What does "out" do in C# and what is the difference of the pointer?

Question

I was playing Space Engineers and it is possible to add custom codes, called in-game script, in C#. Finally, I came across the need to use such a out, but I didn’t understand what he does and why he exists.

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One of the functions is exactly:

float Velocidade = 0;

if (!float.TryParse(Argumentos.Argument(1), out Velocidade)) {
      // ...
}

// ...

When I tried to use the TryParse Visual Studio simply pointed out an error and suggested using out, getting out Velocidade (or instead of Velocidade or &Velocidade).

The code worked. But I still don’t understand why the out exists and what it actually does (and what advantage it has), with C# allowing pointers, as far as I am aware.

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Anyway, what does the out and why use it? Why not use pointers?