I got to thinking last night that theoretically, with enough hair, the air resistance would slow you down so that your terminal velocity would be low enough to land unharmed. How long would it need to be? How would one go about calculating this?

I assume you need some kind of drag coefficient and a density for hair to start with. Not sure where to find that information.

I mean if every variable aligns with any possible edge case that can bleed off velocity including three body interactions with the moon. Is there ever a situation where some substantial (car++) or enormous (skyscraper+++) size rock lands on the surface without explosive energy? Align stars, consult math mediums, play some ZZ Top, piss off Bary the narcissist, or conjure a primordial black hole, just land me a big rock in my yard Science Santa. I want an m-type for Maymass, but any type will do if you can land it.

Why is the spring strengthened in the middle?

It doesn't seem to affect the spring's buckling characteristics.

My speculation is that it's to reduce spring noise. That strengthened region at the middle is where the spring will buckle outwards most, resting against the barely visible side rails on the inside of the case. Instead of just one wobbly contact point it now has three rigid ones as a "skate" to reduce the stick-slip noise when opening and retracting the tip. Is this right?

(The pen is a Mitsubishi Uni-Ball Power Tank, pretty much my favorite model.)

How does the Moon influence the stability of the Earth's axial tilt and how does this affect long-term climate conditions and seasonal variations on the planet?

(Note: I'm not talking about FFI, but healthy people.)

It's said that we need sleep because waste products, such as adenosine (which is a CNS depressant) build up in our brains while we're awake. When we sleep, the glymphatic system activates and flushes it out. Too much adenosine is known to cause a slower heart rate, the body temperature to decrease, immune system to weaken, hallucinations, and more.

I read about how a Chinese guy (in 2014 or 2012?) deliberately stayed awake for 11 nights with no sleep at all to watch the world cup, and he died. The articles said he died of sleep deprivation.

Here's the part which confuses me. I understand why too much of a CNS depressant waste product in your brain would be deadly, since it'd supress vital functions such as breathing, heart rate etc. I'm just wondering why it wouldn't make you automatically pass out and sleep, long before it got to that level as it's something which very gradually builds up in your brain the longer you're awake.

My kid got a little round box of soapy solution at the fairground with a wire loop to blow bubbles with. She was pretty excited with it for few minutes, then lost interest. Kept it on her desk when she got back home.

The next morning, she tried to blow some more bubbles with it, but the soapy solution appeared to be as dead as plain water, i.e. zero bubbles came out when she tried with the wire loop.

What kills the "bubbleness" of soapy solution over time ? The concentration of the remaining solution should've remained the same since the box was closed shut overnight.

Hey, so I just watched the Veritasium video "Something Strange Happens When You Trust Quantum Mechanics" (https://www.youtube.com/watch?v=qJZ1Ez28C-A), and it got me thinking.

The video talks about how light takes every possible path and ends up following the one with the least action. Super cool concept. But then, around the 30-minute mark, there’s this wild experiment where a laser is aimed at one side of a mirror, and there's a diffraction grating placed on the other side. Even though the laser isn’t hitting the grating directly, you still see light coming out from that side. That part really tripped me up.

So here’s my question: Where is the energy for that “other path” coming from?

My gut says energy has to be conserved, so if light is somehow taking a new path via the grating, does that mean the original laser beam is losing energy? Maybe it just gets dimmer?

But then I thought… what if you could make a really clever diffraction setup that always pulls light along some super-efficient path? Could you, in theory, siphon off light energy from a bulb on the other side of the planet without anyone near the bulb noticing?

And if the original beam's intensity is not lowered, then we would have generated free energy!

So is this really about energy moving along a new path, or are we just bending scattered light in a clever way to make it look like something more mysterious is going on?

And does this negate the "mirror test" idea? That is, an animal failing to recognise that the creature in the mirror is themselves, but can recognise themselves in water, shows that their problem isn't with the concept of reflectivity or "self", but something about the mirror's version of themselves that they can't quite grasp?

A follow-up question: Does an animal recognise its own shadow, and does this count as a kind of "self-awareness" when their shadow is moving around in the world but they don't lose their mind over it?

Thank you!

Hi there, I'm not familiar in this space at all which is why I'm asking in this community to understand it better from a science perspective.

So the way I understand it they haven't created a 100% exact genetical copy of a dire wolf since they don't have a complete DNA sequence that's fully preserved and intact.

Apparently they made 20 edits to the Gray Wolf genes which I assume aren't all the edits needed for a fully genetically identical dire wolf.

So my question is if that means that the wolves they created are overall still more similar to a gray wolf when you could go back in time and compared them to actual dire wolves. Or did they actually make the core changes that are so significant that the wolves overall actually are more similar to actual dire wolves and therefore naturally fit into that ecosystem niche that gray wolves don't?

And even if they're more similar to actual dire wolves than gray wolves and naturally fit into that ecosystem niche I wonder if they would still have some perceivable differences. Like if we could travel back in time and compare them to the dire wolves created by evolution, is it likely that we would find any differences or are these only neglectable genetical differences that don't have any effects on any perceivable aspect in their nature such as behavior, appearance, cognition, capabilities etc. or would there still be small differences that would differ from the majority (individual differences neglected of course)?

It seems a little odd that other crops have been cultivated to literally suit people's tastes and interests, yet many trees...Seemingly not as much?

I recognize the growth cycles are much longer, in some(many?) cases far exceeding individual human lives, but whole civilizations have been relying on trees for ages. Have none, not even isolated parts of them, been stable enough to take on this experiment?

I have a small hard drive that is making a constant high pitched sound that is typical of the drive, and not very noticeable to the average person, but I have pain induced noise sensitivity. I am curious about how to calculate damping potential. As an initial guestimate, the frequency is very near to my maximum audible range and likely around 12kHz-16kHz. It is a little higher than the switch mode power supplies that I can also hear if it is dead silent in the room, although the drive is a higher amplitude. Addressing the noise with a solution is probably beyond the scope of anything I would actually do, but knowing how to solve it is far more interesting to me. (ELI15 )

I ask this question because of this comment chain (and totally not because I got down voted and my ego is too fragile, it is most definitvely absolutely positevly me asking for the science. I swear)

https://lemmings.world/post/23635250/14708515

If you can go through it, please do, there are some references for some claims, if not you can go through the following ai generated summary (if it helps, it is a local llama)

The original poster (sga) expressed concerns about the practice of trimming cat nails, comparing it to declawing and suggesting that it may cause trauma for the cat. Other users (Bamboodpanda and Chairman Meow) responded that trimming cat nails is a normal and necessary practice, especially for indoor cats, to prevent overgrown nails and damage to furniture. sga argued that cat claws are an essential part of a cat’s predatory nature and that trimming them may impair their ability to hunt and defend themselves. Chairman Meow countered that cat nails are not as robust as sga suggested and that trimming them does not impair their usability. sga provided several sources suggesting that indoor cats often engage in predatory behavior outdoors, despite being fed at home. SupremeDonut responded that the sources sga provided referred to free-range and feral cats, rather than indoor house cats. sga provided additional sources to support the claim that indoor cats also engage in predatory behavior outdoors. sga also mentioned the hypothesis that some amount of injuries or exposure to allergens can be beneficial for children’s immune systems, and provided a source to support this claim.

Lately SciAm has been running and re-running an article on social media, focusing on plastic cooking utensils, storage etc. as sources of microplastic accumulation in humans.

I'm not disputing that plastics in food prep do contribute to microplastic bio-accumulation - my question is, are these actually dominant sources?

Comparative numbers haven't risen to the forefront of my web searching.

If say 75% of our microplastic uptake is via water and food that was already contaminated (by landfill seepage and wind-borne urban dust) before it entered our homes, then telling consumers to replace all their plastic spatulas and storageware with wood, glass and metal ... is just Big Plastic shuffling off responsibility onto consumers, just like it did with the lie of plastics recycling.

https://phys.org/news/2025-03-dark-energy-rattling-view-universe.html

Hello, I'm not sure if this is the best place to post something like this, but here we go. The above link is of new findings from DESI (the Dark Energy Spectroscopic Instrument) that's been written about by a handful of news outlets this week, and the TL;DR is that the expansion of the universe might not be as consistent as previously thought.

My question is: Could it be possible for the overall universe to only look like it's expanding because the expansion is currently happening within our visible universe? And that in other portions of the universe, far outside of our visible universe, it might be stationary, or even contracting?

To put it another way, could it be possible that the universe as a whole is rippling or oscillating, maybe due to the effects of the big bang, and that our visible universe is such a tiny spec, that from our perspective it only appears that the entire universe is expanding?

I've watched a number of talks where astrophysicists have said that the big bang didn't start from a single point and expand outward like it's usually depicted, but that it happened everywhere all at once. So, from my limited understanding, it doesn't seem like that would contradict what we see from the cosmic microwave background (CMB).

Am I way off base here? Or is this one of those questions that simply can't be currently answered?

Thanks in advance.

Hi, I was wondering if polyphasic sleep is dangerous? What kinds of long term health effects could it have? Did anyone try it?