Since photons are massless,
they travel at c
, which is called the speed of light because the photon was the first known example of a massless particle. So the short answer to the question is that a photon knows to travel at the speed of light because it is massless.
How do photons travel when moving away from a light source?
A photon is a pulse of an electric field which when it collapses produces a magnetic field which when it collapses produces an electric field and so on and on until either the electric field and/or the magnetic field is absorbed by something. In other words
the photon propagates itself
thus moving away from the source.
How does light travel from a light source?
Light waves travel out from their source
in straight lines called rays
. Rays do not curve around corners, so when they hit an opaque object (one that does not allow light to pass through it), they are blocked from reaching the other side of that object.
What causes a photon to move?
A photon of light does not accelerate to light speed. Rather,
a photon is already traveling at light speed c when it is created
. It’s not like a photon jumps from a speed of zero to light speed instantaneously. Rather, a photon is always traveling at c, from the moment of its creation.
Does a photon take up space?
The answer is
mostly a yes
. While as David says, photons are bosons and therefore do not really have a meaning of “personal space”, the accumulation of the photon’s energy causes another very interesting thing to happen – the spontaneous creation of new particles.
How are photons produced?
A photon is produced
whenever an electron in a higher-than-normal orbit falls back to its normal orbit
. During the fall from high energy to normal energy, the electron emits a photon — a packet of energy — with very specific characteristics.
How does light travel from the sun?
When light travels through space from the sun,
all of the frequencies of light travel in a straight line
. When light hits the atmosphere, however, the photons begin to collide with gas molecules. Red, orange and yellow photons have long wavelengths and can travel right through the gas molecules.
Do photons always travel at the speed of light?
The highest-energy photon and the lowest-energy photon ever observed both travel at exactly the same speed
. All massless particles travel at the speed of light, including the photon, gluon and gravitational… [+] But if you’re willing to step outside of a vacuum and into a material, it is possible to slow light down.
How does light travel at the speed of light?
Ergo, light is made of
electromagnetic waves
and it travels at that speed, because that is exactly how quickly waves of electricity and magnetism travel through space.
Does a photon travel in a straight line?
Photons do not travel in straight lines
. Quantum particles do not have trajectories as classical particles do. Photons do not propagate in all directions as a spherical wave does. Photons are not waves.
How does light travel through water?
When light that is traveling through the air hits water,
some of the light is reflected off the water. The rest of the light passes through the water but it bends (or refracts) as it enters the water
. The same thing happens when light hits glass or any other transparent material.
Why do photons travel in waves?
In energy wave theory,
a photon is generated by the vibration of particles, traveling perpendicular to the direction of vibration
. In the particles section, particles were described as waves of energy, creating standing waves from in-waves and out-waves.
Do photons stop moving?
Photons move at the speed of light because they have no inherent mass to slow them down. Because they have no inherent mass,
they can’t really be stopped per-se
, because a photon that wasn’t moving would have no basis to even exist – really all a photon is depends on its movement.
Is a photon an electron?
Photon is a type of elementary particle which acts as a carrier of energy, but the electron is a subatomic particle which occurs in all the atoms. The key difference between photon and electron is that
the photon is a packet of energy while the electron is a mass
.
How does a photon move through space?
As a photon moves through space,
it exhibits oscillating electric and magnetic fields, and can interact with charged particles
. These interactions slow it down, and cause it to move at a speed less than the speed of light as long as they’re in a material.
What happens when two photons collide?
When a high-energy photon collides with matter
it will often transform into an electron–positron pair
– a process that involves the energy of the massless photon being converted into the masses of the pair. A similar conversion occurs when heavy ions are smashed together at high energies at facilities like the LHC.
Are photons just energy?
As should be obvious,
energy is just one of many properties that photons carry
. Photons are much more than “pure energy”. Photons can exist just fine without having mass since they carry many other properties to make them physically real.
Does light have weight?
Well if you read a textbook, you will find out that light can be thought of as being made up of particles called photons. These photons have no mass! So there is the simple answer,
light has no mass and no weight
.
How do photons turn into electrons?
A photon can spontaneously degenerate into a particle with mass and its antiparticle in a process known as
pair production
. In this process, the energy of the photon is completely transformed into the mass of the two particles. For example, a photon can turn into an electron and an anti-electron.
Where do light photons go?
When a photon is absorbed by matter,
it disappears
and the matter reconfigures itself according to the energy content it received.
How are photons created in the sun?
The sunlight is made up of tiny “packets of light” called photons, that originate in the Sun’s core.
The photons are born in a nuclear fusion, when hydrogen cores smash together to make helium
. As a byproduct of this reaction, a huge amount of energy is released in the form of photons.
How far do photons travel?
But for light itself, which is already moving at light speed… You guessed it, the photons reach
zero distance
and zero time. Photons can take hundreds of thousands of years to travel from the core of the Sun until they reach the surface and fly off into space.
How does light hit the Earth?
The Sun’s energy gets to the Earth
through radiation
, which you can prove just by standing outside and letting the sun’s rays warm your face on a sunny day. Every object around you is continually radiating, unless its temperature is at absolute zero, at which point its molecules completely stop moving.
Why is space dark?
Because space is a near-perfect vacuum — meaning it has exceedingly few particles — there’s virtually nothing in the space between stars and planets to scatter light to our eyes
. And with no light reaching the eyes, they see black. —What color is the sunset on other planets?
Do photons slow down in water?
Yes. Light is slowed down in transparent media such as air, water and glass
. The ratio by which it is slowed is called the refractive index of the medium and is always greater than one.
How does a photon look like?
A photon just looks like
a blink of light from a small point
. So, when you see a photon (if your eyes are sensitive enough), you see a blip of light. The “size” of a photon is much weirder since photons aren’t “particles” in the traditional macroscopic sense of the word.
Is light faster than darkness?
Darkness travels at the speed of light
. More accurately, darkness does not exist by itself as a unique physical entity, but is simply the absence of light. Any time you block out most of the light – for instance, by cupping your hands together – you get darkness.
