Many religious arguments are about morality and ethics and how people relate to each other and life. The subset of religious arguments about science are sometimes made from ignorance, but not necessarily, as for example, when people disagree about abortion and stem cell research for religious and scientific reasons.
We’ve found quite a few. 20+ at last count, across all kingdoms. At this stage it seems like such mechanisms are universal. Do a Google search on evolvability.
I don’t see why you think the two are mutually exclusive. The number of surviving great, great grandchildren is just as much a measure of reproductive success as the number of surviving children.
ID could be good science. Although it would not be much use right now. There are many organisms on Earth right now that did not occur entirely from unguided natural selection. From glow in the dark bunny rabbits to poodle, humans have influenced or changed organisms in ways that could not have occurred in an unguided system. Right now, we have a good idea of which organisms those are, but what if civilization collapsed and all biological knowledge was lost? When the time came to redevelop modern biology, the need to identify bred or genetically modified animals would arise.
For that matter if we ever figure out how to get out of this solar system and find other life bearing worlds, identifying designed organisms may be be important in identifying ecosystems that once supported intelligent life.
Jonathan
I was somewhat taken aback last week when flipping channels came upon evolution denying, Intelligent Design promoting on EWTN, the Catholic cable channel. It was quite a show, I thought I was watching James Kennedy. Plitdown Man, no transitional fossils, Darwinist, materialist, blink of an eye emergence of complex life. The priest actually said “in the blink of a eye in geologic time” yea a few hundred million years but he did not say that. I have always been taught that Catholics accepted evolution but in the past few years there have been some troubling remarks from the recent pope now blatant evolution denying on one of the premier Catholic media outlets. I wonder if they are going to officially change over to creationism?
This second example you give is not really true. General relativity tells us that accelerations are indistinguishable. The only chance you’d have to separate the two cases is by waiting a long time. There’s no non-gravitational acceleration that can be applied indefinitely, so eventually the car in space will stop accelerating.
What about tidal forces? Acceleration is evenly applied. Standing on earth there is a minute difference in the force felt by your feet and your head.
The acceleration of the space car does not have to been evenly applied. I believe this can be done by using non-parallel rockets on the outside of the room.
Not unless one is attached to my feet and one to my head(and I would not need any fancy equipment to tell the difference if that were the case). The acceleration I feel is caused by the force of the floor on my feet. If I have two precision force meters, one at head height and one at foot height, both attached to the same metal stand, then I would get a different result in the two situations.
I’m not sure about that. The difference in magnitude in the gravitation case is due to the 1/R[sup]2[/sup] loss from spherical spreading. If the acceleration in the space case were designed to simulate the same spherical spreading, I think there’d be a similar loss.
Don’t forget your frame of reference is also being affected by the acceleration. The “down” direction varies inside the car in both cases.
The difference is that for a rocket to cause acceleration it must apply a force. It can only do that through physical coupling (pushing on the frame which is pushing on the floor, which pushes on the bottom of the stand, which pushes on the force meters). You would need to use a distance variable force field such as gravity or electrical potential, or have multiple physical attachments, not just to the hull of the ship, but to the things inside. And, again, I think I would notice if my head was attached to a rocket.
Pleonast, I’m not sure what you were saying. I thought that your comment about the non-parallel rockets was a joke, but now I’m not so sure.
Besides tidal forces, in the elevator car there would also be a slight difference in the direction of gravity on the left and right sides of the car - the vectors point to the center of the planet and wouldn’t be parallel.
The points raised by Pope Benedict have more to do with the philosophical debate than the science. When Dawkins and company claim that evolutionary theory does away with God, then the pope feels the need to say, “Does not.” Nothing published or spoken by the pope is in opposition to the science behind evolutionary theory.
As to EWTN, while it may be the “premier” Catholic network in the sense that it is pretty much the only network devoted to Catholic broadcasting, it has a very definite Right wing tilt to its programming and, being an American outfit, it tends to pick up a lot of American Right wing views–such as skepticism about evolutionary theory. EWTN is still a private company that is not an arm of the Catholic Church.
There is no major Catholic educational institution that fails to support evolutionary science. (I do not know of any minor institutions that do, but I will not be surprised if one turns up in Nebraska or near St. Louis.)
No, not joking.
I’m imagining the elevator car in space, with many small rockets attached to all sides providing the acceleration. The acceleration can vary the same way as the spherical gravitational force. That is, the sides of the car will not be parallel and will be accelerating in non-parallel directions.
In situations involving General Relativity, it’s not correct to consider gravitation to be a force. Instead, it’s a pseudo-force–dependent on the frame of reference. In this case, our frame of reference is accelerating, and not a simple linear acceleration, but one that is spherically shaped. The part that I believe is tripping you up is your implicit use of an inertial frame of reference.
Consider an inertial observer watching the contents of the space car accelerate past. If a small test particle is released in the car, the inertial observer will see it continue to travel with its initial velocity, because there are no actual forces on the particle. However, to an observer in the accelerating frame, the particle will appear to accelerate due to a force. If the rockets accelerating the car are chosen appropriately, this force will be indistinguishable from a gravitational force.
In the same way, the elevator car sitting on Earth is not in an inertial frame (even assuming a non-rotating Earth) because of the gravitational field. An inertial observer* would see the dropped test particle does not change its velocity, while the observer in the car will describe an accelerating particle. Indistinguishable from the other case.
*In case it’s not clear, an inertial observer is one that has no net external forces on them. In the case of the Earth-bound car, the inertial observer is in freefall–because gravitation is a pseudo-force, not an actual force.
I understand the point about accelerating reference frames. The problem is that an object at rest (in the relation to the system) inside an accelerating car is only acted upon by the normal force of the floor. No matter how many rockets of what type you use, the floor, and anything attached to it, is only accelerating at one rate. To reproduce the tidal force on a body in the system you have to have a way to couple a different amount of force.
Jonathan
The test I had in mind doesn’t require a hugely long period of time. Simply hold a weight in each hand with your arms spread and drop them. In a closed box accelerating in a straight line through space, the weights will drop in perfectly parallel lines. On Earth, however, their paths will ever-so-slightly converge as each is attracted to Earth’s center of gravity.
Different parts of the floor are accelerating in slightly different directions. The walls are accelerating in slightly different directions. Any motion, and thus any acceleration, is measured with respect to the floor and walls, and therefore any measurements in that accelerating frame of reference will observe a “force” that can exactly mimic the “force” due to Earth’s gravity.
The observed “force” is due entirely to the motion of the accelerating frame of reference. There’s no need for a physical mechanism. Pseudo forces are due entirely to the frame of reference.
Even assuming you can create a semifluid medium that has the structural strength to hold a person/and or test equipment, I am only standing on one section of the floor.
My head is attached to my neck, is attached to my torso, etc. Unless you can couple a seperate force directly to my head, there will be no difference in the apparent force at my feet vs. my head. I don’t care what the walls or the other portions of the floor are doing if I have a sensitive enough scale in each hand I will get a different reading by holding one up high and one down low.
Jonathan
The convergence is possible in the closed box if it is not undergoing linear acceleration. If the walls are ever-so-slightly accelerating apart (in an inertial frame), your measurements with respect to them will show the particles moving together.
I think you are not understanding the accelerating frame of reference. The pseudo force is not due to any physical mechanism, but the frame of reference itself. It doesn’t matter how things are connected. It matters with what frame of reference you are measuring things. How are you going to measure the “weight” of the object? Any method you use is going to depend on a length or time, which will depend on the frame of reference.
While they may both be true, I don’t see them as being true in the same way. Gravity is merely the name given to a force. We know is is there, we know what it does, but we don’t know HOW it does it. Science has no consensus (unlike with evolution) on the process of gravity.
Similarly, even those of us who acknowledge that species change and can eventually change into other species over time don’t KNOW that evolution is the sole process which causes that change (the force).
Wait, why wouldn’t the weights drop in a straight line toward the Earths center of gravity? What force would cause a dropped (non-propelled) weight to fall in a direction that’s not directly toward the earth’s center?