- Series:Astronomy, Transcript English
“And God made two great lights; the greater light to rule the day, and the lesser light to rule the night: he made the stars also. And God set them in the firmament of the heaven to give light upon the earth, and to rule over the day and over the night, and to divide the light from the darkness: and God saw that it was good.”
If you fire a beam of laser light at the Moon, how long will it take to get there?
At first, some might suggest that this is a relatively easy problem. Speed equals distance divided by time, so surely we can calculate how long the light will take. But do we really know how fast the light travels from Earth to Moon? Creationist astrophysicist Dr. Jason Lisle suggests that we don’t.
What we know is the average speed of light. To measure the speed one-way, we would need a clock at either end. These clocks would need to be synchronized, presumably by sending a radio signal. But that signal itself travels at the speed of light—the very value we are trying to measure. Alternatively, we could synchronize both clocks on Earth, then take one of them to the Moon. But time operates at different rates at different speeds. Therefore, the journey that the Lunar clock makes from Earth to Moon actually desynchronizes it from the Terrestrial clock.
All we can do is measure the average speed, by bouncing the laser off the Moon, and receiving it back on Earth, where the same clock that registered the start of the laser’s journey can register its return. The speed one-way might, in fact, be very different from the speed the opposite way. This is one possible explanation for how light could travel over millions of light years, while only taking a day to reach the Earth, because the speed from distant star to Earth might, in practice, be much faster than the known average. Other creationists have other models, but all rightly depend on Genesis 1 being literal history.
Prayer: We stand in awe at Your universe, O Lord. So much is out there that blows our minds! Yet, You made it all, and declared it to be good, so we praise Your wonderful Name. Amen.
Author: Paul F. Taylor
Ref: Lisle, J.P., Anisotropic Synchrony Convention—A Solution to the Distant Starlight Problem, Answers Research Journal 2:191–207, 2010, , accessed 6/22/2017
Image: Adobe Stock, licensed to author