If you read the history of radio, early radio pioneers were always picking up mysterious radio signals. Guys like Marconi were reporting strange transmissions-which seemed to come from outside the planet. I remember that in the 1920’s, an Amherst College astronomy professor claimed to have picked up a signal from Mars. Needless to say, as radio technology advanced, such reports became fewer. My question: what were these “signals”? Some say that they were either natural radio emissions (from the Sun, Jupiter, etc.), others that they were “howlers” radio signals generated by lightning.
Or were the Martians trying to warn us (before we filled the ether with crap like “I Love Lucy”?
Nah, these anamolies were most likely picking up terrestrial based RF (e.g. sources broadcasting from elsewhere on Earth, reflecting off the ionosphere and making the broadcast origin appear as if it was coming from Mars by happenstance, etc.).
You might be interested in Wow! signal - Wikipedia
If you were trying to send a radio signal to extraterrestrial intelligent life, what frequency would you use? How about hydrogen, the most abundant element in the universe? That’s just what we found.
Could pulsars have been heard by early 20th century radio receivers or do you need a big radio telescope to pick them up?
It depends on what type of radio receiver you are talking about, but your typical early 20th century radio receiver generated too much internal noise to pick up something as weak as a pulsar. As they worked on making better radio receivers in the 1930s, they discovered that they just couldn’t get all of the noise out of them, and that’s when they came to the realization that there was radio noise coming from things like the sun. Efforts to produce lower noise receivers accidentally resulted in the discovery of cosmic background radiation in the 1940s. So it probably wasn’t until the 1940s or 1950s or so that you could theoretically pick up a pulsar.
Pulsars may have been picked up by radio astronomy equipment in the 1950s or early 1960s, but if they were, they were probably ignored as being terrestrial noise. The first pulsar wasn’t officially discovered until 1967. It was named LGM-1 for “Little Green Men” (i.e. aliens).
You really need a directional low noise receiver to pick one up, so communication type of equipment isn’t going to accidentally pick up a pulsar (unless you are setting up the equipment and just happen to point the receiver up at the right point in the sky while installing it).
Nah, that’d be a terrible choice, since it’s the most abundant element in the Universe. If you pick up a transmission at 22 cm, it’s not too hard to contrive a situation where it’s coming from natural hydrogen. Now, if you really wanted to send a signal and make it clear that it’s coming from intelligences, you’d pick some simple irrational mathematical constant, like pi, e, or phi, and transmit at a frequency or wavelength that’s that times the hydrogen hyperfine transition.
Nitpick: a 1420 MHz radio signal has a 21 cm wavelength. And agreed, it would be best used as a reference base for the encoding of the information content of the signal. The hyperfine transistion of neutral hydrogen was used as the base for length and time measurements on the pictorial plaques in the Pioneer probes, although it is unlikely that they will ever be encoutered by intelligent alien life.
However, while the trandenscental numbers, and in particular e and pi are special to us (because our basic counting system is based upon integers and ratios) they may not be at all special to an alien form of life that does not use discrete counting or Euclidian geometry. It would probably be better to use a continuous three dimensional fractal function such as a Rössler system or an Apollonian sphere as a fundamental basis to establish artificiality of the signal, as the fractal pattern should be discernable whether one intreprets the signal in discrete counting steps or a continuously varying function.
Stranger
Wait. Are you saying that advanced extraterrestrial lifeforms will be better mathematicians than the majority of people who post on teh internets?
That’s awfully elitist of you. Elite, elitist, elitest.
It is less a question of “better” than of how they fundamentally view the description of nature. That we learn integeter arithmatic first is not that it is more basic or easier to understand conceptually, but because the constructs of our society are built around discrete units of counting. The fact that we have a regular number of individual digits which are often used as an instrument for counting tends to reinforce their applicability, and as a result, we try to force everything that we experience in the world into categories or bins that can be discretely counted.
However, once you get past counting apples and start dealing with continuous, distributed, or differential phenomena, that mind set becomes a hinderence. And since nearly all natural phenomena are not discrete (at the levels we can naturally perceive without the aid of microscopes) we end up making artificial distinctions or simplifications; for instance, two navel oranges are considered equivalent (both are oranges) even though they may be of wildly varying size. Even at levels where phenomena are discrete–at the levels of molecules or below–the actual mechanics are stochastic along a continuum, which causes an apparent paradox for us, but is not problematic when you stop trying to force the system to be a set of discrete particles and accept them as continuous fields with point-like loci where they interact.
An alien intelligence which does not perceive or model the world as discrete chunks may not have any conception of integers or discrete bases, and therefore trying to communicate in terms of harmonic values of a transcedental number may not mean anything to them. A clearly artificial differential signal, such as one developed from a fractal system, however, would likely be recognized by any intelligence, provided they could interpret the underlying encoding system, and of course can receive a radio frequency signal.
Stranger
Thanks…I also seem to recall that Nikola Tesla (when he wasn’t talking to pigeons and worrying about ladies pearl earrings), claimed to have picked up strange signals as well-could be have actually done so?
I’ve done research on the development of space flight and extraterrestrial communications. From what I’ve seen most of the people in the game thought like engineers, not mathematicians. I don’t know exactly when the proposal to consider non-digital phenomena arose, and for all I know it’s something you invented, but I don’t remember seeing it in any of the early writings on the subject. Perhaps it’s a measure of how our thinking has to progress beyond the bare minimum of creating and listening to signals just to play in the pros. And my dig about teh internets was in reference to the many posters who propose to give us “science” when real science involves concepts many light years above their ken.
Did he pick up electrical signals? Of course he did. Everybody did. Were they anything of interest other than natural noise, internal noise, and bounced noise? Of course not.
And here I was going to propose “Shave and a Haircut” as the best universal primer message.