January 8 - Celebrate Galileo!

 Posted on January 8, 2021

This post is an update of the 1/8/2010 post:

On this date in 1642, Galileo Galilei died. At 78 years of age, Galileo was blind and ill, and he had lived the last 8 years of his life under house arrest, although he was permitted to travel to doctors and to receive visitors.

House arrest? For one of the world's greatest scientists?

Galileo believed that the Earth moved around the Sun, rather than the reverse, and this seemed to go against some Biblical passages when interpreted literally. Because of this, there was controversy between Galileo, on one side, and the Pope, the Inquisition, and the Catholic Church, on the other. After a trial, Galileo was found guilty of heresy and placed under house arrest. (The Church has of course since then pardoned Galileo, and apologized as well - but it took it's sweet time! The pardon and apology occurred in 1992!!)

Galileo's achievements

January 7 marks the 400th+ anniversary of one of Galileo's achievements: observing some of Jupiter's moons. He didn't immediately know what they were—he labeled them “three fixed stars”—but as he observed the “stars” each night, he realized that they were circling Jupiter. A fourth appeared, as well. Galileo realized that they were moons orbiting another planet just as our moon orbits Earth.

Above, this is something like what Galileo was able to
see as he looked at Jupiter. The four "fixed stars" that
always seemed to be near Jupiter were, as Galileo
realized, moons that orbited Jupiter rather than the
Earth. In modern times, we have sent robotic space
probes past Jupiter, and we have managed to get some
close-up photos of these four moons - which are called
the Galilean moons.

This is one bit of evidence that Galileo was able to use when discussing the old idea that everything circled the Earth—these moons were clearly circling Jupiter, not Earth.

Galileo is credited with pioneering the experimental scientific method, building the first high-powered telescope, discovering the phases of Venus and sunspots, confirming the Copernican theory of the solar system, and developing many key ideas of physics. He demonstrated that the velocity of a falling body is not proportional to its weight (the experiment pictured below), described the parabolic paths of cannonballs, and invented a water pump.

Timeline of the greats

This timeline shows the lifetimes of some of the greats of the time: Michelangelo in green, Shakespeare in orange, Galileo in red, and Newton in purple.

Notice that Galileo was born the year Michelangelo died... and died just a few days after Isaac Newton was born. Using the birth and death years given, can you compute how old each of these men were when they died?

One of my favorite Galileo quotes:

“Mathematics is the language in which God wrote the universe.”

Galileo is often called the founder of modern science because, instead of merely sitting and pondering things, he did experiments and measured his data as carefully as he could. He also set up standards of length and time so that others could replicate his experiments at other times and places. But he went further: he used mathematics to reason out laws of motion and so forth.

Star gaze tonight!

Winter can be a great time to watch the skies, since in gets dark early. (Of course, it's not so good when it's cloudy!) Before you head outside, try checking out what you can expect to see. One website is Space.com.

Remember, we are used to seeing fantastic photos of space stuff...but many of these photos come from space probes or telescopes launched into space, out of Earth's atmosphere!

You will not be able to see these sorts of gorgeous nebulae in your home telescope - but you will see the Moon more up-close-and-personal, and you can even learn to take rad pix like this one:

And you can study the skies even without a telescope. Maybe you can borrow a good pair of binoculars? If so, you may get the sort of peek into the heavens that Galileo had with his telescopes!

Above, the Galilean moons through binoculars.
Below, Galileo using his telescope.

Do some virtual experiments.

This site has some great interactive demos on the topics of falling objects, projectiles, inclined planes, and pendulums. Great stuff!

Also on this date:

Earth's Rotation Day  

Physicist Stephen Hawking's birthday

Commonwealth Day in the Northern Marianas

Anniversary of the death of Galileo

(original post)

Elvis Presley's birthday

Bubble Bath Day

Argyle Day

Joy Germ Day

Anniversary of the first Lithuanian language book

Anniversary of Marie-Sophie Germain winning a math / science medal 

National Winter Skin Relief Day

Plan ahead:

Check out my Pinterest pages on:

• January holidays
• January birthdays
• Historical anniversaries in January

And here are my Pinterest boards for:

• February holidays
• February birthdays
• Historical anniversaries in February
  
  
  
  
  

February 9 – Happy Birthday, Brian Greene

Posted on February 9, 2016

 Brian Greene has worked on mirror symmetry and the flop transition, and he deals with Calabi-Yau manifolds, relating the conifold to one of its orbifolds.

If you aren't sure what any of that means, that makes two of us. Actually, given the fact that my spell check program doesn't know many of those words, I suspect that makes billions and billions of us that don't know what that means!

Okay, let's get down to things we DO get: Brian Greene, born on this day in 1963, is a theoretical physicist and string theorist. He is also a professor at Columbia University, an author of books for the general public, chairman of the World Science Festival, and occasional TV personality on The Big Bang Theory and PBS specials.

String theory is a possible explanation for why there is gravity, along with other deep questions of physics and cosmology. String theorists hope their theory can join the theories of Relativity and of Quantum Mechanics, the physics of the very large and the physics of the very small. Basically, it is a Theory of Everything.

(I think!)

Actually, several sources explain that string theory is a theory of quantum gravity, which is the field of physics that is trying to describe the force of gravity according to the principles of quantum mechanics.

If you want to know more about string theory, check out this website: String Theory for Kids (and Clever Adults). 

Here is a super-short explanation of string theory...and here is today's birthday honoree, Brian Greene himself, talking about string theory.

Also on this date:

Mardi Gras 

Carnival 

Kanaval in Haiti 

Pancake Day 

Extraterrestrial Culture Day 

Carnival de Oruro in Bolivia








Toothache Day  

Doctor Aletta Jacobs's birthday

Read in the Bathtub Day

Feast of St. Maron in Lebanon

Mini-golf and Volleyball Day

Glaciologist and aerial photographer Erich Dagobert von Drygalski's birthday

Losar in Tibet

Plan ahead:

Check out my Pinterest boards for:

• February holidays
• February birthdays
• Historical anniversaries in February

And here are my Pinterest boards for:

• March holidays
• March birthdays
• Historical anniversaries in March

May 29, 2010

Solar Eclipse Experiment Confirms Theory of Relativity – 1919

On this day in 1919, Sir Arthur Eddington led a team of scientists who took the opportunity of a rare total solar eclipse to measure the amount that the Sun's gravity bends starlight.

These measurements agreed with the prediction made by Albert Einstein in his Theory of Relativity. It was one of the first confirmations of the theory, and Eddington's work quickly became both famous and controversial.

Einstein wasn't the first to suggest that really large objects could bend light; Henry Cavendish and Johann Georg von Soldner both pointed out that Newton's theory of gravity makes this prediction. Einstein came up with his Theory of Relativity in part to explain things not explained by Newtonian principles, and he came up with a different prediction for the amount that light should bend in a gravitational field. Einstein's prediction was twice as large as Soldner's!

Sir Arthur Eddington realized that an upcoming total solar eclipse would allow scientists to test the new Theory of Relativity. During a total solar eclipse, the Moon entirely covers the Sun, and stars that appear in the sky near the Sun can be observed. Eddington's team did observations simultaneously in a city in Brazil and in Sao Tome and Principe on the west coast of Africa, and their measurements found that light was deflected (bent) the amount predicted by Einstein.

Eddington's results, as I said, were widely publicized, making the front page of most newspapers. (How often does the result of a scientific experiment make the front page of newspapers?) According to Wikipedia, this publicity had the effect of making Einstein and his theory world-famous.

Eddington's Results: Einstein Is Right!
But...Is Eddington Right?

I mentioned that Eddington's results were also controversial. Some scientists suggested that there were errors and possibly confirmation bias. Wow! Confirmation bias sounds bad, doesn't it?

Actually, it's really common, and it plagues all of us, not just scientists. Confirmation bias is the very human tendency to see what we expect or want to see—to only notice the things that confirm a belief or opinion or hope, and not to notice things that conflict with the belief / opinion / hope. Notice that we do this without knowing we are doing it! We cannot completely trust our own brains!

Confirmation bias is one reason that doctors don't often operate on or diagnose loved ones, and detectives don't investigate loved ones. Confirmation bias tells us that, when we keep up with current events, we should read and listen to several different perspectives—keeping in mind the fact that our minds will tend to better remember the stuff we agree with, and will tend to forget the stuff we prefer not be true.

We all indulge, to some extent, in wishful thinking—but if we are aware of this tendency, we can reduce its effect on our memory and reasoning.

Scientists try to eliminate confirmation bias by searching for falsifying data (in other words, trying to prove something wrong), doing double-blind tests (in which neither the experimenter nor the subject knows what to expect—for instance, when testing a new medicine, in a double-blind test, neither the experimenters nor the subjects know which bottles hold medicine and which hold flavored and colored water), and by repeating observations.

The people who suggested that Eddington's results might be tainted by this bias were right to question the results. They turned out to be wrong—Eddington was right—but the questioning itself was right-on.

Does that make sense to you?

You see, Eddington was an early supporter of Einstein's theory, and he had already become the major explainer of the theory in Britain. So he had every reason to want the results of his observations to back up the theory as correct. Naturally, many scientists wanted to repeat the observations to see if the results stood up. And Eddington's results—and Einstein's theory—were backed up by observations made during a solar eclipse in 1922 and many, many times since then.


Play “Guess the Rule”

A hypothesis is a guess about what's going on. It tends to be a thoughtful guess, what we call an “educated guess,” not just some random idea.

If someone said that she had one specific rule in mind, and your goal was to guess her rule, your job would be to come up with one or more hypotheses (guesses) about what the rule is—and then to test your idea. The person with the rule (let's call her the Ruler) gives you one example that follows her rule:

2, 4, 6

One of the students tests these three numbers:

10, 12, 14

The Ruler says, "Yes, that follows my rule." The next student tests these three numbers:

108, 110, 112

The Ruler says, "Yes, that follows my rule." Another student suggests:

234, 236, 238

The Ruler says, Yes, that follows my rule."

Do you think you know what the rule is?
What three numbers would you test, when it's your turn?
I have the answer below, but I want to mention that this game is set out in more detail on the internet. For example, this excellent group lesson for teens or adults, written from a teacher's point of view, explains this game and its value to students. Another lesson (again meant for older kids and adults) has several “problems,” one of which is this same game. There are links to suggested answers.

Answer:Most people, when they see the three numbers given by the Ruler, hypothesize that the rule is counting up with three consecutive even numbers. (Consecutive means the very next one in a particular number sequence.) When they see other students test this theory with more sets of increasing consecutive even numbers, and the teacher agrees that those sets follow the rule, their hypothesis is confirmed over and over, and they become more and more convinced that they are right.

But they are wrong, and they are going about testing the idea in the wrong way.

When you come up with a guess such as “counting up with three consecutive even numbers,” you should test the hypothesis with something that would not fit the hypothesis in just one way. For example, you could try:

• counting down with three consecutive even numbers
• counting up with four consecutive even numbers
• counting up with three non-consecutive even numbers (such as 10, 22, 50)
• counting up with three consecutive odd numbers

As you try to prove your original hypothesis wrong, you will more quickly and more surely find out whether or not it is right or wrong.

In other words, if you want to confirm an idea, try to prove it wrong.

In this particular game, the rule is: count up. That's it. Doesn't matter if the numbers are even or odd, consecutive or non-consecutive. Doesn't matter how many numbers there are. All that matters is that the numbers increase!

More Games!

You can play the familiar game of Mastermind to practice making confirming-or-refuting tests. If you don't have this game (or if there is nobody around to play), try the online version here.A similar game using words is called Jotto. Try out that game here.

Going back to Einstein's prediction...
Ummm....Why does light bend around large objects?

It's pretty complicated, but you can look at the diagram here to see how large objects “dent” spacetime, causing spacetime to curve. (Click "Watch Web Preview.) The path of light moving in a “straight” line in a curved universe will itself curve!

If you're interested in more, this website has some upper-level math, but it also has some diagrams you might want to see. Here is another website with some great diagrams about the geometry of the universe. I love this stuff!