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Methane concentrations observed in martian autumn, and a true colour map of Mars (NASA/Università del Salento.)

"The answer might come from NASA's Mars Science Laboratory rover, called Curiosity, scheduled to land on Mars in August 2012, carrying with it the Sample Analysis at Mars (SAM) suite, which will measure a multitude of trace constituents and isotopes from gas and solid samples. ...A more comprehensive test is planned in 2016 with the ExoMars Trace Gas Orbiter (TGO), which will be part of the joint ESA/NASA dual mission ExoMars Program. The TGO will scan the atmosphere for exotic trace gases, such as methane."

Of course, we think Mars' methane could come from methanogenic life there.

Earthlike extrasolar planets are one of Sasselov's specialties, and he easily gets the reader up to speed about them by recounting the relevant history, chemistry, astronomy and other related fields. I thought I already knew this stuff, but I had never heard of, for example, ice VII, ice X and ice XI that are denser than water and would be found on oceanic super-Earths.

Most of the extrasolar planets discovered so far are gas giants, like Jupiter. These would be unlikely to harbor life, at least not life as we know it. Our kind of life needs minerals and a variety of things found only on rocky, "Earthlike" planets. That's why they especially interest Sasselov. And he has helped to pioneer methods for detecting them. Beyond finding them, he has thought deeply about how life would flourish on them. He concludes that life would have an easier time on ones that are larger than Earth — hence, "super-Earths."

Sasselov also knows big bang cosmology thoroughly, and describes the universe as "young." If so, the minerals needed for life are even younger, and life must originate from nonlife, as is the consensus. He overrates the progress of the RNA World, writing, "RNA ...is capable of catalyzing its own replication" (p136). At best, these would be very short strands, in entirely unnatural environments. And he says nothing about the software aspect of the origin-of-life problem, but this is wise, because there is nothing to say. Notably, he finds interplanetary panspermia "quite plausible" (p157).

Hubble Reveals a New Type of Planet, Harvard-Smithsonian Center for Astrophysics, 21 Feb 2012: "Our solar system contains three types of planets: rocky, terrestrial worlds (Mercury, Venus, Earth, and Mars), gas giants (Jupiter and Saturn), and ice giants (Uranus and Neptune). Planets orbiting distant stars come in an even wider variety, including lava worlds and 'hot Jupiters.' ...[A] new type of planet...GJ1214b... is a waterworld enshrouded by a thick, steamy atmosphere."

Finally he promotes synthetic biology as one of the three great milestones in human history. Now we can create a new kind of life, with its own separate tree. His enthusiasm for it is palpable. In all, the book tells an enjoyable, entertaining, informative story. I am going to read it again.

Dimitar Sasselov is a Professor of Astronomy ar Harvard University and the founder and director of the Harvard Origins of Life Initiative.

Dimitar Sasselov, The Life of Super-Earths: How the Hunt for Alien Worlds and Artificial Cells Will Revolutionize Life on Our Planet, ISBN-10: 046502193X, 240 pages, Basic Books, 24 Jan 2012.

Figure 1: Extruded morphology of "microbes". Top: Image adapted from Figure 2a of Hoover (2011) showing purported extraterrestrial microbe. Bottom: Image of clay extruded from a homemade extruder showing similar morphology. "Microbes" are extruded from the porous CI matrix as sulfides alter to sulfates under the influence of ambient humidity. Image credit: Lauren Vork, www.ehow.com

The poster isolates a single filament cropped from one of Hoover's photographs, while the original, uncropped FESEM image shows a dozen or so filaments. These have sizes and detailed morphologies that are consistent with known genera and species of cyanobacteria — far more convincing evidence than a single filament. But Fries compares this one to an extrusion of clay squeezed through the perforated cap of a plastic soda bottle.

The cropping also omits the scale bar, allowing the clay extrusion to look smaller, when it is actually larger than the microscopic filament by three orders of magnitude. If the clay extrusion were imaged with a Scanning Electron Microscope at comparable magnification and resolution, the superfucial resenblance would vanish entirely. Yet, following this comparison, Fries claims that the microfossils in Orgueil, which Hoover interprets as the remains of cyanobacteria, are merely extrusions from magnesium sulfate veins in the stone. It is hard to take this criticism seriously. We think Fries must be joking.

Richard Hoover's photographs of fossilized microorganisms in carbonaceous meteorites have been studied by the world's leading experts on cyanobacteria and micropaleontology and identified as biological. NASA astrobiologist Chris McKay, for one, commented, "If these structures had been reported from sediments from a lake bottom there would be no question that they were classified correctly as biological remains." We urge anyone who may be curious to actually look closely at the full evidence.

The drilling took 20 years, and preventing contamination of the lake was a major concern. When the lake was penetrated, water rushed upward into the borehole as expected, flushing the drilling fluid and its potential contamnants away. This water then quickly froze, sealing contaminants out. The testing of water samples is postponed until spring returns to Antarctica.

Much of what living cells do is carried out by "molecular machines" - physical complexes of specialized proteins working together to carry out some biological function. How the minute steps of evolution produced these constructions has long puzzled scientists, and provided a favorite target for creationists.

To probe this puzzle, Thornton and his team reconstructed the evolution of one such molecular machine, a "proton pump" that maintains acidity in cellular compartments in many species. This machine includes a subunit made of six proteins forming a ring (colored in figures). These six proteins usually exist in two kinds, but in fungi the ring has three kinds of proteins. How did the increased complexity of the fungal version evolve, they ask. This evolutionary step apparently took place more than 800 million years ago, so there is a lot of past to reconstruct. We admire their work to make this reconstruction plausible.

The geneticists conclude that, following gene duplications, paralogs of an original protein underwent mutations and diverged slightly. Only one or two amino acid substitutions reduced their capability to link together as before — a loss-of-function. After that, the proteins could link together only in a specific order to complete the ring structure. That is the likeliest explanation for the complication of the fungal version of the six-protein ring. (The logic is well illustrated in commentary by molecular biologist W. Ford Doolittle, and further elaborated in a subsequent article by Deeds et al.) Following this reconstruction of events, Thornton comments,

"Gene duplications happen frequently in cells, and it's easy for errors in copying to DNA to knock out a protein's ability to interact with certain partners. It's not as if evolution needed to happen upon some special combination of 100 mutations that created some complicated new function." Thornton proposes that the accumulation of simple, degenerative changes over long periods of times could have created many of the complex molecular machines present in organisms today.

We are relieved to know that darwinists have been puzzled by something nontrivial, but we think the new analysis does not justify Thornton's broad conclusion. First, the slightly more complicated fungal protein pump does no more than the simpler version did, so no new function was gained. More importantly, the conclusion ignores something obvious. Paralogs that vary slightly from the original are ubiquitous and easy to explain, but the first version, the "original," remains unexplained. While paralogs relate to each other, the whole family usually lies well-isolated (>100 mutations removed?) in nucleotide sequence space. If it were not so, identifying and naming gene families would be much more difficult. In brief, the divergence of paralogs does nothing to explain the existence of a paralog family. And the divergence of these specific proteins does not in any way account for the creation of the proton pump of which they are parts.

This research is quite commendable, but its implications are being exaggerated. The apparent motive for this exaggeration it to suppress criticism, as hinted in the media release. But understanding the world is the proper motive for science. When understanding is adequate, criticism does not need suppression.