Hmm.. satellites? A planet with 'advanced civilization' would have satellites or other objects orbiting. Also devices that fly - so some radar can pick a plane in the sky? its Transponders? Scan the sea for large floating objects?
On the dark side one should be able to observe lights, and the same locations during the day should have cities (and not i.e. forest fires or volcanoes)?
On the light side one would be able to 'zoom in'/scan the surface and see structures or other shapes that would imply some manipulation of the surroundings on large scale.
How about antennas picking up multiple signals (radio, tv, etc.?)
For the case that it's pre-cities/pre-industry, good luck... Good luck zooming in and spotting 10 'planet-lings' (from Earthlings) with their planet-goats crossing a valley.
Having played A LOT of Starcontrol II though I can imagine that sending small crafts to the surface would help verify suspicions.
Based on us though, detecting non-advanced life is more important. We have one life form that has done things to make itself more detectable by launching satellites and having radio - for 100 years. Go back 200 years and what can you detect? How about 10,000 years? How would you detect the dinosaurs - that is what the a civilization in the Andromeda galaxy would be seeing now (or maybe just after they went extinct) - if they can detect earth life. That is the nearest large galaxy (I'm not counting small/satellite galaxies, though this might not be valid)
> Having played A LOT of Starcontrol II though I can imagine that sending small crafts to the surface would help verify suspicions.
the humans didn't discover deep subsurface bacteria until the 01990s; they'd been living in small crafts on the surface for millions of years without ever noticing the kilometers of life below the top few meters
they didn't even know about archaea until the 01970s
reasoning from fictional evidence merely leads you to mistake the authors' beliefs (or even narrative tropes they know to be false) for objective fact
IF the primitive aliens were anything like us, you could point something like FIRMS at the planet and wait a few weeks. One of the first things I would qualify as an anthropogenic (xenogenic??) signature, visible from space, would have been
regularly setting semi-controlled brush fires to make hunting and foraging easier. Nice bonus it gives you some idea of tribal migration patterns!
ed. - but it requires high-res direct imaging of the planet
The planets tend to be very far away. Seeing individual continents is not probable, much less any features. Heck, often the planet itself is visible only as a speck of shadow.
SETI is our attempt at the radio wave interpretation. The Sagan paper gives us non-radio detection methods as well (spectography, interpretations of reflected ligjt, and so on).
It may be possible to get much higher resolution images of exoplanets in the not too distant future by taking advantage of gravitational lensing and our own sun [1]. There are a few related advancements required before we can do that, although the thought that it could happen in our lifetimes is really exciting.
Super interesting - thanks for sharing! Glad to hear that there is so much momentum pushing this forward. I'm with the presenter: I desperately want this to happen in my.. I mean our.. lifetimes.
Ever since reading about this I have wondered if alien civilizations have been watching Earth in HD for millions of years, from thousands of lightyears away. Are they watching the Romans sail and fight wars now? Will they see nukes go off in a couple thousand years?
Even better, is it predictable that by a few thousand years ago we would probably be getting to space about now? Does this actually give credibility to the idea that aliens may visit and watch us from up close now? Perhaps there are probes arriving now-ish that were dispatched thousands of years ago.
Hmm.. satellites? A planet with 'advanced civilization' would have satellites or other objects orbiting. Also devices that fly - so some radar can pick a plane in the sky? its Transponders? Scan the sea for large floating objects?
On the dark side one should be able to observe lights, and the same locations during the day should have cities (and not i.e. forest fires or volcanoes)?
On the light side one would be able to 'zoom in'/scan the surface and see structures or other shapes that would imply some manipulation of the surroundings on large scale.
How about antennas picking up multiple signals (radio, tv, etc.?)
For the case that it's pre-cities/pre-industry, good luck... Good luck zooming in and spotting 10 'planet-lings' (from Earthlings) with their planet-goats crossing a valley.
Having played A LOT of Starcontrol II though I can imagine that sending small crafts to the surface would help verify suspicions.