Comments on: Astronomers look at one patch of sky and see no signs of alien life

By: Spectrum Shift

Spectrum Shift — Sat, 12 Sep 2020 03:16:49 +0000

Ok, so how did we get that movie “A Long Time Ago in a Galaxy Far, Far, Away”?

By: Cotour

Cotour — Thu, 10 Sep 2020 16:27:41 +0000

“The assumption is that there are civilizations using radio frequencies.”

A solid assumption, what other method for communication would a evolving civilization use?

And I have made this point before, the likelihood of intelligent life to exist and eventually developing technology to communicate using the electro magnetic spectrum and us being able to detect their activities in a friendly overlapping existence timeframe has got to be very thin.

We exist in the last 4.5 billion years of the existence of this entire universe. 9.5 billion years of universe existed before our solar system even began to be coalesced.

Working the other end of the equation, how long does an advanced lifeform that has developed advanced technology last? And how long does anything that they had pumped out into the universe remain to be detected?

I would think in the big picture view, not very long.

By: sippin_bourbon

sippin_bourbon — Thu, 10 Sep 2020 15:59:22 +0000

wayne

The reasons why they were forced to cut back to 50k watt transmissions are just an interesting.

By: J. J. Hall

J. J. Hall — Thu, 10 Sep 2020 14:03:24 +0000

The aliens turned off their radios because they received my telepathic command to do so. If you want to talk to aliens come to my bungalow in NY and for $250.00 I will tell you what is on their mind. Usually they ask you to give me more money! (LOL)

By: wayne

wayne — Wed, 09 Sep 2020 02:50:49 +0000

…on the transmitting side of the equation->

“WLW’s 500,000 Watt Transmitter”
K7AGE
https://youtu.be/CbHjcwIoTiY
31:30

“in 1932 WLW increased their power from 50,000 watts to 500,000 watts. They were the only AM broadcasting station in America ever to operate at 500,000 watts. Much of the old transmitter still exists. It is really a high power amplifier with a high level modulator (360,000 watts). The amplifier was driven from their existing 50,000 watt Western Electric transmitter. The system used 20 100,000 watt tubes ($1,600 each in 1932) that required water cooling that used a cooling pond located outside the station.”

By: Edward

Edward — Wed, 09 Sep 2020 01:55:28 +0000

MadRocketSci wrote: “In order to get a signal to another starsystem, you need a high-gain dish or apeture pointed at the target system to confine the energy to a beam that isn’t too wide.”

Right now our SETI searchers are not trying to get a readable signal out of the noise, they are trying to find a tiny non-random pattern buried deep in the noise. The mathematics and methods are postdoctoral, but should they find something non-random then they will concentrate on verification and trying to dig out and interpret the signal. Start with the easy and work toward the hard.

The assumption is that there are civilizations using radio frequencies.

By: mkent

mkent — Wed, 09 Sep 2020 00:17:53 +0000

It’s not just communications signals that are looked for. The most detectable signals humanity has put out over its lifetime that could be recognized by an extraterrestrial intelligence came from the early-warning radars used by the United States and the Soviet Union during the Cold War. High-powered focused beams can go quite a ways further than communications signals and still be recognizable as artificial.

By: MadRocketSci

MadRocketSci — Tue, 08 Sep 2020 17:38:12 +0000

If I’m doing the math right, the disc of the sun puts 1.77E-14 W/m^2 into a band from 100-101 MHz. We’d have to outshine that to be visible from interstellar distances.

1E-25 W/m^2 is something like 1.5 photons/(m^2-sec) so unless you have a gigantic dish to integrate the signal, it’s going to be very spotty too.

By: MadRocketSci

MadRocketSci — Tue, 08 Sep 2020 17:29:01 +0000

It’s been a while since I’ve done the math for interstellar communications, so I may be wrong, but IIRC, an omnidirectional signal, even an extremely powerful one (1GW), will peter out to 1E-25 W/m2 before even travelling a lightyear. In order to get a signal to another starsystem, you need a high-gain dish or apeture pointed at the target system to confine the energy to a beam that isn’t too wide. Even then, it’s going to be a serious power investment.

So, ET has to know we are here and specifically want to talk to the solar system. He’ll also have to have some patience: If they started broadcasting in (throw a dart at the dartboard of geological time) 800,000,000 BC, then they’re out of luck.

If there were some interstellar civilization with a communications network, it’d be a network of tightly focused directional signals, probably with as short a wavelength as they could manage for focusing effectiveness

By: Ray Van Dune

Ray Van Dune — Tue, 08 Sep 2020 17:21:00 +0000

Take an expert naval signalman, the kind that uses semaphore flags, and put him on the Moon with a powerful telescope. Ask him to search for evidence that there is intelligent life on the Earth by looking for signs of other flag signalers. He won’t be able to find any such evidence.

Please show how my thought experiment is incorrect and/or irrelevant. Or correct and/or relevant, if you find it so!

Ps. Honestly, I must admit that I find it a bit surprising that such radio surveys have always come up completely empty.