National Taiwan University (Lecture by Prof Chen Pisin)

  • Black hole
    • A region exhibiting gravitational effects so strong that nothing, even particles and electromagnetic radiation such as light could escape after passing the event horizon. The event horizon is a boundary where nothing can escape after passing it.
  • Wormhole
    • It is the solution of the Einstein field equations having a non-trivial structure linking separate points in spacetime, much like a tunnel with two ends, each at separate points in spacetime. Such connections are consistent with the general theory of relativity, yet their existence remains hypothetical.
  • Neutrino
    • It is the fermion that interacts only via the weak subatomic force and gravity and is much more lighter than the other known elementary particles.
  • It is mainly about Cosmology and other fundamental forces of the universe, they also talked about the growth of the universe
  • When people realised that the the planets are actually drifting away from earth through the infrared telescope, they started to speculate that actually that there is something called dark energy and that the event that began the universe, known as the Big Bang, the equation to prove the theory is as follows:
  • A1 –A2 /t1–t2=limit   triangle a/triangle t= da/dt=a
  • Light is used as a scale in the universe, thus light years are used to measure distance.
  • The lower the frequency of a wave particle, the lower its temperature
  • Speed of light is as below:
  • V = f λ
  • During the Big Bang, the universe inflated quickly and it heated up
  • After 300 000 years, known as the age of cooldown, the electrical forces pushing the protons apart become weaker and they begin to bond with other protons, neutrons and electrons to form atoms.
  • This caused the formation of the first stars, galaxies, clusters, and superclusters
  • The very funny thing about galaxies is that all the stars, nebulae and other constituents orbit a center.
  • At first the scientist thought that the orbiting nature of galaxies work through centrifugal force.
  • They theorised that the systems further from the centre would be the slowest, but they orbit at the same speed as the systems closer to the centre.
  • Centrifugal force is expressed as f=mv2/r
  • Black holes is actually a very interesting topic in astronomy.
  • The gravitational field generated by black holes are such that, beyond the event horizon, not even light is fast enough to escape.
  • The only way for a black hole to die is for it to expel so much Hawking radiation that it evaporates. However, black holes in our universe are just too young to experience this phenomenon..
  • When two black holes collide, the amount of the gravitational force is lower than what we would expect.
  • This is because the gravitational force that is expelled is dispersed into the vast emptiness of the universe.
  • The gravitational pull of a black hole is attributed to the fact that a black hole is made up of warped space-time, as speculated by Albert Einstein.
  • The elements from hydrogen to lawrencium only make up about 4 percent of the entire universe.
  • About 21 percent of the universe is dominated by dark matter and 75 percent by dark energy.
  • While neither of them have been found, but there is strong evidence to suggest that they exist.
  • Dark matter attracts things,while dark energy repelled to have what we have it today, expansion in the universe rapidly
  • There is a special type of things called the neutrinos.
  • It is one of the most funny type of element as it can change into any three forms while other things can’t
  • It is very hard for it to get located as it rarely interacts .
  • Black body radiations: it is about anything that has temperature emits radiation. Alternatively it is the radiation emitted from a body that can only be seen in the Infrared spectrum.

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