<p>Electric and magnetic fields can and do exist in a vacuum. Electromagnetic waves are just fluctuations in electric and magnetic fields. In a vacuum (meaning no charges or currents, which do require the presence of matter), then the solutions to Maxwell's equations are electromagnetic waves.</p>

CC BY-SA 4.0
2020-05-20T14:55:22.350Z
2020-05-20T14:55:22.350Z
ProfRob
<p>It's an interesting question which can get you quickly into deep physics.</p>

<p>The simple way to view it is the light being made up of photons, which can be viewed and act as particles. Then, when the photon interacts with another particle, phenomena occurs which make them look like oscillating - so from the wave domain - like interference for example. But this doesn't mean that before this interaction, while traveling through the empty space, there had to be some medium oscillating. Conversely, protons, electrons and others which we regularly look at as just particles also show wave behavior when interacting, which makes us a bit more comfortable about consistency in the building blocks of the universe.</p>

<p>The more complicated way to view it is to go further and find out how the photon or light wave "works" in more detail. There is one given answer that they are oscillations in the electric and magnetic fields. But then there's the question of what are the electric and magnetic fields and how do they go from point A to point B through nothing at all? And it quickly gets into quantum field theory and even the nature of spacetime. </p>

<p>I would say that it's safe to pack these quantum field mechanisms into the abstract notion of photon as particle, at least for a person which is not a theoretical physicist. Then theoretical physicists go into the quantum field bits, but these are themselves an abstraction over something else, it goes on and on. </p>

CC BY-SA 4.0
2020-05-20T18:26:33.897Z
2020-05-20T18:26:33.897Z
radu_cloud
<p>I wanted to know how radiation moves in vacuum of space and why it doesn't need any medium ?
( Like sunlight reaching a planet )</p>

CC BY-SA 4.0
2020-05-20T14:13:20.307Z
Why should it? Photons only travel in a vacuum. They alternate between photons and something else when traveling through a physical medium.
David Hammen
CC BY-SA 4.0
2020-05-21T01:21:41.203Z
Your question will be likely closed here, but you've got your answer already. Next time try https://physics.stackexchange.com with pure physics problems.
peterh
CC BY-SA 4.0
2020-05-21T12:11:02.040Z
@antispinwards - we only have limited canned close reasons, so often folks try to find the closest one to the reason they want.
Rory Alsop
<radiation><vacuum>
Why does radiation not need a medium to travel?
Deoxzy
# Why does radiation not need a medium to travel?

(Asked by: username_0 on 2020-05-19)

I wanted to know how radiation moves in vacuum of space and why it doesn't need any medium ?
( Like sunlight reaching a planet )

**Tags:** radiation, vacuum

> **Comments:**
> **username_1**: Why should it? Photons only travel in a vacuum. They alternate between photons and something else when traveling through a physical medium.  
> **username_2**: Your question will be likely closed here, but you've got your answer already. Next time try https://physics.stackexchange.com with pure physics problems.  
> **username_3**: @antispinwards - we only have limited canned close reasons, so often folks try to find the closest one to the reason they want.  

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## 2 answers

### Answer by username_4 on 2020-05-20. Score: 6

Electric and magnetic fields can and do exist in a vacuum. Electromagnetic waves are just fluctuations in electric and magnetic fields. In a vacuum (meaning no charges or currents, which do require the presence of matter), then the solutions to Maxwell's equations are electromagnetic waves.


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### Answer by username_5 on 2020-05-20. Score: 1

It's an interesting question which can get you quickly into deep physics.

The simple way to view it is the light being made up of photons, which can be viewed and act as particles. Then, when the photon interacts with another particle, phenomena occurs which make them look like oscillating - so from the wave domain - like interference for example. But this doesn't mean that before this interaction, while traveling through the empty space, there had to be some medium oscillating. Conversely, protons, electrons and others which we regularly look at as just particles also show wave behavior when interacting, which makes us a bit more comfortable about consistency in the building blocks of the universe.

The more complicated way to view it is to go further and find out how the photon or light wave "works" in more detail. There is one given answer that they are oscillations in the electric and magnetic fields. But then there's the question of what are the electric and magnetic fields and how do they go from point A to point B through nothing at all? And it quickly gets into quantum field theory and even the nature of spacetime.

I would say that it's safe to pack these quantum field mechanisms into the abstract notion of photon as particle, at least for a person which is not a theoretical physicist. Then theoretical physicists go into the quantum field bits, but these are themselves an abstraction over something else, it goes on and on.


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