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Even if Oumuamua was a probe how would that explain the second interstellar sucker we're discussing here? The closest star system that could harbor life is 4 li

Even if Oumuamua was a probe how would that explain the second interstellar sucker we're discussing here? The closest star system that could harbor life is 4 light years away. So even if Oumuamua signaled home that it found a planet with little brown beings it would take them at least 8 years to send a second probe. Oumuamua was detected just two years ago.

sandworm101 7y ago
>> The closest star system that could harbor life is 4 light years away. Under the conclusion that space-born civilization would remain around stars. If we one day tap into other energy sources, ie whatever is powering dark energy, stars may become irrelevant or even awkward to be around. A civilization of kilometer-wide cities could be just beyond Pluto and still totally outside our perceptions.
- elorant 7y ago
  In which case you don't need to send probes hundreds of meters long. You'd send something much more compact and undetectable. You don't have to worry for probe's longevity so to enclose it inside an asteroid since you're launching from relatively shorter distances. Oumuamua as an alien probe sounds probable. Two of them in a span of two years, not so much. Besides contrary to Oumuamua this one has all the characteristics of a comet.
  - sliken 7y ago
    You are assuming that the civilization that sent it is trying to be stealthy. Not to mention at only 60,000 mph (Oumuamua) or 90,000 mph (C/2019 Q4) these probes need to be designed for many 100,000 years of travel if not millions. During that time they will see quasars, supernovas, and a wide variety of high energy particles. Might well make more sense to have many feet of rock as shielding instead of trying to keep a high power energy source going for that long. If you are patient gravity assisted slingshots makes quite a bit of sense.
    - elorant 7y ago
      And how does a second probe in a two year span fits this theory? If you send out probes with the intention to crawl the galaxy for hundreds of thousands of years then the chances of two of them entering the same region in a two year timespan are nonexistent.
      - sliken 7y ago
        Well lets assume there's probes somewhat equally distributed in the galaxy, and that there's many tiny probes and fewer larger probes. Assuming enough technology for replicating probes the number of probes in the galaxy is limited only by time and materials. Presumably if you are watching a galaxy you are quite patient and a few 100,000 years is no big deal. With that kind of experience you've likely figured out what signature events are related to the rise of intelligence. It's hard to speculate on the technology, sensors, and intelligence of the probe makers. Maybe the signature even to watch for is plankton, oxygen, and being in the Goldilocks zone (billions of years ago)? Changes in atmospheric chemistry related to clearing forests and cooking? (1000-10,000 years ago)? Emissions of radio waves (75 years)? Whatever that threshold was, it might have been triggered in the past and a slow moving smaller ship was first (Oumuamua), now a few years later a somewhat faster (15%) larger ship is coming for a look. Fun to think about anyways... at least we saw this one coming so anyone that wants a closer look will have the chance.
        elorant 7y ago
        15% faster is too low. If they're far away, as the scenario with the long term probing implies, then the second probe should be orders of magnitude faster.
sliken 7y ago
Well presumably anyone smart enough to mass produce interstellar probes would be able to make pretty decent sensors for a probe that's 100-1000 meters long (Oumuamua). Might even pick an asteroid that's long and thin and core it out and put a big telescope inside. At least some speculation on Oumuamua lead to the conclusion that it had unusually low mass for an object so large. Oumuamua might well have reported something interesting 1000 years ago when it was 0.09 light years away. Maybe changes in the atmospheric chemistry related to human activity. Also note C/2019 Q4 is approaching at about 50% faster than the previous. It looks like it's a comet with a tail... or is that a retrorocket?

sandworm101 7y ago

>> The closest star system that could harbor life is 4 light years away. Under the conclusion that space-born civilization would remain around stars. If we one day tap into other energy sources, ie whatever is powering dark energy, stars may become irrelevant or even awkward to be around. A civilization of kilometer-wide cities could be just beyond Pluto and still totally outside our perceptions.

elorant 7y ago
In which case you don't need to send probes hundreds of meters long. You'd send something much more compact and undetectable. You don't have to worry for probe's longevity so to enclose it inside an asteroid since you're launching from relatively shorter distances. Oumuamua as an alien probe sounds probable. Two of them in a span of two years, not so much. Besides contrary to Oumuamua this one has all the characteristics of a comet.
- sliken 7y ago
  You are assuming that the civilization that sent it is trying to be stealthy. Not to mention at only 60,000 mph (Oumuamua) or 90,000 mph (C/2019 Q4) these probes need to be designed for many 100,000 years of travel if not millions. During that time they will see quasars, supernovas, and a wide variety of high energy particles. Might well make more sense to have many feet of rock as shielding instead of trying to keep a high power energy source going for that long. If you are patient gravity assisted slingshots makes quite a bit of sense.
  - elorant 7y ago
    And how does a second probe in a two year span fits this theory? If you send out probes with the intention to crawl the galaxy for hundreds of thousands of years then the chances of two of them entering the same region in a two year timespan are nonexistent.
    - sliken 7y ago
      Well lets assume there's probes somewhat equally distributed in the galaxy, and that there's many tiny probes and fewer larger probes. Assuming enough technology for replicating probes the number of probes in the galaxy is limited only by time and materials. Presumably if you are watching a galaxy you are quite patient and a few 100,000 years is no big deal. With that kind of experience you've likely figured out what signature events are related to the rise of intelligence. It's hard to speculate on the technology, sensors, and intelligence of the probe makers. Maybe the signature even to watch for is plankton, oxygen, and being in the Goldilocks zone (billions of years ago)? Changes in atmospheric chemistry related to clearing forests and cooking? (1000-10,000 years ago)? Emissions of radio waves (75 years)? Whatever that threshold was, it might have been triggered in the past and a slow moving smaller ship was first (Oumuamua), now a few years later a somewhat faster (15%) larger ship is coming for a look. Fun to think about anyways... at least we saw this one coming so anyone that wants a closer look will have the chance.
      - elorant 7y ago
        15% faster is too low. If they're far away, as the scenario with the long term probing implies, then the second probe should be orders of magnitude faster.

sliken 7y ago

Well presumably anyone smart enough to mass produce interstellar probes would be able to make pretty decent sensors for a probe that's 100-1000 meters long (Oumuamua). Might even pick an asteroid that's long and thin and core it out and put a big telescope inside. At least some speculation on Oumuamua lead to the conclusion that it had unusually low mass for an object so large. Oumuamua might well have reported something interesting 1000 years ago when it was 0.09 light years away. Maybe changes in the atmospheric chemistry related to human activity. Also note C/2019 Q4 is approaching at about 50% faster than the previous. It looks like it's a comet with a tail... or is that a retrorocket?