15 Gripping Facts About Galileo

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Getty Images

Albert Einstein once said that the work of Galileo Galilei “marks the real beginning of physics.” And astronomy, too: Galileo was the first to aim a telescope at the night sky, and his discoveries changed our picture of the cosmos. Here are 15 things that you might not know about the father of modern science, who was born February 15, 1564.

1. There's a reason why Galileo Galilei's first name echoes his last name.

You may have noticed that Galileo Galilei’s given name is a virtual carbon-copy of his family name. In her book Galileo’s Daughter, Dava Sobel explains that in Galileo’s native Tuscany, it was customary to give the first-born son a Christian name based on the family name (in this case, Galilei). Over the years, the first name won out, and we’ve come to remember the scientist simply as “Galileo.”

2. Galileo Galilei probably never dropped anything off the leaning tower of Pisa. 

With its convenient “tilt,” the famous tower in Pisa, where Galileo spent the early part of his career, would have been the perfect place to test his theories of motion, and of falling bodies in particular. Did Galileo drop objects of different weights, to see which would strike the ground first? Unfortunately, we have only one written account of Galileo performing such an experiment, written many years later. Historians suspect that if Galileo taken part in such a grand spectacle, there would be more documentation. (However, physicist Steve Shore did perform the experiment at the tower in 2009; I videotaped it and put the results on YouTube.)

3. Galileo taught his students how to cast horoscopes.

It’s awkward to think of the father of modern science mucking about with astrology. But we should keep two things in mind: First, as historians remind us, it’s problematic to judge past events by today’s standards. We know that astrology is bunk, but in Galileo’s time, astrology was only just beginning to disentangle from astronomy. Besides, Galileo wasn’t rich: A professor who could teach astrological methods would be in greater demand than one who couldn’t.

4. Galileo didn't like being told what to do.

Maybe you already knew that, based on his eventual kerfuffle with the Roman Catholic Church. But even as a young professor at the University of Pisa, Galileo had a reputation for rocking the boat. The university’s rules demanded that he wear his formal robes at all times. He refused—he thought it was pretentious and considered the bulky gown a nuisance. So the university docked his pay.

5. Galileo Galilei didn't invent the telescope.

We’re not sure who did, although a Dutch spectacle-maker named Hans Lipperhey often gets the credit (he applied for a patent in the fall of 1608). Within a year, Galileo Galilei obtained one of these Dutch instruments and quickly improved the design. Soon, he had a telescope that could magnify 20 or even 30 times. As historian of science Owen Gingerich has put it, Galileo had managed “to turn a popular carnival toy into a scientific instrument.”

6. A king leaned on Galileo to name planets after him.

Galileo rose to fame in 1610 after discovering, among other things, that the planet Jupiter is accompanied by four little moons, never previously observed (and invisible without telescopic aid). Galileo dubbed them the “Medicean stars” after his patron, Cosimo II of the Medici family, who ruled over Tuscany. The news spread quickly; soon the king of France was asking Galileo if he might discover some more worlds and name them after him.

7. Galileo didn't have trouble with the church for the first two-thirds of his life.

In fact, the Vatican was keen on acquiring astronomical knowledge, because such data was vital for working out the dates of Easter and other holidays. In 1611, when Galileo visited Rome to show off his telescope to the Jesuit astronomers there, he was welcomed with open arms. The future Pope Urban VIII had one of Galileo’s essays read to him over dinner and even wrote a poem in praise of the scientist. It was only later, when a few disgruntled conservative professors began to speak out against Galileo, that things started to go downhill. It got even worse in 1616, when the Vatican officially denounced the heliocentric (sun-centered) system described by Copernicus, which all of Galileo’s observations seemed to support. And yet, the problem wasn’t Copernicanism. More vexing was the notion of a moving Earth, which seemed to contradict certain verses in the Bible.

8. Galileo probably could have earned a living as an artist.

We think of Galileo as a scientist, but his interests—and talents—straddled several disciplines. Galileo could draw and paint as well as many of his countrymen and was a master of perspective—a skill that no doubt helped him interpret the sights revealed by his telescope. His drawings of the Moon are particularly striking. As the art professor Samuel Edgerton has put it, Galileo’s work shows “the deft brushstrokes of a practiced watercolorist”; his images have “an attractive, soft, and luminescent quality.” Edgerton writes of Galileo’s “almost impressionistic technique” more than 250 years before Impressionism developed.

10. Galileo wrote about relativity long before Einstein.

He didn’t write about exactly the same sort of relativity that Einstein did. But Galileo understood very clearly that motion is relative—that is, that your perception of motion has to do with your own movement as well as that of the object you’re looking at. In fact, if you were locked inside a windowless cabin on a ship, you’d have no way of knowing if the ship was motionless, or moving at a steady speed. More than 250 years later, these ideas would be fodder for the mind of the young Einstein.

10. Galileo never married, but that doesn't mean he was alone.

Galileo was very close with a beautiful woman from Venice named Marina Gamba; together, they had two daughters and a son. And yet, they never married, nor even shared a home. Why not? As Dava Sobel notes, it was traditional for scholars in those days to remain single; perceived class difference may also have played a role.

11. You can listen to music composed by Galileo's dad.

Galileo’s father, Vincenzo, was a professional musician and music teacher. Several of his compositions have survived, and you can find modern recordings of them on CD (like this one). The young Galileo learned to play the lute by his father’s side; in time he became an accomplished musician in his own right. His music sense may have aided in his scientific work. With no precision clocks, Galileo was still able to time rolling and falling objects to within mere fractions of a second.

12. His discoveries may have influenced a scene in one of Shakespeare's late plays.

An amusing point of trivia is that Galileo and Shakespeare were born in the same year (1564). By the time Galileo aimed his telescope at the night sky, however, the English playwright was nearing the end of his career. But he wasn’t quite ready to put down the quill: His late play Cymbeline contains what may be an allusion to one of Galileo’s greatest discoveries—the four moons circling Jupiter. In the play’s final act, the god Jupiter descends from the heavens, and four ghosts dance around him in a circle. It could be a coincidence—or, as I suggest in my book The Science of Shakespeare, it could hint at the Bard's awareness of one of the great scientific discoveries of the time.

13. Galileo had some big-name visitors while under house arrest.

Charged with “vehement suspicion of heresy,” Galileo spent the final eight years of his life under house arrest in his villa outside of Florence. But he was able to keep writing and, apparently, to receive visitors, among them two famous Englishmen: the poet John Milton and the philosopher Thomas Hobbes.

14. Galileo's bones have not rested in peace.

When Galileo died in 1642, the Vatican refused to allow his remains to be buried alongside family members in Florence’s Santa Croce Basilica; instead, his bones were relegated to a side chapel. A century later, however, his reputation had improved, and his remains (minus a few fingers) were transferred to their present location, beneath a grand tomb in the basilica’s main chapel. Michelangelo is nearby.

15. Galileo might not have been thrilled with the Vatican's 1992 "apology."

In 1992, under Pope John Paul II, the Vatican issued an official statement admitting that it was wrong to have persecuted Galileo. But the statement seemed to place most of the blame on the clerks and theological advisers who worked on Galileo’s case—and not on Pope Urban VIII, who presided over the trial. Nor was the charge of heresy overturned.

Additional sources: The Discoveries and Opinions of Galileo; Galileo's Daughter; The Cambridge Companion to Galileo.

10 Juicy Facts About Leeches

Ian Cook
Ian Cook

Leeches get a bad rap, but they’re actually pretty cool once you get to know them—and we're finding out more about them, even today. Recently, a team led by Anna Phillips, curator of parasitic worms at the Smithsonian National Museum of Natural History, discovered a new species of medicinal leech (pictured above) in a Maryland swamp. We asked parasite expert and curator at the American Museum of Natural History Mark E. Siddall to share some surprising facts about the worms we love to hate. 

1. Not all leeches suck blood.

Hematophagous, or blood-feeding, species are only one type of leech. “The vast majority of species are [hematophagous],” Siddall tells Mental Floss, “but it depends on the environment. In North America, there are probably more freshwater leeches that don’t feed on blood than there are blood-feeders.” And even among the hematophagous species, there are not too many who are after you. “Very few of them are interested in feeding on human blood,” Siddall says. “Certainly they’ll do it, if they’re given the opportunity, but they’re not what they’re spending most of their time feeding on.” 

2. Leeches are everywhere.

Japanese leech on a log
Pieria, Wikimedia Commons // Public Domain

“Every continent on the planet has leeches, with the exception of Antarctica,” Siddall says. “And even then there are marine leeches in Antarctic waters.” Humans have co-existed with leeches for so long, according to Siddall, that just about every language has a word for leech. 

3. Leeches have made a comeback in medicine.

Bloodletting for bloodletting’s sake has fallen out of favor with Western physicians, but that doesn’t mean medicinal leeches are enjoying a cushy retirement. Today, surgeons keep them on hand in the operating room and use them as mini-vacuums to clean up blood. “That is a perfectly sensible use of leeches,” Siddall says. Other uses, though, are less sensible: “The more naturopathic application of leeches in order to get rid of bad blood or to cure, I don’t know, whatever happens to ail you, is complete hooey,” he says. How on Earth would leeches take away bad blood and leave good blood? It’s silly.” 

4. Novelist Amy Tan has her own species of leeches.

Land-based leeches made an appearance in Tan’s 2005 book Saving Fish from Drowning, a fact that instantly put the author in leech researchers’ good graces. “There are not a lot of novels out there with terrestrial leeches in them,” Siddall says. So when he and his colleagues identified a new species of tiny terrestrial leeches, they gave the leech Tan’s name. The author loved it. “I am thrilled to be immortalized as Chtonobdella tanae,” Tan said in a press statement. “I am now planning my trip to Queensland, Australia, where I hope to take leisurely walks through the jungle, accompanied by a dozen or so of my namesake feeding on my ankles.”

5. Leeches can get pretty big.

The giant Amazon leech (Haementeria ghilianii) can grow up to 18 inches and live up to 20 years. And yes, this one’s a blood-feeder. Like all hematophagous species, H. ghilianii sticks its proboscis (which can be up to 6 inches long) into a host, drinks its fill, and falls off. Scientists thought the species was extinct until a zoologist found two specimens in the 1970s, one of whom he named Grandma Moses. We are not making this up.

6. Leeches make good bait.

Many walleye anglers swear by leeches. “A leech on any presentation moves more than other types of live bait," pro fisher Jerry Hein told Fishing League Worldwide. "I grew up fishing them, and I think they're the most effective live bait around no matter where you go." There’s an entire leech industry to provide fishers with their bait. One year, weather conditions kept the leeches from showing up in their typical habitats, which prevented their collection and sale. Speaking to CBS news, one tackle shop owner called the absence of leeches “the worst nightmare in the bait industry.”

7. Leech scientists use themselves as bait.

Siddall and his colleagues collect and study wild leeches. That means hours of trekking through leech territory, looking for specimens. “Whether we’re wandering in water or traipsing through a bamboo forest,” Siddall says, “we are relying on the fact that leeches are attracted to us.” Do the leeches feed on them? “Oh my god, yes. We try to get them before they feed on us … but sometimes, obviously, you can’t help it.”

8. Leech sex is mesmerizing.

Like many worms, leeches are all hermaphroditic. The specifics of mating vary by species, but most twine themselves together and trade sperm packets. (The two leeches in the video above are both named Norbert.)

9. Some leech species make surprisingly caring parents. 

“There’s a whole family of leeches that, when they lay their eggs, will cover them with their own bodies,” Siddall says. “They’ll lay the eggs, cover them with their bodies, and fan the eggs to prevent fungus or bacteria from getting on them, and then when the eggs hatch, they will attach to the parent. They’re not feeding on the parent, just hanging on, and then when the parent leech goes to its next blood meal it’s carrying its offspring to its next blood meal. That’s pretty profound parental care, especially for invertebrates.”

10. You might be the next to discover a new leech species. 

Despite living side-by-side with leeches for thousands of years, we’ve still got a lot to learn about them. Scientists are aware of about 700 different species, but they know there are many more out there. “I’ll tell you what I wish for,” Siddall says. “If you ever get fed on by a leech, rather than tearing off and burning it and throwing it in the trash, maybe observe it and see if you can see any color patterns. Understand that there’s a real possibility that it could be a new species. So watch them, let them finish. They’re not gonna take much blood. And who knows? It could be scientifically useful.”

9 Facial Reconstructions of Famous Historical Figures

A facial reconstruction of King Richard III unveiled by the Richard III Society in 2013
A facial reconstruction of King Richard III unveiled by the Richard III Society in 2013
Dan Kitwood/Getty Images

Why look at a painting of a historical figure when you can come face to face with one? Forensic facial reconstruction using scans of skeletal remains allows researchers to create 3D models of the face through a combination of science, history, and artistic interpretation. The results may be somewhat subjective, but they’re fascinating anyway. Here are nine facial reconstructions of famous people.

1. Richard III

In 2012, King Richard III’s skeleton was found below a parking lot in Leicester, England, where in 1485 he was hurriedly buried after dying in battle. A reconstruction (above) shows a young man, only 32 years old, with a gentle, approachable face. It’s a far cry from the child-murdering villain portrayed by Shakespeare and other writers. One thing they said does seem accurate, however: The skeleton had a curved spine from scoliosis, suggesting that Richard’s humpback may have been real.

2. Bach

J.S. Bach’s bust has sat on innumerable pianos for centuries, but he only posed for one portrait in his lifetime. So this reconstruction of his face—which was taken from a bronze cast of his skull—offers an interesting glimpse into the man beneath the 18th century wig. You get the same thick neck, underbite, and stern brow you see in the painting, but the reconstruction’s friendly, confused stare lacks the soul of the real man … and his music, for that matter.

3. Shakespeare

Apparently, no one knows anything about Shakespeare for sure—his hair color, his sexual orientation, how he spelled his name, whether he liked his wife, etc. Some people aren’t even sure whether he wrote his plays or not. So this rendering, taken from a death mask found in Germany, is bound to be controversial. But if it is Shakespeare, it’s pretty intriguing. It shows a man who suffered from cancer and had a sad, soulful face.

4. Dante

Maybe it’s because The Divine Comedy dealt with the ugliness of sin that Dante Alighieri is usually depicted as unattractive, with a pointy chin, buggy eyes, and enormous hooked nose. But a reconstruction done from measurements of the skull taken in 1921—the only time the remains have been out of the crypt—reveals a much more attractive Dante. The face has a rounder chin, pleasant eyes, and smaller nose than previously thought. It’s a face with character.

5. King Henri IV

The mummified head of France’s King Henri IV was lost after the French Revolution until a few years ago, when it showed up in a tax collector’s attic. In his day, Henri was beloved by everyone except the Catholic fundamentalists who murdered him in 1610. The hard-living king looks a bit old for his 56 years, but there’s a twinkle in his eyes. What the model cannot show, however, was how much the king stank—apparently he smelled of ”garlic, feet and armpits.”

6. Cleopatra’s Sister

Cleopatra hated her half-sister Arsinoe IV so much she had her dragged out of the temple of Artemis and murdered. In 2013, researchers said they had discovered what may be Arisone’s body, based on the shape of the tomb, carbon dating, and other factors. The resulting facial reconstruction shows a petite teenager of European and African blood. And yeah, maybe this is closer to what Arsinoe would look like if she were trapped in The Sims, but since Cleopatra’s remains are long gone, this may be the closest we get to knowing what she looked like.

7. King Tut

King Tutankhamun, whose famous sarcophagus has traveled far more than the “boy king” did in his 19-year lifetime, had buckteeth, a receding chin, and a slim nose, according to 3D renderings of his mummy. His weird skull shape is just within range of normal and was probably genetic—his father, Akhenaten, had a similarly shaped head. Tut’s body also had a broken leg, indicating he may have died from falling off a horse or chariot.

8. Copernicus

Nicolaus Copernicus, who challenged the belief that the sun revolved around the earth, died in 1543 at age 70. When his body was found in 2006 in a Polish church and confirmed by matching DNA to strands of his hair left in a book, the Polish police used their forensic laboratory to make this portrait. They made sure to include Copernicus’s broken nose and the scar above his left eye. Who knew that the Father of Astronomy looked so much like the actor James Cromwell?

9. Santa Claus

The remains of St. Nicholas, i.e. Santa Claus, have been in a church in Bari, Italy, since they were stolen from Turkey in 1087. This reproduction, taken from measurements of his skull, reveal that St. Nicholas had a small body—he was only 5’6”—and a huge, masculine head, with a square jaw and strong muscles in the neck. He also had a broken nose, like someone had beaten him up. This is consistent with accounts of St. Nicholas from the time: It turns out that Santa Claus had quite a temper.

A version of this list was first published in 2013.