It is impressive how little heat escapes, mainly due to the extremely slow convection in the earth. This is a good thing because it has kept the iron core fluid for billions of years and a magnetosphere that protects against loss of hydrogen and water in the process.

An active core will release gasses to be accumulated on the surface of the planet through tectonic activity and volcanism. It will also generate a magnetosphere under the right conditions, which again shield those gasses from being blown away by stellar winds - but this is a very minor factor compared to the venting of gasses from an active core.

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This is a slight simplification. The heat flow from the Earth's interior to the surface is negligible compared to the heat recieved from the Sun, but if the Earth orbited much further away (say, if you swapped Earth and Pluto around), internal heat would represent a much more significant contribution to surface temperature. But that temperature would be very low, well below what known complex life could survive.

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>it does make it possible to have atmosphere

You mean a magnetosphere protecting against solar dissociation. This isn't exactly the case, you would still have an atmosphere, you'd just lose the lightest elements like hydrogen. This is bad for earth because it would end up with an atmosphere and surface devoid of water like Venus.

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The laws of physics do not specify an absolute velocity, and the speed of light is a maximum that any observer can measure any object going, no matter how fast the observer is going relative to some reference point.

The important context here is that velocities do not compose by simple addition, but by a Lorentz transform. If I see two objects moving away from me in opposite directions at half the speed of light, those two objects will see each other moving away at less than the speed of light. This is where you also see phenomena such as time dilation, length contraction, etc... come from.

To expand on this, Aristotle believed that all matter was made up of a mix of four different elements: fire, air, water, and earth; in that order. Things wanted to return to their natural place.

The Sun was above the air of the sky because fire was naturally above air. If you created a fire here on Earth, one of the effects was that sparks would rise, and this was seen as the element fire naturally seeking its place above the air.

Rain was element water that got above element air, and wanted to be beneath it. That's why rain fell. Your average objects, like a rock or a piece of metal, would fall because they were made of element earth. Thus they were naturally attracted to earth, and if they find themselves unsupported in element air, they will naturally fall.

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It can deflect solar winds to mitigate their stripping away the atmosphere, but you can have atmosphere without an active core.

He put numbers to it which required developing calculus and building on Galileo's and Brahe's/Kepler's observations.

Did you not read the question before answering or did you just feel like being obtuse?

I did the math a while back- you have to be crazy close, like 100s of km, to a merger for the gravity waves to affect you directly. /u/StandardSudden1283 Even a 'cold' pair of BHs (no accretion disk) would kill you from tidal forces at a much greater distance.

The article/u/kanrith links to suggests the waves could cause earthquakes or something on the planet you're on, and so indirectly hurt you, but its not verry convincing.

Yeah. People figured out "earth pulls stuff". He blew it open to "all stuff pulls all other stuff"

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I'm happy to be corrected. Mostly I wanted to push back on the myth that proteins are somehow digested into some sort of universal protein sludge that's completely interchangeable.

My primary point is that we get glycine from collagen and that we need it because we can't make enough. I'm sure your expertise exceeds mine, but do I have that right?

I have a slightly related question. Because we are basically seeing back in time, the net velocity of the CMB is basically the same as the net velocity of the big bang, right? However, by conservation of momentum, we know that the velocity of the center of mass of any system is conserved. So it should be conserved from the big bang up until now. Thus, shouldn't our velocity with respect to the CMB match our velocity with respect to the velocity of the observable universe's center of mass? Does it?

That's a great point I hadn't considered, thanks!

The second point still breaks my brain, but I'm happy to take your word for it that both are true.

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