Last week, the Titan submersible imploded as it went down to explore the wreck of the Titanic, killing all five passengers. People now appear to be confused as to what caused the implosion, and why the Titanic did not suffer the same fate. 

On Thursday, conservative radio show host Jesse Kelly tweeted: "I have a really dumb question: If the water pressure is so bad that it can crush a sub like Whoopi Goldberg stepping on a grape, how is the Titanic sitting on the bottom and relatively intact?"

Some were of course quick to mock this request, with one doctor commenting that "These are the people who want to debate scientists".

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Others appear confused too, however, so let's go through it. First up, let's look at why implosions occur. Implosions are where objects collapse in on themselves, the result of a difference in pressure between internal and external pressure. 

"When a submersible is deep in the ocean it experiences the force on its surface due to water pressure," Arun Bansil, professor of physics at Northeastern University explained in a piece for Northeastern Global News. "When this force becomes larger than the force hull can withstand, the vessel implodes violently."

Implosions can occur at the surface too as long as there is lower pressure on the inside of an object vs the outside, e.g. by removing the air inside a tank to create a vacuum. 

So, why did the Titan implode but the Titanic didn't? Well, parts of the Titanic did implode, while others did not. The stern section of the Titanic likely imploded around 60 meters (200 feet) below the surface.

The parts which did not implode avoided this particularly destructive event as the air had been released from within, causing the pressure to be equal on the outside and inside (conditions under which implosion will not occur).

Enough of the ship avoided this implosion, leaving it (relatively speaking) "intact". 

All “explainer” articles are confirmed by fact checkers to be correct at time of publishing. Text, images, and links may be edited, removed, or added to at a later date to keep information current.