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Author Topic:   How did a new satellites get in the right position?
RAZD
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Posts: 20156
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Message 16 of 35 (427451)
10-11-2007 2:07 PM
Reply to: Message 1 by techristian
10-11-2007 10:25 AM


The satellite must mysteriously set itself up so that it is neither pulled back by gravity nor let loose into space. It must have that perfect balance between just enough gravity but not too much gravity.

I wonder why you think this is a problem. Cosmologists & astrophysicists can run the orbit equations backwards and see what happens, and they don't see any problems cropping up in the 4.5 billion or so period of existence of the solar system.

It must have that perfect balance between just enough gravity but not too much gravity.

There are literally an infinite number of orbits that any planet can have around a star. Thus there is no "perfect balance" to be achieved, rather one out of an infinite number of possibilities.

We can even restrict earth to orbits within the habitable zone and there are still an infinite number of possibilities.

How did the satellites get to that perfect spot in the first place?

Planets, moons, and asteroids condensed out of material that was already in orbit, so they were already in orbit when they were formed.

Some of those orbits were stable and some were not. Those with unstable orbits have been eliminated (crashed into other objects or ejected into space), so what you are seeing are the remnants that have been stable enough to survive the last 4.5 billion years. But orbits are not totally stable, they are still changing, and there are still collisions between objects (Schumacher-Levy is one example).

To look at these remnants and wonder why they have such "perfectly" stable orbits is a post hoc ergo propter hoc fallacy coupled with an argument from incredulity.

Enjoy.


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Dr Adequate
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Posts: 16107
Joined: 07-20-2006
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Message 17 of 35 (427453)
10-11-2007 2:09 PM
Reply to: Message 14 by LinearAq
10-11-2007 2:03 PM


He said new satellites and not new moons or planets so I assumed he was talking about man-made ones. Do you think he was asking the question because he is so blindingly ignorant of gravity that he thought he could trip someone up?

Yes, I'm afraid so. As he said, "Such as the Moon in relation to the Earth or the Earth in relation to the Sun?"

Yes, it's just another bleedin' Fine-Tuning Argument.


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Taz
Member (Idle past 1582 days)
Posts: 5069
From: Zerus
Joined: 07-18-2006


Message 18 of 35 (427454)
10-11-2007 2:15 PM
Reply to: Message 1 by techristian
10-11-2007 10:25 AM


When I was younger, I was on a trip with my family through the rockies. On the way there, we saw some very beautiful mountain ranges. We looked up and saw really big rocks and boulders looking like they might fall flat on someone's head anytime now. My mom thought out loud "how come those rocks aren't smashing anyone?" My dad answered "god created the mountains such that they wouldn't hurt us."

My older brother then said, "you could think of it that way, or you could think of it this way. How long have that mountain and those rocks been there?"

I think it was my sister that immediately got it and said something like "whatever rocks that were going to fall had already fallen in the past. The ones that are left are there because they aren't likely to fall."

Same thing with our moon. If it wasn't in a stable orbit, we wouldn't be having this conversation. Trying to attribute this to a god is like attributing your existence to the tooth fairy. Out of the millions and millions of sperms, each carrying a different genetic combination, the right one just happenned to make it first to the egg that resulted in you. Would you be here asking this question if another sperm happenned to have made it there first?


Disclaimer:

Occasionally, owing to the deficiency of the English language, I have used he/him/his meaning he or she/him or her/his or her in order to avoid awkwardness of style.

He, him, and his are not intended as exclusively masculine pronouns. They may refer to either sex or to both sexes!


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Taz
Member (Idle past 1582 days)
Posts: 5069
From: Zerus
Joined: 07-18-2006


Message 19 of 35 (427456)
10-11-2007 2:18 PM
Reply to: Message 14 by LinearAq
10-11-2007 2:03 PM


LinearAq writes:

He said new satellites and not new moons or planets so I assumed he was talking about man-made ones. Do you think he was asking the question because he is so blindingly ignorant of gravity that he thought he could trip someone up?


This was my first thought, too, until I read to the part where he mentioned the moon.

To be honest, my reply was going to be "those satellites are there because NASA got on their knees, prayed, and god came down and swooped them up into orbit."


Disclaimer:

Occasionally, owing to the deficiency of the English language, I have used he/him/his meaning he or she/him or her/his or her in order to avoid awkwardness of style.

He, him, and his are not intended as exclusively masculine pronouns. They may refer to either sex or to both sexes!


This message is a reply to:
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techristian
Member (Idle past 2393 days)
Posts: 60
Joined: 04-03-2002


Message 20 of 35 (427563)
10-12-2007 12:22 AM


I'm trying to see this.
I'm trying to see this. OK we have a Big Bang. Particles flow out in a straight line from the central explosion. There are no large bodies with gravity YET and so nothing to slow the particles down from moving in a straight line. The particles could continue to move in this straight line for infinity ,but somehow they start to move in orbits ?????

Dan

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crashfrog
Inactive Member


Message 21 of 35 (427564)
10-12-2007 12:39 AM
Reply to: Message 20 by techristian
10-12-2007 12:22 AM


Re: I'm trying to see this.
There are no large bodies with gravity YET and so nothing to slow the particles down from moving in a straight line.

Collisions with each other.

The particles could continue to move in this straight line for infinity ,but somehow they start to move in orbits ?????

Orbits come long, long after particles have begun to clump together into hydrogen atoms.

They don't just "start" to move in orbits. Objects that intersect the gravity wells of massive objects at the correct distance and vector enter orbits. Other things don't and they shoot off into space.

It's hard to understand what you find puzzling about that. When you look at objects in orbit, you're obviously only seeing the objects that had the correct position and speed to enter orbit in the first place. Obviously, everything that didn't never entered an orbit, so you don't see it when you look at orbits.

What's hard to grasp about that?


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Taz
Member (Idle past 1582 days)
Posts: 5069
From: Zerus
Joined: 07-18-2006


Message 22 of 35 (427567)
10-12-2007 1:09 AM
Reply to: Message 20 by techristian
10-12-2007 12:22 AM


Re: I'm trying to see this.
tech writes:

I'm trying to see this. OK we have a Big Bang. Particles flow out in a straight line from the central explosion. There are no large bodies with gravity YET and so nothing to slow the particles down from moving in a straight line.


What on earth are you talking about? Everything exerts gravitational force on everything else. The mass of the whole universe exert gravitational force on the individual particles.

You really ought to learn a thing or two about physics before making these rediculous claims.

And no, rocks can't orbit mountains.


Disclaimer:

Occasionally, owing to the deficiency of the English language, I have used he/him/his meaning he or she/him or her/his or her in order to avoid awkwardness of style.

He, him, and his are not intended as exclusively masculine pronouns. They may refer to either sex or to both sexes!


This message is a reply to:
 Message 20 by techristian, posted 10-12-2007 12:22 AM techristian has not yet responded

  
Rahvin
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Posts: 3964
Joined: 07-01-2005


Message 23 of 35 (427571)
10-12-2007 1:28 AM
Reply to: Message 20 by techristian
10-12-2007 12:22 AM


Re: I'm trying to see this.

I'm trying to see this. OK we have a Big Bang. Particles flow out in a straight line from the central explosion. There are no large bodies with gravity YET and so nothing to slow the particles down from moving in a straight line. The particles could continue to move in this straight line for infinity ,but somehow they start to move in orbits ?????

Dan

You're understanding of the Big Bang is far too close to a conventional explosion. In reality, it wasn't similar at all. The Big Bang is less about particles flying away from a single point and more about the actual space expanding. Imagine a bunch of dots on a deflated balloon. Now, inflate the balloon. The dots will spread apart, but it's not the same as all of them simply flying away from each other.

Gravity casues the early matter to be held together despite the expansion of space. The result is essentially a multitude of clusters of matter, which are the precursors to modern galaxies.

This is still very much an oversimplification, so please bear with me.

Unfortunately, the Big bang doesn;t really have anything whatsoever to do with the formation of a solar system - it's a completely different topic (there were no heavy elements, for example, in the first eons of the universe's existence).

Planetary formation is very different.

Given a nebula, which is basically just a large amount of gas in a localized area, the gravitational attraction of the gas will cause it to concentrate itself and squeeze towards the center of mass. If there is a sufficient amount of gas, the force of gravity will be sufficient to induce nuclear fusion, and birth a star.

The remaining material, still circling the star in what's essentially a whirlpool into the new star's gravity well, will have some clusters of debris at the appropriate distance and speed to have a stable orbit with the star. The material in between these orbits will either be flung into space, accrete to the orbiting bodies due to their gravitational attraction, or fall into the new star.

Once this process is complete, a solar system will have formed. Occasionally a stray asteroid will be captured by a planet's gravity and become a new satellite rather than being drawn down into a collision (as seems to be the case with the two diminutive moons of Mars, for instance). Some moons will form from the debris left over from the planet's formation, happening to be in a stable orbit, exactly as the planets formed around the star.

The important things to remember:

1) The Big bang wasn't an "explosion" in the way we think of a stick of dynamite. Space expanded, matter was not being propelled away from itself.
2) Gravitational attraction causes matter to clump up, which prevents the even distribution and decreasing density that you're envisioning.


Every time a fundy breaks the laws of thermodynamics, Schroedinger probably kills his cat.

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Dr Adequate
Member
Posts: 16107
Joined: 07-20-2006
Member Rating: 7.7


Message 24 of 35 (427617)
10-12-2007 8:56 AM
Reply to: Message 20 by techristian
10-12-2007 12:22 AM


Re: I'm trying to see this.
Again, I'm just bewildered to know why you'd go around talking about the Big Bang without first making the slightest effort to find out what it is.

Particles flow out in a straight line from the central explosion.

Sheesh, who told you that?

---

Here's a thought for you.

If cosmology could be debunked by contrasting what you think you remember learning about it with what you think you remember of high-school physics, then would this not also be apparent to physicists? Would people like, for example, Einstein, have noticed the problem way before you did?

Hint: when you find yourself in disagreement with all the world's physicists about physics, this is a sure sign that you have failed to understand something.

Edited by Dr Adequate, : No reason given.


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techristian
Member (Idle past 2393 days)
Posts: 60
Joined: 04-03-2002


Message 25 of 35 (428427)
10-16-2007 11:57 AM


quote:
You're understanding of the Big Bang is far too close to a conventional explosion. In reality, it wasn't similar at all. The Big Bang is less about particles flying away from a single point and more about the actual space expanding. Imagine a bunch of dots on a deflated balloon. Now, inflate the balloon. The dots will spread apart, but it's not the same as all of them simply flying away from each other.

Now let's look at this balloon again, shall we? If this balloon is a perfect sphere and expands evenly then the particles will indeed move out in a straight line. Right? Because we have RED SHIFT on many of the stars, this would indicate that the universe is still expanding at near light speed. This would also indicate that the expansion was even faster at the very beginning.

Now let's look at this balloon again. Imagine the spherical balloon expanding at near light speed , evenly from the center point. I would call this an EXPLOSION. It is a matter of semantics.

BTW I have read a few good SECULAR books on cosmology since my graduation from formal education. However I admit it has been over 10 years so I'll need to break them open again. "GRAVITY'S LENSE" is one of them.

Dan Laskowski


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crashfrog
Inactive Member


Message 26 of 35 (428432)
10-16-2007 12:06 PM
Reply to: Message 25 by techristian
10-16-2007 11:57 AM


If this balloon is a perfect sphere and expands evenly then the particles will indeed move out in a straight line. Right?

No, not at all. They're constantly colliding and interacting with each other, having their straight paths deflected, etc.


This message is a reply to:
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Modulous
Member (Idle past 395 days)
Posts: 7789
From: Manchester, UK
Joined: 05-01-2005


Message 27 of 35 (428444)
10-16-2007 12:34 PM
Reply to: Message 25 by techristian
10-16-2007 11:57 AM


Now let's look at this balloon again, shall we? If this balloon is a perfect sphere and expands evenly then the particles will indeed move out in a straight line. Right?

Yes - but remember that our balloon model has no other forces, just expansion. It is only an analogy for expansion, nothing else.

Because we have RED SHIFT on many of the stars, this would indicate that the universe is still expanding at near light speed.

The universe is expanding, there are parts of it that are moving away from our position at a rate that can be thought of as faster than the speed of light.

This would also indicate that the expansion was even faster at the very beginning.

This fact alone does not indicate that the expansion was even faster at the very beginning - however the evidence currently points to something that probably resembles:


Click to enlarge

Now let's look at this balloon again. Imagine the spherical balloon expanding at near light speed , evenly from the center point. I would call this an EXPLOSION. It is a matter of semantics.

We can define explosion in such a way as to include inflation, but it would be confusing and unnecessary. When we normally speak of explosions we think of objects moving through local space violently from a central point of space. The word explosion doesn't really cover it since the latin 'ex' implies 'away' and 'away' has plenty of space related connotations which don't make sense when it is the space itself that is expanding. In inflation, one particle can remain where it is and the amount of space between it and another particle can be increasing. Neither particle is moving through space away from the other - in fact they could even be moving through space towards each other - and the distance between them can continue increasing.

Explosion just doesn't work as an adequate description (can you imagine calling it an explosion where all the particles all started moving towards each other, but space itself stretched to keep them seperate?), and that is why expansion and inflation are preferred terms. They help avoid confusions with the kind of physical activity we would normally expect to find in what we traditionally call an 'explosion'.


This message is a reply to:
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Dr Adequate
Member
Posts: 16107
Joined: 07-20-2006
Member Rating: 7.7


Message 28 of 35 (428454)
10-16-2007 12:57 PM
Reply to: Message 25 by techristian
10-16-2007 11:57 AM


Now let's look at this balloon again. Imagine the spherical balloon expanding at near light speed , evenly from the center point. I would call this an EXPLOSION.

Hold on. The analogy is between the whole universe and the surface of the balloon, not between the whole universe and the balloon including its interior.

The surface of the balloon has no "center point" --- every point on the surface of the balloon is moving away from every other.


This message is a reply to:
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Annafan
Member (Idle past 2870 days)
Posts: 418
From: Belgium
Joined: 08-08-2005


Message 29 of 35 (428650)
10-17-2007 5:01 AM
Reply to: Message 25 by techristian
10-16-2007 11:57 AM


techristian writes:

Because we have RED SHIFT on many of the stars, this would indicate that the universe is still expanding at near light speed.

That wouldn't be quite the best way to put it I think.

First of all, the measured redshift is the combination of how the stars/galaxies are moving (away) through space, and how the space itself between us and those stars/galaxies is constantly expanding.

I believe every unit of space is thought to be expanding at the same rate. The reason why more distant objects display a higher amount of redshift, is that they are seperated from us by MORE space. MORE units of space expanding at the same rate means more rapid removal in total.

Since the early universe, light from distant places has been trying to reach us. Light from some of the more distant areas hasn't had enough time to reach us (this is beyond our observational horizon). And it also WILL never be able to reach us, because by now expansion has created so much space between us and those places that the current expansion results in them moving away from us at a higher speed than the speed of light. (not violating relativity since it is not a speed through space) Effectively, our observational horizon is shrinking such that we potentially see less and less of the total universe.


This message is a reply to:
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Dr Adequate
Member
Posts: 16107
Joined: 07-20-2006
Member Rating: 7.7


Message 30 of 35 (428680)
10-17-2007 9:29 AM
Reply to: Message 25 by techristian
10-16-2007 11:57 AM


This would also indicate that the expansion was even faster at the very beginning.

No. If space expands uniformly, then the rate at which two objects embedded in it "move" away from one another must be continually increasing.


This message is a reply to:
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