QuirkScience

Mount Everest vs Mariana Trench

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Season 2: the deep ocean · Posted ·

The short answer

Mount Everest's summit is 8,849 m (29,032 ft) above sea level. The Challenger Deep, the deepest point of the Mariana Trench, goes down 10,935 m (35,876 ft). Stand Everest on the bottom and its summit is still about 2,086 m (6,844 ft) under water.

The top of the world would sit in total darkness, with more than 200 atmospheres of water pressing on it.

Six Eiffel Towers, and still wet

The Eiffel Tower has been 330 m tall since it got a new antenna in 2022. Stack six of them on Everest's summit and the stack is 1,980 m tall. That's still about 100 m short of the surface. A seventh tower would reach 2,310 m and finally poke out.

All that water is heavy. Every 10 m of seawater adds about one atmosphere of pressure. So 2,086 m of water adds about 209 atmospheres. Add one more for the air above the sea and you get about 210 in all.

Dark, but not unlit

Sunlight can be detected down to about 1,000 m in the ocean, and none is left below that. Everest's summit would sit at 2,086 m, so the last sunlight fades out about 1 km above it.

The only light down there comes from living things: animals and glowing bacteria. One study of deep sea video off California counted animals from the surface down to about 3.9 km. About 76% of them could make their own light. That's roughly three out of four.

Who could reach the summit

No person gets to the bottom of the Challenger Deep without a deep diving submersible. Every crewed visit so far has used one: Trieste in 1960, Deepsea Challenger in 2012, Limiting Factor from 2019 and Fendouzhe from 2020.

Some animals could reach the drowned summit on their own. A tagged Cuvier's beaked whale dove to 2,992 m (9,816 ft) on a single breath, the deepest mammal dive on record. The same study recorded a dive that lasted 137.5 minutes. A summit 2,086 m down would be within that whale's reach.

Key numbers

WhatNumberSource
Height of Mount Everest above sea level8,849 m (29,032 ft); measured as 8,848.86 mAl Jazeera, 8 Dec 2020
Depth of the Challenger Deep, Mariana Trenchabout 10,935 m, give or take 6 m (35,876 ft)Greenaway et al. 2021, Deep Sea Research I (NOAA repository)
Water above Everest's summit if it stood on the bottomabout 2,086 m (6,844 ft)Our arithmetic from Al Jazeera, 8 Dec 2020 and Greenaway et al. 2021, Deep Sea Research I (NOAA repository)
Height of the Eiffel Tower since 2022330 mKTVU / Associated Press
Six Eiffel Towers stacked1,980 m, about 100 m short of the surfaceOur arithmetic from KTVU / Associated Press
Deepest sunlight in the oceanabout 1,000 mNOAA Ocean Service
Dark water between the last sunlight and the summitabout 1 kmOur arithmetic from NOAA Ocean Service
Pressure on the drowned summitabout 210 atmospheresOur arithmetic from NOAA Office of Marine and Aviation Operations
Deep sea animals on video that make their own lightabout 76%, roughly 3 in 4Martini & Haddock 2017, Scientific Reports
Deepest Cuvier's beaked whale dive on record2,992 m (9,816 ft) on one breathSchorr et al. 2014, PLoS ONE

What the film simplifies

For teachers

Runtime 1 minute 2 seconds · Topics: Ocean depth, Mountains, Water pressure, Deep sea life · Full script below

Ask your class

  1. Everest is 8,849 m tall and the Challenger Deep is 10,935 m deep. If Everest stood on the bottom, how much water would be above its summit?

    Answer

    About 2,086 m (6,844 ft), or roughly 2 km.

  2. The Eiffel Tower is 330 m tall. Why does the film stack six towers on Everest's summit and not seven?

    Answer

    Six towers reach 1,980 m, still about 100 m under the surface. Seven would reach 2,310 m and stick out of the water.

  3. No sunlight reaches below about 1,000 m. So where does the light around the drowned summit come from?

    Answer

    From living things: animals and glowing bacteria that make their own light. In one study of deep sea video, about 3 in 4 of the animals counted could do it.

The script

Everest: Put me down, Pressure! I'm Mount Everest!

Pressure: Relax. Let's see if your head stays dry.

Everest: My head? Climbers need oxygen tanks just to reach it!

Pressure: My visitors need submarines.

Host: Everest: almost nine kilometers up. The Mariana Trench: almost eleven down.

Pressure: In you go!

Snailfish: Oh! Hi, neighbor!

Everest: Mmmph!

Host: Everest's feet hit the bottom, and its top is still two kilometers under water.

Pressure: Six Eiffel Towers on your head, and still not dry!

Everest: Hey! Who turned off the sun?

Pressure: Sunlight quit a kilometer above you.

Everest: Then what's that?

Pressure: This deep, the only lights are alive.

Host: Three out of four animals in the deep make their own light.

Everest: But... I'm the top of the world!

Pressure: Not down here.

Everest: ...Now I need an oxygen tank.

Host: Everest's new climbers? Whales. One dove almost three kilometers on a single breath.

Everest: ...Show off.

Host: Next: the Moon picks a fight with the ocean. Follow!

Sources

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