Documentary 4 | Neutron stars, dark matter, dark energy.

Neutron stars. Definition:
Neutron stars are stellar remnants resulting from the explosion of a massive star (supernova). After the explosion, the core collapses under the influence of gravity into a small, dense body consisting mainly of neutrons.
Characteristics:
1. Size and density:
Diameter: only about 10-20 kilometers.
Density: can reach kg/m³.
2. Gravity:
The force of gravity on the surface of a neutron star is equal to a billion times the force of gravity on Earth.
3. Rotation:
Neutron stars rotate at very high speeds, which may reach hundreds or thousands of revolutions per second.
4. Magnetic field:
They have enormous magnetic fields, millions of times stronger than the strongest magnetic field on Earth.
Types:
Pulsars: emit regular pulses of radiation.
Magnetars: stars with very strong magnetic fields.
Its importance:
Neutron stars help in studying matter under enormous pressure and extreme conditions that cannot be simulated on Earth.
Dark energy
Definition:
Dark energy is a hypothetical energy that explains the acceleration of the expansion of the universe that was discovered through measurements of distant galaxies.
Evidence of its existence:
1. Acceleration of the expansion of the universe:
Scientists have discovered that the expansion of the universe is accelerating instead of slowing down, which cannot be explained by gravity alone.
2. Cosmic microwave background radiation:
It explains the distribution of matter and energy in the universe.
Properties:
It represents about 70% of the total content of the universe.
It is characterized by negative pressure that causes the expansion of space.
Proposed theories:
1. Cosmological Constant:
Dark energy is considered a constant property of space itself.
2. Quintessence:
It suggests that it is a dynamic type of energy that changes with time.
Dark matter
Definition:
Dark matter is invisible matter that does not interact with light or any other type of electromagnetic radiation, but affects it by gravity.
Evidence for its existence:
1. The motion of galaxies:
The speed of rotation of stars at the edges of galaxies is not proportional to the visible mass.
2. Gravitational lenses:
The bending of light coming from distant galaxies indicates the presence of additional invisible mass.
3. Large-scale cosmic structure:
The distribution of galaxies in the universe requires the presence of additional matter to explain the current formation.
Properties:
It represents about 27% of the content of the universe.
It interacts only by gravity, and does not absorb or reflect light.
Proposed theories:
1. Weakly interacting particles (WIMPs):
Hypothetical heavy particles that explain dark matter.
2. Axions:
Hypothetical light particles that are possible.
The relationship between neutron stars, dark energy and dark matter:
Neutron stars: represent one aspect of the visible and material universe.
Dark energy and dark matter: represent the mysterious and invisible aspect of the universe, and constitute the vast majority of the universe's content.

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Is anti matter and dark matter same? If no then what is the difference between them?