The Drake Equation, revisited

The Drake Equation, as we’ve discussed in class in the most recent unit, is a formula intended to project an estimate of how many intelligent societies could exist in the universe. The formula multiplies a series of interdependent variables–the rate of formation of Sun-like stars, the number of planets in a habitable zone per solar system, etc.–to get a probabilistic grasp on whether there’s life out there, and if so, whether it is organized in communicable civilizations.

Seems like the underlying idea is pretty adaptable to whatever your situation, though. While doing some background reading, I found a brief essay by Peter Backus, a British Ph.D. student of economics, that took the Drake equation in a totally new direction. Mr. Backus’s question: how likely am I to get a girlfriend?

Backus presents the original Drake equation before toggling the variables to fit his needs. Once he establishes his base values–the population growth rate and the percentage of that population that is female–he adjusts the subsequent variables for age, attractiveness, education level, and more. He also takes into account his own age, perhaps analogous to the section of the Drake equation that measures the longevity of a communicable society…? Either way, it boosted his chances.

When it’s all said and done, Backus predicts that there are a little over 10,000 ladies in the UK who fit his criteria for girlfriend potential. That’s on par with a few of the Drake equation estimates that we did in class, though just like the real equation, I feel like there’s a huge margin of error. What if all those girls–just like all those other communicable civilizations out there–don’t know that he exists?

Skepticism: A Greek contribution to science

(bust of Agrippa, one of Greece’s best skeptics)

One of the biggest philosophical contributions the ancient Greeks made to the development of modern science–which our textbook hints at, but never goes into much detail about–is the Greek school of skepticism. Skepticism basically developed as an alternative to fundamentalism, a philosophical doctrine that encourages us to make judgments with ultimate devotion to maxims or theories we’ve already conceived. The rise of skepticism ties directly to the ancient Greek commitments to reasoning from observations and to finding natural explanations for phenomena, and it’s reflected in modern science in that scientists are obligated to discard old hypotheses when better explanations are made available. Imagine a world without Greek skepticism–it’s likely no one would ever have accepted the heliocentric model, since we already had a preexisting theory, the Ptolemaic geocentric model (never mind that it was incorrect!).

Despite skepticism making a huge contribution to the progress of science, the theory still has some problems, perhaps the most famous of which is the Five Modes of Agrippa. Essentially, once we concede that skepticism is the most appropriate epistemological school of thought for us to follow, we face five problems. First, thinkers are bound to disagree about what facts we can conclude if we’re rigorously testing them. Second, if we’re always asking “why?,” when do we stop? There’s a progress ad infinitum that might totally keep us from acquiring real knowledge. Third, there’s an issue of relation or relativity–through skepticism, how can we tell if things are objectively true, or if they’re just true in relation to other things? Fourth, we can’t be sure if the facts we’re asserting are only hypotheses or assumptions. Fifth, any justification we can acquire for knowing something could involve a vicious circle in which we can only justify the things we know by making circular arguments (so we can’t really justify them).

Science today has tended to move past these purely philosophical criticisms and adapted a pragmatic approach to discovering knowledge–that is, scientists use experiments, and as a society we essentially agree that the consistent results of repeated, well-formed experiments result in the acquisition of knowledge. However, philosophers still struggle with these more formal questions about skepticism, and even though popular philosophy tends to side with the skeptics, it’s interesting to see what kinds of questions are still raised about a piece of philosophy that heavily informs our scientific method.

A more “earthbound” use of the Doppler effect

When I was reading about the Doppler effect in the textbook, I found it easy to visualize the way we use the Doppler effect to understand the movements of astronomical objects, but I didn’t realize that we had other uses for Doppler a little closer to home. After doing a little bit of research, I learned that one of the biggest applications of the Doppler effect is one that we all dread: a policeman’s speed radar gun works thanks to Doppler.

As someone with a propensity to drive a little too fast sometimes, I thought I should do my research. It turns out that radar guns send electromagnetic waves at a moving object (e.g., your car), and when those waves hit the object, they bounce back at the gun, which has a receiver as well as a transmitter. The receiver interprets the wavelength of those reflected waves, and since the Doppler effect tells us that the degree of blueshift that occurs when an object moves toward us is dictated by the speed of that object, a policeman can tell how fast you’re going based on how much shorter the wavelengths bouncing off your car are, versus how short they would be if you were driving the speed limit. So, the next time you get pulled over for speeding and the officer asks if you know how fast you were going, you not only know, but you know how he/she knows, too 🙂

Historical Astronomers in Context

Galileo Galilei: 15 February 1564–8 January 1642

Occurrences during Galileo’s life:

The Thirty Years’ War began in 1618 and was fought throughout Europe largely because of religious turmoil between Catholics and Protestants. The war was noteworthy because it was so destructive and long-lasting, and therefore had a large impact on European culture as a whole.

Rene Descartes published Discourse on Method in 1637, toward the end of Galileo’s life. Descartes’s treatise outlines rationalism as an alternative philosophy to the prevailing empiricism of the time that has been presented by philosophers like John Locke. Descartes’s theme of rational intuition as the most reliable means of attaining knowledge is still pervasive in modern conversations about epistemology.

Another famous figure of the time:

William Shakespeare also lived at the same time as Galileo–he was born (historians guess) 26 April 1564 and died 23 April 1616. Shakespeare, of course, is renowned for the literature he produced, including the famous plays Hamlet, Macbeth, A Midsummer Night’s Dream, and so on.

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Taking a closer look at the historical context of the lives of so many influential astronomers helps create a backdrop for thinking about science at this time. All these astronomers lived during the Enlightenment, and of course, the list of influential figures alive during that era doesn’t stop at astronomers–to know that Descartes, Shakespeare, and countless others were all producing their finest work in the same cultural climate. It’s really fascinating to think about the sheer quantity of groundbreaking ideas and theories that were being simultaneously produced. I also wonder how much each of these individual scientists and thinkers benefited from having so many intellectual equals around them–it seems utopian, almost, for all these genius thinkers to have so many other engaged people to discuss their ideas with!

The night sky…

(click the photo to link to the source!)

Notice anything strange about the night sky in this photo? For one, you won’t find Polaris (the North Star)…have you caught it yet? This is the night sky as seen from Mt. Cook in New Zealand. As you’d expect, because the vantage point of someone in the southern hemisphere is different from that of someone in the northern hemisphere, the set of stars and constellations visible down under is totally different.

I studied abroad in Christchurch, New Zealand, last semester, and one of the biggest “culture” shocks I had to deal with was looking up at the night sky and not recognizing anything I saw. As someone who enjoys stargazing, this was something I noticed quickly, and the feeling it produced was way more foreign than anything else I experienced. It literally feels like you’re on another planet.

Over time I became more able to recognize the constellations unique to the southern hemisphere, like the Southern Cross, the constellation featured on both Australia’s and New Zealand’s flags. I also learned that some of the constellations are visible in both hemispheres. There’s a really cool graphic illustrating the visibility of certain constellations by hemisphere here. Nifty, right?

Powers of Ten and orders of magnitude

For my first “real” blog post, I chose to check out the Powers of Ten video. I was interested in this prompt in particular because in my geomorphology class, we’ve been discussing orders of magnitude as a means of talking about geological concepts like subsidence, uplift, and the residence time of sediments, so I thought I’d try to bridge what I’ve been thinking about in the two classes. Here’s the video below:

The video begins with a focused image of a picnic within a meter-by-meter square pans out to one greater order of magnitude every three seconds until reaching a  square measuring 1 x 10^24 m². Because orders of magnitude increase exponentially (that is, at 10³m, a much more vast space is covered than at 10²m), we quickly lose sight of the picnic, and by the time the video has panned out to a 10^7 meter square, the entirety of planet Earth is visible.

The video is impressive because it takes a relatively straightforward mathematical concept and illustrates its artful qualities. One line of the narrative I found especially noteworthy–at the final panned out image of the universe at 1 x 10^24 m², when the perspective is limited to a blurry, dark black void, the narrator makes the point that “the emptiness is normal–the richness of our own neighborhood is the exception.” I’ve always felt insignificant at the thought of the immensity of space, but the narrator’s comment is a nice counterpoint: as a hub of activity, Earth is also unique.

The video frames orders of magnitude as an interesting thought experiment, reminding us that the overwhelming majority of the universe, from a molecular to an intergalactic level, is outside our natural point of reference. In my opinion, that’s one of the most fascinating parts of modern science: the fact that we’re able to artificially expand our periphery of scale and examine the world at differing orders of magnitude. If that doesn’t profoundly influence one’s perspectives, what could?

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Hey there, I’m Dylan–I’m a junior at Vanderbilt majoring in philosophy and earth & environmental science. The outdoors are my big passion, and I’m really into rock climbing, paddling, and anything that will turn into an adventure. Here’s me at the beginning of the Abel Tasman Coastal Track in New Zealand, scoping the low tide beauty. This backpacking trip took three friends and me four days and three nights to complete, with our trip culminating in an…*interesting* traverse of the coastal trail at high tide.