Complete these sentences by matching the phrases below? (picture below)
2 answers:
The right answers are mentionned in the picture:
Doppler effect
The Doppler effect, or Doppler-Fizeau effect, is the frequency shift of a wave (mechanical, acoustic, electromagnetic or of another nature) observed between the measurements at transmission and at reception, when the distance between the transmitter and receiver vary over time. If one generally designates this physical phenomenon under the name of Doppler effect, the name of "Doppler-Fizeau effect" is reserved for the electromagnetic waves.
Cosmic microwave background radiation.
Cosmic rays are very fast charged particles from the interstellar medium. These particles are mainly protons (85%), helium nuclei (14%), electrons (1%) and other atomic nuclei.
Their energy is typically 1 GeV (the energy that would have an electron accelerated by a voltage of a billion Volts), but it sometimes rises to 10 power 11 GeV. These particles may have been accelerated during Supernova explosions. The Sun also emits particles of high energy, but generally much lower than GeV.
Particle accelerators:
A particle accelerator is an instrument that uses electric or magnetic fields to drive electrically charged particles at high speeds. In other words, it communicates energy to the particles. There are two main categories: linear accelerators and circular accelerators. Numerous small linear accelerators are used in medicine (anti-tumor radiotherapy).
Big Bang Theory:
The Big Bang is a scientific theory that tries to explain the first moments of the Universe. This is the beginning of the expansion of the Universe, about 13.7 billion years ago, when the Universe was extremely dense and hot.
This is not the beginning of the Universe as we often say, because we do not know what was before (or even if there was a before). The Big Bang is a scientific theory partly confirmed by certain astronomical observations. If we know that the universe was initially hot and very dense, the theory does not say what is at the origin of the Big Bang. It is therefore different from the creation of the world (religious hypothesis).
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