Could an alien civilization with technology like ours detect us? What would they see, and from how far? Understanding Earth’s visibility could help scientists searching for alien life. On February 3, 2025, the SETI Institute stated that Earth’s signatures could be seen nearly as far as the Milky Way’s center.

A peer-reviewed study in The Astronomical Journal suggests that analyzing our own signals might guide ET searches. Co-author Macy Huston explained:

“Our goal with this project was to bring SETI back ‘down to Earth’ for a moment and think about where we really are today with Earth’s technosignatures and detection capabilities.

“In SETI, we should never assume other life and technology would be just like ours, but quantifying what ‘ours’ means can help put SETI searches into perspective.”

Humanity has been broadcasting signals for over a century through various wavelengths. The study models a “mirror Earth,” assuming other civilizations might be similarly noisy. Our lasers, radios, city lights, pollutants, and spacecraft all contribute to our technosignature.

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The study examined how far Earth’s signals travel. Arecibo Observatory’s broadcasts reached 12,000 light-years, the star-dense Milky Way center. Deep Space Network signals can travel 65 light-years before fading. Closer civilizations, like those around Proxima Centauri (4.36 light-years away), could detect laser beams, radio waves, and even atmospheric pollution.