Showing posts with label Copernicus. Show all posts
Showing posts with label Copernicus. Show all posts

April 17 - Happy Birthday, Giovanni Riccioli

 Posted on April 17, 2021

This is an update of my post published on April 17, 2010:



Born on this day in 1598 in Italy, Riccioli became an astronomer. He and another astronomer he worked with, Francesco Maria Grimaldi, carefully studied the moon using telescopes.

Not only did they study the moon, they drew a map of it and named many of the craters and other features they saw. We still use the lunar names Riccioli and Grimaldi assigned today.




During Riccioli's life, the Catholic church (including the Jesuit order) stood officially opposed to Copernicus's idea that the earth traveled around the sun rather than vice versa. (Do you remember what happened to Galileo?) Riccioli, who was a Catholic priest of the Jesuit order, apparently took the church's stance as his own and even argued against the ideas of Galileo and others in a book he published in 1651.



But did he really believe that the Earth stood still and the sun orbited around it? Or did he just say that so that he wouldn't be thrown out of the church or otherwise punished?

We will never know. But we do know two things:

First, Riccioli complimented Copernicus's hypothesis for being simple and elegant, even while he was arguing against it.

Second, Riccioli and Grimaldi named a large crater after Copernicus, and they named other important features after Copernicus's supporters, including Galileo. They even named craters in that same general region after themselves...

Copernicus Crater is the bright one
in a relatively uncratered portion of the
Moon.

Some other craters they named after other Jesuit astronomers, and these all lay in a different part of the moon, near Tycho.

Tycho Crater is the bright one with
all the rays extending from it.

Some say that these two things indicate that Riccioli really did believe the heliocentric hypothesis that states that the sun, not the Earth, is the center of the solar system.

Seeing Doubles


Another of Riccioli's contributions is that he realized that the star Mizar was really two stars, Mizar and Alcor. We now know of many double stars, which don't just appear to be nearby in the night sky, but which actually are near each other and which, in fact, revolve around each other. If you live in the Northern Hemisphere, you should be able to spot the Mizar / Alcor star system – it's the middle "star" in the handle of the Big Dipper.





Picturesque Lunar Names

Earlier lunar observers had named the flat-looking dark plains of the moon maria, or seas, even though they aren't water at all! Instead of naming the seas after famous scientists, as they named the craters, Riccioli named them after moods, such as Tranquility, Serenity, Crises; or after weather conditions, such as rain (Mare Imbrium), clouds (Mare Nubium), and cold (Mare Frigoris). All these names were in Latin.


The circle marked "Landing" in the Sea of
Tranquility is the spot where Apollo 11 landed
and became the place where humans first
walked on another world.


Whose names?


We often find that the first person to discover something gets to name it, but apparently several people named the moon's features before Riccioli and Grimaldi did so—and yet these earlier names didn't catch on. In 1645, Michel Florent van Langren named most of the visible features of the moon, many of them honoring a Catholic “royal” of his time or a Catholic saint. In 1647, Johannes Hevelius published his own map, which ignored all the names suggested by van Langren. Hevelius's names were names from places on the Earth, especially place names from the ancient Greek and Roman world. A few years after that, when Riccioli and Grimaldi named the same features, THOSE are the names that stuck!


What's in a name?

People throughout history have told stories of various goddesses of the moon, and some of the goddess names are used today in modern words. Match the numbered items with the lettered items below:

1. Selene
2. selenology
3. selenography
4. selenium
5. Luna (match with two items)
6. lunar
7. lunatic (and loony)
8. Artemis
9. Diana

----------------------------------------- 

A. the study of the moon
B. a chemical element
C. Roman version of Artemis
D. early Greek goddess of the moon
E. having to do with the moon
F. name of Earth's moon
G. insanity, crazy (it used to be thought that the moon caused madness)
H. Roman version of the goddess Selene
I. the “geography” of the moon
J. later Greek goddess of the moon and the hunt

 



ANSWERS: 

1. D 
2. A 
3. I 
4. B 
5. F and H 
6. E 
7. G 
8. J 
9. C


Phases of the moon



Can you see a full moon tonight? Without waiting for nightfall or using Google, is there a way to find out?

Hopefully, you looked at the moon last night, and the night before. People who make frequent observations know what to expect in the future, and people who routinely look up at the sky are likely to spot beauties such as “falling stars” and lens-shaped clouds and halos around the moon. 

And they know where and when to look for the moon, because they know if it is waxing (with the illuminated portion getting larger and larger, every night), or waning (with the illuminated portion getting smaller and smaller, every night).

Many printed calendars mark “full moon,” “new moon,” “first quarter” and “last quarter.” 

Here is a free online site that shows you the phases of the moon for today, tomorrow, yesterday, and every day!
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February 19 - Happy Birthday, Nicolaus Copernicus

Posted on February 19, 2021

This is an update of my post first published on February 19, 2010:




The German/Polish polymath (a person who is learned in many different fields) Nicolaus Copernicus was born on this day in 1473. He was an astronomer, mathematician, doctor, translator, artist, Catholic clergy, jurist (one who studies, develops or applies the law), governor, military leader, diplomat, and economist. He was a polyglot (a person who speaks many different languages) as well; he spoke German, Latin, and Polish with equal fluency, and he also knew Greek and Italian!

During his lifetime, Copernicus might have been known to many as his powerful uncle's personal secretary, perhaps, or as the published translator of some poems written in Greek. However, we know him today from his contributions to astronomy and, more generally, to science.



Even though astronomy was just a sideline for Copernicus, he was able to work out the heliocentric, or sun-centered, model of the solar system.

For thousands of years it was thought that the Earth sat still at the center of the universe, and everything people could see in the sky, from the Moon and Sun to the planets and stars, circled around it. People thought this was true because we experience the world this way—as we stand on the Earth, we do not feel as if it is in motion, and we clearly see the Moon, stars, and Sun moving in our skies.

However, in order for our observations of the observed movements of the planets to make sense, we cannot suppose their paths around the Earth to be simple circles. Instead, thinkers like Ptolemy invented little circles cycling around larger circles—epicycles, deferents, and equants—in a very complicated system.



Copernicus demonstrated that, by simply moving Earth out of the central spot and supposing that it was in motion, too, most of those complications fell away.


Copernicus's system started with the idea that the Sun is the unmoving center of the universe. Mercury and Venus circle the Sun in closer orbits than the Earth's, and Mars, Jupiter and Saturn circle the Sun in farther orbits. According to Copernicus's model, the firmament doesn't move; this outermost celestial sphere was pictured as a sort of rigid shell onto which the unchanging stars were attached.

The fact that the unmoving sun and firmament (the stars) seem to move around the Earth once per day was explained, in the new Copernican system, by the idea that the Earth itself is spinning around like a top, rotating on its axis once a day. So the Earth has two motions—spinning on its axis and revolving around the sun.


You probably noticed...

...Hopefully you noticed that Copernicus wasn't entirely correct in every aspect of his heliocentric model of the universe.* However, he was correct that the sun was the center of the solar system, and this Big Idea was so important to astronomy, science and philosophy, that scientists have credited him with starting a scientific revolution!
*The sun is not actually the center of the universe. It's pretty far out from the center of the Milky Way galaxy, even, hanging out in an obscure corner of one of the spiral arms. Nor is the Milky Way galaxy the center of the universe. As a matter of fact, the phrase “the center of the universe” might not even make sense.

 



Also, there is no firmament. There is no solid shell or sphere onto which stars are glued. Instead, the stars are much larger and much farther away than they seem, great balls of burning gas similar to our sun, and they are at all different distances away from us. Stars—even our sun—are in motion, too, revolving around the center of their galaxies even as the galaxies rush away from each other. Also, the stars certainly aren't unchanging—new ones are born, older ones die.

 

The firmament - which of course doesn't actually exist - is pictured here in gold.

 

Finally, of course, there are many bodies in the solar system that Copernicus didn't know about, most noticeably two more planets, Uranus and Neptune.

Ahead of His Time
Copernicus's Big Idea was a bit too radical for most people of his time, and for more than a century, most people didn't accept it. Remember, some of Galileo's findings confirmed the Copernican system, but he was put on trial and then under house arrest because of it—and that was 100 years later!

Watch a short video about Copernicus.

Find out more about Copernicus's Big Idea.
Check out how much simpler the Copernican Sun-centered system is than the Ptolemic system of old here. This website has a lot of great info - and you can scroll down to a simple animation comparing the two systems.

Copernicus has been honored with many memorials, with his face on Polish money, with a crater on the moon named for him, and most recently with a new element (atomic number 112) named copernicium.

This salt sculpture of Copernicus can be found
in a salt mine in Poland.






(Third Friday in February)

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