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Comment by thanatos519 | Hacker News Reader

But seriously, what could we do to make ourselves evident in every direction to distant beings with telescopes at least as good as ours? Something that would never ever happen naturally.

I'm thinking something passive (i.e. reflective) and orbiting a Lagrange point... maybe one we don't need much, like Mars L4 or L5. Make a dozen reflective spheres, of mirror mylar inflated with a little bit of some big-molecule gas that won't leak out. Arrange them in a static icosahedral form at the Lagrange point.

From any angle except perhaps very normal to the ecliptic, there would be a distinctive changing pattern of reflected light. Maybe each sphere could have a different notch filter coating on it so there would be some signal on the spectrograph too.

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It would have to be huge to be seen with telescopes as good as ours.

Looking at https://en.wikipedia.org/wiki/List_of_smallest_exoplanets:

- https://en.wikipedia.org/wiki/SDSS_J1228%2B1040_b has about 1/1000 the radius of Jupiter, but only could be detected because it’s heavy at 70% of the mass of the sun.

- https://en.wikipedia.org/wiki/Kepler-37b is larger than the moon.

So, it seems we can’t (¿yet?) build such a structure in a way that makes it visible enough.

If we let go of the idea that a proposal must be feasible with current tech, here’s an idea: split the sun in two halves, creating a binary star system. Then, merge the two again. Repeat. That should draw attention.

Yeah that's not bad. Any way to work prime numbers into it? I'm thinking bright objects worked into an orbit, with the gap between each reflector in orbit being say 5, 7, 11, 13, 17 so you'd see these periodic increases in brightness in an unmistakable pattern?

It would be much easier to pick the nearest N stars and point lasers at them with a peculiar frequency that would stand out on any spectra.

This random quora answer[1] suggests lasers could potentially have a spread of ~0.1 arcseconds so that would be (10 * 60 * 60)^2 * 40k ~ 1e13 times less power required (per target) than an omnidirectional source.

[1] https://qr.ae/pvZZjd

In order to have something visible in every direction is just impossible I think. It's best to just do something like flash lights or radio waves in such a way to spell out the first few prime numbers. EM waves spread out naturally from a small source, that seems much easier to me.

consider the situation at home of already being evident to other species and its results

Aye. Our sensory apparatus, let alone our ability to process the totality of inputs from it, is pretty limited. WTF can comprehend even what fungi "feel"? And we're of the same origin.

Maybe in 100 million years? Chump change, of course, even in biological time; but then "we" won't be worrying about triangles.

I think parent meant that whenever another species notices you, it tries to kill you or hide.

More generally, a mutual lack of understanding or cooperation regardless.

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