Adam Frank is creative, kind, delightful, and precise (to borrow some of the words he uses to describe his teacher, Bruce Balick). His The Little Book of Aliens leaps into some of the biggest and most important (and least understood) questions that humanity faces. Are we alone in the universe? What other forms of life could there be? Where are they? How can we know? What would the existence (or nonexistence) of alien intelligences tell us about ourselves? Why are we here?

Little Book is great fun; there's at least one beer joke every chapter, along with silly self-deprecating asides. Prof Frank is accurate in his science and artful in his explanations. Chapter 7, for instance, offers a lovely nutshell-dense explanation of chemistry and biology. And as an example of Frank's style, consider this fragment from Chapter 6:

OK, now on to planetary atmospheres.

By analyzing starlight that has traversed an exoplanet's atmosphere, astronomers can nail down exactly what the atmosphere is made of. If there are absorption lines of water in the starlight's spectrum, then there's water vapor in the planet's atmosphere. If there are absorption lines of carbon dioxide, then there's carbon dioxide in the planet's atmosphere. This process is called atmospheric characterization. It is even more of a scientific miracle, and I'm not letting us move on until we properly genuflect at its awesomeness.

Sitting here on Earth, an astronomer can figure out exactly what's in a planet's atmosphere even if that planet is tens, hundreds, or thousands of light-years away. Thanks to this radical new method, we can see exactly what's floating around in the atmospheres of planets that may never, ever be visited by a human. It is totally insane and amazing that we Homo sapiens, basically just a bunch of hairless monkeys, have figured out how to probe distant alien atmospheres. If nothing else, this achievement should make you a little bit proud of us as a species in spite of all the other horrible stuff we do.

Now let's get back to the story.

Atmospheric characterization is a big deal by itself because ...

Bottom line: in the past few decades, advances in observational astronomy have begun to provide real data on planets orbiting other stars — a huge leap forward in understanding the likelihood of life elsewhere in the galaxy. What will we learn tomorrow? Wow!

_{(cf Edge of the Universe (1999-06-08), Fast Forward (2002-02-21), Ron Bracewell (2004-01-21), What We Know (2006-08-15), Little Book of Cosmology (2023-03-31), ...) - ^z - 2024-01-28}