Avi Loeb

And they're not very far away.

You can imagine technological craft being parked in the solar system.

Any object bigger than a football field will not be visible at distances larger than 10 times the Earth-Sun separation for the telescopes we are operating now.

So there could be

plenty of technological objects far away, bigger than the biggest rocket we ever built, bigger than Starship, a football field size.

Beyond 10 times the Earth-Sun separation, it wouldn't reflect enough sunlight.

This is 10 AU?

Yeah.

Is that what you mean?

10 AU.

And so I did a calculation about 15 years ago where I said, in collaboration with Ed Turner, a colleague of mine from Princeton, I said, what if there are artificial lights

the outer solar system okay would we detect them so at the time there was the hubble space telescope and we asked them how if you take the deepest images of the hubble space telescope how much light can you detect and we found that from the distance of pluto we would be able to see a city like tokyo okay it's still pretty pretty difficult to see

Yeah, but a city like Tokyo consumes a small fraction of the power supply on Earth.

Right.

And...

There could be some infrastructure.

Yeah, it's difficult to see.

So it may be there.

And the way for you to figure it out, if you were to observe a point of light, is that as this object recedes away from the sun, it gets dimmer faster if it reflects sunlight than if it generates its own light.

Another way to look at it, if you have a technological object approaching us,