Could an alien civilization be watching us?

Yes—scientifically, it’s possible.

If an alien civilization is far away, they would be seeing Earth in the past because light takes time to travel. At 1,000 light-years away, they’d see Earth as it was 1,000 years ago. To see us right now, they’d need to be extremely close.

They might notice us in a few ways:

• Radio signals: Our broadcasts have only reached about 100–130 light-years out, so only nearby stars could have picked them up.
• Atmosphere: Even from much farther away, they could spot signs of life by looking for oxygen, methane, and other biosignatures in Earth’s atmosphere.
• Deliberate silence: Some theories, like the Zoo Hypothesis, suggest advanced aliens might already know about us but avoid contact.

Bottom line: watching us is plausible in theory, but there’s no evidence that anyone is doing it.