Scientific ideas to make you look smart (and what they really mean)

As Professor Stephen Hawking's Reith Lecture on black holes approaches we invite you to brush up on your scientific icebreaking openers....

Provided by Jim Al-Khalili, presenter of The Life Scientific

Jim Al-Khalili

You can’t unshuffle a pack of cards or unstir the milk in your coffee.

1. There are no event horizons in a traversable Lorenzian wormhole

A wormhole is a tunnel through spacetime. In the 1930s, Einstein suggested that it could be made by joining two black holes, but it was shown – theoretically – by Kip Thorne that spacetime can be warped to make a stable wormhole that you can travel through (traversable).

2. Time travel is easy as long as you follow a closed timelike curve

Closed timelike curves are the correct way of defining a loop through spacetime that brings you back to where you started, before, you started: time travel to the past.

3. You can’t cheat the second law of thermodynamics

The 2nd law states that the amount of disorder in a system will always increase: you can’t unshuffle a pack of cards or unstir the milk in your coffee.

4. What you’ve just said contains zero Shannon entropy

Entropy is the amount of disorder in a system. But, if it is related to the amount of information in a message then it is called Shannon entropy.

The Goldilocks zone is the place where conditions are ‘just right’, like Baby Bear’s porridge in the Goldilocks fairytale. The anthropic principle states that the reason our universe is so finely tuned to be just right for us to live in is because if it wasn’t we wouldn’t be around to ask the question in the first place.

In the 1920s physicists in Copenhagen, led by Niels Bohr, argued that quantum mechanics is only about what we can say about reality (epistemology) rather than describing reality itself (ontology). It’s a philosophical argument that still rages… in some quarters.

7. If you don’t find quantum mechanics baffling then you haven’t understood it

Quantum entanglement states that two distant particles can be in instantaneous communication.

This quote by Niels Bohr emphasises that quantum theory is meant to be baffling and if you don’t see that then you don’t know enough about it.

8. Quantum entanglement doesn’t violate causality

Quantum entanglement states that two distant particles can be in instantaneous communication. But Einstein showed that this would mean faster than light communication, which violates something called causality – that is, when an effect comes before its cause, which is logically impossible. But the fuzziness and unpredictability of the quantum world means we don’t need to worry about this.

9. Einstein said God doesn’t play dice. Well, not only does he play dice, but he throws them where we can’t see them

Einstein hated the unpredictability of the microscopic world described by quantum mechanics. But quantum physicists have shown that he was wrong and that in fact it is even weirder than he could have possibly imagined.