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Why would you expect the speed of light to be slightly less in the atmosphere than in a vacuum?
Wiki User
∙ 11y ago
This is from Wikipedia article 'speed of light'
In passing through materials, the observed speed of light can differ from c, as a result of the time lag between the polarization response of the medium and the incident light. The ratio of c to the phase velocity of light in the material is called the refractive index. The speed of light in air is only slightly less than c. Denser media, such as water and glass, can slow light much more, to fractions such as and of c. Through diamond, light is much slower-only about 124,000 kilometres per second, less than of c.[14] This reduction in speed is also responsible for bending of light at an interface between two materials with different indices, a phenomenon known as refraction. Since the speed of light in a material depends on the refractive index, and the refractive index may depend on the frequency of the light, light at different frequencies can travel at different speeds through the same material. This effect is called dispersion. Classically, considering electromagnetic radiation to be a wave, the charges of each atom (primarily the electrons) interact with the electric and magnetic fields of the radiation, slowing its progress. A more complete description of the passage of light through a medium is given by quantum electrodynamics.
The atmosphere is denser than the "vacuum" and light travels slower in denser medium.
Wiki User
∙ 11y ago
Wiki User
∙ 9y agoIn a vacuum there is no matter to interact with, with matter present the photons of light are delayed by repeated absorption by that matter and then reemission from that matter. This process not only delays the photons due to the time between absorption and emission, but scatters the light randomly causing the photons to take longer paths than they would in a vacuum (where they follow simple straight paths).
Wiki User
∙ 12y agospeed of light depends upon density of that medium.
Atmosphere is more denser than vacuum,so speed of light is grater in vacuum than atmosphere.
Wiki User
∙ 10y agoBecause there's nothing in the vacuum that might cause it to change.
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Can you give an example of light traveling in a vacuum?
The sun rising every morning. Its' light traveled about 93,000,00 miles through a vacuum in order to be seen.If you accept that the space between the Earth and the Moon is lacking in atmosphere, that is, its a pretty good vacuum, then the simple fact that you can see the Moon (and Sun and Stars) is enough proof for me.
Is vacuum a medium of light?
Light can travel through vacuum, but it is not a medium.
Can a beam of light be seen as it passes through a compound?
Depends on the amount of scattering. In fog, or in slightly cloudy water, it's easy to see a beam of light. In a vacuum, no scattering effects are seen.
What are the speed of electromagnetic waves?
Electromagnetic waves are "light" so they travel at the speed of light. Approx. 300,000,000 meters (186,282 miles) per second, in vacuum. Slightly less in material media.
What is the speed of an electromagnetic wave in a vacuum?
it is about 300,000 kilometers per second.
Light from the sun travels through space to the earths atmosphere What will light waves do when they move from empty space into matter made up of different gases?
They will slow down slightly compared to their speed in vacuum, they will bend slightly as they enter the atmosphere, and they will follow a path through it that continues to curve slightly.
How fas does light travel?
Light in its fastest state in a vacuum only can travel at 3.0*10^8km/s but as it enters the earth's atmosphere, the atmosphere is full of dust particles and layers of gases which can effect the speed of light slightly, in the earths atmosphere light travels at 2.89*10^8 km/s .
What makes light waves change speed as they travel from the sun to the Earth's surface?
Light has a single speed in a vacuum - which is almost 300,000 kilometers per second. Once light enters Earth's atmosphere, it will be slightly slower.
Where is the speed of light at its fastest?
The speed of light is fastest in a vacuum. All other media slow the speed of light down, albeit very slightly.
How many is light speed?
The speed of light is 299,792,458 meters (186,282 miles) per second, in vacuum. It's slightly less in a material medium.
Do particles in the atmosphere slow down either the speed of light or radio waves as they travel outward into the universe?
Light and radio waves travel slower through air than they do through space or vacuum. But as soon as they leave the atmosphere and get into space or vacuum, they speed up to 299,792,458 meters per second.
How fast does light travel out of a vacuum and why is this important to astronomy?
it depends on the medium the light is travelling through. In a vacuum, light travels ~299,000km/s. In air, light travels ~298,000km/s. And in water light travels ~225,000km/s. Essentially you take the speed of light in a vacuum and divide by the refractive index of the material the light is passing through, this will give you the new speed of light in that medium. As for the importance in astronomy, I am not sure, but I will guess that it has to do with light refracting as it enters the earth's atmosphere ever so slightly. this may throw off measurements a bit or result in slight corrections in telescopic direction and focus. Other than that I am not sure as I have never heard of this being an issue.
Why stars seen to twinkle?
That`s because of small disturbances in the earths atmosphere. Planets don`t twinkle because their light is stronger, whereas the light of stars is weak enough to have their light slightly bent by the moving atmosphere.
Can you give an example of light traveling in a vacuum?
The sun rising every morning. Its' light traveled about 93,000,00 miles through a vacuum in order to be seen.If you accept that the space between the Earth and the Moon is lacking in atmosphere, that is, its a pretty good vacuum, then the simple fact that you can see the Moon (and Sun and Stars) is enough proof for me.
What is the speed of light from sun to the earth?
The sun is roughly 8 minutes and 19 seconds away from earth in light speed!!! Imagine how far away it is in normal earth speed!?!? The speed of light is about 186,000 miles per second.
Why star twinkle?
As the light from the star travels through the turbulent atmosphere of the Earth it is refracted in a random sort of a way. This results in the observed twinkling.
Do stars look different from space?
The only difference of the twinkling caused by the distortion of light due to the earths atmosphere which is not present in a vacuum.
