[ does anyone know the answer to this] A spaceship travels at 0.9999c. How long does the crew need to wait in their time, for Earth to reach the year 2100 (78 years)? (Give your answer in years)

Sawyer is studying diffraction. he draws a diagram of a plane wave to show how light waves travel. which best describes sawyer’s error? the wave fronts should be perpendicular to the direction in which the waves move. the arrow showing the direction of movement of the waves should be pointing to the left. the arrow showing the direction of movement of the waves should be pointing downward. the wave fronts should be both parallel and perpendicular to the direction in which the waves move.