Why we should listen to scientists

In this blog, there are a few topics that I try hard to avoid, because they rarely serve my primary main underlying goal: trying do to-mystify the scientific process (especially with regard to astronomy). One such topic I avoid like the dickens is politics, as the best political commentary I can muster would, if I were lucky, only alienate half of my audience. But today, I can't avoid the topic. Politics often sticks its nose into science (stem cell research, global warming, and science education are a few of the big topics of recent years), and the debate over these topics is often not based in science (good or bad) at all. But at least the debate is public, and it offers us scientists a stage, however imperfect, for trying to spread what we've learned about these subjects.

Earlier this week, the Bush Administration tried to quietly announce some whopping changes to the Endangered Species Act (ESA). As far as I understand it, the basic impact is that government agencies will no longer need to seek an independent review for projects that may impact an endangered species. Of course, they could still seek a review, but given that the review often slows down and forces changes to projects, does anyone honestly think that they would?

These reviews typically include scientists who collect evidence (most provided by the agency required to seek the review) and decide if a project would have a significant negative impact on an endangered species, and if there are changes that can be made to the project to lessen that impact. Sometimes those changes may be very expensive, and sometimes these reviews can really slow down the process. And a negative review can torpedo projects.

Is the ESA perfect? No. Sometimes the delays seem silly (like a bike path in California being delayed because it crosses territory of an endangered beetle), though there are often larger issues at stake. So, if the government wants to debate the process and make changes, I can go along with that. But let's at least do it in public. The U.S. is, after all, a republic; if we can't debate laws in public and have to change them in secret, then we've lost the most important rights that millions of men and women have died for over the past 240 years.

Some argue that the scientists involved in the review care more about endangered salamanders than they do about human beings. We are called elitists who think we know more than John Q. Public, and therefore our opinions have no value. Well, frankly, when it comes to science, we do know more than John Q. Public. That's not snobbery. It would be snobbery/elitism if we thought that our extra knowledge in scientific matters made us better than other people, but we know better. If the plumbing in my apartment breaks, I call the plumber, because I know that he/she knows much more about plumbing than I do. When my car quits running, I take it to the shop, because I know the mechanic knows much more about cars than I ever will. And I think the plumber and mechanic would be within their rights to say that they know more than I do about those subjects; I wouldn't be able to argue with them. So, when it comes to ecology, how can a career bureaucrat ever claim to know as much as the career biologist? The ecologist who says, "I know more about that than the bureaucrat, so please give my opinion some consideration" is not being snobbish, but just asking for the same deference we give to experts in other walks of life. Scientists are not crazed misanthropes bent on world domination, nor do we put our own personal ambition above the needs of our fellow man. We want humankind to progress, just in a way that doesn't take down the rest of life with it. We humans are part of a very complex and interconnected biological system, and if we fail to take care in our dealings with that system, we may be asking for trouble.

I often hear or read wisecracks about how stupid scientists are being when proposed developments are delayed because of impacts on endangered salamanders or frogs. And, I would have to agree that if the question were, "us or the frogs?", I'd side with us. But the question is not that simple; there are usually larger issues at play than just the endangered species. Often, the biggest danger of a shopping mall or an interstate to a salamander is not the increase in cars running over the poor creatures, but the loss of habitat, because the wetlands in which the salamander likes to live will have to be drained or altered. And while wetlands, swamps and bogs may not seem like very desirable things for humans, they can have tremendous impacts on us. For instance, there is strong evidence that a loss of wetlands increased the damage from Hurricane Katrina. While those lost wetlands would not have prevented the devastation from the monster storm, they may well have lessened the impact.

The Bush administration has claimed that the independent scientific reviews are no longer necessary because agencies have developed sufficient expertise to conduct their own reviews without scientific input. But science is constantly changing; we are continuing to learn more about the connections between environments, species, and humans. And these connections change with time. Bald eagles and alligators don't need the same types of protection they did 30 years ago, and pacific salmon need protections that they didn't just a few years ago. Who is going to be more up to date on the current environmental needs, a Ph.D. ecologist or the manager of a road construction project? I'll believe the ecologist on the environmental issues (though I'd take the manager's advice on the bridge design).

The fact is that, despite the extensive delays sometimes caused by environmental protection laws (though egregious cases exist, they are rare), our environment is in much better shape than it used to be. And that bodes well for humans. Compare a smoggy day in LA to a smoggy day in Beijing, and ask yourself which air you'd rather breathe. Environmental laws made that difference. Or read Silent Spring and then look at the change in bald eagle population since that time. The Endangered Species Act made that difference.

I have no problem with a healthy public debate on the details of environmental law and the role of scientific reviews within that law. But silent changes gutting existing laws (that have saved many species and have improved our human quality of life) without so much as a word of public discussion is wrong. It's antithetical to democracy. It blatantly ignores the voices of scientists whose life work is directed toward improving the lives of humans, both living and in future generations. It threatens the continued (and improving) health of the ecosystem of which we are an integral part.

Weekend TV

This weekend I was flipping through TV channels, when I stumbled across a show in progress that was discussing the interaction of the mineral magnetite in meteors with Earth's magnetic field and the aurora. I thought that this seemed like a pretty complicated subject to be discussing on TV, but I've seen more complicated things. And I'd missed the start of the show, so I didn't really know what the show was about. Then, in a span of a few seconds, the truth about the show was revealed.

The narrator summed things up roughly as follows: "Dr. X, a plasma physics researcher, has shown that meteors and the Earth's magnetic field may be responsible for the enhanced levels of magnetite." Then the video changed from a pretty movie of the aurora (northern lights) to an animation of a cow floating off the ground up into the air. "But Ms. Y still claims that aliens are abducting the cows."

My brain did a mental flip-flop, and I started laughing really hard. Once I calmed down (and changed the channel), I did some Google "research" and pieced things together. Evidently, cattle are often found dead on the range, and some UFO believers researched a few of these and found what were supposedly enhanced levels of magnetite on the ground in the area. So, I guess the plasma researcher was explaining how you can get magnetite on the ground. I don't need an expert to tell me how to get a dead cow; I can think of many reasons that do not involve aliens.

I hate to be a killjoy and skeptical about this, but I will state unequivocally that aliens are not abducting cattle. Or humans. Or any other creature. Natural explanations for the poor cows' deaths not only exist, but seem much more likely than aliens travelling hundreds of light years for an opportunity to kill cows.

Honestly, I'd like to think that there are intelligent aliens out there. And I'd even welcome a visit, as long as they are more like E.T. than Predator. But a desire to believe aliens exist is no substitute for hard, cold evidence.

What evidence should we require? The only kind that science accepts -- iron-clad. For intelligent life, this could be as dramatic as the appearance of aliens in a public setting or as subtle as detection of communications. But dead cows on the range don't meet that level of proof. Sorry.

Editing Note in the interest of full disclosure: A few hours after posting this article, I realized that my original title had nothing to do with the post (the article went in a totally different direction than I expected), and could be construed as demeaning, even though it wasn't meant to be. So I changed it to the title above before any complaints came in.

Sometimes it's the messenger, not the message, that matters

Last week, famed physicist Stephen Hawking made news by stating that he thinks there is life elsewhere in the Universe. Hawking's speech was given as a part of a celebration of NASA's 50th birthday.

I'll admit, I am a little surprised at how much press Hawking's comments have received. Granted, his speech had all the ingredients needed for a media frenzy: a celebrity scientist making a statement on a popular topic in a public forum.

But the scientist in me is perhaps a little too jaded. Hawking is famous (and rightly so!) for his work on black holes, general relativity, and the interface of gravity (which dominates the large-scale universe) with quantum mechanics (the physics of fundamental particles). He doesn't work on astrobiology (the study of life in the Universe). And so, while Hawking's opinions are undoubtedly well-informed, he is not an expert in that field. From a scientific viewpoint, I'd personally place much more weight on the opinions of an astrobiologist than on Hawking's opinions on this subject.

And Hawking's opinion, that life may be quite common but that intelligent life is very rare, is not a groundbreaking statement. In the past couple of decades, this has become a fairly common opinion. Life has existed on the Earth for over 3 billion years, but complex organisms have existed for only the last 550 million years or so. And only in the last few million years has "intelligent" life appeared, though there is much argument over what constitutes "intelligent" life. If you go by the definition that intelligent life is capable of communicating with life on other planets, then Earth has only had intelligent life for 100 years (though this is a little too strict, I think).

So, if life is out there in the Universe and it is similar to life on Earth, then most of the life out there is probably some sort of algae soup, not friendly, space-faring gardeners. And, therefore, Hawking's remark is not earth-shattering.

But this story shows how the messenger can be just as important as the message. In the eyes of the general public, Stephen Hawking is an expert in all things astronomical. Therefore, whatever he says about life in the Universe carries much more weight with the public than anything a preeminent astrobiologist might have to say.

So, for that reason, I don't have a problem with Hawking getting credit for expounding commonly-held opinions. If he were to start claiming that aliens from Venus are taking over our planet, then I'd have a problem. But, if science and education are being served, more power to him.

Earth Day 2008

Image Credit: NASA/JPL-Caltech/University of Arizona

Today is Earth Day! But I promise not to fill this space with discussion of climate change and sustainability and the like, as there is plenty of that discussion out there already.

However, I would like to note how crucial studies of the Earth are to astronomy research, as looking inward gives us a reference point for interpreting what we see when we look outward.

Planetary astronomers get the most direct help from studies of the Earth. Other planets and moons have volcanoes, fault lines, atmospheres, and weather. It is not hard to imagine how understanding lava flows on Earth may help us to understand the history of Martian volcanoes, or how knowledge of cloud formation on Earth can help us understand why Venus is shrouded in clouds, or even the development and structure of clouds on Jupiter.

In the next decade, we will most likely discover Earth-sized planets around other stars. And as we develop more and more sophisticated technology capable of analyzing light from those planets, we will likely begin to detect other atmospheres. How reliably can we interpret those findings from far away? Studies of the Earth from afar (like the above picture of Earth and our Moon taken from Mars late last year) can tell us what we can and cannot detect from far away.

Finally, as we begin to look for life on other planets, we need to know how to look for life. Most importantly, are there any unambiguous signs of life that we'd be able to see from hundreds of light-years away? Our atmosphere has concoctions of molecules, like methane, oxygen and ozone, that we don't think other planets can have without life producing them. But maybe other non-biological processes that we haven't thought of could be at work. Do we need to look for signs of chlorophyll? Would alien plants use chlorophyll? What if we see some strange molecule that we don't have on Earth. Could we identify it and discover if it is a marker of life?

These are all important questions, and while studying our own planet may not provide us with unambiguous answers, maybe we can get some guidelines toward solving these problems. And, in the meantime, we'll continue to learn more about our home planet, our relation with it, and how we should best maintain it.

Hubble sees organic molecules in another solar system

Image credit: NASA, ESA and G. Bacon

This afternoon, NASA announced that the Hubble Space Telescope detected organic molecules in the atmosphere of a planet circling another star.

First, let me emphasize: Hubble did not discover evidence of life on another planet. Organic molecules (generally molecules made mostly or fully of carbon and hydrogen atoms) are quite common in the Universe. Carbon is made in stars and during supernova explosions, and is one of the most abundant atoms after hydrogen and helium. And the organic molecule found, methane, is quite common in the atmospheres of Jupiter, Saturn, Uranus, Neptune, Saturn's moon Titan, and even in some of the coolest brown dwarf stars.

So, why the big deal? It is because we are detecting the signatures of chemistry on a planet outside of our solar system. We can now begin to probe the chemical make-up of this planet, and from that begin to test our models of giant planets around other stars.

How did Hubble detect the methane (and water) in this planet? The planet in question, which has the extraordinarily boring name of "HD 189733b", is about 63 light-years away toward the constellation Vulpecula, a tiny, forgettable constellation near Cygnus, the Swan, visible during the summer months in the northern hemisphere. The planet is about the size of Jupiter but is located very close to its parent star, completing an orbit in only 2 days. Compare that to 88 days for Mercury to go around the sun, a year for the Earth, or 12 years for Jupiter! So it is a hellishly hot place, and certainly nothing can live on the planet (which is a big gas bag, like Jupiter), or on one of its moons (if it has any).

The planet passes in front of its parent star, as seen from the Earth, once each orbit. Every two days or so, the star appears to get a little fainter as the planet's shadow crosses the face of the star. The planet only blocks out some of the star's light (about 1%), so these little variations are hard to see.

Some of the light from the star passes through the planet's atmosphere on its way to Earth, and any chemicals in the planet's atmosphere will put a fingerprint on that light. This is a very tiny signal, and very hard to see. But, with time, patience, and a lot of hard work, it can be picked out. In the past, astronomers had detected sodium in the atmospheres of a few planets around other stars. Now, we can add methane and water to that list.

The next step is to compare the various chemicals and the amount of those chemicals that we see with theoretical models of what these planets atmosphere's might look like. These models are really just educated guesses -- if we assume the planets are like Jupiter, and have a chemical makeup similar to that of their parent star, and we make some guesses as to how hot the planet might be, we can use concepts of meteorology and chemistry to calculate what the planet's atmosphere should look like. And the very early indications are that the models aren't quite right. The models predict that water and methane and sodium should be there, but in different amounts. This disagreement is a good thing -- it means we don't yet know everything, and that we can learn a lot by doing more studies like this one.

So, congratulations to the team who made this discovery. Good going -- now, let's get back to work and see what more we can learn about these planets!

Have we found a new Earth?

In a fairly big news story today, Swiss astronomers announced that they found an Earth-like planet orbiting a red dwarf star. The news stories are speculating about water and life on this planet. But let's step back just a bit before we start planning the State dinner for the ambassador of Gliese 581c.

First, let's look at what we know for certain. Gliese 581 is a red dwarf star -- a star smaller and cooler than the sun. Gliese 581 is about 21 light-years away and was already known to have a Neptune-mass planet (Gliese 581b) orbiting the star every five and a third days. Astronomers knew this because the star is wobbling as the gravity of Gliese 581b pulls on it, and we can measure this wobble. But one planet didn't fully explain the observed wobbles. After more observations, the European astronomers figured out that the system must also have a planet at least five times the mass of the Earth orbiting the star every 13 days.

Really, that is all we know. Anything else is guesswork, though these guesses have some scientific basis and are not just idle speculation. If the Gliese 581c is made of rock, its diameter will be about 1.6 or times that of the Earth, and the pull of its gravity will be about 1.6 times stronger than that of the Earth, meaning that if you weigh 180 pounds on the Earth, you'd weigh 290 pounds on Gliese 581c. However, it could be made of ice, and therefore be larger, or it could have a lot of gas (like Uranus or Neptune), in which case it could be quite a bit larger. We don't know.

We also know that, at the distance that Gliese 581c is from its parent star, it lies in a "sweet spot" where temperatures are just about right for water to exist as a solid, liquid, and a gas, as it does here on the Earth. Scientists call this the "Habitable Zone," since life as we know it could live there. However, just because a planet is in the Habitable Zone around a star doesn't mean the planet could support life. Maybe it doesn't have any water. Maybe it has an atmosphere like Venus and is a thousand degrees on the surface. Maybe it doesn't have an atmosphere at all. We don't know.

Another issue with Gliese 581c is that it is so close to its parent star that the same side of the planet almost certainly faces the star, just like the same side of the moon always faces the Earth. This would make one side of the planet fairly hot, and the other side frigid cold (although an atmosphere could help mitigate this effect). It may be that all the water on the planet is locked in giant ice caps on the side of the planet away from the star. We don't know.

In short, Gliese 581c is a very interesting discovery, and the astronomers who found it have made a very important find. But the find illustrates how little we know about planets in other solar systems. It will likely take years before we learn much more about Gliese 581c, and it may be decades or longer before we can ever separate its light from the light of its parent star (separating the light would make it easier to study its atmosphere). But you can be certain that astronomers will continue to study this planet and to search for more and more Earth-like planets around other stars!