Another Goldilocks Planet?

An artist's rendering of Kepler 22b.
NASA image in the public domain.

More than a year ago, I discussed a planet named Gliese 581g. It was hailed as a “Goldilocks planet,” which means it is not too far away from its star and not too close to its star. Instead, it is at just the right distance, allowing it to receive the right amount of energy from the star so that stays warm enough to support life. Unfortunately, it’s not even clear that the planet really exists. One team of astronomers is confident that it does exist, but another team is confident that it does not. The latest analysis that I have seen adds more evidence to the “does not exist” side of the debate.

Well, the Kepler project has found another Goldilocks planet. I blogged about the Kepler project just a few days ago. It is a project designed to find planets that are roughly the same size as earth. They have found many, many such planets, and one of them, currently called Kepler 22b, is about 2.4 times the size of earth. What makes it special, however, is that it orbits a star similar to the sun, and it orbits that star at a distance which would allow it to receive just the right amount of energy to keep it warm enough to support life. Unlike Gliese 581g, there seems to be no doubt that the planet exists.

The popular media is abuzz with the news, and as usual, they aren’t being very accurate in their reporting. For example, here is how a writer tells the story:

Kepler-22b’s radius is 2.4 times that of Earth, and the two planets have roughly similar temperatures.

Such a statement is nonsense, given what the Kepler team actually discovered.

If you look at NASA’s own report, you find that the news is not nearly as rosy as the popular media is making it out to be.

The NASA press release, for example, tells us that we don’t even know if the planet is predominantly solid, liquid, or gas! Thus, to say that we know it’s temperature is roughly the same as that of earth is ludicrous! After all, the proximity to the sun isn’t the only thing that affects the temperature of the planet. Earth’s average temperature, for example, is about 14 degrees Celsius (57 degrees Fahrenheit). Without the greenhouse gases that exist in its atmosphere, however, earth’s average temperature would be -18 degrees Celsius (0.4 degrees Fahrenheit).1 If that were the average temperature of earth, life as we know it almost certainly would not exist.

So while Kepler 22b may have a temperature that is suitable for life, the fact is that at this point, we really have no idea. If it has no atmosphere at all, it is probably too cold for life. If it has an atmosphere that is low on greenhouse gases, it is also probably too cold for life. If it has an atmosphere that is filled with greenhouse gases, it is probably too hot for life. As a result, it is important for now to concentrate on what we do know.

As far as I can tell from NASA’s press release, we know that Kepler 22b is larger than earth. We don’t really know its mass, which is why we don’t know whether it is mostly solid, liquid, or gas. Without knowing its mass, we don’t really know what its gravitational field is, which is one of the many factors that control what kind of atmosphere it can have. Too little gravity means it can’t hold on to much of an atmosphere; lots of gravity means it can hold on to a very thick atmosphere.

Unfortunately, it seems that even NASA can’t help but make it look like we know more about the planet than we really do. Notice the artist’s rendering of the planet above. This illustration comes from NASA, and it shows that Kepler 22b has clouds surrounding it. Since we have no idea whether or not Kepler 22b has an atmosphere, we most certainly have no idea whether or not it has clouds!

So until we know some very basic facts about Kepler 22b, it is silly to start talking about its average temperature. It is most certainly possible that its temperature is in the range necessary for life as we know it to exist. However, it is more likely that the temperature is either too hot or too cold to support life as we know it.

Of course, even if the temperature is right, that is only one of many, many factors that must exist in order for a planet to support life. Thus, we are a long, long way from determining whether or not this planet has any life on it.

Now as I said in my previous post about the Kepler project, anyone who believes that life is simply the result of random chemical reactions acted on by some selection mechanism should be astonished that it happened even once in the universe. Given its impossibly low probability, the thought that it could happen twice is clearly absurd. However, as a creationist, I wouldn’t be surprised to find life outside of earth. God creates according to His own purposes, and He therefore might have created life on more planets than just earth. Until I see serious evidence for such life, however, the proper scientific position is one of skepticism.

Unfortunately, the popular media doesn’t know much about science, which is why it is reporting this story in an irresponsible manner.


1. Steven L. Horstmeyer, The Weather Almanac, 12th Ed., John Wiley and Sons 2011, p. 319
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  1. gracekalman says:

    The popular media doesn’t know much about reporting in a responsible manner. It does know how to report its agenda.

  2. Rio says:

    i got kind of worried when i saw this on the news thanks for clearing it up

  3. Ben Fournier says:

    It is kinda sad how quickly bold statements are made loudly, often only to be retracted quietly later when shown incorrect. In a 1962 copy of Bowditch, in the chapter on astronomy, it does some describing of the planets in a clear manner making tentative statement of what the situations on them may or may not be (from the vantage of not having robotic probes yet sent but only working with telescopic and spectroscopic observations). That’s cool. But so many reports in media and even items in modern textbooks seem to make a point to try to be overly sensational about everything.

  4. Pyrodin says:

    Perhaps they are trying to get more support and funding for space exploration?

    1. jlwile says:

      Pyrodin, I don’t think that’s really the goal, at least not directly. I think NASA just wants to make astronomy research look more exciting so as to generate the public’s interest. That might lead to increased funding, but I don’t think that’s necessarily the direct goal.