Fire and Knowledge

Maybe you’ve heard: astronomers have discovered a new planet (Gliese 581c) 20 light years away that they speculate is similar to Earth. In one popular article, the summary states:

It’s got the same climate as Earth, plus water and gravity. A newly discovered planet is the most stunning evidence that life - just like us - might be out there.

That summary is completely misleading. Why?

1. We haven’t actually seen the planet. Astronomers calculated that the planet is probably there by its gravitational effects. But they haven’t actually seen it. That means we don’t know very much about the planet and calling it “new earth” is, as Treebeard might say, a little hasty.
2. We have no idea if there is water on it. They said “plus water” like we know it has water. We don’t.
3. We have no idea if it’s “the same climate as earth.” We do not know what kind of atmosphere it has or whether it has oxygen. We don’t even know if the temperature is similar. The type of atmosphere it has will have a large impact on temperature.
4. They say it is “the most stunning evidence that life - just like us - might be out there.” How is this “stunning evidence”? We don’t know if there is any life on it. And if there is, it is doubtful it will be anything like us (for one, the gravity is probably twice as strong which means it would result in very different lifeforms).
5. This doesn’t increase the odds of Earth-like planets. The article says “the real importance is not so much the discovery of this planet itself, but the fact that it shows that Earth-like planets are probably extremely common in the Universe.” There’s at least two problems with that sentence:
1. If the real importance is not the planet itself, why is so much attention being put on it? Why isn’t the emphasis on the new probability of Earth-like planets? Without knowing more about this planet, we don’t know if the probability of Earth-like planets is higher, because we don’t know if this is an Earth-like planet yet!
2. Saying this increases the odds of Earth-like planets is like a blindfolded person selecting a marble out of a jar, suspecting the marble might be blue (but not really knowing), thus leading him to the conclusion that the odds of blue marbles in the jar has increased.

All that to say, beware ye of article summaries.