Galileo Galilei: The Starry Messenger

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February 15 marks Galileo’s 461st birthday.


The man has a long list of accomplishments in the field of astronomy attributed to his name, including improving and developing the telescope, discovering sunspots, and proving that earth was not the center of the universe.


One of Galileo’s most widely-known accomplishments is the discovery of Jupiter’s four largest moons, also known, aptly, as the Galilean Moons. Their names—Ganymede, Io, Callisto, Europa—are widely known, but the consequences of their discovery are more significant than you might think. Because Galileo was an early developer of the telescope at a time when the science of astronomy was experiencing radical progress, he sometimes had the luxury of pointing his spyglass skyward and stumbling on a previously undiscovered object. To wit, the astronomer actually observed Neptune in 1612 and marked it in his notes as an insignificant, dim star. And while you can imagine Galileo’s initial discovery of these moons as being similarly haphazard, he quickly realized something significant had happened.



Upon his first observation, three of the Galilean Moons were arranged in a straight line extending outward from Jupiter.


Not altogether unremarkable in a sky full of bright objects, but it was the first indication that there was something unique about these spots. “Three fixed stars, totally invisible by their smallness,” Galileo remarked in his initial notes. After observing these objects on subsequent nights, he realized that their positions were changing relative to Jupiter, in ways that did not make sense for "fixed stars.” Within days, he realized that the three spots he initially observed were orbiting Jupiter, and that there was indeed a fourth object moving in conjunction with the others.


It’s an interesting enough discovery, but it was also inevitable. In fact, another astronomer, Simon Marius, working independently of Galileo around the same time, also discovered these moons and gave them the names we know them by today (Galileo had initially named them “The Medicean Stars” in honor of his patron-to-be).












The reason that this discovery really altered the course of astronomy is twofold.


The first is that it disproved once and for all old Aristotelian notions about the cosmos. Aristotle believed that every object in the night sky orbited around the earth, and Jupiter’s moons were the first objects to be observed not following this pattern of behavior. The second reason is that it would set Galileo down a path toward acceptance of the heliocentric model of the universe (i.e., the Sun being the center of the universe), which famously led to him being tried and found guilty of heresy, besides influencing a great deal of his later work.


These dual pillars of significance are actually parts of the same idea on a deeper level. Old notions about the universe (including geocentricism) emphasized the importance of the earth, and led people to believe that they were at the center of the universe. The fact that Jupiter had a few moons rotating around it did not directly contradict the geocentric model, but it laid a framework for a more holistic way of thinking about the cosmos. That is, it exposed the scale of our universe as being something much larger and more complicated than our own planet or even our own solar system. Carl Sagan famously pointed to a photo of the earth sent back from the Voyager 1 in which the earth appears no larger than a pixel. He described our planet as a “pale blue dot,” the significance of which, if any, was dubious. Galileo opened the door to this line of thinking, and allowed us to begin seeing the universe as something bigger and more mysterious than just our corner of the neighborhood.















Your Thoughts


  1. Galileo avoided being burned at the stake (for claiming the Earth orbited the Sun) by recanting his scientific observations and spending the last nine years of his life under house arrest. Have we greatly advanced in our debating skills over the past 400 years, or is violence still too prevalent as a form of “dissenting opinion?”
  2. Humanity once thought the universe was only what could be seen in the night sky. Does the vastness of the universe we know today make you feel we are insignificant? Or does it fill you with wonder over what miracles and possibly what other life forms may be out there in that vastness?
  3. Do you welcome announcements of new scientific discoveries and get excited at the prospect of new discoveries always bringing a clearer picture of reality into focus? Or do you fear new science will ruin comfortable traditional ways of thinking?












Comments43
anonymous's avatar
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K4nK4n's avatar
When it comes to real-life historical characters, Galileo had always been my idol since I was a kid.
KovoWolf's avatar
  1. Galileo avoided being burned at the stake (for claiming the Earth orbited the Sun) by recanting his scientific observations and spending the last nine years of his life under house arrest. Have we greatly advanced in our debating skills over the past 400 years, or is violence still too prevalent as a form of “dissenting opinion?”
    Galileo was a brilliant scientist who brought forth idea's that where not popular in the age and time of the renaissance. Religious oppression was very strong and anything that went beyond the popular belief was believed to be unholy and consequences for this offense was usually one's life. Despite Galileo's articulate discussions about his discoveries of the cosmos, he was still marked by the church as committing heresy. I think the articulation of debates are roughly the same as they where 400 years ago, but the subjects in question and in debate are in coloration with the times we live in. With the natural flavor of debates, you get heated discussions but at least it won't cost your head ( in almost all cultures ) by voicing your opinion in this day and age.  


  2. Humanity once thought the universe was only what could be seen in the night sky. Does the vastness of the universe we know today make you feel we are insignificant? Or does it fill you with wonder over what miracles and possibly what other life forms may be out there in that vastness?
    Every time I look into the night sky, I'm humbled. We are reminded of how small we are in the vastness of the cosmos. I think it's hard for our brains to conceptualize, to fathom or wrap our head around just how large our universe truly is. To contemplate the vastness of interstellar space. We are the witness to the very brink of time and space. We should be proud of our accomplishments and put our place in the cosmic perspective of life. There are billions upon billions of galaxies
    beyond Andromeda so the possibility of life being out there is very feasible and that thought alone is worth getting excited about.


  3. Do you welcome announcements of new scientific discoveries and get excited at the prospect of new discoveries always bringing a clearer picture of reality into focus? Or do you fear new science will ruin comfortable traditional ways of thinking?
    Science is the joy of discovery. You have to step outside the realm of comfort and tradition to discover new things. Advancements in the field of science is growing and expanding every day and it brings us closer to answers for the uknowns. Yes I welcome new discoveries : )
JACAC's avatar
a . g r e a t . m a n . f o r . h i s . t i m e
f a n t a s t i c . d e s c o v e r i e s
:clap:
Danubium's avatar
Actually, Galilei was never threatened with being burned at the stake.

He was silenced for being a douche to the Pope who happened to fund his research, and for his metaphysical assertions about his model being not a human interpretation of reality, but reality itself, even though it made no sense in Aristotelian physics, and was mathematically inferior.
applelings's avatar
This is faaaantastic stuff!
blockbro's avatar
Galileo wasn't the first to DESCOVER that the earth went around the sun. Geocentricity was a theory until Galileo official established an proved it with completely solid scientific evidence.
Danubium's avatar
Galilei's framework was worse than the Aristotelian model.
It was Newton who made the first truly sensible and accurate model.
blockbro's avatar
True. Newton had the upper hand knowing the most about physics.
ZachValkyrie's avatar
It was a HYPOTHESIS until Copernicus codified it. Now it is a THEORY.
blockbro's avatar
Thank you for catching my mistake. I don't know how I let it slip by. 
ZachValkyrie's avatar
That's ok. We all mess up sometimes.
PetrINFJ's avatar
What a shame.. there is no astrophotography featured. I hoped to see some great images of Jupiter, the Great red spot and 4 popular moons, but instead there are just all these drawings, and photo manipulations.. and other arts (and I am sure that I saw few of these on the internet already.. and can't decide, if it's realy by the credited artist or if it isn't).
cheezebawls's avatar
Galileo is da real MVP

and nice journal btw :love:
HaniSantosa's avatar
Thank you very much for featuring my work! And brilliant article too :D
TESM's avatar
Some of these historical embellishments in this article are a bit misleading, and heliocentricism is typically the popularized belief that he was tried and found guilty of "heresy," which isn't entirely accurate.

Galileo (kind of a jerk) writing the Pope, at the time a military and political leader (and a jerk in his own right), into his diologue as "the idiot" was probably a poor move on Galileo's part. Many churchmen agreed with Galileo's findings and tested them for their accuracy (i.e., what is now called the Vatican Observatory).
Tadrix's avatar
1. Depends, but still, for humanity violence always remains the simplest answer to everything.

2. Both.

3. To put it simple, "new discoveries" rule, "traditional ways" suck, because "we always did it that way" in the face of innovation is not a valid point (rational one). Different methods should be compared and that which yield better results — used. In this context, "comfort" is blindness.

Speaking about point raised by martimG: Yes, mostly. Sometimes, though, fumes were fanned away to prevent that.

At any rate, before G. Galilei was Nicolaus Copernicus (Mikołaj Kopernik).
martimG's avatar
Indeed, it talks about cruelty of a human being when they prevent you from dying one way to die another worse. Same with torture, that was limited to one session, but often people have two and they call it one with a break in the middle.

Note: I agree with you on 3, the mechanics are well described by Thomas Kuhn. Sadly, it seems Galileo didn't manage to prove its ideas when his enemies launch for him. Dialogue Concerning the Two Chief World Systems is mostly a logic work.
theveryfoxytaco's avatar
No, it wasn't HIM who discovered that, it was someone else...
martimG's avatar
The imprisoment of Galileo was not related to his scientific point of view, that were welcome (he was a personal friend of the pope, so that's cheating), problem was his theology related concepts (and some lack of human relationship skills). He actually claimed he was framed. It seems he also never was in danger of being burn alive.

Side note: people on fire pyres die by asphyxia (no good anyway).

Sources (so you can agree or disagree with them):

www.quora.com/Why-were-Galileo…
www.quora.com/What-is-the-most…

Bonus track (?), for those who want to read and know more about Galileo works, a key book:
www.webexhibits.org/calendars/…
 
ArrestingAries's avatar
A really great read, the Universe is such a marvelous place. So much to learn about, it's a really great thing that we've had people like Galileo to really try to go and understand a it, making big statements in their time and giving us something to help understand more amazing thing about the universe as we know it.
FellitoRockero's avatar
Wherever you are, I hope it's in the stars, Galileo.
hosagu's avatar
"E pur si muove!"
This is the best ever quote done as telling mankind: you'll see someday I am saying what you can't or don't want to accept and face.
It is a matter of relativity. Humility.
anonymous's avatar
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