Wonderful answer I thoroughly enjoyed reading that. You must have some sort of background in this stuff?

So going beyond the magnetic shielding concept, what about the idea that an active core and volcanoes are required to release the gases into the atmosphere in the first place?

Edit: scratch that I just seen your other comment answering that question already.

Losing the requirement for having an active core, I would assume, would drastically increase the number possible habitable worlds out there.

This is fascinating stuff to think about, even though it is basically completely irrelevant to day-to-day life.

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That makes sense, since captured gas would basically be mostly be hydrogen, other vital gases would have to come from solids or gases trapped in the solids that created the planet, which will need an active core and volcanism to release.

The important thing is that he wasn’t trying to work out why apples fell from trees, if there is any truth to the legend at all, he was just inspired, by an apple falling, to come up with gravity.

This isn't correct beyond a surface reading.

We know that quantum mechanics and general relativity cannot both be correct, because they conflict with each other.

But more probably, it seems like both are incomplete. There's a lot of unexplained stuff in space too - like dark matter, where some people propose a modified set of gravitational laws to explain motions instead introducing dark matter (which has never been measured). Very theoretical of course.

But we also have been completely unable to add any sort of gravity to quantum mechanics at all. The accepted models of QM more or less ignore gravity entirely because its power is negligible at quantum scales anyway.

What we know is that the extremes - extremely tiny scales, extreme velocity, extreme gravity - has complicated laws of nature, which happen to trend towards simpler forms as conditions approach everyday life. But you can't really conclude anything else based on that.

> Some physicists are questioning if General Relativity is totally accurate. It's a great approximation, but Quantum Theory may be an even better description of the Universe.

This is just nonsense. The two theories are describing entirely different things. Describing "the entire universe" is outside the scope of general relativity, which only describes gravity. Meanwhile, describing gravity is outside the scope of most Quantum Theory, and those that do include gravity lead to inconsistencies - or even worse, contradictions.

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>A brain's processing power isn't connected to brain size.

I mean there's some connection. A roundworm with 302 neurons can't process as much as a fly, which can't process as much as a mouse, which can't process as much as a human.

But it's not at all a 1:1 variation. Especially since neuron density can vary enormously in brains of different species.

But if you eat collagen, wouldn't it break down into the same amino acids that it could later be rebuilt from?

That's not Newton's gravity, that's Einstein's relativity. Newton's simply posited that massive objects pulled things to them, not that they warped space-time.

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I still don't understand why .6c plus .6c cannot equal 1.2c, I only know that it can't.

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Well yes and even a little bit humoristically according to relativity there is no real gravitational force existing between objects. Mass is just bending and curvature of the spacetime. So the bigger object the more curvature on the fabric of spacetime and smaller objects fall in to them, because of the curvature. In the end Newton was actually wrong with gravitation.

This is one of several reasons the heliocentric theory took so long to catch on, despite being proposed as far back as the ancient Greeks. The existing conception of physics described above fits quite nicely with a geocentric universe, but doesn't mesh at all with a heliocentric theory. You need a whole new sort of physics (like gravity) to make sense of that.

Incidentally, this also means that Earth's position at the "center of the universe" in the geocentric theory wasn't quite as special as we sometimes think today. The earth was at the center, but the center wasn't necessarily seen as the "best" spot, it was more at the bottom of the cosmic pile, the place where all the dirt falls down to. The outer regions, aka the heavens, were often considered the "best seats" (due to their association with, well, heaven). There was often thought to be a "Fifth Element" (yes, the movie got its name from this idea) that inhabited the highest reaches away from earth and was what the stars and planets were made of.

This also means that the movement of the planets was seen as a fundamentally different sort of thing than the movement of apples. Apples were following the nature of earth, going toward the center. Planets were following the nature of their element, moving in perfect, ordered circles in the heavens.

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Collagen is digested just like any other food: very simply put, your body breaks it down into its constituent parts and uses those parts in a manner that the conditions in your body demand. The thing is, a lot of tissues in your body are built from the same kinds of substances, so once you digest that collagen, there is no guarantee your body will use its constituent parts to create more collagen. That doesn't mean eating collagen is meritless: it contains valuable amino acids. But your body isn't necessarily going to use those amino acids to create the same kind of connective tissue.

Cooking meat denatures the proteins that it holds, which actually helps their bioavailability. There is the thinking that cooking the hell out of something will reduce the amount of usable protein, but I don't remember ever seeing any hard data about this.

Momentum is only conserved in aggregate when there is no external influence. Parts of the system can still transfer momentum between each other. It's quite permitted for us to change our momentum, as long as other things have a change in momentum that is equal and opposite to our change.

I don't have specific sources for "net momentum of the universe is zero in the CMB frame of reference", but it sounds like a good expectation. If we found a way to test that, it would provide either a confirmation or open new scientific questions. Unfortunately, as the observable universe is only a subset of the whole universe, I suspect that we cannot determine the net momentum of the whole universe.

The momentum of the Earth, or a vehicle, or the Sun, or our galaxy, could vary from the aggregate due to any number of interactions. For instance, the Earth orbiting the Sun must involve the Earth and Sun having different velocities, so they can't both match the CMB. As it happens, neither does.

Even pointing a flashlight into space would cause a tiny change of momentum for the Earth: the outgoing photons have momentum, so the flashlight (hence the Earth, indirectly) must experience a change in momentum in the opposite direction.

in newton's time, astronomers had figured out that the earth and other planets go around the sun.

what they didn't understand is why. obviously the sun illuminated the planets, but what made the planets go around it? one illustration showed angels pushing the planets in their orbits. another idea was maybe the sun was magnetic. newton's revelation was that gravity, which made apples fall, was the same force that made the planets orbit the sun.

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Probably not even that. Venus will have lost most of it's hydrogen as it stopped having liquid water. Which is a chicken and egg problem sort of, because the presence of life protects against that, by providing a sink for CO2 and by generating an ozone layer. the former keeps the water liquid (allowing oceans to store more CO2) while the latter protect water in the atmosphere from photo-dissociation

A magnetic field also may not help that much either. Hydrogen is light enough that the Earth losses it anyways. As long as the hydrogen remains as water, its not going to be lost that much faster. Meanwhile a run away green house effect would still end with Earth striped of its hydrogen over time. It'd just take a bit longer.

There’s nothing we’ve found that says it has to have the value that it does, or that it can’t change at all, so it’s not completely out there to investigate the maths of if it did change over time and whether that predicts anything measurable.