The cosmic vacuum, by what does light propagate?

There was a time when scientists believed that there was a species in the universe called the ether.

of matter, ether:

The first to propose the "ether" was the ancient Greek philosopher Aristotle.

Aristotle believed that the lower realm was composed of the four elements of fire, water, earth, and air; The upper realm plus the fifth element.

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Newton discovered gravitation.

After that, we encountered a difficult question: in the cosmic vacuum, what medium does gravity propagate? In order to find a complete solution, Newton resurrected Aristotle's theory of the "ether", arguing that the "ether" is the medium of gravity in the vacuum of the universe.

Later, physicists developed the theory of "ether", believing that "ether" is also the propagation medium of light waves. Light, like gravity, is propagated by the "ether". They also postulated that the entire universe was filled with "ether," a thin, imperceptible medium made up of very small elastic spheres.

In the 19th century, Maxwell.

The theory of electromagnetism also puts the propagation of light and electromagnetic waves.

The medium is said to be a weightless "ether" that can be absolutely permeable.

The ether "has both electromagnetic properties and the transmitter of electromagnetic action, as well as the properties of mechanical mechanics, and it is an absolutely stationary frame of reference."

All movement is carried out in relation to it. In this way, the theory of electromagnetism is harmonized by Newtonian mechanics. The concept of "ether" as a common carrier of light, electricity, and magnetism has been widely accepted by people, forming a "ether science".

The above information is quoted from:

Can be later"ether". "The doctrine was denied, and the propagation of light became another problem.

This page will give you a holistic view of the propagation of light:

In a vacuum, the speed of light will reach its maximum due to the absence of obstacles, and its propagation in a vacuum is no different from that in a medium, light is an electromagnetic wave, and its propagation does not require a medium.

The universe is not vacuum, but the proportion of matter that exists is too scarce compared to the earth, because space is infinite. The phrase "the universe is vacuum" should be understood to mean that most of the universe is infinitely close to a vacuum (such as the space around planetary moons such as the Earth and the Moon), but even so, strictly speaking, it is not a vacuum in the absolute sense, and an absolute vacuum means that there is no matter, which is impossible. Light travels in the form of waves, electromagnetic waves, which do not require any medium.

First of all, let's distinguish between mechanical waves and electromagnetic waves.

A mechanical wave is a form of motion that propagates in a medium, and what travels is the form of motion and energy.

Electromagnetic waves are the propagation of an energy field, and the principle is that a changing electric field produces a changing magnetic field, and a changing magnetic field produces a changing electric field, and no medium is required.

Light is an electromagnetic wave.

Don't confuse the two and think of light as mechanical waves.

It depends on the medium to spread, ah, junior high school physics, right?

Light is propagated by a wide variety of impurities in a vacuum.

Vacuum knowledge has no air, but there are other mediums, which are transmitted by the medium.

It is impossible to have an absolute vacuum, and it is propagated by the medium alone.

It must have spread through the air, no one knows.

Light can only travel through the air, and I don't know what to rely on.

It is propagated by a medium, and it is not known what the specific medium is.

Does a medium be needed for the propagation of light? I don't think so.

Of course, light can propagate in a vacuum, it is propagated in a vacuum in the form of electromagnetic waves, and light does "uniform linear motion" in a vacuum, and the state of motion of photons depends on whether humans have observed it; Photons in the microscopic world can rotate both to the left and to the right at the same time.

Light can travel in a vacuum. Light is an electromagnetic wave within the observable range and is propagated by the mutual excitation of the changing electric field and magnetic field, and the propagation of electric and magnetic fields does not require a medium, so the propagation of light does not require a medium.

Light can propagate in a vacuum, in the form of electromagnetic waves, in a vacuum at a speed of about 3 10 5 kilometers and seconds of continuous "uniform linear motion".

It can be propagated, the light emitted by the sun is in a vacuum state for a long distance to the earth, and the light travels in the form of particles, at a speed of 300,000 kilometers per second.

Why does light travel in a vacuum, but sound cannot? After reading it, I suddenly realized.

Light is a particle wave that is also an electromagnetic wave, not a mechanical wave, and the propagation of mechanical waves depends on the medium. It can propagate both in a transparent medium and in a vacuum because it has wave-particle duality.

Why does light travel in a vacuum, but sound cannot? After reading it, I suddenly realized.