Intelligence Squared - Science Flashcards
Special Relativity
Space and time are not separate entities. They are inextricably merged together into a structure called spacetime - a four-dimensional fabric that can be warped by matter.
Matter and energy tell spacetime how to curve. Spacetime tells matter how to move.
General Relativity - the first time that a theory has been conceived to define the Universe. It’s a fundamentally new language. It was a new theory of gravity defining it as acceleration within a higher dimensional space as opposed to a force acting between 2 massive objects (Newton’s theory of gravity). Newton’s theory of gravity did not fit with special relativity and this bugged Einstein.
Special relativity defines objects moving at a constant speed. General relativity defined objects moving at accelerated speed. The genius of Einstein was understanding that you don’t need a force to accelerate an object. You just need to change the geometry of spacetime. You can do away with forces and explain everything in terms of the geometry of spacetime. Gravity is not a force.
Analogy - a canonball on a rubber sheet.
We can dispense with the Newtonian idea of gravity being a force. Rather we can describe it by the notion of objects moving freely in curved space. There is no force pulling us down. Rather a chair is pushing up on us.
The general theory of relativity cannot explain the acceleration of the expansion of the Universe.
We don’t know how quantum matter can change our understanding of spacetime. We don’t yet have a theory of quantum gravity.
Ptolemy - Earth centred Universe. This is a theological and medieval Universe. Astrology and astronomy are still linked.
Copernicus - sun-centred universe. Circular orbits of the planets. What scared people most was the idea of the Earth revolving.
Kepler - eliptical orbits. Still naked eye observation. His mother was tried as a witch. Galileo - first time a telescope was used.
Brian Cox and Alice Roberts
We know the universe has 350 billion galaxies in the observable universe. And that it extends for 90 billion light years across the observable part.
In the milky way there are circa 200 billion stars. 1 in 10 has an Earth-like planet. So 20 billion - and that’s just in our small galaxy - only 100k light years across.
Science proceeds by fallibility. We are no longer at the centre of the universe but the intellectual ascent to demote ourselves was stunning.
“Astronomy is what has replaced theology. We have less of the terrors but less of the comforts.”
The paradox between the inevitability of our existence from a multiverse point of view to the infinitesimally small likelihood of our conception.
Our attention has been besieged. A wealth of information creates a poverty of attention. Attention is a rare but precious commodity. Performance is highest at full attention.
There are 3 kinds of empathy:
1/ Cognitive empathy - know how other people are thinking
2/ Emotional empathy - immediate felt sense of what is going on with other person
3/ Empathic concern - being predisposed to help.
The brain is the last organ of the body to become anatomically mature in the mid-20s. During that time the principle of neuroplasticity is extremely important. Neuroplasticity says that repeated experiences shape the brain. For example if a child has an experience of empathy and then a second, the circuitry for empathy grows.
The ability to manage emotions is inextricably linked to the ability to pay attention.
One definition of maturity is lengthening the gap between impulse and action.
Have we reached the end of physics?
1915 was an exciting time for science. We were given both general relativity and quantum mechanics. Relativity and quantum mechanics appear to suggest that the universe should be a boring place. It should be dark, lethal and lifeless.
Why does all this interesting stuff exist? Why is there something rather than nothing? This contradiction is the most pressing problem in fundamental physics. At the heart of this problem are 2 numbers. If these 2 numbers didn’t take such values the universe as we know it would not exist.
1/ Finding the Higgs at the LHC proves the existence of a cosmic energy field. The Higgs particle has a constant value everywhere. If it wasn’t for this value the universe would not exist. There is a problem. GR and QM tell us that the value of the Higgs should be either ON (extemely high value) or OFF (in space). In both cases no physical structure or life could exist. However, we find that it is slightly on. This is the first dangerous number: the strength of the Higgs field.
2/ In 1998 we made the astonishing discovery that the expansion of the Universe was accelerating, driven by a mysterious repulsive force called dark energy. Our best idea is that dark energy is the energy of empty space itself. If you use QM to calculate the value for dark energy we get 10 to the power 120 times stronger than the value we observe in astronomy. This is the second dangerous number (the strength of dark energy - it has no known explanation). Einstein failed to combine general relativity and quantum physics which may have given us the answer.
Superstring theory supports the idea of the multiverse where we just happen to live in a universe with these 2 values.
Quantum biology
Quantum mechanics was developed in the 1920s. It is a set of beautiful and powerful mathematical rules and ideas that explain the subatomic world. It’s a world built on probability and chance, a world where particles can behave like spread-out waves.
Quantum physics underpins organic chemistry as it gives us the rules which explain how atoms fit together. Organic chemistry scaled up in complexity gives us something called molecular biology, which gives us life itself.
Quantum tunneling says that a particle can suddenly appear on the other side of an impenetrable barrier.
