Filippo Biondi

The satellite is flying in the space and it is following his path, a very precise path, which is called orbit.

Here we have the Earth.

The Earth is rotating in one day, one rotation.

And let's say the satellites are flying following this path.

South Pole...

North Pole, South Pole, North Pole.

While they are orbiting around the Earth, the Earth is rotating like that.

And the orbit will remain constant because of the conservation of the angular momentum.

And so every day, one satellite has the chance to observe any part of the world in one day.

so they use electromagnetic wave to catch the photos and this electromagnetic waves has a central frequency centered at 10 gigahertz

okay so they flash the earth and they return the the signal the reflected signal and they store it in the in the memory they digitalize this information they store it in the in the memory like that

So, while I am sending the electromagnetic waves, these electromagnetic waves interact with the Earth.

If the Earth is vibrating, the electromagnetic waves are frequency modulated because of the Doppler effect.

The Doppler effect is that effect that goes to interfere with the frequency of any kind of oscillating phenomena, also sound.

Do you know, have you noticed, Matt, when you are watching an ambulance with the, how you say, how you call it?

Siren.

The siren that is on.

While the ambulance is approaching you,

you hear the sound of the ambulance rising in frequency, like that.

And when it passes your zero Doppler here and goes behind of you, the frequency of the sound that is emitting the ambulance decreases.