Celestia Forums

Many components of the universe (moons, planets, stars, galaxies) spin. From my fairly mis-informed guess, I'm thinking these spins are due to the interaction of gravity, and frictional forces. Can someone with better insight explain the basic principles causing spins, or point me to an online reference of such?

Kolano wrote:Many components of the universe (moons, planets, stars, galaxies) spin. From my fairly mis-informed guess, I'm thinking these spins are due to the interaction of gravity, and frictional forces. Can someone with better insight explain the basic principles causing spins, or point me to an online reference of such?

Take a look at the article on angular momentum at wikipedia.

- Hank

in 1980, my HS physics teacher, Fred Meyers, said that Earth's initial rotation was provided by God. That was the year i flipped him off in class....had to apologize for being disrespectful.

yamo wrote:in 1980, my HS physics teacher, Fred Meyers, said that Earth's initial rotation was provided by God. That was the year i flipped him off in class....had to apologize for being disrespectful.

That sounds like something I'd do too, although I would NEVER
apologize.

Refer to Hank's Wiki link above though, and remember that an object
in motion will tend to STAY in motion unless acted upon by an outside
force. Since space is - for the most part - a vacuum, the outside
force is hard to come by unless it happens to be gravity from another
body, or occasional impacts, or friction from particles which do exist
in space.

Just some scientific thoughts from a guy who has NO scientific
background.

Thanks, Brain-Dead

First off regarding rotation. I personally prefer the Ask an Astronomer site at Cornell. They do a great job explaining things.
http://curious.astro.cornell.edu/questi ... number=416

My understanding is that the rotation of most massive solar system objects starts with the initial rotation of the gas/dust cloud that they originated from. The initial spin of the cloud could be a result of magnetic, thermal and gravitational interaction of the particles. Over time, knots of material clump together and then you have kinetics to throw into the mix. It would take hundreds of millions of years to get rolling (heh)... As I understand it, a close by supernova can kick things off though by sending waves through a gas cloud too.

BobHegwood wrote:

yamo wrote:in 1980, my HS physics teacher, Fred Meyers, said that Earth's initial rotation was provided by God. That was the year i flipped him off in class....had to apologize for being disrespectful.

That sounds like something I'd do too, although I would NEVER
apologize.

Secondly,

As a teacher myself, I would hope for the apology even though I believe it lays a foundation for future offense. Respect for our instructors seems to have become more of a problem with each passing year. At least it seems that way in America from watching my parents teach for 30 years and myself for 10. When I was in HS, the brothers (catholic school) would have thrown me up against a wall (and did ).

Instead, and this is what I tell my students to do today, ask the instructor to prove it. Where is the evidence, what backup do you have, etc. I teach kids with behavioral problems so I see the finger response every day, teaching them to critically debate an issue is far more useful. Sorry to harp on this, but we have a bunch of young'uns that frequent this site and I want them to know that I believe you will get farther with discussion than a isolent gesture any day.

buggs_moran wrote:

BobHegwood wrote:

yamo wrote:in 1980, my HS physics teacher, Fred Meyers, said that Earth's initial rotation was provided by God. That was the year i flipped him off in class....had to apologize for being disrespectful.

That sounds like something I'd do too, although I would NEVER
apologize.

Secondly,

As a teacher myself, I would hope for the apology even though I believe it lays a foundation for future offense. Respect for our instructors seems to have become more of a problem with each passing year. At least it seems that way in America from watching my parents teach for 30 years and myself for 10. When I was in HS, the brothers (catholic school) would have thrown me up against a wall (and did ).

Instead, and this is what I tell my students to do today, ask the instructor to prove it. Where is the evidence, what backup do you have, etc. I teach kids with behavioral problems so I see the finger response every day, teaching them to critically debate an issue is far more useful. Sorry to harp on this, but we have a bunch of young'uns that frequent this site and I want them to know that I believe you will get farther with discussion than a isolent gesture any day.

I'm very sorry to dispute you here my friend, but ANY teacher
trying to foist their RELIGIOUS view of our creation and/or the
workings of the Solar System should be SHOT in my opinion.

This is unless the student is enrolled IN a religious institution
where his/her parents expect that kind of education. Having
been somewhat rebellious in my youth (and also in my old age),
I was actually suspended for my activities in our educational
system quite a few times.

What teachers are meant to do is EDUCATE. They are NOT meant
to mold malleable young minds with religious fanaticism.

Sorry, but that's just ME.

Oh don't get me wrong Bob, I don't believe in religion in the classroom under any circumstances. I am a secular humanist. I was responding to "giving the finger" as a means to an end. That is what I disagree with.

If students understood what science was from the get go, they would never accept justifications such as "it just is" or "God did it". I am by no means justifying the teacher's indiscretion of bringing religion into the classroom.

Sorry if I didn't make that clear...

buggs_moran wrote:Oh don't get me wrong Bob, I don't believe in religion in the classroom under any circumstances. I am a secular humanist. I was responding to "giving the finger" as a means to an end. That is what I disagree with.

Thanks for your explanation - and for NOT jumping down my throat
like many of my former teachers used to do. I admit it though... I was
a bad student. Was too busy trying to stay alive during my youth.

When I went to college later in life, it was because *I* wanted to go,
and not because someone else told me I had to go. Graduated from
Sinclair Community College in Dayton, Ohio with a 4.0 GPA.

How's that for a Brain-Dead old Geezer?

BobHegwood wrote:When I went to college later in life, it was because *I* wanted to go,
and not because someone else told me I had to go. Graduated from
Sinclair Community College in Dayton, Ohio with a 4.0 GPA.

How's that for a Brain-Dead old Geezer?

Oh we are going SO far off topic here (sorry Selden & Kolano)

4.0, daaamn, I can't even come close.

Ahh, beautiful Dayton. Been there a few times. Love Wright-Patterson. Every time I get out there (last time was 93') I find the Valkyrie, gorgeous plane IMHO (aerospace engineering degree, I can't help it, bomber or not).



Of course, I did do the right after HS thing, went and got a degree in something I ended up not liking, and then of course, there were no jobs... Teaching is great, but I think one day I will go back to school for some astronomy related field. I think I'd like the Neil DeGrasse Tyson (as if) route, teaching, writing, & astronomy... I have a good friend who went back to school and became a child psychologist at 60. "They" always say it's never too late to learn. "They" also say we're getting 15" of snow tomorrow, whoopee fun commute...I hate "they".

BobHegwood wrote:When I went to college later in life, it was because *I* wanted to go,
and not because someone else told me I had to go. Graduated from
Sinclair Community College in Dayton, Ohio with a 4.0 GPA.

How's that for a Brain-Dead old Geezer?

I've never understood how the educational system and this Grade Point Average system works in America, so when someone says 4.0 GPA this means nothing to me.

I assume your score (between 0 and 1)for 5 subjects is averaged, so the maximum possible is 5? IS that right?

So your 4.0 represents an average of 80% over 5 subjects?

Would someone be kind enough to explain the US system?

Here we have roughly a ternary system:
Primary: roughly ages 5-12 (often split into 2 schools, Primary 5-10yrs, and Intermediate 11-12 years)
Secondary (also known as "High" School): ages 13-17
Tertiary (University)

Now, as I understand it, your "College" is the equivalent of our "Secondary School" (or perhaps just the last 2 years of Secondary School) ??

Chuft-Captain wrote:Would someone be kind enough to explain the US system?

Now, as I understand it, your "College" is the equivalent of our "Secondary School" (or perhaps just the last 2 years of Secondary School) ??

The scale used in America in places I am familiar with is from 0.0 to 4.0, so 4.0 is the maximum. Colleges here are tertiary education. Universities are organizations with multiple colleges within them. We call secondary education high school too. It is often split into junior and senior high schools or middle and high schools.

My school district has five schools, the kindergarten for age 5 years, primary for grades 1-3, intermediate for grades 4-5, middle for grades 6-8 and high for 9-12. The K-5 or K-6 grades are often considered the elementary school grades. Sixth grade is sometimes part of middle school and sometimes part of elementary school, depending on the school system. It seems to me that middle schools with grade 9 and no grade 6 are junior highs. The school buildings in my district below middle school used to be K-6 schools, then they split them up into the current system, adding grade 6 to the Jr. high to make it into a middle school and moving grade 9 to the high school.

Regarding angular momentum, I wonder if all of the macroscopic angular momentum in the universe adds up to zero, with stuff that spins one way having their spin canceled out by other matter that spins in other directions.

Ultimately all spin came from the initial "big bang" and slight differences in temperature. It influence can be seen in the cosmic microwave background radiation.

If you want to try a simple experimental, get a bowl of water, and drop a few drops of dye into it. you will see as the dye settles to the bottom. It creates a bunch of vortexes on its way down. Each one of these little vortexes is like what happened, is still happening with the original primordial gas of interstellar space. From a big picture perspective you can says that all interstellar gas has some spin to it as a whole. It not very well understood, but at some point the gas condenses, and do to the law angular momentum, as a system condenses it inherits that original spin.

-Matt-

Chuft-Captain wrote:
So your 4.0 represents an average of 80% over 5 subjects?

4.0 GPA means that I scored 100% in every subject in every college year.
Then too, I only attended a 2-year college and received an
Associate's Degree.

Very sorry about the topic malfunction... My fault.

MKruer wrote:Ultimately all spin came from the initial "big bang" and slight differences in temperature. It influence can be seen in the cosmic microwave background radiation.

-Matt-

Well there you go... An efficient and believable explanation.

BobHegwood wrote:I'm very sorry to dispute you here my friend, but ANY teacher trying to foist their RELIGIOUS view of our creation and/or theworkings of the Solar System should be SHOT in my opinion.

Rather... harsh, might I say?
Personally, I am very religious, but I agree that religion probably shouldn't be taught in school. Even if I weren't religious, I would not wish for teachers to be shot for teaching something contrary to modern beliefs. I would like to think we have abandoned that way of thinking in the middle of the last mellinium.

Unfortunately in many regions people are still being murdered on a more or less regular basis for having beliefs or opinions that are contrary to the general opinion.

Hungry4info wrote:

BobHegwood wrote:I'm very sorry to dispute you here my friend, but ANY teacher trying to foist their RELIGIOUS view of our creation and/or theworkings of the Solar System should be SHOT in my opinion.

Rather... harsh, might I say?
Personally, I am very religious, but I agree that religion probably shouldn't be taught in school. Even if I weren't religious, I would not wish for teachers to be shot for teaching something contrary to modern beliefs. I would like to think we have abandoned that way of thinking in the middle of the last mellinium.

VERY sorry again here my friend, but don't you people realize that I
was kidding? Holy Moly....

Be that as it may, however, foisting one's religious beliefs on an
unsuspecting child is akin to murder in my opinion. You're killing the
child's natural curiosity. Nuff Said...

Gentle friends,

Please remember that the discussion of religion is not allowed on the Celestia Forum.

selden wrote:Gentle friends,

Please remember that the discussion of religion is not allowed on the Celestia Forum.

MY fault entirely, Selden...

I am very sorry, and please feel free to delete me, ban me, or
banish me to the nether-realms if that is what you feel is appropriate.

I just tend to rebel sometimes.

BobHegwood wrote:I am very sorry, and please feel free to delete me, ban me, or banish me to the nether-realms if that is what you feel is appropriate.

No please don't do that .

I see BobHegwood as a friend.