So we're talking subspace channels here?
Posted on 12/28/2016 6:25:39 PM PST by Steely Tom
Who doesn't love a good mystery story? What happens when that story is 5 milliseconds long and comes from a place millions of light-years away?
This episode of _Conversations with an Astrophysicist_ Dr. +Katie Mack and +Scott Lewis dig into the mysterious *Fast Radio Bursts* that have been observed over the past few years. Astronomers are still seeking out the source of what these seemingly random blasts of radio light, but Katie & Scott are on the case to discuss what we know, and hopefully narrow it down a bit.
In my view, the Milky Way galaxy (let alone, the entire universe) is far too vast for me to assume that we, on this smallish mudball, circling a second rate star, in the hinterlands of an unremarkable collection of stars, are the one and only form of intelligent life there is.
There are two hundred BILLION stars in our home galaxy, and even more galaxies in the the observable universe. The staggeringly incomprehensible numbers involved, lean towards a universe teeming with life - advanced and otherwise.
At some point, we’re going to tap into a signal from one of them, though I highly doubt it will be anywhere in the radio spectrum, which is much too slow for interstellar communications.
So we're talking subspace channels here?
Somewhere, in a galaxy far away, scientists are enjoying I Love Lucy.
Thanks. It sounds as though they COULD be the work of intelligent beings. Next question: Since we know the planets and stellar bodies give off musical sound; what else out there could do that, and sweep the frequencies? You’re the scientist. I’m just a dumb farmer, but very curious.
I could imagine an angularly limited radio source on a body that is rotating quickly. At the body turns toward earth, the frequency is higher because of Doppler shift and starts lowering as the source rotates, eventually away from earth.
The angular limitation could be a characteristic of the source (I’d think not likely) or just a function of absorption by the rest of the “body” when it is turned away from earth.
There are two hundred BILLION stars in our home galaxy, and even more galaxies in the the observable universe. The staggeringly incomprehensible numbers involved, lean towards a universe teeming with life - advanced and otherwise.
...
To counter those big numbers, the available evidence points to the probability of life, especially intelligent life to be extremely small.
We cannot understand the language of terrestrial bees, Apis mellifera.
We can’t hope to understand extraterrestrial Aliens.
They came, but since they looked like dogs, nobody paid any attention
Australia Is probably one of the nicer places from which to observe the southern sky.
L-I-M, as I understand your RADAR description, the carrier was sinusoidal -- linearly frequency-swept (modulated) over a 1MHz range by a 1KHz "sawtooth" signal. Every millisecond, the modulation frequency would reach peak, then instantly drop back 1 MHz, and begin its sweep again... (IOW, I'd guess that early RADARs were modulated by a VCO -- driven by a relaxation oscillator-generated sawtooth...)
OTOH, a point source on a rapidly-spinning sphere -- Doppler-modulated by the angular velocity -- would sinusoidally reach a peak frequency, and sinusoidally drop back to minimum. Then, with the signal occluded by the object, the signal would be attenuated (below detectable level) for half a revolution, and then the half-sinewave signal would reappear. (Basically a frequency-modulated signal, driven by a half-rectified sine wave...)
Going to go "bomb" my bandwidth allocation, watch the video, hope for a look at the actual signal, and -- I hope -- stop speculating... '-)
Back soon...
Your understanding of LFM is spot on. Originally LFM used a dispersive delay line, with delay proportional to frequency to modulate the signal. Virtually all modern radar systems use digital waveform generators, and multiplier chains.
https://en.wikipedia.org/wiki/Chirp
Absence of evidence is not evidence of absence.
Humankind has only just begun taking its first tentative steps outside its own front door. In a universe as big as ours, it's no wonder we haven't yet discovered lifeforms elsewhere. We've barely begun exploring our own back yard.
Only when our technology has advanced sufficiently to enable us to easily explore other star systems, will we be able to gather enough evidence to answer the question of alien life.
I would call it both amplitude and frequency modulated...
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Well, there you have it, folks -- have at it! '-)
Seems ol' Gene Rodenberry had his finger on the answer.
A culture that has mastered faster than light space travel, will have also developed faster than light communication technology.
Wow! that almost goes back so far as to touch on my present avocation -- archaeology! '-)
The evidence keeps piling up that life isn’t there, especially in our own backyard. (Even here on life friendly Earth the ratio of biomass to mass is one part in ten billion.) And with technology that allows us to see beyond our Solar System, the evidence is much better now than when Fermi made his famous observation.
But the most compelling evidence is the study of the tree of life. The probabilities for the events that led to us are extremely low. There was only one common ancestor that evolved around a hydrothermal vent. Mitochondria only happened once. Chloroplasts only happened once. All of those developments only happened once in billions of years. The fact there is only one tree of life is excellent evidence that life like us is exceedingly rare, and it’s dependent on the same physics and chemistry that exists everywhere in the universe.
All ET proponents have is the alien in the gaps of our knowledge and the gaps keep getting smaller.
FReepMail for you...
I agree. He was unusually imaginative, and had an eye for the big picture. Also (and as you probably know) he recruited some of the most talented writers in the SF world to write some episodes of TOS, which I think surely deserves a place in television's "Golden Age."
The episodes The Cloud Minders and A Taste of Armageddon were among those which stuck with me for the rest of my life, and are relevant today.
Also the episode And The Children Shall Lead was (I think) Rodenberry's gentle criticism of the youth/hippy movement of the 1960s. If you take it in that way, it seems to indicate that Rodenberry was fundamentally a conservative.
Also, it could be argued that he was possibly the first producer of a popular program to introduce what we call today multiculturalism, by including human characters from many ethnicities. Of course there had been Black characters in leading roles on TV before (Bill Cosby in I Spy comes to mind), but Lt Uhura was not only Black but also African, as you may recall from the episode in which had her memory wiped out and had to be taught everything from scratch, starting with Swahili, her native language. I believe that was the first time I ever even heard the word "Swahili," and I'm sure that was the case for many other eleven-year-olds.
The whole "subspace communication" thing illustrates that Rodenberry was aware of exactly what you stated, that the speed of light is much to slow for a civilization that can truly explore the universe.
As I said before, humans have only begun taking the first few tentative steps outside their local environment, and have barely scratched the surface of those few worlds we’ve visited or probed.
In time, we could find that only one planetary system in a million hosts life. Given the incalculable number of planetary systems in the universe, life would still prove to be abundant.
Naturally, this is all speculation on our part, but the probabilities involved argue for the existence of life elsewhere.
If the f/t relationship had been dead linear, a perfect straight line, I'd be much more inclined to give a big "Hmm!"
Been trying to envision a signal emitted from the bottom of a deep shaft -- on a spherical object that is (very) rapidly "tumbling" on multiple axes. On most passes, (except perfectly on-axis) it seems to me that even a linear signal would have some circular doppler distortion in frequency...
But, that would seem to be more "natural" than "designed".
What blows my mind is the sheer power of the beast! Even with inverse square attenuation over millions of light years of distance, that is a "bright" signal... (That, of course, assumes that the astrofolks got their source correctly identified...)
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