Respuesta :
Your statement is not completely correct.
When an object is moving towards the observer, its measured wavelength decreases,(it is not correct if measured length) because the waves are compressed.
When an object is moving towards the observer, its measured wavelength decreases,(it is not correct if measured length) because the waves are compressed.
That's true. It doesn't even need to be very high speed, although the effect is too small to measure at low speeds.