Starship Asterisk*

zloq, I need to apologize to you. I sounded highly critical of those who question the idea that a hammer and a feather would fall at equal speeds, but your reasoning is interesting and your questions valid. Ann Thanks Ann. I did notice your earlier tone was kinda harsh, but I thought maybe you mist...

Yes - keep it simple by bringing in quantum effects. My point was that you said "exactly equal" twice in a single note - and all along I have been saying the difference in fall time is nonzero, strictly based on Newtonian mechanics. My hope is that kids in grades 6-8 are given a correct ex...

And if you do that, you need to consider that there will be a point where the mass difference between the dropped objects and the large body is so large that the difference in velocity is less than 10 -43 seconds, which means that the two land at exactly the same time. Or, you can just recognize th...

I clearly have failed for you - but I am not concerned about that. I don't know how to make this more clear for others: a videocamera on the moon recording a falling hammer would see it fall fairly slowly. A videocamera on the moon would see the earth fall much faster. There is nothing subtle about ...

The video is meant to demonstrate a *theory* in action. I am talking about the *theory*, quite separate from the experimental difficulties of measuring small, but real, effects. Just because an effect is difficult to measure, or swamped by noise *in a measurement*, it doesn't mean it isn't playing a...

I am discussing correct theory vs. incorrect theory. The video on the moon is meant as a demonstration of theory in action, and I think it should be explained as follows: The equivalence principle says that one mass in the gravitational field of another mass will feel a force proportional to the pro...

I think it's important to separate an accepted principle from the complexities that result when that principle is applied to a dynamic process. As a principle, it is regarded as an absolute. When applied to a time-dependent two-body problem, the results are not absolute at all. The principle is abso...

Actually no - I don't get how this is somehow confused with the moon landing hoax, for example. People are bringing in other complicating effects that would make it hard to measure this effect - but they are outside the Newtonian realm of the demo. Deepstar1 showed insight that - surely - something ...

I'm describing everything in the specific context of Newtonian physics and the equivalence principle - which is also the context of the demonstration. This thread, and the demonstration, imply in very absolute terms that a fundamental principle of nature will cause the falling of one body onto anoth...

I don't see evidence in this thread that it is obvious - since the implication throughout is that the fall time is independent of mass - due to the equivalence principle. You both brought up esoteric compounding effects, which aren't needed as complications when simple Newtonian physics plays a role...

I'm just talking about simple Newtonian physics - nothing else. No photon pressure or rotation. A big spherical, solid moon and a small, spherical solid mass dropped onto it. A heavier mass will hit the surface in less time than a lighter one. This is a small effect, but it's worth noting here since...

People were talking about measuring the times really carefully. If you did - sure - you would find that a heavy object dropped by itself will hit the ground sooner than a lighter object of the same size - with or without air resistance. No relativity involved or anything.

zloq

Can you provide a reference to such a tube - either for purchase or that someone built in a lab? If you have expertise in the topic area - I assume you have references. If it is trivial to make such a tube - and you have done it yourself - surely there is a paper or product somewhere. Can you descri...

You saw the green of [OIII] glowing in a tube in "the lab?" Yes. I have a set of spectroscopic reference tubes, which are interchangeable in a lamp fixture. Do you know where I can buy a tube like that? IIRC, mine came from Melles Griot about 20 years ago. The lamps themselves have "...

We need to distinguish the possible range of perceived color when viewing an OIII source with the range that is possible when viewing an OIII astronomical source. The example of bright green I gave was looking at a reference tube in the lab. You saw the green of [OIII] glowing in a tube in "th...

In this Hubble palette image, the orange foreground star and the blue stars inside the nebula all seem to be more or less the same color: Hi Ann- That's a good example of what I'm talking about. The key thing to note about the image is that it has a full range of hues - from red to blue to green an...

Take the 10,000K blackbody and look at the filter intensities, convolved by the filter widths; take the square root of the values to allow for the transfer curve used, and you get almost exactly the R, G, and B values that can be measured off the published image. The Hubble palette is mostly used i...

But otherwise, your analysis is very similar to mine, and comes to the same conclusion, so I guess we are largely in agreement. Umm - no. You said the filters are 5-10nm wide... and you didn't consider the different bandpass as being very important in how much continuum gets through. I pointed out ...

Narrow band filters have notches that are 5-10nm wide. With nebular emission sources, the very narrow emission line dominates, because it is usually much stronger than reflected or scattered continuum light. But for stellar sources, the continuum energy around the emission/absorption line dominates...

I think the reason that most stars have a similar color is largely unrelated to any emission or absorption at the narrow bands chosen. I think it is mainly just a consequence of where the three wavelength samples are coming from on the similar blackbody spectrum shared by most stars. The magenta is...

I'm sorry - but that is only a statement of your opinion of models - not a statement of models themselves. I'm not sure what that means. I only pointed out that there are now some very complex models describing the behavior of meteoroids throughout their atmospheric phase, and those models have bee...

In fact, there are some very good models now describing the behavior of meteors in the atmosphere. I'm sorry - but that is only a statement of your opinion of models - not a statement of models themselves. The issue isn't terminal velocity vs. hypervelocity - it is terminal velocity vs. something w...

It is perfectly reasonable to consider all meteorites to be falling at terminal velocity, unless we are specifically talking about rare cratering events. I think it's important to distinguish simplified models of typical scenarios from what can actually happen in the complex situation of a large ob...

Kinetic energy of a 1 kg meteorite at 90 m/s terminal velocity = 4,050 Joules. You are assuming the object has reached its terminal velocity. If it explosively fragmented from a much larger, faster body say 1km above the ground, it would only shed part of its velocity from drag before hitting the e...

I've never really seen anything formal. I've done the calculations, and I've seen others do them as well. It's one of those things that comes up from time to time. There are quite a few papers on the temperature of meteoroids in space. Wylie in 1934 confronts the notion that meteors are fireballs -...