What is light? And how does it travel so fast?

Question

Science is not my best subject so please bare with me with this one...

If light is not matter but a wave of energy, therefore not made up by elements but charges.... what makes it the fastest thing known to man? Is it because it is the most simplest of all things making it weightless? But arent we all weightless in space anyway? Or is that different ie.Atomic mass? So if there is a way to breakdown matter to charges will it then be possible to travel like light? But then you will have to combine all the particles again together to bring it to its original state.

And also... what is space? is it just a big nothingness? or is it made up of charges that within the right environment could form more complex things like atoms?

"the law of conservation of energy states that energy can not be created or destroyed, it can only be changed from one form to another"

Any thoughts on this anyone?

Answer 1

light is the thing u see wen u on the switches in ur house ..they have their own supersonic jets..

Answer 2

I think light is both a particle and a wave, which is really wierd. It has a lot of properties which make it a really odd thing as well. Such as its speed relative to anything is always the same. So basically if you were moving backwards from someone at half the speed of light and the shined a flashlight on you it would strike you at the speed of light, not half the speed of light. Asking what space is is a tough question. You might want to read some stuff on string theory. I'm not great at science either, but I think it is created by the combination of more elementary dimensions than what we are used to. We are all weightless in space, but we all also have mass. Also we all have inertia, which means if you are moving and hit a brick wall that isnt moving relative to you in space you are still going to get hurt. The inertia is believed to be caused by the attraction of all the matter in the universe on an object.

Answer 3

The answers to your questions have challenged many of the greatest minds in history so it's extremely foolhardy to try to give a simple answer. In bearing (but definitely not baring) with you I will nevertheless attempt this daunting task.

In some ways light behaves like particles and in other ways, like, as you mention, waves. Corrrespondingly there are two theories of light. the particle theory and the wave theory. We have to accept that both are correct. The waves of light are electromagnetic waves i.e they consist of an electric and magnetic fields each oscillating at a high frequency. They are basically the same as radio waves. The speed at which the waves propagate through space is determined by the electric and magnetic properties of space just as the speed of propagation of waves on water is determined by the properties of water. Light waves themselves, being only fields, have no mass and no charge. I would not wish to pronounce on what is the simplest of all things but anyhow light is pure energy and no mass. You seem to confuse weight and mass; we are indeed all weghtless in space but not massless. It's important you sort out your thoughts on this elementary difference. In breaking down matter in certain ways (e.g.burning) it is possible that (usually very small amounts of) the energy contained in the matter (E=mc2) can be converted into light but to reconstitute the original matter from this light is unimaginable (refer to the concept of "entropy").

Space is a concept we have invented to help us understand and relate to what we observe. It is easy to relate to this concept since it seems to fit in very clearly with our everyday experience, We can readily appreciate rulers, set squares, heights and depths etc. Space gets more complex when things are happening well outside our normal range of experience and in particular because we observe that the speed of light is always the same independent of the speeds of either the source or the receiver. Space certainly contains particles and charges but these are not space itself. Space is only an idea.

I am not sure what you are asking about conservation of energy but there is also conservation of mass and the fact that mass and energy are themselves interchangeable.

Bramble.

Answer 4

Light is not made of charges. A photon has zero charge. Photons only ever travel at the speed of light. In fact, photons cannot exist except at that speed.

As for what makes the speed of light what it is, it is basically a function of the electric permittivity and magnetic permeability of free space. These are simply fixed values. Nobody knows why they are what they are. Physics is not concerned with knowing why they are, only knowing WHAT they are, which we do.

In the absence of a gravitational field, you are weightless. However, you are NOT massless. Massive particles cannot become massless.

Answer 5

Light is what we see.
It is a corpuscule mass flux whose actual substance is not understood. Perhaps one day science will see the light.
As far as we know it is neither electric nor magnetic.
The word electromagnetic was coined to describe a moving electric field relative to a moving magnetic field . In reality it has nothing to do with a moving micromass particle flux.

Answer 6

think of "light" as positive-negative oscillations of the e&m fields. when a particle absorbs energy, the positive (or the negative) field proton or electron absorbs only the negative or positive part of the oscillatory field of the light. thus e=mc^2. the velocity of light is the combination of the permittivity and permeability of free space, which calculates to 186,282 m/s. space is the "medium" which separates objects.

Answer 7

interesting and fundamental questions.

light is an electromagnetic (EM) wave in the visible spectrum meaning the wavelength of the EM wave is detectable by your eye, and all EM waves (everything from radio and micro waves on up to x-rays, gamma rays, and cosmic rays) move at the same speed. in a vaccuum, this speed is exactly 299,792,458 meters per second (or approximately 186,000 miles/second) which we usually designate with the variable "c" as in e=mc^2 which gives the amount of total energy for something of mass m when that something is at rest.

so, in a sense, matter is just another form of energy as one can be converted into the other. einstein proved it conceptually and mathematically and it was shortly thereafter proven experimentally.

you are right to say that it has no mass, however, it is not made of charges; it's "made" of electric and magnetic fields and I'll explain shortly. charged particles can however create light. see, from electrodynamics, we know that when an electrically charged particle (meaning a particle that produces an electric field in the space around it), like a proton or electron, moves through space, this changes the electric field and it is this changing electric field which induces a magnetic field...and that's really all a magnetic field is.

so a changing electric field creates a magnetic field. vice versa, a changing magnetic field creates an electric field which is why we use magnets in generators to create voltage used to power our homes.

so an electromagnetic wave is when a changing electric field induces a changing magnetic field...which then induces a changing electric field and so on. it is this cycle of one field inducing the other that makes up what an EM wave (including light) is and it's propagation through space.

as it turns out, when an electric field changes, the magnetic field it induces is in a perpendicular direction to the direction the electric field is changing, and the direction of an electromagnetic wave produced is perpendicular to both of these changing fields which determines what direction the EM wave travels. and this process of inducing another field in space is very fast and propagates very quickly through space...at the speed of light. so this is why light is of no mass and moves very, VERY fast.

space, like time and mass, is a fundamental quality of our universe. this means that it can really only be defined basically by how much of it there is. so it's like asking "what is time?" the only real way to define time is how much time passes and the unit of time we typically use is a second and every thing else is derived from a second (minute, hour, etc.).

similarly, space is distance...that's it, and it's standard unit of measurement is a meter. our universe has 3 spatial dimensions which means we can measure length (1-D space), area (2-D space), and volume (3-D space). so space is defined by how much there is whether it's in between things or the space something takes up.

so you can't really call time or space "nothing," because if time were nothing, it wouldn't pass, and if space were nothing, there'd be no distance.

they used to think space was made up of a medium they called " luminiferous Æther" or just "ether" (not as in the chemical, Diethyl ether which is commonly called ether). all known waves (like sound waves for instance) require a medium to travel through, but EM waves could travel through a vaccuum, so scientists thought there must be a medium that exists in a vaccuum (meaning in outer space and in the space between all matter) that light travels through. this was disproven by the Michelson–Morley experiment in 1887. since EM waves like light are simply the propagation of changing electric and magnetic fields, they do not require a medium to travel through.

so space itself is not made up of particles in the way say the atmosphere is made up of particles, but for any region in outer space larger than something on the quantum scale of distances, there are particles in that space. so for any tiny volume of space in between the sun and earth, for instance, there are particles in this space, most of which are hurled out from the sun. "outer space" is really just defined as the space outside the space taken up by celestial objects like the earth, stars, moons, etc. it is a vaccuum because there are so few particles relative to in a dense atmosphere like earth's that the pressure is almost zero.

it's really interesting that although light moves so fast through space, our universe is SO big, that there are stars so far away, their light has not yet reached the earth.

again, good questions.

Answer 8

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Answer 9

A wise science teacher once told me that lightyears are so fast that they measure it in lightyears

Answer 10

Light travels at 186,000 miles per second. What is it? BRIGHT!