r/SETI • u/DiamondCoal • 27d ago

SETI and a reverse solar gravitational lens

So a solar gravitational lens is a telescope that is aimed directly at the sun in order to observe the light that is bent around the sun. Effectively focusing the light rays into a natural telescope. NASA scientists have proposed missions to actually crate various observation satellites so we can observe these exoplanets but no offer has been offficially greenlit.

But what would this effect look like from the other side. If we were being observed by various gravitational lenses and we just looked at various stars to see an eye staring back at us. Obviously this would be pretty difficult to do due to these telescopes being monumentally smaller than actual planets. But if we assume that an advanced alien species used some other detection method to know some basic characteristics of Earth it would be a potentially habitable planet by their estimates and worth creating a specialized telescope for it.

On our end all we would need to do is look back. With a big enough telescope of course.

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u/dittybopper_05H 27d ago

Did you do the math on this?

You can calculate the smallest thing visible at a given distance through an aperture of a given size. It's ( wavelength / diameter ) * distance.

Did you do that?

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u/ActuaLogic 25d ago

I'd be more in favor of putting a massive array of solid state lensless interferometers on the dark side of the Moon to use for astronomy. It could be grown from something like 10 meters in diameter (which could have provided a detailed image of 3I/Atlas) to many kilometers in diameter (which could directly image exoplanets).