Tuesday, March 20, 2018

Changing My Mind

As far back as I can remember in my life I was interested in science and technology particularly in the manned exploration of space and the human endeavor to land a person on the moon. As a teenager and young adult, this interest in science combined with my Christian faith motivated me to read books on the integration of science with Christianity. Most of the books I read during those years promoted a "young earth" view of the Bible and science stating that the universe was less than 10,000 years old and that scientists were misinterpreting the data when they proposed that the universe started with a Big Bang almost 14 billion years ago. At that time I was not aware of much material written from a Christian and biblical perspective that promoted an "old earth" view of the Bible that agreed with the scientific timescale of the universe as determined by modern observations.

Saturday, March 10, 2018

Are Earth-like Planets Common?

It seems that every few months newspaper and magazine headlines will declare something like "Scientists have discovered an Earth-like planet." Such headlines probably lead the reader to imagine a planet with an environment much like we see on Star Trek or Star Wars where we could land our spaceship, take off our spacesuit, and frolic around the countryside. But what do scientists mean when they say that they have discovered an "Earth-like" planet? How likely is it to find a planet that can support higher life forms (defined as anything more complex than bacteria)? Are planets like the earth common or rare? Let's explore the answers to these questions.

When scientists say that an Earth-like planet may have been discovered, they actually mean one of three things. Either (1) the planet is in such an orbit around its central star that allows the temperature on the planet to possibly harbor liquid water, or (2) the planet is about the same size as the earth, or (3) the planet is solid and rocky rather than gaseous. Of course any one of these criteria, or even all three, does not actually give us a true Earth-like planet. We know that our moon is in the correct location to contain liquid water, but it is not "Earth-like." We know Venus is about the size of the earth, but it is not "Earth-like." We know that Mercury is rocky and not gaseous, but it is not "Earth-like." So none of these criteria really give an Earth-like planet. Headlines and sound-bites are not meant to be precise but to draw attention, and it is much more exciting to proclaim an "Earth-like" planet has been found rather than a "Venus-like" planet (if even that could be claimed).