Exoplanets and Life in the Universe

“Star Wars,” “Star Trek,” and other movies and television shows featuring space travel and alien life have fascinated people for decades. Yesterday, we examined how intergalactic travel would not be anything like what the movies depict. Other galaxies are many light-years away, and the laws of physics will not allow us to travel even one percent of light speed. Nevertheless, people are still concerned about exoplanets and life in the universe.

Regardless of whether we can go to other galaxies far, far away, or even solar systems within our own galaxy, astronomers are searching for “exoplanets.” An exoplanet is any planet outside of our solar system, and scientists are trying to find one that could support life. (We have dealt before with the question of why the universe is so large.)

Scientists look for planets orbiting stars that are so far away we can’t even see the stars with our unaided eyes. How is it possible to find planets that we can’t see, even with our best telescopes? They use at least three methods. When a planet transits in front of a star, it blocks a small amount of the star’s light. Very sensitive instruments detect that change. A star may wobble slightly because of orbiting planets, causing a detectable color shift due to the Doppler effect. Finally, astronomers sometimes use gravitational lensing to detect an orbiting planet if it causes bending of the light from a distant star.

Those are some methods astronomers use, hoping to find exoplanets and life elsewhere in the universe. However, unlike in the movies, the stars and their planets are so far away that we could never go there. Even sending a radio signal to those possible planets would take thousands or even millions of years, traveling at the speed of light. Getting a message back would take an equal amount of time.

There are so many requirements for life that the chances of any of those planets supporting advanced life would be almost infinitely small. If there is some form of life on any of them, how will we ever know? God could have created life elsewhere in the universe, but we have no evidence one way or the other. The Bible doesn’t tell us, and science can only look and hope for a clue. Whether or not life exists on other planets or moons, we believe the fine-tuning of Earth for life is evidence for God’s existence.

— Roland Earnst © 2021