Those herds of migrating quadrupeds evolved from land-based quadruped ancestors, like most mammals. They already had an effective mode of locomotion for their environment that could develop and become more refined.

Our most direct ancestors were tree dwellers, with hands for hands and hands for feet, with hands and feet that were both built for gripping branches, and shoulders and hips that were both built for climbing and swinging. So as our ancestor's environment became less tree-dense, we came from a very different starting point that animals that were already quadrupeds.

For whatever reason, it was more advantageous for our ancestors to develop bipedalism rather than returning to being quadrupeds. There are lots of factors here, and we don't know all of them. One very likely factor is that, we already had limbs adapted for grabbing stuff, and having two limbs free for holding and carrying things has proven to be extremely advantageous for us.

There was a post a couple days ago where someone was staunchly asserting that space is not actually expanding and that objects really are moving away from one another kinetically, with multiple citations on the subject (which I didn't look too far into). There was a bit of discussion and a couple people agreed with them.

This was the first I'd heard about that. All modern material I've ever seen on astrophysics (the last twenty five years or so?) talks about the universe expanding.

How solid is the scientific consensus on this subject? Is it actually contentious at the moment, or was this person stating an belief that is currently kind of fringe?

Now that's interesting.

Have they identified any specific aesthetic traits that are involved in what makes a nest more attractive? I figure it must be a difficult thing to test, but I'm now very curious about convergent evolution of aesthetic tastes.

I've heard one interpretation that a virus particle could be thought of as analogous to a seed, and that an infected cell effectively becomes a virus organism.

Ahh, okay.

I think I have one more follow up question, about how the nutrients actually get from blood to the cells. I guess it's... capillaries have pretty broad coverage throughout the whole body, right? What's the furthest a living cell is likely to be from any capillaries?

This is making me realize a question I didn't know I had about the circulatory system.

How do the "delivery" vessels connect back to the "return to the heart" vessels? Does blood come out from the capillaries and then get taken up by other capillaries?

There are also multiple different "diseases" that are all caused by the same infectious agent (virus, bacteria, etc.). They just present completely different symptoms depending on various conditions such as the patient's age, how the infection occurred, etc.

I've never managed to get a straight answer I can wrap my head around for why light slows down in refractive media. Turns out "we don't know for sure and there's lots of heated disagreement on it" was the actual answer I needed. Thank you.

Do artificial satellites also experience this tendency to be pushed into equatorial orbit?

So, to make sure I'm understanding this correctly - One form of reactor has superheated water kept under pressure so it won't boil, and that superheated water heats another body of water that does boil, and then a different type of reactor directly boils the water without that intermediary step?

How does that compare to the further most reaches of the solar system? (Like, to the Heliopause? Is that the considered the edge of the solar system?)

In addition to the points everyone else has brought up, it's important to note that you're sort of always tracking moving objects with your eyes.

If you're not resting on something, your head is basically never completely still. Try moving your head from side to side while staring at one word in this sentence - your eyes will reflexively rotate on their own to stay locked on.

This isn't completely the same. Your vestibular system senses your head's rotation, and your eyes reflexively move in response to that, so they have a little more information to work with here. But essentially, it's just kind of the nature of our eyes to lock onto persistent visual objects, whether your or the object are the ones that are moving.

> The thing to understand about photons is that they are just little bits of electromagnetic energy.

This is a big thing to understand. Photons are essentially just little energy fluctuations. When they're absorbed, that means their energy is taken up by a charged particle (generally a proton or electron), and that energy is converted into another form of energy, which could be, for example, heat, electrical current, or chemical reactions.

Your outermost layer of skin cells is relatively safe from this because it's made to be less reactive and protect from outside threats like this (My detailed anatomy knowledge is fuzzy, but my understanding is that you're basically protected by a layer of keratin, which soap does not act on), but yes it does break down animal cells, and this is one of the main reasons that soap is toxic to ingest.

The coywolf is also an up-and-coming hybrid. A mix of coyote, dog, and two different wolf species that is becoming increasingly common.

So, are you saying that past a certain magnitude threshold, the force of gravity effectively causes the expansion of space in that region to stop?

As every day, Princess Elmyra spent her afternoon waiting by the lake, attended by an old woman. They repeat this same refrain every day.

"One day..." The princess says wistfully.

" One day, my lady," her attendant replies.

"Prince Tomason will return."

"So he will."

"And when he does," the princess placed a hand over her heart.

"When he does," the old woman said.

The princess raised a determined fist in front of her face, "I'm going to punch him so hard his grandmother will feel it."

"Very good, my lady," the old woman said, dutifully polishing the princess's heavy iron gauntlet.

I don't know the answer for sure, but the prevalence of farting in Humans is generally a consequence of microbes in our gut digesting our food for us and putting off gasses as a byproduct. There are other reasons gasses end up in your digestive tract, but this is the big one.

I don't know if ants are as reliant on microbes for their digestion as we are, but they definitely have less room for gas in their guts. But then, you'd expect ant farts to be tiny anyway.

I've been playing Control lately, and was just thinking this prompt reminds me of that.

The prompt is basically, "everything's gone to shit, but you discover you're the main character of a videogame".

A few other random orienteering tips I've learned. Plants will often lean one way or another in response to sunlight and prevailing winds. You can sometimes look for which way trees lean, or which side of a tree has thicker foliage cover to orient yourself.

If you're lost and trying to find your way, one of the best things you can do is find a clear, elevated spot that lets you survey the landscape (be very careful about climbing. The last thing you want when lost in the woods is a broken leg). Look for easily recognized landmarks, and look for signs of water. Knowing which species of tree grow by river banks can help, but you can often spot water by looking for especially lush spots in low lying areas. If you do find a water source, it's a fair bet that following it downstream will lead to civilization eventually.

Oh, that's really interesting. So that's perhaps the reason why we so often use spatial metaphors for time and for memorization?

As a resident of Albuquerque, how can I get involved in seeing RCV implemented here?

It's not like the story was written in the ancient past. The authors were well aware of solar eclipses.

The main idea was that it never gets dark on this planet. The darkest it ever gets is still significantly brighter than a full moon. Enough that before the eclipse event no one on this world had ever seen "the stars". Darkness is so alien to the people of the story that things like mining in dark caves are highly specialized and require a ton of psychological training.

Personally, I think the resulting madness when people see darkness and the stars is a little played up for drama, but I think it's not hard to imagine how terrifying darkness could be if you've never actually experienced it.

(The people in the story were also completely unaware that there was a universe beyond their solar system, and had no idea what to make of the stars)

Is that how the planet was set up? It took it more to mean that the planet was in a four or five star solar system, rather than just that there were enough neighboring star systems to illuminate everything.

What are th odds that, say, a brown dwarf could be lurking close, undetected?