The reason that brown dwarfs are found in binary systems is probably because they are too faint to see on their own. It was only fairly recently that we could rule out Nemesis, which was a hypothetical brown dwarf star orbiting around Sol.

One annoying thing about blackbody radiation is that is still looks like blackbody radiation after Doppler shifting. It's why the CMB has a blackbody temperature of 2.7K, even though it is coming from ionized hydrogen.

Temperature is a statistical quantity that happens to be proportional to average energy in a system of particles following a Maxwell-Boltzmann distribution. However, it is not proportional to average energy by definition. If the gas has a non-zero average velocity in your frame it is not following an MB distribution, so it's temperature is not proportional to its average energy in your frame.

As a side note, you would observe blackbody radiation that was red- or blue-shifted depending on your motion that could make the gas appear warmer or cooler.

No, for the same reason that going from low to high doesn't transmit all that energy into the pressure. Neither pressure nor motion can have a sudden discontinuous change.

Sound results from a combination of particle motion and pressure. The motion changes the pressure, the pressure changes the motion. Impedance is how those two are related; a high impedance means that acoustic waves have higher pressure with lower motions, low impedance means low pressures and high motions. With the exception of things like firm barriers (which can be seen as regions with infinite impedance), neither pressure not motion can make a discontinuous jump.

When a wave encounters a barrier, waves face a dilemma. First, since impedance is changing, and impedance is the relationship between motion and pressure, one or both of those must change. Second, neither can change suddenly. The solution to this is that the discontinuity applies to the wave as a whole, not one particular ray, so if you have two waves within the two different mediums (Ie one reflected and one transmitted), there is a wave combination that satisfies both requirements.

​

A more physics based answer: Consider the case of an open-closed tube. You are intuitively seeing why the sound bounces off the closed end, because the particles cannot physically move through that barrier. That barrier will provide an additional pressure to ensure that the motion at that point goes to zero. If you send a wave pulse to that end of the tube, the back of the tube will push back hard enough to stop the displacement of the particles, but it cannot do that without also pushing back hard enough for the velocity of those particles to go back, causing a reflected wave pulse going the other way. The open end would seem to let particles move freely, but the open end is fixed to atmospheric pressure*, so the (gauge) pressure of the wave at that point will have to be zero*. The wave pulse sent that direction will not have the expected resistance to its motion that it had in the tube, and as a result the air will move in mass out of the tube, but will do so in the form of a pulse traveling back into the tube. The pulse traveling back into the tube will have the same direction of particle motion, opposite direction of pressure.

​

*In reality the atmosphere does not have zero impedance, just a lot less than the air in the tube, which is why mouth effects comes up when trying to apply this

Take a bunch of measurements all over the world and do a weighted average.

Welp, that's what I get for thinking phone=voice, and looking at those channels (and even then ignoring that carriers have started using data channels to carry voice).

Those bands still don't intersect any of the Wifi bands. The BRS band comes close to Wifi 2.4GHz band, so a new cell jammer could block old an old wifi router if the jammer was either poorly designed, or designed to block wifi as well

Amorphous solids are not liquid. They are amorphous solid. They have properties of both solids and liquids, but they are neither.

There are far more than 7 states, and it is pretty likely that any list you or I or an expert in the field could come up with would be incomplete 20 years from now.

You are dying on the hill of 'There are more than four states of matter, but we must place everything in one of those states'

It may vary with location, but in the USA the lowest wifi frequency is 2.4GHz, and the highest cell frequency is 2.2GHz

It is similar to both liquid and solid. If we were sticking to the big 4, it would reasonably be a solid. If we are allowing an expansion of the defined states, it would be a separate state that is neither liquid nor solid.

Edit: Note that in the article they keep switching between calling them 'solids that behave like liquids' and 'liquids that behave like solids'. Suggesting that neither category is really applicable.

Glass is not a liquid. It's either a solid using the grade-school definition, or in a separate state of matter that is almost, but not quite, solid.

Still the generally accepted answer. One fairly recent modification is that it looks like Theia hit Earth twice. Still not a perfect theory: some isotope ratio studies don't quite match the model, and our computer models of the collision suggest Theia was going slower than we would reasonably expect (Which itself could mean that Theia started life as an Earth-Trojan