How long would a pebble take to reach the bottom of the Mariana Trench?

Wednesday 22nd July 2009
Submitted by Robert Matthews
Merlin Hetherington, Spain

Located in the Pacific roughly halfway between Japan and Papua New Guinea, the Mariana Trench is the deepest part of the ocean, and plunges down over 10,900m below sea level. A pebble dropped overboard would take just over an hour to reach the pitch-black seabed, where temperatures hover just above freezing and the pressure is over 1000 times higher than at the surface.

How long do bank notes stay in circulation?
previous qanda Article
Does everyone blink at roughly the same rate?
next qanda Article
Q&A Tabs

Phlegm is the mucous secretion of the respiratory passages. The cilia cells that line these passages are continually driving the phlegm upward to the throat, where it triggers the swallow reflex...

Beard hair is quite different to head hair; it is coarser, curlier and doesn't fall out as we get older. Comparatively little work has been done on the genetics of human hair colour, but it is...

It’s long been known that just over-heating, let alone burning, some foods can lead to the formation of compounds linked to cancer. These include heterocyclic amines and so-called polycyclic...

It depends on how high (or low) you set the bar of fluency. Ziad Fazah, born in Liberia, brought up in Beirut and now living in Brazil, claims to be the world's greatest living polyglot, with...

Strictly speaking, viruses can’t die, for the simple reason that they aren’t alive in the first place. Although they contain genetic instructions in the form of DNA (or the related...

All female mammals have a clitoris, the sole purpose of which is to react to sexual stimulation, and presumably this stimulation has evolved to be pleasurable for most species. But establishing...

To create a sound, we have to set matter - whether it's a gas like air, a liquid or even a solid material - in regular motion, creating a wave of specific frequencies, which we hear as a sound of...

Mirrors don’t reverse left and right either – that’s just our interpretation of what happens. Your reflection in the mirror is actually reversed front to back – if you have...

Discovered by an American student named Gary Flandro in the mid-1960s, the slingshot manoeuvre usually involves spacecraft briefly 'coat-tailing' a planet orbiting the Sun, extracting some of the...

The ice disappears because the wind blows away water molecules that have evaporated or 'sublimed' from the ice, so the ice slowly shrinks in size. The molecules that escape are those with the...

We use cookies to improve your experience of our website. Cookies perform functions like recognising you each time you visit and delivering advertising messages that are relevant to you. Read more here