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Fair-Ad3639 t1_j4xdvau wrote

Reply to comment by Weed_O_Whirler in Whats stopping us from sending a probe into a black hole if we haven't already? by stealth941

Quick correction here: transmission power falls off per the inverse square law only given an idealized isotropic antenna. Focused beams using, for instance, lasers, do not experience the same losses.

But yeah, it's cuz it's far.

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Weed_O_Whirler t1_j4xgk6q wrote

But over long distances, it re-becomes inverse square again. After the waist of a laser beam, it spreads out like an inverse square law again, and when you're dealing with lightyears, most of the spread will be after the waist.

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Fair-Ad3639 t1_j4xitxi wrote

Yep! Turns out you're correct (says Google). Lasers do follow the inverse square law. https://www.quora.com/Is-the-light-from-lasers-reduced-by-the-inverse-square-law-as-distance-grows-similar-to-other-light-sources

How powerful the transmitter will need to be is also a function of the gain of the antenna. In this case, the spread angle of the laser

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dumb_password_loser t1_j4zja46 wrote

But the spread angle is inversely proportionate to the aperture.
If you send multiple probes that spread out a bit and couple them optically, they can transmit coherently with a huge effective aperture. (like the reverse of a telescope array)

And if the black hole is big enough, you can maybe use its gravitational field to increase the aperture using some mathematical sorcery.

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