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Wow that was fascinating, and exactly the type of phenomenon I would like to learn more about, thank you!

Indeed, that's one reason to be highly skeptical of that study. The "cosmological coupling" doesn't make sense in the context of general relativity. The global scale factor is not locally even a thing. In certain cosmological spacetimes, the scale factor isn't even uniquely defined globally.

The authors motivate the cosmological coupling by citing the behavior of black holes placed in otherwise homogeneous universes. Such black holes grow over time, but they grow by accreting the surrounding fluids (which are present due to the assumption of homogeneity), not by magically eating the scale factor, as the authors seem to suggest.

The only interpretation of the black-holes-as-dark energy idea that might make sense relativistically is that black holes have a negative-pressure coupling to other black holes. Then as the black holes separate from each other due to cosmic expansion, the negative pressure feeds them mass. This achieves the same outcome without positing a magical coupling to the global expansion factor.

Calcium carbonate is vulnerable to attack by acids, so as the amount of acid in the water increases, the rate of reactions between the acid and the shells of marine animals goes up. This in turn means that the marine animals have to dedicate more resources to replenishing the shells to avoid death - and in a competitive natural environment "more" isn't always available.

The reaction is as follows: CaCO3 (s) + 2 H^(+) (aq) -> Ca^(2+)(aq) + CO2 (g) + H2O (l)

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Repeating a response I made to a similar question elsewhere in the thread:

Relative velocities of distant objects aren't well defined in curved spacetimes. It's often said that distant objects are receding faster than light, and there are standard ways of writing down their distance such that the distance grows faster than the speed of light. However, there is no relativistically meaningful sense in which these objects are moving faster than light in relation to us. Also, the distance isn't uniquely defined either.

In intuitive terms, the relative velocity is the angle between two vectors in spacetime. Imagine drawing two arrows on a sheet. If those arrows are in the same place, you can measure the angle between them. If they are in different places, but the sheet is flat, you can also define the angle between them uniquely. However, if they are in different places and the sheet is not flat, the angle between the arrows is not uniquely defined.

Recent study suggests otherwise doesn’t it? Yet to be confirmed independently I guess, but hasn’t it very recently been posited (maybe also evidenced) that black holes are driving expansion by returning energy to the quantum vacuum? Does this not mean expansion would indeed be physical?

"Being affected by gravity" and "moving along curved spacetime" are the same thing. That's the whole point of general relativity: gravity can be described as objects following geodesics in curved spacetime.

E=mc² is the formula for the specific case of a stationary, massive object. That clearly does not apply to a photon. The full equation is E²=m²c⁴+p²c², which simplifies to E=pc for a massless particle like the photon.

> unique scents that they can recognize

I swear, humans' poor sense of smell sometimes makes us like a blind person studying art, keenly aware of sculpture by hopeless at understanding paintings.

Imagine how much more we'd know about the natural world if we weren't almost "blind" to one of the most important senses of most animals.

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> Special relativity says that velocity measured in an inertial frame will never exceed the speed of light, but cosmologically distant galaxies are not inertial from our perspective.

We are in an inertial reference frame, so we are measuring from an inertial reference frame, it shouldn't matter what frame they're in, SR works just fine on accelerating objects, as long as the observer is inertial. If you meant to say we're not in an inertial reference frame, it's a very poor explanation, because that's just a No True Scotsman fallacy, but also just seems wrong? The whole point of inertial reference frames is that you can tell whether you're on one or not with a local experiment.

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I saw a study a few years back that indicated that dogs can remember thier siblings for up to 4 years of being apart. I cant find the video but this was tested by getting groups of siblings back together after varying timeframes. The ones who had been apart for over 4 years didn't seem to recognise each other anymore.

Not sure about parent/child relationships though and also not sure if this would count for seperate litters.

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Complete layman, so take this with a grain of salt, but isn't the relativistic view of gravity that it bends space-time? So when you're in free fall you appear to be accelerating with respect to the ground, but you're actually in an innersial reference frame, while the ground is accelerating upwards through ever contacting space.

If gravity contacts space, then of course it will counteract the expansion of space.

You seem to be thinking relativistically about the expansion of the universe, but Newtonianly about gravity.

Sufficiently distant objects have apparent recession velocities greater than the speed of light, but this doesn't break any physical laws. Special relativity says that velocity measured in an inertial frame will never exceed the speed of light, but cosmologically distant galaxies are not inertial from our perspective.

The CMB rest frame is the frame of a comoving observer, that is, one who is at rest with respect to their (cosmologically) immediate surroundings. At different locations, the CMB rest frames are different. There's no global "center of momentum frame" if the universe is homogeneous, only local ones.

(I should also note that in curved spacetimes, reference frames only make sense locally. However, this is more minor consideration, in a certain technical sense. While the impact of the difference in the velocities of different comoving observers scales linearly with their separation, the impact of curvature scales as the square of the separation. So the latter only becomes important at very large separations.)