, two relatively minor, one HUGE.
1) In order to make sense of any signal, one must understand the code (or language, if you prefer) in which it is written. For example, unless one knows that short positive radio signals followed by three long ones followed by three more short ones (ie, dit-dit-dit, dot-dot-dot, dit-dit-dit) is Morse Code for "S-O-S", receiving that message would cause interest, but would not mean anything.
Since the mid-1980s the Internet has not communicated using continuous signals, but has instead sent packets of information. More specifically, in a process called TCP/IP. Unless the receptors of the signals from your computer are designed to take these packets and re-assemble them into a coherent message, what comes to the receiver will be complete gibberish.
2) Even if the receiver was able to re-assemble the TCP/IP packets (let's say, using brute force computing power), it still would not make sense UNLESS s/he had the means to sort out these digital signals into an image. If your photo had been stored in jpeg format, the receiver would have to have some means of changing a series of bits into a jpeg photo. This is SOMEWHAT analogous to being able to figure out that the above signal is "S-O-S" but not knowing that this means "Emergency! Send help!"
3) More problematic is the simple fact that signals degrade as they travel through space. Any signal from any transmitter becomes weaker by a inverse square law. For example, a signal that has lost half its intensity after one kilometer will have lost 75% of its intensity after two kilometers, and 99% of its intensity at ten kilometers. Eventually, radio signals become so weak that they are not distinguishable from background quantum noise.
Because noise can not be reduced in our Universe, the only way to improve the signal to noise ratio is to increase the signal intensity. The above chart shows how difficult it would be for even a 1kW broadcast antenna to be detected at ten light years from us; the incredibly weak microwave signals from the microwave relay tower that is carrying your jpeg files would be impossible (note that word -- I did not say DIFFICULT) to separate from noise in much less than a light year.
Summing up, there are many reasons not to send that photo of yourself being stupid onto the Internet. Concerns that ETI on Alpha Centauri will see them in a few years should not be one of them.