Starry Messenger: Cosmic Perspectives on Civilization by Neil DeGrasse Tyson

Author:Neil DeGrasse Tyson [Tyson, Neil DeGrasse]
Language: eng
Format: epub
ISBN: 9781250861498
Google: LZtVEAAAQBAJ
Barnesnoble:
Publisher: Henry Holt and Co.

EIGHT

COLOR & RACE

Once again, people are more the same than different

In the early twentieth century, we figured out that stars themselves can look very different from one another when you analyze their spectra. At the time, a roomful of computers classified tens of thousands of stars by their “spectral type,” binning them into fifteen lettered categories: A through O. With better data and with an emergent understanding of quantum physics, these categories would be culled and further divided into ten numbered subcategories as well as nine other categories represented mostly by Roman numerals that track a star’s evolutionary state. In recent decades, several additional spectral types would accommodate very dim stars that were not yet discovered when the original data were compiled. A coded system of three dozen additional symbols would further accommodate highly unusual or peculiar features on top of an otherwise ordinary star.

That roomful of computers was composed of sentient carbon-based life—computationally fluent and scientifically literate women hired by the men of the Harvard College Observatory to do the tedious measurements and bookkeeping of all the data.1 Little did the men know that spectral classification was not just the act of cataloging data, it would establish the entire subfield of stellar evolution. Sexist culture notwithstanding, we are aware that stars in the Galaxy and across the universe represent a continuum of properties that we slice into hundreds of bins for our conversational and scientific convenience. The Sun, if you are curious, is spectral class G2V. Polaris, the North Star, F7I.

Back on Earth, many places will label your skin color black or white or brown. That’s it. When you report to police whom you glimpsed committing a crime, they fully expect you to draw from only one of those three categories. The world’s staggering range of human skin color has been reduced to three shades, and somehow everybody’s okay with that. Maybe you added red and yellow, to include Native Americans and Asians, even though nobody’s skin is any of these colors. White people don’t disappear when they walk in front of snowbanks. And while skin color can get very dark, nobody is pure black. You’ve surely never met anyone fire-engine red or lemon yellow. So our color categories are simply lazy and feed whatever racist proclivities we might otherwise possess. Consider that President Barack Obama’s mother was White American with European ancestry. His Kenyan-born father was literally African American. Obama arrived in this world with a skin color halfway between the two—a light-skinned Black person. In the US, Obama was America’s first Black president. Now imagine Obama as the light-skinned leader of an African country. If we invoke symmetric reasoning, that population could justifiably see him as their first White president.

In astrophysics we have a word for the reflectivity of a surface: “albedo.” We invoke it often when analyzing how much solar energy a planet’s surface absorbs compared with what gets reflected by cloud tops or shiny topography. A surface with an albedo of 0 absorbs all incoming energy.

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