• Question: what would happen when an unmoveable object meets an unstoppable force

    Asked by chemistryboi262017 to Alex, Alison, David, hayleypincott, Thomas on 8 Jun 2018.
    • Photo: David Mills

      David Mills answered on 8 Jun 2018:

      …and then the universe exploded!

      Science doesn’t really work that well with infinities (which is basically what this question is asking – infinite force hits infinitely stationary thing)

      There’s a way to get some idea though, let’s accelerate a planet, about the size of Earth to just under the speed of light – this is a good approximation of an unstoppable force.
      This would carry 1/2 MV^2 of energy or roughly 2.7 × 10^41 joules

      Let’s smash this into the sun (a pretty good approximation of an immovable object)

      What happens?

      Fight!

      https://www.dropbox.com/s/br2w1ntpqweuibz/Universe%20Sandbox%20%C2%B2%20-%2020180608-170043%20Video.gif?dl=0

      That’s the result of my simulation. The sun wins!

    • Photo: Hayley Pincott

      Hayley Pincott answered on 8 Jun 2018:

      I’m glad David answered because I have no idea. Brilliant question though because it got me thinking.

    • Photo: Alex Alamri

      Alex Alamri answered on 11 Jun 2018:

      From my point of view as a neurosurgeon, the Times when I see this kind of thing tends to be things like car accidents and other times when people can get into bad accidents.

      The brain is very very delicate and if it gets knocked around, it can become damaged or bleed.

      One of my jobs, in an emergency, is to make sure that the bleeding stops, otherwise people can become very very sick!

    • Photo: Thomas Perriment

      Thomas Perriment answered on 18 Jun 2018:

      Great simulation, David! This is a great question, as it really shows how hard it is to consider infinite values in science. Scientists like to measure things when developing theories, because you can use that as evidence to support your idea, where we get into trouble is when you can’t measure something! If there is an unstoppable force (this is an infinitely strong thing, the actual strength of which can’t be measured) and an immovable object (infinitely resistant), you have two infinities fighting against each other of which there is no mathematical answer! If we imagine an immovable object, let’s use the sun as an example, and an unstoppable…. wait… you didn’t say unstoppable object…. a force could be a wave! Sometimes even concrete and metals can’t stop radiation from passing through it, and even though the metal or concrete isn’t moved, some particles can pass through these objects as particles OR waves. So depending on the force, we either have a situation in which the question can’t be answered (if the unstoppable force is an object) but if that unstoppable force is a wave (a form of electromagnetic radiation) then depending on the properties of the object and wave, it might just pass through! The force remains unstoppable and the object never moves.

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