There Might be Life in Space, but This Paper Didn’t Prove It

An article published in the Journal of Cosmology last month made headlines with its bold claim: alien life can be found in Earth’s atmosphere. The rest of the scientific community ins’t convinced. The Journal of Cosmology isn’t a “peer reviewed” journal, which is the gold standard for scientific work. This means papers the journal publishes aren’t really evaluated for quality or accuracy. In fact, it’s even been labelled “predatory” by one research librarian. As a general rule, it’s also really not a good sign when a paper making a bold claim mainly cites other papers by its authors.

The lack of peer review on the paper seems justified; there’s not much data.  The paper relies almost entirely on just microscope images . Virtually any structure that has a bend or fiber is declared evidence of life, for no clear reason. (This may be a trend, as PZ Myers basically made the same complaint of a previous Journal of Cosmology paper claiming to have found bacteria in meteorites)

If you can see four bacteria in this post, I will give you a prize*

If you can see four living things in this post, I will give you a prize*

This paper claims the images are of diatoms or diatom-like lifeforms, but they don’t show any as reference and their images aren’t magnified like most that try to show diatom structures.

A known diatom from Earth.

The authors also try really hard to link the alleged cells they see to alleged organisms responsible for the red rains in Kerala, India several years ago (those claims inspired similar controversy and seemed to rely on evidence that was only slightly more firm than what is offered here). If you’re going to make that connection, though, maybe you should show an image of that.

Aside from images, the only other data the paper mentions is a technique to measure the amount of elements in the sample. The paper only says the samples are high in carbon and oxygen, but don’t provide numbers.  They say that means what they’re looking at isn’t a mineral, but it’s worth pointing out there are in fact many meteoroids that are mostly carbon and oxygen so they might be looking at weird dust from those. That’s it; no attempt to extract any potential organic matter (though that’s also a dime a dozen in space, even without life).

The people at the Journal of Cosmology say other scientists are irrationally opposed to the idea that life on Earth may have originally come from outer space. While that’s not the dominant opinion in biology right now, it actually is something mainstream scientists are looking at. It’s just that, as Carl Sagan said, “extraordinary claims require extraordinary evidence”. And a bad SEM image is not the latter.

*The prize is my affection.

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Real Stars Break Down Alcohol Through Quantum Mechanics, Not Their Liver

When most people think of astronomy, they think of physics. Many astronomers are technically astrophysicists, and even if that’s not their title, most have a physics background. (If you’re really in the know, you might know that planetary science is a distinct field that draws a lot on geology as well as astronomy.)  But another aspect of space science that’s grown a lot over the last decade or so is astrochemistry. Astronomers have been able to study chemical compounds in celestial bodies since the the middle of the 20th century, when radio telescopes could detect spectral emissions unique to certain molecules (both nearby and across the galaxy) and even more so when space probes could directly analyze celestial bodies in our solar system. But there’s also a lot of chemicals just out in the middle of space, and the list keeps getting longer and includes increasingly more complicated compounds. Astrochemistry looks at these chemicals and tries to understand how they could form in astronomical environments.

One of the bigger puzzles for astrochemists has been understanding how alcohols are formed and destroyed in space. Space is too cold for methanol to break up into the highly reactive methoxy radical in a way similar to most reactions on Earth. While UV radiation exciting molecules enough to break them apart can explain how some chemicals are formed (and why UV light gives you cancer), lab tests couldn’t detect methoxy after exposing methanol to UV radiation. Dust wasn’t even acting as a catalyst. It actually turns out the reaction works best when the methanol is in its gaseous form at low temperatures because those conditions are optimal for quantum tunneling.

The procession of a chemical reaction in normal, bulk circumstances (on the left) and via quantum tunneling (on the right). From Richard Helmich.

Tunnelingis a phenomenon that only occurs in quantum mechanics. There’s really no good analogy in the classical physics we’re most familiar with. To very quickly sum up, if an electron is in place A and can also be in place C, but A and C are separated by a region B where it shouldn’t be able to travel, it can sometimes still end up in C by tunneling through B. This is also generalized to more than just physical space. Tunneling means particles can do things they shouldn’t have the energy for, like the reaction picture above. Quantum mechanics just says that it won’t happen very often and it can take some time. This is where the low temperature comes in. As we’ve talked about before, temperature reflects molecular motion. At the low temperatures of open space, the methanol and hydroxide are moving relatively slowly. When they bump into each other, this means they won’t bounce off immediately, and in that longer frame of time, an electron is more likely to jump from the methanol to the hydroxide. It turns out this tunneling reaction is really efficient at lower temperatures: lab experiments showed methanol reacted 50 times faster at -210 degrees Celsius than at room temperature. The researchers are also confident that quantum tunneling can explain many other reactions in space.

BANG! POW! Straight to the Moon(s)

The Economist had two great piecees last week about why moons may be the next big thing in the search for life.  The articles are wonderful, and I highly recommend that you read both of them.  And also highly recommend The Economist as a place for science news.  They are one of the few general newspapers/news magazines  where I think nearly all their science and technology articles are well written.  My only complaint is they don’t always have articles I find interesting.

The one thing I’d like to expand on a bit is our poor (or at least, I think so) definition of the “habitable zone”, or if you watched Battleship this summer, you might also be familiar with the other name for of “Goldilocks planet“.  Currently, if you hear someone talking about a habitable zone, they probably mean one thing:  the region where a planet can orbit a star and maintain liquid water.  But that actually is a really vague definition.  A lot of this also depends on the planet you’re looking at.  How much light a planet reflects is a big factor in how much heat it can keep.  (In fact, Ice Ages are feedback loops because of this – the ice caps are really shiny compared to dirty and water and can reflect off a lot of heat and prevent their melting, leading to more ice and less heat)  And we need to consider the composition of the planet.  Without the greenhouse effect of carbon and the salt content of our oceans, Earth’s water would freeze over a lot more often.  Of course, there are still ways to control for this.  People typically define the properties of a hypothetical planet they look at when calculating habitable zones.  And generally, there is a limit to where you can put something a certain star and expect liquid water (Mercury’s position would be a no-go, unless you were dealing with some particularly crazy atmospheres I think).

But that’s not what bothers me.  It’s that while some form of habitable zone/Goldilocks planet has gone on to permeate the broader culture, we’ve also kind of forgot to explain how this is an oversimplification.  Like the first article mentions, we expect water on lots of moons on planets outside the habitable zone because of tidal or magnetic heating.  And we could probably use better explanations of why NASA’s focus for astrobiology is to “follow the water”.  Even though I do worry about “carbon chauvinism“, there are good reasons people expect life to use water and carbon instead of other biochemistries.