Does anybody know why most planet orbits in solar system all lie down close to the equatorial plane of Sun's rotation axis, with planets translating in the
same direction, and exhibiting non-retrogade rotations?.
Planetary Orbits
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 Sir Thanksalot |
Planetary Orbits |
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Posts: 1 (08/20/08 02:43 PM) |
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Posts: 50395 (08/20/08 03:36 PM) CoAdmin.w/Grace06 |
Hello ST.
Welcome to The Round Table. I'm not sure we know why. The orbital disk might seem to be a violation of the law of entropy; and we might expect orbits to be random, in 3 dimensions. Obviously not. It seems it results from the accretion disk. I believe Pluto is ~17 degrees out of plane. But as you know, it's lost its "planet" status (by palace [laboratory?] coup), and probably won't regain it until the 5 years is up. I believe the celestial mechanics of it is, material outside the plane of the accretion disk gets deflected either into the sun, or out of the system too easily. It's mainly (or only) the material in the plane of the disk that manages to maintain stable orbit. And by the way, not all of it does. Some of it has been flung out into space, or drawn into and assimilated by the sun. I hope that helps. Thanks for joining us ST. Visit often. Post a lot. |
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Rambo123UK |
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Posts: 719 (08/20/08 04:08 PM) Caution: slippery when wet |
Pluto lost its status as a planet because it doesn't resemble one. While it was a unique case it could be seen as an aberration, but when the other Kuiper
Belt Objects started to be found it was obvious that Pluto fell into this category. Couple with the fact that extrasolar substellar companions have now been
found (about 300 or so, last time I checked) the definition of a planet is more crucial to pin down.
As to why planets orbit around the sun in the equatorial plane and same direction, this is because of conservation of angular momentum. The proto-planetary nebula that became the sun started out as a cloud of gas and dust but as it collapsed it would start to take on the average angular momentum of the component parts, which was amplified as the collapse continued (like a figure skater spinning faster as they pull their arms in). This means that the sun and planets that were all part of that cloud will conserve that same angular momentum (spin/rotation). The disk is not, as Sear would have it, a violation of the universe's laws of conservation of energy, but a validation of it. However, orbits of captured objects can be modified over time by tidal forces. It takes about a billion years to turn a retrograde orbit into a prograde one. There is also a component of the force that acts to draw the orbit into the equatorial plane. P.S. I'm pretty sure Sir Thanksalot has posted here before, yet this is shown as a new post. Have you purged the member list recently?
The truths of religion are never so well understood as by those who have lost the power of reasoning.
-- Voltaire BIBLE BABBLE |
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Errol Grey |
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Posts: 1988 (08/20/08 10:39 PM) Minister |
Pluto is on a 5 year suspension? I guess putting it on double secret probation didn't work?
Mai di meno, si muove!
Galileo |
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Posts: 50403 (08/21/08 05:03 AM) CoAdmin.w/Grace06 |
"Pluto lost its status as a planet because it doesn't resemble one." Rambo It sure is out of step. The general trend is; rocky planets closer to the sun, gas giants farther away. One of the considerations about what should enable a celestial body be deemed a planet is whether it's got enough dynamic geology and self-gravitation to become roughly spherical. "While it was a unique case it could be seen as an aberration, but when the other Kuiper Belt Objects started to be found it was obvious that Pluto fell into this category. Couple with the fact that extrasolar substellar companions have now been found (about 300 or so, last time I checked) the definition of a planet is more crucial to pin down." Rambo I've wondered whether they're to some degree judged by the company they keep. Perhaps a debris field of countless objects might be viewed differently than a single object the size of one of those fragments, but in solitary orbit. "As to why planets orbit around the sun in the equatorial plane and same direction, this is because of conservation of angular momentum. The proto-planetary nebula that became the sun started out as a cloud of gas and dust but as it collapsed it would start to take on the average angular momentum of the component parts, which was amplified as the collapse continued (like a figure skater spinning faster as they pull their arms in). This means that the sun and planets that were all part of that cloud will conserve that same angular momentum (spin/rotation)." Rambo Is that clearer ST? "The disk is not, as Sear would have it, a violation of the universe's laws of conservation of energy, but a validation of it." Rambo ? I wasn't as much addressing energy, as order. And I wasn't asserting an affirmation, only what might be the appearance. "The orbital disk might seem to be a violation of the law of entropy ..." sear The indisputable fact remains, emit a volume of particles, such as smoke, and they tend to naturally form a cloud. They fill 3D space; rather than form a disk. The formation of a disk of smoke particles in that situation would also seem to be [this addresses appearance ONLY] a violation of entropy. "However, orbits of captured objects can be modified over time by tidal forces. It takes about a billion years to turn a retrograde orbit into a prograde one. There is also a component of the force that acts to draw the orbit into the equatorial plane." Rambo One of the gas giants, either Uranus or Neptune is reported to have a rotational axis ~parallel with its plane of orbit. I thought the explanation for this was the spin it acquired from the objects that compose it (billiard ball physics). "P.S. I'm pretty sure Sir Thanksalot has posted here before, yet this is shown as a new post. Have you purged the member list recently?" Rambo Back at Ez, I knew it was an option. But it never made any sense to me to do so. I doubt Grace06 did either. Perhaps the server hiccoughed or something. "Pluto is on a 5 year suspension?" EG EG, I'm not sure if it's the Astronomical Union or not. But there's a group of scientists that meet, and decide such matters. And what happened on the Pluto deal is, a few upstarts waited until the big cheeses weren't around, and then sneaked in the demotion. Due to the bylaws of their organization, the issue can't be revisited for 5 years. But the big cheeses weren't happy about Pluto's classification change. And at the time it happened they indicated their intention to restore Pluto's status as planet. But they have to wait the 5 years to make it happen. Whether in the intervening time their resolve will weaken is anyone's guess. |
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Rambo123UK |
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Posts: 723 (08/21/08 06:23 AM) Caution: slippery when wet |
Re the member list, I seem to recall this happened to someone else a few months back. Perhaps there is an automatic dumping of old members after some period,
or perhaps posts from the EZ days are not counted? It just seemed strange to me.
Re energy/entropy - entropy is just the useable energy of the system. Entropy is not really "disorder" (as creationists would have it). However, I think I see the distinction you intend. This is explained by the cloud taking on the average angular momentum as it collapses. If it never collapsed to form a star and protoplanetary disk then the material would still be in random orbits. Gravitational collapse is the cause of the disk. Potential energy from the gravitational collapse is used to lower the "disorder" of the system, but the laws of conservation of energy are adhered to. Uranus would not have naturally formed with a 98 degree axial tilt, so it is thought that a collision between protoplanets caused this during the early history of the solar system. But that is not the same as the orbit being retrograde.
The truths of religion are never so well understood as by those who have lost the power of reasoning.
-- Voltaire BIBLE BABBLE |
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Dannytoro |
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Posts: 665 (08/21/08 07:14 AM) Lebanese Inuit |
.....Plutophobia is an ugly thing.....
"40 years of economic chaos brought to you by the two party system"
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Posts: 50407 (08/21/08 07:55 AM) CoAdmin.w/Grace06 |
Rambo,
@TRT's member counter has been vexed since -the great [Ezboard] hack-. We lost significant member count because of that. In @TRT's last days @Ez, I think our member count was a little over 500. And if I recall correctly it was you that helped us reach that #500 mark. (Thanks Rambo!) When we migrated to Yuku, our member count leapt upward again. I think it increased by ~200 or so. Right now the current count listed is "818 Total members". But you're right. We've had problems with individual counters. I looked into how to fix it locally. It turns out there's code which will do that. Here's a sample of some of those commands:
So I tried this one: pseud : add : 2601 I spent quite a while inserting that code into all sorts of different places in @TRT's skins. But it never affected an actual post count. Nope, not sure why not. Dt, It does seem a bit conspiratorial against Pluto. BTW, I don't know if it was deliberate, but Astronomer / Professor / Author Bob Berman suggests that Pluto was named in honor of astronomer Percival Lowell. The first two letters in "Pluto" are Percival Lowell's initials. |
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Errol Grey |
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Posts: 1990 (08/21/08 05:12 PM) Minister |
PLUTO
Gender: Masculine Usage: Greek Mythology (Latinized), Roman Mythology Pronounced: PLOO-to (English) [key] Latinized form of Greek Πλουτων (Plouton), derived from πλουτος (ploutos) meaning "wealth". This was an alternate name of Hades, the god of the underworld. This is also the name of a dwarf planet (formerly designated the ninth planet) in the solar system. http://www.behindthename.com/name/pluto The name Pluto was first suggested by Venetia Burney (later Venetia Phair), an eleven-year-old schoolgirl in Oxford, England.[23] Venetia was interested in classical mythology as well as astronomy, and considered the name, one of the alternate names of Hades, the Greek god of the Underworld, appropriate for such a presumably dark and cold world. She suggested it in a conversation with her grandfather Falconer Madan, a former librarian of Oxford University's Bodleian Library. Madan passed the name to Professor Herbert Hall Turner, who then cabled it to colleagues in America.[24] http://en.wikipedia.org/wiki/Pluto
Mai di meno, si muove!
Galileo |
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Posts: 50422 (08/21/08 08:16 PM) CoAdmin.w/Grace06 |
EG,
I did not know that. What I'm wondering is, Bob Berman is an impressive guy. I doubt he'd just make something up. So maybe his point was, regardless of who "suggested" it, perhaps those that made the final decision did so at least in part on the basis of Percival Lowell. I'm not sure. I haven't read any of Berman's books. But he's sometimes featured on NPR around here. That's where I heard him make the claim. |
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Rambo123UK |
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Posts: 725 (08/22/08 06:43 PM) Caution: slippery when wet |
As I understand it, Sear is correct, and the name of Pluto was chosen partly to honour Lowell who was the man who had started the search for the tenth planet.
The truths of religion are never so well understood as by those who have lost the power of reasoning.
-- Voltaire BIBLE BABBLE |
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Posts: 50460 (08/22/08 10:02 PM) CoAdmin.w/Grace06 |
Berman is a cool dude, and an obvious astute expert (readily evident listening to him speak).
I haven't read any of his books. But they're supposed to be amateur friendly. Cosmic Adventure : Other Secrets beyond the Night Sky The book he's written which I've heard him mention most is Secrets Of The Night Sky. |
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Rambo123UK |
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Posts: 727 (09/18/08 03:09 PM) Caution: slippery when wet |
It was TCY (The Christian Yahwist) who I was thinking of who returned after a while to find his post count returned to zero here.
The truths of religion are never so well understood as by those who have lost the power of reasoning.
-- Voltaire BIBLE BABBLE |
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Posts: 51251 (09/18/08 07:18 PM) CoAdmin.w/Grace06 |
I've heard a variety of nutty things happening to Yuku lately.
Perhaps "The Peter Principle" is at work here. If I recall correctly, "The Peter Principle" is: When we do well at work, we're rewarded with promotion. If we do well in the job we're promoted into, we're promoted again. And we're likely to continue to be promoted, as long as we're doing well. But as soon as we're given a job we don't excel in, we're not promoted. Instead, we're kept in that job that we don't do well. So the idea is, we rise to our own minimum level of incompetence. Ezboard's service, and perhaps Yuku's as well suggests to me the site is understaffed, and over-worked. |
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