5 ms·
Earth's Radio Bubble: Every signal we've ever sent into space
- analog31 5mo agoSomething that I muse about is that this bubble may indeed be a thin shell. My rationale is that already the bulk of our communications are confined to waveguides -- optical fibers. Our wireless comms continue to be engineered to produce less power and to be almost indistinguishable from noise. Much of our AC power travels along paired wires whose fields cancel one another at the equivalent of an inverse-fourth law or worse. Soon they may all be DC. The civilizations who are "out there" may only have a narrow time window to pick up our signals. Like we've fashioned a poor man's Dyson sphere.
- marcus_holmes 5mo agoAgreed. Also, the audience and business model for commercial radio and television stations are declining, and it's easy to see a point where nobody listens to radio or watches television any more and they stop broadcasting.
- amarant 5mo agoI'm surprised anyone does either of those things now! Well except for that one special time of year, but honestly Eurovision ought to be streaming online instead of broadcasting on TV already!
- marcus_holmes 5mo agoAliens will enjoy the kitsch just as much as we earthlings surely?!
- amarant 5mo agoGood point! I can hardly think of a better way to start friendly relations with extraterrestrials than broadcasting Eurovision to them.
- wa2flq 5mo agoThere was a Star Trek book (The Abode of Life?) that had a planet that where the communication was mostly confined to the planet. I think Uhura detected the planet from the background noise.
- chasil 5mo agoI think that an atmosphere with measurable oxygen gas is a far longer lasting, pervasive and interesting signal that by itself could prompt investigation. The oxygen has been here for far longer than us, sometimes at much higher levels.
- DoctorOetker 5mo agochemistry has more reactions than just with oxygen, oxygen alone is a poor indicator of life...
- adrianN 5mo agoWe don’t have a lot of examples of technological life forms that don’t need oxygen.
- deleted 5mo ago[deleted]
- jerf 5mo agoOxygen is a highly reactive element that on a cosmological time frame instantly disappears by bonding with things. It is very difficult to come up with an explanation other than "life" for why an atmosphere would be full of oxygen; it may well be impossible to come up with an explanation other than "life" for why an atmosphere would be full of oxygen for 500 million years, especially on a ball of iron. Even having a transient explanation would be very difficult.
- marcus_holmes 5mo agoNot all living organisms use oxygen (even on our planet), true. But you don't get free oxygen on a planet without life to continually produce it. It's a good indicator of some forms of life.
- api 5mo agoEarth has been screaming it has a very likely biosphere for at least 500 million to a billion years. To anyone with huge space based telescopes. So why no visitors? If there had been, we wouldn’t know. Any probes that dropped into our planet any further back than a few tens of thousands of years (and less if they landed in a hot wet region) might be gone by now. They’d have been eaten by corrosion and mechanical erosion and eventually by plate tectonics. They also likely would have been small, meaning even if they got fossilized we’d have to get super lucky to find one. The energy required to accelerate something to meaningful fractions of light speed and then decelerate at the other side means a probe is probably an orbiter the size of a basketball and then a little drone the size of a golf ball or something. We might have had dozens or hundreds of little visitors over the last billion years and we’d never know unless we got real lucky. Flyby missions are also likely due to the physics. The energy for slowing down might instead be spent just going faster to get results faster. The probe just streaks past at 7% the speed of light and takes a bunch of pictures and measurements.
- boznz 5mo agoNice article. I had to go down this rabbit-hole researching my first book. Actual likelihood of anyone actually being able to receive these past a few tens of LY is quite low without very sensitive receivers. Also as another commenter pointed out the window for receiving us is closing as more modern wide-band and spread-spectrum signals are more power efficient, directed, and look much closer to noise than data.
- api 5mo agoA lot of people think the “great silence” from SETI means something, unfortunately. A civilization using only low power radio wouldn’t be detectable in the Centauri system.
- meatmanek 5mo ago> What they first received Shouldn't every cell in this column be the same?
- marcus_holmes 5mo agoI assumed that it was something to do with signal strength, but re-reading it, you're right, this doesn't make sense.
- cosmicSap 5mo agowhy? each star receives a different signal because the bubble has been expanding since 1900 so a star 4.2 LY away received whatever we were broadcasting in 1904, while a star 25 LY away is only now receiving our 1925 broadcasts. The column reflects what signal has actually reached each star so far, not what we're broadcasting today
- josuepeq 5mo agoI was thinking about this a few weeks ago. Doppler shift would substantially change the wavelength, and frequency too. Perhaps the number of light years a wave has traveled moving in the same direction that Earth is moving in, would be less distance than the side facing the direction that we are moving away from. The Earth, and Solar System are always moving in motion; I would imagine doppler shift would also have a significant impact on the success of receiving such transmissions.
- diziet 5mo agoThe velocity of the Solar System rounds to 0 when expressed as a fraction of c.
- socalgal2 5mo agoI asked a friend at JPL, if there was a civilization at Alpha Centauri and they were sending out the same types of signals as Earth does today, could we detect those signals at Earth with our current tech? Answer: No (which the article also mentions in so many words)
- keithnz 5mo agothe article seems way too generous, we'd barely be able to detect things like 1980s tv broadcasts, they fall below galactic noise before alpha centauri, let alone 50 light years out.
- deleted 5mo ago[deleted]
- DamnInteresting 5mo agoI wrote an article about this same general topic way back in 2007[1], wherein I conducted a thought experiment with an Arecibo observatory traveling away from Earth. I calculated that even mighty Arecibo would be unable to detect Earth's omnidirectional FM radio as far out as Saturn, let alone from another star. Since that writing, we've lost Arecibo observatory, discovered gobs of exoplanets, started scrutinizing those exoplanets with JWST, and increased our radio sphere radius by another 19 lightyears. [1] https://www.damninteresting.com/space-radio-more-static-less-talk/ https://www.damninteresting.com/space-radio-more-static-less...
- fuckinpuppers 5mo agoMakes me think of the intro to Contact, which was a really cool “visualization” of this… with Hitler and the 1938 Olympics being the first tv broadcast of strength, which aligns with reality
- derbOac 5mo agoThis was portrayed in the film Contact (1997) closely to what's described in this piece (maybe it's in the book too? I haven't read it).
- nik282000 5mo agoRead the novel, or listen to the audiobook. The film was good but totally misses the punchline at the end of the novel.
- throw0101a 5mo ago> 1936: Berlin Olympics first major TV broadcast Bit of a plot point in Sagan's novel (and the movie adaptation): * https://en.wikipedia.org/wiki/Contact_(novel) https://en.wikipedia.org/wiki/Contact_(novel)
- sidewndr46 5mo agoGiven that we don't receive signals like this from at least some direction in the universe, I feel like we can be relatively certain that once this signal reaches some specific area humanity will be toast.
- RF_Enthusiast 5mo agoWBCQ in Monticello, ME (USA) says it broadcasts to outer space via a modulated laser. From <http://www.wbcq.com/ http://www.wbcq.com/>: WBCQ’s laser broadcasting service is available to beam your program into outer space via our high-powered, modulated, laser system. So in addition to broadcasting worldwide over shortwave radio, you can transmit into space over our high-powered lasers. It’s a lot of fun. The cost for this service is $50 an hour.
- wahern 5mo agoLasers obey the inverse square law as perfect collimation isn't possible. But I guess as a practical matter it does make it easier to achieve a particular energy level at a target. You still apparently need megawatt scale lasers just to discern a signal from Alpha Centauri, though: https://academic.oup.com/mnras/article/516/2/2938/6668809 https://academic.oup.com/mnras/article/516/2/2938/6668809 (I dunno how to calculate the other way around--from here to there--as it's partly a function of the origin star's luminosity.)
- rao-v 5mo agoI’d love for this chart to also capture the loudest signals we’ve sent. Surely somebody must have accidentally broadcasted a non-directional megawatt radio signal at some point right? Actually humm maybe nukes are our brightest non directional transmission?
- carlostkd 5mo agoDiscovery live in another planets can be challenging but the real question is: Are we sure that we want to discover them? What if they are not friendly?
- GJim 5mo ago> What if they are not friendly? And the purpose of them choosing to attack another civilisation across interstellar space would be.....?
- HelloUsername 5mo ago> And the purpose of them choosing to attack another civilisation across interstellar space would be.....? They don't like my stupid face
- GJim 5mo agoHarsh. But fair.
- cwmoore 5mo agoIn our orientation with the Sun, I think the bubbles should be cardioid and not spherical. But with the nature of the inverse-square law and background noise, it doesn’t seem to matter.