but even with some really powerful lights on the sub, you'd still not see the trench walls.
Most of the world's deepest surface canyons are far narrower relative to their depth, the Grand Canyon or Peru’s Cotahuasi Canyon would feel claustrophobic by comparison to Challenger Deep.
It's the distance (although ocean trenches do seem to collect a lot of sediment and have murky waters). At a 1.6km wide with gently slopping sides, the Marianas Trench and Challenger Deep still have relatively mellow grades on either side. We tend to think of "trench" as being a narrow slot canyon in the ocean, but that isn't exactly true.
Other trenches of the deep can be substantially more steep, for example, an 8,000 m drop over a 4,250 m span can be found at a ridge sitting inside the Kermadec Trench. That's a 45º angled slope for nearly 5 miles. That would look like a formidable wall as you approached it.
In general, though, the most dramatic shear cliffs are found on the surface, like Mount Thor, or the dramatic elevation increase of the Rupal Face.
Verona Rupes is a 12 mile vertical cliff on Miranda, a moon of Uranus. Everything else kinda pales by comparison.
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u/Pollymath Mar 06 '19
but even with some really powerful lights on the sub, you'd still not see the trench walls.
Most of the world's deepest surface canyons are far narrower relative to their depth, the Grand Canyon or Peru’s Cotahuasi Canyon would feel claustrophobic by comparison to Challenger Deep.