How does light comes from space when there is no medium in space?
Light does not need a medium like sound and water waves. An EM wave, in effect, travels on itself.
This is a fundamental property of magnetic and electric fields. Each one can generate the other kind.
A changing electric field creates a changing magnetic field. That changing magnetic field creates its own changing electric field. That changing electric field creates its own changing magnetic field and this goes on and on.
There are two types of waves namely:
•Mechanical waves (require a medium for medium to travel)
Example for Mechanical waves:
•Electromagnetic waves (doesn't require a medium to travel)
Example for Electromagnetic waves:
Light can travel in no medium because it is a Electromagnetic wave which does not require a medium to travel.
Here comes a controversial answer that by no means reflects the consensus of the scientific community, but which is my personal view.
Just like all other waves, light also needs a medium for propagation. It's called the ether, which is an extremely sparse, not observable medium that occupies the entire universe. Despite its extreme sparsity, the energy density is also extremely high. One bucket full of ether contains enough energy to melt the entire world.
The concept of ether as a medium for propagation of light was abandoned 130 years ago, after experiments performed by Albert Michelson en Edward Morley. That was a mistake - because the ether does exist, and just like all other known waves (sound waves in the air, water waves in water, shockwaves in the Earth's crust), also light requires a medium for propagation: the ether.
The concept of ether eliminates the un-elegant dualistic model for light propagation (either a wave or a particle whenever you need one of the two). The particle behaviour of light can be explained by the corpuscular character of the ether ‘particles', its wave character can be explained identically to sound and water waves.
Space IS the medium light is oscillating in.