The media has been full of stories today about the press conference held by NASA to announce a paper published in Science. They haven’t done a very good job of explaining what scientists have found, so I’d like to try to clear some things up. I’d also like to use this opportunity to highlight some of the recent stories about the state of science.
The paper, entitled “A Bacterium That Can Grow by Using Arsenic Instead of Phosphorus,” reports a rather significant discovery, but it is not terribly groundbreaking to anyone who has spent some time thinking about astrobiology.
Before I get into what was found, we have to cover some basic science. Life on Earth is mostly based on six elements: carbon, hydrogen, nitrogen, oxygen, phosphorus, and sulfur. There are obviously other elements involved in life, but these are the most prevalent. I’m sure everyone remembers vaguely what a periodic table looks like from high school chemistry. For reference, there’s the relevant section of one below.
You’ll notice that the elements are organized in a very specific way: each column contains elements that share similar properties. You’ll notice that phosphorus (P) and arsenic (As) are in the same column. Because of this, it’s been hypothesized that life could use arsenic in place of phosphorus. (In the same way, you’ll notice that carbon (C) and silicon (Si) are in the same column. It has also been hypothesized that life could arise based on silicon rather than carbon). It’s not particularly hard to see how arsenic could replace phosphorus when you think about it. Arsenic is poisonous to us because it is similar enough to phosphorus to bind to the same receptors as phosphorus, but is different enough to simply shut down the relevant reaction. The big problem is that arsenic effectively blocks respiration and starves the cell.
Now, some of the headlines that ran today involved the phrase “arsenic-based life.” This is a misnomer. I would also rule out any seemingly outrageous claims you’ve heard or read. Nothing was actually found in the wild; the paper presents the results of an experiment.
The scientists took extremophile bacteria from Mono Lake in California, which has a relatively high concentration of arsenic. In the lab they then effectively starved the bacteria, by depriving them of phosphate, but providing arsenate, which is a similar compound except with arsenic instead of phosphorus. The amazing thing about this experiment is that the bacteria continued to grow in the presence of arsenate, albeit at a slower pace than controls that had access to phosphate. And based on indirect evidence, it appears that the bacteria actually replaced the phosphate in the backbones of its DNA with arsenate, though this hasn’t been proven.
So what does this mean? Well, it means that life as we know it is more robust than we thought. These bacteria can survive, and even grow, in the presence of what would be a toxic compound to almost any other form of life. In a sense, it is a wonderful demonstration of the power of natural selection. The reason NASA’s Astrobiology Institute was involved is that this can be considered very good evidence that life can exist in the presence of arsenic rather than phosphorus. Scientists now have the ability to measure the chemical composition of exoplanets by using spectroscopy. Spectrographers have been searching for what are known as “biomarkers,” or elements and compounds that would allow for life, such as water, carbon dioxide, oxygen, methane, and nitrogen. Now arsenic can be added to the list. What’s very interesting is that Saturn’s moon Titan may have an environment conducive to life that uses arsenic. Either NASA or the European Space Agency will have to send more robotic missions to Titan if we want any more information. It’s worth noting that the Astrobiology Institute saw its funding cut in half by the Bush Administration.
This comes on the heels of an announcement yesterday from researchers at the Harvard-Smithsonian Center for Astrophysics and Yale University that there are probably at least three times as many stars in the universe than previously thought. The astronomers have realized that elliptical galaxies, which are about a third of all known galaxies, actually contain many more cool, dim dwarf stars than was thought. Because of this, elliptical galaxies could in fact contain as many as a trillion stars, well above the previous estimate of about a hundred billion.
Yesterday also saw an announcement from the UK’s Met Office that the Hadley/CRU, the institute that was the subject of “climategate,” has in fact incorrectly measured global temperature rise. Though it turns out that they were underestimating how much global temperatures have risen (something many scientists had already pointed out), so the climate deniers probably won’t take much comfort from this.
On the flip side of things, yesterday saw the official announcement from Answers in Genesis that it will be building a theme park next to its “museum,” one of the several locations in the United States where people can go to see science distorted to a staggering extent. (For those of you unfamiliar with the creationist movement in the US, it holds that evolution is false and that the biblical account of creation is the accurate representation of reality. There is variation in beliefs, but Answers in Genesis represents a large fraction of our population when it asserts that the world and universe are 6,000 years old and that humans and dinosaurs coexisted. I don’t think I need to mention that in the 151 years since the publication of Darwin’s On the Origin of Species there have been exactly zero discoveries to support this position. It also happens to contradict all of modern physics, cosmology, astronomy, chemistry, and biology).
What’s interesting about this announcement is that AiG was joined at the press conference by Steve Beshear, the Democratic governor of Kentucky, who is supportive of the project. AiG is seeking $37.5 million in state tourism development incentives. This has produced a fascinating debate on church-state issues. It also leaves one wondering why a sitting governor would be supportive of one of the organizations most dedicated to eviscerating the quality of American science.
There was one last story in the news recently: the Republican House Leadership’s website “YouCut” has expanded its reach to the National Science Foundation (NSF). For those of you not familiar with YouCut, Americans are encouraged to propose ways to reduce the federal budget through spending cuts and these proposals are voted on. President Obama’s recent decision to order a pay raise for federal workers seems to be in response to this website.
Now, NSF grants are very difficult to get and applications are vetted rigorously by scientists. So why anyone would think any of that money is going to waste is beyond me. But apparently the Republican leadership thinks so. They’re encouraging people to look through the list of grants for terms that would be indicative of wasteful spending. Among the suggested terms are “culture” and “media,” which I find staggering. I have no idea why they were included in the list, but their inclusion does prove that whoever wrote it doesn’t have any understanding of science.
If you search for “culture” you receive 1,352 hits and if you search for “media” you get 2,342 hits. I know it’s been a long time since high school biology, but these terms must be ringing some bells. Perhaps some of you have heard of cell cultures, tissue cultures, organ cultures, or microbiological cultures. And “media” is in effect food, generally for organisms such as bacteria or yeast. These terms are taught in biology 101 and the majority of these grants are for basic research, quite a lot of it medical in nature. Why the Republicans would want to cut funding for regenerative biology or antibiotic research escapes me.
This leaves one wondering about the future of science in the United States. We are achieving great heights in all disciplines, but we are also the only western nation (unless you count Turkey) where a significant portion of the population denies basic science, notably evolution and climate change, though the left has issues with vaccine deniers as well. I need not list the wonders science has brought us; one cannot even comprehend the number of discoveries and inventions since the Scientific Revolution. No other way of thinking in the history of species has done more to advance the human condition and, it can be argued, done more to inspire us. It is a great tragedy that this has not translated into an enthusiasm for understanding and a commitment to the scientific values of parsimony, evidence, falsification, logic, and intellectual honesty. These is a real cost to our society for denying science on the basis of no evidence. One can’t help but wonder how long it will take our country as a whole to realize this.