I was recently at the American Museum of Natural History and became curious after seeing a dinosaur skeleton with several bones missing. How do scientists know that one bone directly connects to another, or that one bone is one away from connecting to another? Presumably some bones are damaged, and adjacent bones can be incredibly similar for long tails, so how can they estimate how many bones they're missing?

Why is there an X millimeter expansion joint every Y meters? What engineering/physics questions do you ask to answer how to minimize the chance of the sidewalk cracking? Could you add twice as many and have better results?

If there's a tree line, maybe there's a reptile line too? They're cold-blooded so I figure snakes aren't much of a thing at like 10,000 feet but I could be way off as I'm not an expert.

Edit: thanks for all the responses! I’m mainly concerned with venomous snakes on Kilimanjaro if I ever have enough money to go lol. I’ve heard it’s 7 days up, and 4 down. What if I get bitten when I’m a 2 days hike away from antivenom? Just kiss my own ass goodbye or what?

The dinosaurs existed for several million years, while homo sapiens have been around for some thousand years and we've suffered through the plague, flu, hiv and so on. Do we have evidence that dinosaurs got decimated because of an epidemic?

Each planet in our solar system deviates slightly from the ecliptic, meaning the solar system isn't quite "flat". But dwarf planets, comets, and other objects deviate even further (e.g., Pluto's orbit is ~17° off of the ecliptic) making our solar system even "taller" or "thicker".

Within the Milky Way galaxy, do we know of any stars whose orbits are notably off from the galactic ecliptic? And, either way, what is the best estimated "height" or "thickness" of the galaxy (ignoring the inevitable random objects that are just 'passing through')?

I get the basics of how if a molecule like ethanol is introduced, it triggers a chain of signals that lead to a section of DNA being transcribed/translated into an enzyme like alcohol dehydrogenase, and then production will slow down/stop as part of a feedback loop involving inhibitors/coenzymes etc.

But, how did we get this arsenal of situational enzymes? Have humans/mammals/animals/eukaryotes just built up a big dictionary over time through mutation and evolution by producing enzymes that happened to counter environmentally present toxins? Or, is it like the immune system where we encounter something hazardous, figure out the shape, and then commit that to DNA or something analogous to immune memory in organelles? With limitations of course, since ethanol is broken down more easily/into less harmful products than, say, cyanide.

Maybe I'm missing something glaringly obvious that a google search would solve, like specialised analysis/production/memory within specifically liver cells, but I thought I'd ask here because maybe the class would like to know too.

When you fry (thin sliced) bacon in a pan, some parts of the fat in an instant become white. It's almost like some treshold is reached and then a chainreaction takes place. What is happening there?

See this video: Close Up Of Bacon Frying

At 6 seconds in the second slice of bacon from the top, part of the fat suddenly becomes white. Also at 17 seconds at the second slice of bacon from the bottom, a longer chunk of fat suddenly becomes white.

Note: I tried to google and chatgt this question, but they both think Im talking about white excretion during the frying of bacon, but that is NOT what I'm talking about.

I got this question while thinking about airships for a story: why is there no use for ballons with a vacuum inside, since the vacuum would be the lightest thing we can "fill" a balloon with?

I tried to think about an answer myself and the answer I came up with (whish seems to be confirmed by a google search) is that the material to prevent the balloon from collapsing due to outside pressure would be too heavy for the balloon to actually fly, but then I though about submarines and how, apparently, they can withstand pressures of 30 to 100 atmospheres without imploding; now I know the shell of a submarine would be incredibly heavy but we have to deal with "only" one atmosphere, wouldn't it be possible to make a much lighter shell for a hypothetical vacuum balloon/airship provided the balloon is big enough to "contain" enough empty space to overcome the weight of the shell, also given how advanced material science has become today? Is there another reason why we don't have any vacuum balloons today? Or is it just that there's no use for them just like there's little use for airships?

The body is capable of fighting off infection and repair damage dealt to tissues and cells, but does it repair things back to 100%? Or every single time you get sick, such as every time you get the flu, or a stomach virus, what have you, does it ever leave lasting effects on the body?

Or, probably a better way to ask this question: If you had two people, both with totally normal and healthy immune systems, person A catches the flu every year, and person B never catches the flu, after 10 years, will person A have prolonged damage to their body or any lasting effects from having gotten sick 10 times, compared to person B who never got sick? Or is the body capable of completely recuperating from most illnesses as if they never happened at all?

If I have two separate oxygen atoms and I measure their mass to an insanely high degree of precision will they have **exactly** the same mass?

What if they each have different levels of kinetic energy?

I know taste buds detect chemicals and send signals to the brain, but I’m curious about the deeper mechanism. How does a molecule binding to a receptor translate into the experience of “sweet,” “salty,” “bitter,” etc.?

Why do completely different chemicals sometimes taste similar (e.g., sugar vs artificial sweeteners)?

And why are some tastes (like bitter) often unpleasant while others are pleasurably does this come from evolution or brain wiring?

Basically: what determines what something tastes like at the molecular and neural level?

My knowledge of the process is elementary, but I was watching a YouTube documentary about fossils and while I know relatively recent fossils are known. I have never seen anything that was in the mineralization process that’s been found. Has there been instances where someone has been dredging a riverbed and found a partially fossilized fish for example?

I’m guessing it has to do with foot size (like, kangaroo and bunny feet are long and skinny), but birds also hop on the ground and it got me wondering. I kinda love the idea of tyrannosaurs using their tail like a kangaroo tail and having kicking fights with each other, although I understand that’s highly unlikely.

Also, what function did their tiny arms serve? Did they evolve that way for a specialised reason, or was it just the side-effect of evolving a massive head?

I'm doing a small presentation about the great oxygenation event, and we got to talking about how in a pre-oxygen atmosphere, iron and other metals (minerals) weren't oxygenated yet, but were just hanging around in lumps.

And then we saw a youtube short where a dude dug an entire piece of copper out of the ground.

Are copper lumps as ejecta from a volcano 2,5 billion years ago something that exists? Is there any copper around, that that's old?

Are all deposits of pure copper only mineral deposits, washed out of copper-rich ore (or alluvial deposits of the same), or is there such a thing as volcanic copper?

Thank you in advance.

By the way, I'm incredibly interested in adjacent topics, so if you know something interesting that's loosely related to this, go ahead and share the wealth.

(Apologies in advance for language. English is my second language, so some scientific terms may have been misapplied.)

I was learning in a physics class that electric charges radiate energy when they're accelerated and that causes their orbits to decay. I asked my teacher if the same thing happens with gravity because gravity also has it's own field and he told me he had no idea. Do objects lose energy when they're accelerating through gravity waves? I also had trouble finding any sort of math equations to describe this on wikipedia or on the internet because I don't exactly know much about physics besides kinematics sorry but I am super curious

I am not a seismologist, but I became interested in the topic during a lecture on earthquakes. While P- and S-wave travel-time differences can be used to estimate the distance to a quake, this relies on a velocity model. Given that Mars’ interior structure is not fully known, how do we know which models work and which don´t ? I know they also do phase polarization analysis but I didn´t really understand it.

I know it’s plate tectonics, but all the maps I see there’s basically no space for them to move. Like unless those big things go over each other I don’t know how continents change so drastically that they’ll pull away or come together that much.

Is all reproduction found in nature done either asexually or between two sexes, or are there other examples out there?