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Dr. Christopher S. Baird

How do stars move when viewed from a speeding space ship?

Category: Space      Published: February 16, 2013

Public Domain Image, source: NASA/JPL-Caltech/ESO/Univ. of Michigan.

During space travel, the stars don't move or stream past you. The reason for this is that the stars are so immensely far away from you. Consider driving along the highway. The trees at the edge of the road whoosh passed you at an alarming rate as you speed forward, but the distant mountains hardly move at all. All stars are far more distant than mountains and therefore seem effectively fixed to traveling astronauts. The moving effect is known as parallax. Mathematically speaking, the observed location of the stars does actually change as you travel, but the amount is too small to be discerned by human eyes. It takes very sensitive instruments to measure the parallax of the stars. When the Apollo astronauts looked out their window while barreling towards the moon, it looked like they were motionless because the stars didn't move. Stars don't move and they definitely don't make shooting streaks across your field of view. Movie producers perhaps distort this fact of physics in order to add drama. The producers want the viewer to see that the spaceship is traveling at high speeds by making the stars woosh by, when in reality observers would see no movement. If a space ship traveled near the speed of light, the stars would appear bunched up in the forward direction, but would still not move.

Topics: moving stars, parallax, space is big, space movie, space travel, speeding stars, star, stars, streaming stars