Possible Water Vapor Tantalizes Astronomers

The exoplanetary-analysis community is buzzing with news this week of the possible discovery of water on HD189733b, an exoplanet 64 light-years from earth. This “could-be” announcement echoes a similar announcement three months ago that water had been found on HD209458b. We asked at that time,

[w]ould the presence of water on a faraway planet support the story that life arose out of primordial clay? Of course not. Even so, it’s quite telling that there’s so much evolutionary focus on the mere possibility of the presence of water, despite the fact that the steps that would transform water (and other substances) into life have never been found in nature!

While the earlier announcement was “met with skepticism,” as described in “Wanted: One Planet, With Water,” this new claim carries more weight, according to the French scientists who conducted the research, because “the observations were taken in infrared light, which is far better at detecting light-absorption patterns unique to water.” (Scientists cannot observe water in far-flung solar systems directly, but rather analyze light spectrums and use computer programs to search for “specific light-absorption ‘signatures.’”)

Unfortunately for those who want to use this discovery to fuel search-for-life efforts, there are several “problems” with the water on HD189733b. First, the water is in vapor form, not liquid. Phil Berardelli’s ScienceNOW article explains the problem:

But other experts say there’s a big difference between water vapor, as discovered in HD 189733b's atmosphere, and liquid water, which is what astronomers are really hoping to nail down. The new findings are “entirely reasonable,” but they fall short of the main goal of the search, says astrobiologist Margaret Turnbull of the Space Telescope Science Institute in Baltimore, Maryland. Water vapor “is actually fairly common in the universe,” she says, “what is rare is liquid water, and that’s the key to life as we know it.”

The water is in vapor form, not liquid.

On top of that, scientists can’t determine, using the current analytical technique, what the density of water vapor is in the atmosphere of HD189733b; they do not know “whether it is present in only trace amounts or at much higher levels.”

Also noted by the article is that “[m]ost scientists think that life cannot exist without water,” which is cited as the reason why astronomers have been spending the last decade “looking for signs of water on the 200-plus exoplanets now known.”

Perhaps astrobiologists searching for extraplanetary life shouldn’t be looking through telescopes—or so says the (U.S.) National Academies of Science National Research Council. The NRC issued a recent report that suggests more research should be done on earth—using microscopes—to help humans “understand the potential for life based on chemistry that differs drastically from our own.”

Provocatively, the report claims “the search for life on other planets has been hampered by Earth-centric assumptions—that life depends on water, for example.” The authors of the report instead suggest the possible existence of life based on ammonia or formamide, and suggest, among other things, that scientists must “create life in the lab with building blocks not used in Earthly organisms” to help frame and enlighten the search for off-world life. Ironic, since they have thus far failed to “create life” as we know it.

According to Penn State University geoscientist Katherine Freeman, the report “articulately lays out the risks of focusing on life as we know it.” Or, we wonder, does it offer evolutionary scientists a convenient “way out” if potentially watery planets, the current recipient of exoplanetary search resources (as described above), fail to turn up signs of life?

They have thus far failed to “create life” as we know it.

Punctuating the discussion of life—both its many hypothesized extraterrestrial forms and our traditional view of it—are comments by Steven Benner of the Foundation for Applied Molecular Evolution:

The report encourages NASA to consider some “deep questions,” says Steven Benner of the Foundation for Applied Molecular Evolution in Gainesville, Florida. “Why are we here? How did we originate? These are some fundamental questions.”

We couldn’t agree more—and, as a matter of fact, have built a museum with a planetarium (you may have heard of it) to help people ask and answer such questions (including those about the origin of life). Of course, evolutionary scientists are fueling their own projects in their as-yet unanswered quest to answer those questions—including a new Mars-bound life-hunting NASA spacecraft.