At what point is a theory deemed an acceptable and valid model by the scientific community?
How we know when to distinguish between invalid data and limitations of a scientific model in astronomy (i.e. the superluminal neutrinos as an obvious invalid data)?
Given that astronomical objects are so outside the scale of human existence, how do we know that our understanding of them is accurate (similar to how quantum mechanics is so different from the behavior of everyday objects)?
Very good questions! Here are some brief answers, and we can discuss it in more detail in the class:
ReplyDelete1. Depends on the reason why we were unable to affect the outcome of an experiment. For example, history, geology, or paleontology, since the events studied happened in the past. Anything on a large scale, that we have no technology to affect, e.g., climate, evolution, all of astronomy. So what we can do is piece together the evidence, using the established laws of nature, and see if it fits.
2. When it can account for all the available evidence in a logical manner, and not violate any known and well established facts (note: facts, not beliefs). And then, if it can predict an outcome of experiments not yet performed. It is however understood that all theories are imited in their domain, and can be contained within deeper theories; for example, Newtonian physics is what theory of relativity predicts in the regime of small velocities (v << c), and weak gravitational field. Sometimes, though, a theory is shown to be completely wrong.
3. Repeated or new experiments. If independent measurements give the same answer within the errors, then the theory must be at fault.
4. We apply the known physics, and it seems to explain things well, and tests well against the new measurements. Then we can extrapolate what these models predict, and compare with the observations. The key here is that we observe various types of objects (e.g., stars, galaxies) in different evolutionary stages, so even though we cannot observe changes in any individual object over times >> human time scale, we can observe the behavior of _families_ of objects in different evolutionary stages.