**1) **

The wavelength of the matter wave (also called de Broglie wavelength) of an object is given by

where

is the Planck constant

m is the mass of the object

v is its velocity

For a proton, we have:

and the velocity of this proton is

So, its de Broglie's wavelength is:

**2) **

We can use again the same equation:

where in this case we have:

m = 159 kg is the mass of the astronaut + spacesuit

v = 377 m/s is the velocity of the astronaut

Substituting into the equation,

**3) **

Similarly, we can use the same equation:

where in this case we have: is the Earth's mass

is the velocity of the Earth around the Sun

Substituting,