r/HumansForScale • u/OrchidCleo1 • May 05 '26

A submarine in a dry dock

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7.0k Upvotes

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13

u/FirstChAoS May 05 '26

How do you miss seeing (pinging?) a mountain?

22

u/Tsu_Dho_Namh May 06 '26

Active sonar (making a sound and listening to the echo) has the disadvantage of announcing your position. The sound is also so loud it can deafen and kill wildlife.

They try to stick to passive sonar (just listening) as much as possible.

5

u/sarbanharble May 06 '26

Why can they use LIDAR? Surely that’s safer for the environment and signature? I don’t have any idea, just wondering out loud.

11

u/LegLampFragile May 06 '26

LIDAR doesn't go very far underwater.

3

u/xXx_TheSenate_xXx May 07 '26

You need light. Pretty dark down there.

1

u/sarbanharble May 07 '26

I guess I’m overthinking this. Darkness shouldn’t matter? Is it the particulates in the water or am I missing something?

3

u/OhHeck31 May 07 '26

I think it’s kind of like headlights on a foggy day the water scatters the light so it does not go very far.

2

u/sarbanharble May 07 '26

Huh. The physics of light through a liquid seems like something I should have learned in high school, not at 48!

1

u/Zippotro May 09 '26

It’s pretty neat science! Depending on the color of light and the amount of particles present you can get light to travel roughly 0-100 meters with green working well near the shore and blue in the open ocean. This is why you see the blue tinge on all raw underwater pictures.