How do we know the sun is a star?
Today, it's common knowledge, but it took scientists centuries to figure out.
Adam Frank is a professor of astrophysics at the University of Rochester and a leading expert on the final stages of evolution for stars like the sun. Frank's computational research group at the University of Rochester has developed advanced supercomputer tools for studying how stars form and how they die. A self-described “evangelist of science," he is the author of four books and the co-founder of 13.8, where he explores the beauty and power of science in culture with physicist Marcelo Gleiser.
- The simplest questions are often the hardest to answer.
- At first blush, the sun and stars are very different. The former is close and hot, the latter far away and cold.
- We couldn't confirm the sun to be a star until telescopes and spectroscopes were invented.
Sometimes, as a scientist, you forget how much you take for granted about the amazingness of the universe. The other day, my colleagues and I traded stories about how non-scientist friends would often ask us questions that we don't even realize are questions. One of my compatriots related how a friend had been completely amazed that the sun was just another star. I really loved that story because, when you think about it, humans have only figured out what stars are — and that the sun is a star — very recently in our 300,000-year history.
So let's step back and ask that basic question: How do we know the sun is a star?
Of course, the sun is a light in the sky, and stars are lights in the sky. But for someone starting from scratch, they might seem really different. The sun is only "up" in the day, but the stars are only up in the night. The sun can be so hot that it literally burns your skin. Stars, on the other hand, give off no warmth at all. How did astronomers see that the sun and the stars were beasts of the same feather?
One key point was understanding that their energy output per time (what astronomers call luminosity) is similar. If stars look dim while the sun appears blinding, it's just because the sun is much closer. The luminosity of an object can be found by knowing how bright it appears to be and its distance. That means once you know the distance to an object, you can calculate its luminosity. The problem, then, of determining if the sun and stars had similar luminosities really came down to figuring out their distances. Clever people as far back as the ancient Greeks started estimating how far away the sun was, but distance measurements to the stars took humanity a lot longer.
The problem of parallax
Credit: JustinWick via Wikimedia Commons
The problem for the stars was the method required for calculating distances. The easiest way is what's called parallax, which relies on how a distant object shifts its position relative to a nearby object when you, the observer, shift position. You can see the effect by putting your finger up against your nose, looking at a picture on a wall, and then closing one eye and then the other. The position of your finger relative to the picture on the wall jumps back and forth as you do this.
But here's the catch. The farther away the picture on the wall, the smaller the shift in its position. Since stars are so far away, astronomers had to wait until they had reasonably powerful telescopes before they could get accurate parallax measurements and, hence, accurate distances. Once these were determined, they found that, yes, the sun and the stars pump out comparable amounts of energy every second.
It's worth noting that big stars can be millions of times brighter than small stars, but for our purposes here, what matters is that astronomers were able to determine that stars and the sun were in the same category of "luminous stuff."
We are all star stuff
The next big step in showing that the sun was a star was to show that both were basically made of the same stuff. People had long imagined the sun to be made of burning stuff for obvious reasons, but what kind of stuff? Was it wood, candle wax, or coal? And what about the stars that seemed to burn so less intensely?
The barcode of the sun.Credit: NOAO / AURA / NSF
The answer to this question came with the invention of spectroscopy, which involves sending sunlight or starlight through a prism to break it up into its component colors (like a rainbow). When astronomers did this with powerful enough spectrographs, they saw that the rainbow was not complete. There were dark bands or missing colors as if something had eaten the light at specific wavelengths. The dark lines were not random but appeared in specific patterns. Remarkably, physicists soon found that these patterns of dark lines were like the fingerprints of specific elements (such as hydrogen, helium, nitrogen, and oxygen) in the gas that the light passed through on the way to the spectrograph.
The dark lines, therefore, seen in light from the sun or distant stars were giving astronomers an inventory of their composition. It was telling them what the sun and stars were made of. Lo and behold, the patterns of dark lines for both were basically the same. The stars were made of the same stuff as the sun, and the sun was made of the same stuff as the stars!
This discovery was the true game changer. With spectroscopy, astronomy became astrophysics, and soon a true science of stars began. In the decades that followed, astronomers would unpack the secrets of the inner architecture of stars, as well as the nuclear energy source that powers their titanic engines.
Through all these steps, the sun was finally recognized as just another star in the late 19th or early 20th century. It was our parent ball of nuclear fusion — neither different nor unusual compared to other stars, but, to us, very special.
Metal-like materials have been discovered in a very strange place.
- Bristle worms are odd-looking, spiky, segmented worms with super-strong jaws.
- Researchers have discovered that the jaws contain metal.
- It appears that biological processes could one day be used to manufacture metals.
The bristle worm, also known as polychaetes, has been around for an estimated 500 million years. Scientists believe that the super-resilient species has survived five mass extinctions, and there are some 10,000 species of them.
Be glad if you haven't encountered a bristle worm. Getting stung by one is an extremely itchy affair, as people who own saltwater aquariums can tell you after they've accidentally touched a bristle worm that hitchhiked into a tank aboard a live rock.
Bristle worms are typically one to six inches long when found in a tank, but capable of growing up to 24 inches long. All polychaetes have a segmented body, with each segment possessing a pair of legs, or parapodia, with tiny bristles. ("Polychaeate" is Greek for "much hair.") The parapodia and its bristles can shoot outward to snag prey, which is then transferred to a bristle worm's eversible mouth.
The jaws of one bristle worm — Platynereis dumerilii — are super-tough, virtually unbreakable. It turns out, according to a new study from researchers at the Technical University of Vienna, this strength is due to metal atoms.
Metals, not minerals
Fireworm, a type of bristle wormCredit: prilfish / Flickr
This is pretty unusual. The study's senior author Christian Hellmich explains: "The materials that vertebrates are made of are well researched. Bones, for example, are very hierarchically structured: There are organic and mineral parts, tiny structures are combined to form larger structures, which in turn form even larger structures."
The bristle worm jaw, by contrast, replaces the minerals from which other creatures' bones are built with atoms of magnesium and zinc arranged in a super-strong structure. It's this structure that is key. "On its own," he says, "the fact that there are metal atoms in the bristle worm jaw does not explain its excellent material properties."
Just deformable enough
Credit: by-studio / Adobe Stock
What makes conventional metal so strong is not just its atoms but the interactions between the atoms and the ways in which they slide against each other. The sliding allows for a small amount of elastoplastic deformation when pressure is applied, endowing metals with just enough malleability not to break, crack, or shatter.
Co-author Florian Raible of Max Perutz Labs surmises, "The construction principle that has made bristle worm jaws so successful apparently originated about 500 million years ago."
Raible explains, "The metal ions are incorporated directly into the protein chains and then ensure that different protein chains are held together." This leads to the creation of three-dimensional shapes the bristle worm can pack together into a structure that's just malleable enough to withstand a significant amount of force.
"It is precisely this combination," says the study's lead author Luis Zelaya-Lainez, "of high strength and deformability that is normally characteristic of metals.
So the bristle worm jaw is both metal-like and yet not. As Zelaya-Lainez puts it, "Here we are dealing with a completely different material, but interestingly, the metal atoms still provide strength and deformability there, just like in a piece of metal."
Observing the creation of a metal-like material from biological processes is a bit of a surprise and may suggest new approaches to materials development. "Biology could serve as inspiration here," says Hellmich, "for completely new kinds of materials. Perhaps it is even possible to produce high-performance materials in a biological way — much more efficiently and environmentally friendly than we manage today."
Dealing with rudeness can nudge you toward cognitive errors.
- Anchoring is a common bias that makes people fixate on one piece of data.
- A study showed that those who experienced rudeness were more likely to anchor themselves to bad data.
- In some simulations with medical students, this effect led to higher mortality rates.
Cognitive biases are funny little things. Everyone has them, nobody likes to admit it, and they can range from minor to severe depending on the situation. Biases can be influenced by factors as subtle as our mood or various personality traits.
A new study soon to be published in the Journal of Applied Psychology suggests that experiencing rudeness can be added to the list. More disturbingly, the study's findings suggest that it is a strong enough effect to impact how medical professionals diagnose patients.
Life hack: don't be rude to your doctor
The team of researchers behind the project tested to see if participants could be influenced by the common anchoring bias, defined by the researchers as "the tendency to rely too heavily or fixate on one piece of information when making judgments and decisions." Most people have experienced it. One of its more common forms involves being given a particular value, say in negotiations on price, which then becomes the center of reasoning even when reason would suggest that number should be ignored.
It can also pop up in medicine. As co-author Dr. Trevor Foulk explains, "If you go into the doctor and say 'I think I'm having a heart attack,' that can become an anchor and the doctor may get fixated on that diagnosis, even if you're just having indigestion. If doctors don't move off anchors enough, they'll start treating the wrong thing."
Lots of things can make somebody more or less likely to anchor themselves to an idea. The authors of the study, who have several papers on the effects of rudeness, decided to see if that could also cause people to stumble into cognitive errors. Past research suggested that exposure to rudeness can limit people's perspective — perhaps anchoring them.
In the first version of the study, medical students were given a hypothetical patient to treat and access to information on their condition alongside an (incorrect) suggestion on what the condition was. This served as the anchor. In some versions of the tests, the students overheard two doctors arguing rudely before diagnosing the patient. Later variations switched the diagnosis test for business negotiations or workplace tasks while maintaining the exposure to rudeness.
Across all iterations of the test, those exposed to rudeness were more likely to anchor themselves to the initial, incorrect suggestion despite the availability of evidence against it. This was less significant for study participants who scored higher on a test of how wide of a perspective they tended to have. The disposition of these participants, who answered in the affirmative to questions like, "Before criticizing somebody, I try to imagine how I would feel if I were in his/her place," was able to effectively negate the narrowing effects of rudeness.
What this means for you and your healthcare
The effects of anchoring when a medical diagnosis is on the line can be substantial. Dr. Foulk explains that, in some simulations, exposure to rudeness can raise the mortality rate as doctors fixate on the wrong problems.
The authors of the study suggest that managers take a keener interest in ensuring civility in workplaces and giving employees the tools they need to avoid judgment errors after dealing with rudeness. These steps could help prevent anchoring.
Also, you might consider being nicer to people.
At least 222 typefaces are named after places in the U.S. — and there's still room for more.
- Here's one pandemic project we approve of: a map of the United Fonts of America.
- The question was simple: How many fonts are named after places in the U.S.?
- Finding them became an obsession for Andy Murdock. At 222, he stopped looking.
Who isn't fond of fonts? Even if we don't know their names, we associate specific letter types with certain brands, feelings, and levels of trust.
Typography equals psychology. For example, you don't want to get a message from your doctor, or anybody else in authority, that's set in comic sans — basically, the typeface that wears clown makeup.
A new serif in town
If you want to convey reliability, tradition, and formality, you should go for a serif, a font with decorative bits stuck to its extremities. Well-known examples include Garamond, Baskerville, and Times New Roman. Remove the decoration, and you've got a clean look that communicates clarity, modernity, and innovation. Arial and Helvetica are some of the most popular sans serif fonts.
There's a lot more to font psychology, but let's veer toward another, less explored Venn diagram instead: the overlap between typography and geography. That's where Andy Murdock spent much of his pandemic.
Mr. Murdock is the co-founder of The Statesider, a newsletter about (among other things) travel and landscape in the United States. He remembers his first encounter with a home computer back in 1984 and learning from that Macintosh both the word "font" and the name for the one it used: Chicago.
A map of the United Fonts of America — well, 222 of them.Credit: The Statesider, reproduced with kind permission.
You can see where this is going. Mr Murdock retained a healthy interest in fonts named after places. Over the years, he noted Monaco, London, San Francisco, and Cairo, among many others. "And then, the question of how many fonts are named for U.S. places came up in an editorial meeting at The Statesider," Mr Murdock says.
It's the sort of topic that in other times might never have gone anywhere, but this was the start of the pandemic. "I was stuck for days on end, so I actually started looking into it. At some point, I realized that I could probably find at least one per state." Cue the idea for a map of the "United Fonts of America."
Challenge turns into obsession
But that was easier said than done. Finding location-based fonts turned out to be rather time-consuming. "I definitely didn't realize what I was getting myself into," Mr Murdock recalls. "I could quickly name a few — New York, Georgia, Chicago — but I had no idea that I'd be able to find so many."
What started as a quirky challenge turned into an obsession and a compulsion that would have the accidental font-mapper wake up in the middle of the night and think: Did I check to see if there's a Boise font? (He did; there isn't.)
"The hardest part was knowing when to stop," said Mr Murdock. "Believe me, I know I missed some." In all, he found 222 fonts referencing places in the United States and its territories.
For the most part, these fonts are distributed as the population is: heavy on the coasts and near the Great Lakes, but thin in most parts in between. California (23 fonts) takes the cake, followed by Texas (15), and New York (9).
Some of the fonts have interesting back stories, and in his article for "The Statesider", Mr Murdock provides a few:
- Georgia was named after a newspaper headline reading "Alien Heads Found in Georgia."
- Fayette is based on the handwriting of the record-keeper of a place called Fayette, now a ghost town in Michigan's Upper Peninsula.
- Tahoma and Tacoma are both pre-European names for Mount Rainier in Washington state.
Mostly, the fonts repeat the names of states and cities, but some offer something more interesting, such as the alliterating Cascadia Code or the lyrical Tallahassee Chassis. Other less than ordinary names include Kentuckyfried and Wyoming Spaghetti.
Capturing the spirit of a place
As an unexpected expert in the geographic distribution of location-based fonts, can Mr. Murdock offer any opinion on the qualitative relation between place and typeface?
"Good design of any sort can capture the spirit of a place, or at least one perspective on a place," he says, "but frankly, that only occasionally seems to have been the goal when it comes to typefaces."
In his opinion, the worst fonts reflect a stereotype about a place, rather than the place itself: "Saipan and Hanalei are both made to look like crude bamboo. Those are particularly awful. Pecos feels like it belongs on a bad Tex-Mex restaurant's menu."
California (lower left) is a rich source of location-based typefaces.Credit: The Statesider, reproduced with kind permission.
"Santa Barbara Streets, on the other hand, is quite nice because it captures the font that's actually used on street signs in Santa Barbara. I prefer the typefaces that have a story and a connection to a place, but it's a fine line between being artfully historic and being cartoonishly retro."
Let's finish off Route 66
Glancing over the map, some regions seem more prone to "stereotypefacing" than others: "Tucson, Tombstone, El Paso — you know you're in the Southwest. Art Deco fonts are mostly in the east or around the Great Lakes. In general, you find more sans serif fonts in the western U.S., and more serif fonts in the east, but that's not a hard-and-fast rule."
Noticing a few blank spots on the map, Mr. Murdock helpfully suggests some areas that could do with a few more fonts, including the Carolinas, the Dakotas, Maine, Missouri, West Virginia, New Jersey, and Rhode Island.
Oh, and Route 66. Nearly all of the cities mentioned in the eponymous song have a typeface named after them. "We need Gallup and Barstow to complete the set."
And finally, America's oft-overlooked overseas territories could be a rich seam for type developers: "Some of these names are perfect for a great typeface — Viejo San Juan, St. Croix, Pago Pago, Ypao Beach, Tinian."
To name but a few. Typeface designers, sharpen your pencils!
Map found here at The Statesider, reproduced with kind permission. For more dispatches from the weird interzone between geography and typography, check out Strange Maps #318: The semicolonial state of San Serriffe.
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