October 1, 20232 yr It could be aliens visited our planet eons ago as higher forms of life were evolving. Perhaps we are an experiment. They put some of their DNA in the higher form of primates to see what intelligent life forms would evolve and what they would do with the planet. Of all the life forms on earth mankind doesn't seem to have a niche. The other forms of life all have a habitat but we had no natural habitat and had to make it for ourselves by stealing habitat from the natural creatures and expanding to eventually populate the world with ourselves and build cities and develop technology. We have crowded the natural animals out, deforested much of the planet, developed technology without thought of what it might do to the environment, and took what we could from the planet without giving anything back. We are at a point now where we are looking to colonize other worlds to save a sample of mankind to start over again. UFOs might be just observers of our petri dish planet. How they get here puzzles us because we have not yet understood the physics of real space travel that allows them to travel here in a reasonable amount of time to observe the experiment. Or maybe I'm all wet. Noel The tires are worn. The shocks are shot. The steering is wobbly. But the engine still runs fine.
October 1, 20232 yr 4 hours ago, martin-w said: According to the Fermi Paradox, if just one civilization in our galaxy survived and didn't destroy itself, it would take, even at the sedate velocities we travel, less than the age of the Earth to colonize the entire galaxy. I don't think any civilisation would want to colonise the whole galaxy and, in any case, wouldn't that be spreading their DNA a bit thin? We seem to have difficulty detecting alien megastructures at a distance of 1,447 light years (Boyajian's Star) so we would never detect one 5,000 or 10,000 or even 100,000 light years away. In any case, I feel that alien megastructures surrounding an entire star are pure science fiction. I am sure that highly advanced civilisations could find a more practical way to fulfil their power needs. 4 hours ago, martin-w said: In fact, military radar transmissions during the cold war had the power and frequency to be detected over 100's of lightyears. I assume that is purely theoretical for transmission through a vacuum. Space is full of stuff which, over a distance of many light years, would diminish the power of the transmission and, I suppose it would be very difficult to collimate the beam sufficiently over that distance to maintain its power in the first place. Internet sources have widely different answers but the National Radio Astronomy Observatory gives this answer for a 1 megawatt radar signal: “For reference, the Arecibo Observatory has a radar system that it uses to map the surfaces of the Moon and nearby planets that transmits a signal power of about 1 MW at a frequency of about 2.4 GHz. Let us further assume that the signal is transmitted at a frequency that can penetrate the Earth’s atmosphere and travels unimpeded through space. This 1 MW signal would be just barely detectable at the nearest star, Proxima Centauri, which is at a distance of 4.243 light years.” Dugald Walker
October 2, 20232 yr On 9/30/2023 at 6:21 PM, dmwalker said: In order to be noticed, we would have to have some noticeable activity which could be detected from many light years away. For almost all of the 3 billion years, there was no intelligent life and nothing to be noticed. If they could have spotted our planet in the first place, alien observers might have found our atmosphere interesting but not enough to come and visit. I'd exercise caution in assuming what alien civilizations would find "interesting" when it comes to life here, or anywhere else. Our reference point is a sample size of one.....and we don't even have a good grasp on our own history, how long we've been here, or the path we took to get here. All we have is (kind-of educated) guesses, based on the technology and scientific knowledge available to us today. That's not a lot to work with when taking on the mind-bending vastness of just our own galaxy (both in size and age). Quote What sign of intelligent activity, other than radio transmissions, might they look for? Are you thinking of some kind of advanced technology they might use? My hope is something far more advanced than radio waves. If their reported maneuvering capabilities are accurate (instantaneous acceleration etc.), that may imply they're somehow working around, or outside our known laws of physics.....which opens up a vast (and exciting) range of possibilities. We might be thinking in the equivalent of smoke signals, when others are using long-range Infrared and night vision. DB
October 2, 20232 yr Nobody now knows, or maybe never will know, why we haven't found space aliens. But we can make a reasoned guess. We have looked with project after project for them for over a hundred years. And my guess is that the needed parameters for life are just way too limiting. And that we do not find them because they do not exist. It doesn't cost all that much to keep looking. But I would at the same time not advertise our presence, which I believe Stehpen Hawking would have agreed with, but not say Carl Sagan or de Grasse Tyson. 5800X3D, RTX4070, 600 Watt, one or two 1440p 32" screens, 64 GB RAM, 4 TB PCle 3 NVMe, Warthog throttle, VKB NXT EVO stick, Honeycomb Alpha yoke, CH quad, 3 Logitech panels, 2 StreamDecks, Desktop Aviator Trim Panel. Crystal Light VR.
October 2, 20232 yr Author 14 hours ago, dmwalker said: I don't think any civilisation would want to colonise the whole galaxy and, in any case, wouldn't that be spreading their DNA a bit thin? It wouldn't be spreading DNA thin, it would be generating more DNA. If they are anything like us then expansion would be manifest. Or you could say that all it would take is one species to survive and be inclined to expand its territory, like us. and they could colonize the galaxy in a few million years even at our sedate velocities. Alien isolation is one answer though. Once a given technological advancement is made, it may be that they don't want to advertise their presence, or indeed, colonize beyond a certain distance. https://en.wikipedia.org/wiki/Fermi_paradox Quote Alien species may isolate themselves from the outside world[edit] It has been suggested that some advanced beings may divest themselves of physical form, create massive artificial virtual environments, transfer themselves into these environments through mind uploading, and exist totally within virtual worlds, ignoring the external physical universe.[119] It may also be that intelligent alien life develops an "increasing disinterest" in their outside world.[94]: 86 Possibly any sufficiently advanced society will develop highly engaging media and entertainment well before the capacity for advanced space travel, with the rate of appeal of these social contrivances being destined, because of their inherent reduced complexity, to overtake any desire for complex, expensive endeavors such as space exploration and communication. Once any sufficiently advanced civilization becomes able to master its environment, and most of its physical needs are met through technology, various "social and entertainment technologies", including virtual reality, are postulated to become the primary drivers and motivations of that civilization.[120] Edited October 2, 20232 yr by martin-w
October 2, 20232 yr Author 13 hours ago, dmwalker said: We seem to have difficulty detecting alien megastructures at a distance of 1,447 light years (Boyajian's Star) so we would never detect one 5,000 or 10,000 or even 100,000 light years away. It was based on the premise that given the age of the universe and that civilizations, we assume, would be territorial, that the galaxy should be full of detectable civilizations, including close proximity to our Earth. Maybe not Dyson spheres, as you say, that would be quite an achievement. I recall a civilization capable of building a Dyson sphere or ring world would be a type 2 civilization on the Kardashev scale. As I mentioned earlier, the chain of reasoning isn't considering that the UFO/UAP phenomenon might represent alien probes. Quote Chain of reasoning[edit] The following are some of the facts and hypotheses that together serve to highlight the apparent contradiction: There are billions of stars in the Milky Way similar to the Sun.[7][8] With high probability, some of these stars have Earth-like planets in a circumstellar habitable zone.[9] Many of these stars, and hence their planets, are much older than the Sun.[10][11] If Earth-like planets are typical, some may have developed intelligent life long ago. Some of these civilizations may have developed interstellar travel, a step humans are investigating now. Even at the slow pace of currently envisioned interstellar travel, the Milky Way galaxy could be completely traversed in a few million years.[12] Since many of the Sun-like stars are billions of years older than the Sun, the Earth should have already been visited by extraterrestrial civilizations, or at least their probes.[13] However, there is no convincing evidence that this has happened.[12] Edited October 2, 20232 yr by martin-w
October 2, 20232 yr Author 13 hours ago, dmwalker said: I assume that is purely theoretical for transmission through a vacuum. Space is full of stuff which, over a distance of many light years, would diminish the power of the transmission https://www.sciencefocus.com/space/how-far-from-earth-could-aliens-detect-our-radio-signals Quote In contrast, military radar transmissions set up during the Cold War to detect incoming ballistic missiles have the power and frequency characteristics to be detected over hundreds of light-years – and have already broadcast our existence to any aliens within around 60 light-years of the Earth. Quote This 1 MW signal would be just barely detectable at the nearest star, Proxima Centauri, which is at a distance of 4.243 light years.” Quote The Arecibo message[edit] Main article: Arecibo message In 1974, the Arecibo message, an attempt to communicate with potential extraterrestrial life, was transmitted from the radio telescope toward the globular cluster Messier 13, about 25,000 light-years away.[94] The 1,679 bit pattern of 1s and 0s defined a 23 by 73 pixel bitmap image that included numbers, stick figures, chemical formulas and a crude image of the telescope.[95] Edited October 2, 20232 yr by martin-w
October 2, 20232 yr 8 hours ago, DaviiB said: the mind-bending vastness of just our own galaxy (both in size and age). Yep, it’s not easy for any of us to relate to that vastness. Our galaxy and the universe as a whole is a pretty rural place. Somewhere out there are creatures identical to ourselves. Will we ever meet? Not a hope in hell. All this stuff about alien visitation has nothing to do with physics or biology. It’s about the human condition and our limitless imagination. Thats it.
October 2, 20232 yr 11 minutes ago, DD_Arthur said: Our galaxy and the universe as a whole is a pretty rural place. Rural is a subjective term. If you lived on a small isolated island in the Pacific ocean with only basic tools, you might be inclined to think the same thing about Earth. 12 minutes ago, DD_Arthur said: All this stuff about alien visitation has nothing to do with physics or biology. It’s about the human condition and our limitless imagination. I'm curious to know why you think that in light of everything that has become public in the last few years. DB
October 2, 20232 yr Author 20 hours ago, birdguy said: The other forms of life all have a habitat but we had no natural habitat and had to make it for ourselves by stealing habitat from the natural creatures Nope, mankind evolved on the African Savanah. That was our natural habitat.
October 2, 20232 yr Author 20 hours ago, birdguy said: It could be aliens visited our planet eons ago as higher forms of life were evolving. Perhaps we are an experiment. They put some of their DNA in the higher form of primates to see what intelligent life forms would evolve and what they would do with the planet. There's no evidence of that. 98.8 of our DNA is the same as Chimps. There's nothing alien about the rest. https://www.pbs.org/wgbh/nova/article/dna-human-evolution/ Quote Powerful Switches You've honed in on other regions as well. How would you characterize them? It turns out that the vast majority of these fast-evolving sequences are not genes, the parts of our genome that encode proteins. The pieces that have changed the most in our DNA look like they are switches, switches that turn nearby genes on and off. So what makes a human different from a chimp isn't that we're made up of different building blocks, different genes, but instead that we're using those pieces in different ways.
October 2, 20232 yr Author 1 hour ago, DD_Arthur said: All this stuff about alien visitation has nothing to do with physics or biology. It’s about the human condition and our limitless imagination I'm still keeping an open mind. Although there are times when I sway closer to the visitation hypothesis. Edited October 2, 20232 yr by martin-w
October 2, 20232 yr 4 hours ago, martin-w said: Quote The Arecibo message[edit] Main article: Arecibo message In 1974, the Arecibo message, an attempt to communicate with potential extraterrestrial life, was transmitted from the radio telescope toward the globular cluster Messier 13, about 25,000 light-years away.[94] The 1,679 bit pattern of 1s and 0s defined a 23 by 73 pixel bitmap image that included numbers, stick figures, chemical formulas and a crude image of the telescope.[95] I'd like to see the calculation that shows the signal strength at 25,000 light years or even 100 light years. Perhaps some of the physicists amongst us could comment. This calculation is from Jim Lux at Quora: “ But let’s do a numerical example of something like a large broadcast station, radiating a megawatt.” “Now, if you wanted to make a signal that can be detected easily, you’d make a very narrow band transmission - Above, I assumed the radio station was essentially random noise with 10kHz BW. If we transmit just a narrow carrier (<1 Hz wide), then we pick up another 40 dB. So at a billion km, we’re now at -191 dBW/m^2, compared with -224 dBW/m^2. If we go out to the Kuiper belt, where things like Pluto are, that’s at 6E9 km, and our signal is another 15 dB weaker (-206 dBW), but still detectable. Out at 200 AU (3E10 km), we’re starting to get close - the signal is -220 dBW, and the noise is -224.” “But, if you go out to Proxima Centauri, 4.4 light years, or 4.16E13 km (that’s about 41,600 billion km), the signal has faded to way below the noise floor.” https://www.quora.com/Is-there-a-limit-to-how-far-we-can-send-a-signal-into-space Also, here's an interesting chart at the end of part 2, showing the range limits for the Arecibo 5MW transmitter: https://www.researchgate.net/publication/224263754_Developments_in_the_radio_search_for_extraterrestrial_intelligence Edited October 2, 20232 yr by dmwalker Dugald Walker
October 2, 20232 yr Author 30 minutes ago, dmwalker said: I'd like to see the calculation that shows the signal strength at 25,000 light years or even 100 light years. Well, that was what they did at Arecibo in 1974 for the famous Arecibo message, aimed at M13, 25,000 lightyears away. The message was designed by Frank Drake I recall. The message was aimed at the centre of the cluster. Quote In 1974, the most powerful broadcast ever deliberately beamed into space was made from Puerto Rico. The broadcast formed part of the ceremonies held to mark a major upgrade to the Arecibo Radio Telescope. The transmission consisted of a simple, pictorial message, aimed at our putative cosmic companions in the globular star cluster M13. This cluster is roughly 21,000 light-years from us, near the edge of the Milky Way galaxy, and contains approximately a third of a million stars. The broadcast was particularly powerful because it used Arecibo's megawatt transmitter attached to its 305 meter antenna. The latter concentrates the transmitter energy by beaming it into a very small patch of sky. The emission was equivalent to a 20 trillion watt omnidirectional broadcast, and would be detectable by a SETI experiment just about anywhere in the galaxy, assuming a receiving antenna similar in size to Arecibo's. The message consists of 1679 bits, arranged into 73 lines of 23 characters per line (these are both prime numbers, and may help the aliens decode the message). The "ones" and "zeroes" were transmitted by frequency shifting at the rate of 10 bits per second. The total broadcast was less than three minutes. A graphic showing the message is reproduced here. It consists, among other things, of the Arecibo telescope, our solar system, DNA, a stick figure of a human, and some of the biochemicals of earthly life. Although it's unlikely that this short inquiry will ever prompt a reply, the experiment was useful in getting us to think a bit about the difficulties of communicating across space, time, and a presumably wide culture gap. https://www.seti.org/seti-institute/project/details/arecibo-message#:~:text=The emission was equivalent to,similar in size to Arecibo's. Edited October 2, 20232 yr by martin-w
October 2, 20232 yr 1 hour ago, martin-w said: 98.8 of our DNA is the same as Chimps There are days when I feel that, in my case, it's 98.9% Dugald Walker
Archived
This topic is now archived and is closed to further replies.