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Author | Topic: Quick Questions, Short Answers - No Debate | |||||||||||||||||||||||||||
Dr Adequate Member (Idle past 306 days) Posts: 16113 Joined: |
(4) How do you know this?
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Coyote Member (Idle past 2128 days) Posts: 6117 Joined: |
The teeth are wrong.
If you reduce the size of the upper canines you have what appears to be a bear or some such. The rear teeth look like what are called carnasial teeth. These are not found in fish.
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fearandloathing Member (Idle past 4167 days) Posts: 990 From: Burlington, NC, USA Joined: |
Also the head looks too big/heavy for its body. JMO
If it was real it was no doubt caught near Fukishima "I hate to advocate the use of drugs, alcohol, violence, or insanity to anyone, but they always worked for me." - Hunter S. Thompson Ad astra per aspera
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RAZD Member (Idle past 1427 days) Posts: 20714 From: the other end of the sidewalk Joined: |
... and the tail is floating above the shadow with no visible means for it to be in that position with that head, the head is not partially buried in the sand, so the balance is wrong
... and the seagulls have not pecked the eyes out ... and etc etc etc Enjoy by our ability to understand Rebel American Zen Deist ... to learn ... to think ... to live ... to laugh ... to share. Join the effort to solve medical problems, AIDS/HIV, Cancer and more with Team EvC! (click)
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Taq Member Posts: 10044 Joined: Member Rating: 5.3 |
Consider ion drives, which are also reaction drives. Electric grids accelerate ions to form the exhaust. Where is the pushing there? Acceleration of the vehicle is by conservation of linear momentum, not by pushing against the sides of the chamber. Reminds me of the old physics question of what to do if you are stuck in the middle of a frictionless surface. The answer is to throw your shoe (or any other piece of clothing). You will accelerate in the opposite direction of the shoe. Ion drives work in the same fashion. They just use a smaller shoe.
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crashfrog Member (Idle past 1489 days) Posts: 19762 From: Silver Spring, MD Joined: |
The controlled explosion of fuel in the combustion chamber causes gas to push outward in all directions. In the forward direction it encounters the wall of the combustion chamber, and it pushes against this wall, which being part of the rocket ship imparts a forward force to the whole vehicle. The forces of all the gas that pushes against the sides of the combustion chamber cancels out. There is no force from the gas that exits to the rear because the rear of the combustion chamber is open. The net of all this is a forward force. No, this isn't right at all. Space propulsion has nothing to do with gases being pushed off of anything, or pushing on anything. As Dwise says, it's all about conservation of linear momentum. On an object in space with no external forces acting on it, linear momentum is conserved. That means it has to be the same both before you fire your engine and afterwards. So, if your engine is shooting hot gas particles out that way at a certain velocity, then your space ship has to gain a velocity in the opposite direction, such that the momentum of the gas particles (their mass times their velocity) is canceled out by the momentum of your spaceship. It's conservation of momentum. It doesn't have anything to do with pushing. If you were to find the center of mass of all of the particles of gas you expended plus your spaceship after you fired your engine, you would find that it was exactly identical to the center of gravity of your spaceship plus its fuel before you fired your engine. Generally we're not concerned about this because the point of space travel is to move spaceships and their occupants to a specific place. We don't care about what happens to the fuel exhaust products once they've been accelerated away from the ship, so the fact that the total center of gravity isn't actually moving is just a bit of trivia. Rocket engines have a bell-shaped nozzle not because that's necessary to be "pushed" against, but to keep the gases from expanding too quickly. There has to be some pressure in the engine nozzle to ensure combustion of the gases. Edited by crashfrog, : No reason given.
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Percy Member Posts: 22480 From: New Hampshire Joined: Member Rating: 4.8 |
crashfrog writes: No, this isn't right at all. Yes it is. And so is your explanation. --Percy
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slevesque Member (Idle past 4662 days) Posts: 1456 Joined: |
I think everyone is right here.
It's just that I think people are misunderstanding the law of conservation of linear momentum. This law is just an observation of what happens, and fortunately makes for easier calculations. You could say that the rocket is pushing against it's own exhaust, and it just so happens that linear momentum is conserved. Even if it would not be conserved and some of it were 'lost' somehow in the transfer, we could still move around in space, although we would have to throw away more 'shoes' then we do now. Conservation of linear momentum is directly related to Newton's third law, and IMO it is better to explain it as Dr.A did then through conservation of LM simply because such an explanation can lead down a slippery slope of misunderstanding what that law really is. (I'm feeling I'm not explaining myself well. Hopefully Dr.A will be able to explain this much more briefly and concisely) AbE I'll add a precision: Saying ''linear momentum must be conserved'' is very misleading as an answer because it doesn't have to be conserved. We do observe that it is conserved, but this is because when the two exert a force on each other, it is equal and this entails that linear momentum will be conserved. SO we move through space because one force provoques another, and because they turn out to be equal, linear momentum happens to be conserved. Edited by slevesque, : No reason given. Edited by slevesque, : No reason given.
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Dr Adequate Member (Idle past 306 days) Posts: 16113 Joined: |
Reminds me of the old physics question of what to do if you are stuck in the middle of a frictionless surface. Phone my high school physics teacher and say: "You gotta see this ... I've found a place where the formulas you taught me would actually apply ... if I was perfectly spherical."
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Dr Adequate Member (Idle past 306 days) Posts: 16113 Joined: |
The teeth are wrong. If you reduce the size of the upper canines you have what appears to be a bear or some such. The rear teeth look like what are called carnasial teeth. These are not found in fish. It was the teeth that aroused my suspicion, but then I don't know very much about fish dentition. But they look too mammalian to me. There are more pictures of it here about 1/3 the way down.
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Coyote Member (Idle past 2128 days) Posts: 6117 Joined: |
Dr Adequate writes:
In those views the rear teeth look a lot more like primate teeth, and not at all like carnasials (such as are found in dogs, for example). The teeth are wrong. If you reduce the size of the upper canines you have what appears to be a bear or some such. The rear teeth look like what are called carnasial teeth. These are not found in fish. It was the teeth that aroused my suspicion, but then I don't know very much about fish dentition. But they look too mammalian to me. There are more pictures of it here about 1/3 the way down. Still not something you would find in a fish. Religious belief does not constitute scientific evidence, nor does it convey scientific knowledge.
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Granny Magda Member Posts: 2462 From: UK Joined: Member Rating: 3.8 |
Hi Doc,
Whilst I agree that it's not natural, I don't think that it's a photoshop job. I think it's a model. A Jenny Haniver of sorts. The back of a fish, stretched over a modified mammal skull. Mutate and Survive
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xongsmith Member Posts: 2587 From: massachusetts US Joined: Member Rating: 6.5 |
Coyote writes: Dr Adequate writes:
In those views the rear teeth look a lot more like primate teeth, and not at all like carnasials (such as are found in dogs, for example). The teeth are wrong. If you reduce the size of the upper canines you have what appears to be a bear or some such. The rear teeth look like what are called carnasial teeth. These are not found in fish. It was the teeth that aroused my suspicion, but then I don't know very much about fish dentition. But they look too mammalian to me. There are more pictures of it here about 1/3 the way down. Still not something you would find in a fish. I suspect something they built, rather than photoshopped. Sort of a Piltdown fish. - xongsmith, 5.7d
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bluescat48 Member (Idle past 4211 days) Posts: 2347 From: United States Joined: |
I suspect something they built, rather than photoshopped. Sort of a Piltdown fish. Maybe by the same banana brains who came up with the crocaduck. There is no better love between 2 people than mutual respect for each other WT Young, 2002 Who gave anyone the authority to call me an authority on anything. WT Young, 1969 Since Evolution is only ~90% correct it should be thrown out and replaced by Creation which has even a lower % of correctness. W T Young, 2008
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crashfrog Member (Idle past 1489 days) Posts: 19762 From: Silver Spring, MD Joined: |
Yes it is. How, for instance, would your model be different than this?
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