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!

So when someone screetches their chair I literally feel the ground below me vibrate while I'm lying down on the couch.

I feel like it's from downstairs but does that even make sense?

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 )

Which would work best?

It's currently cold outside. I noticed someone left the bottom window fully open. People on the 4th floor complained about feeling a draft. Now I'm wondering how this works.

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?

Hi scientists of lemmy, I'm a computer scientist with basic college level physics and an interest in physics.

I was reading Cosmos by Carl Sagan yesterday and he mentions that if you use a Geiger counter next to an uranium ingot you will detect the uranium's spontaneous decay as a stream of helium nucleei.

Does helium nucleei mean 2 protons and some number of neutrons? What happened to the respective electrons? Does this mean that each uranium atom, with 92 protons, entirely splits into 46 helium nucleei or does it release some number of helium nucleei leaving another element behind? How does the concept of half life play into this? Does it mean that in a uranium half life, half of my ingot would've become helium? Finally, how is this stream of helium nucleei so dangerous to living beings?

Thanks for your attention

Wolfram alpha has a sunburn calculator:

https://www.wolframalpha.com/input?i=time+to+sunburn

I'm out in the sun much longer then the calculator suggests, but I dont get burned.

How do scientists predict the future climate? Do they just calculate the current trends of temperature growth and take the causes of it into account? Or is there some other way. Is it basically some model y = a1*x1 + a2*x2 + ... or something more complex?

You can look at certain structures in one animal and show how they're made from repurposed parts of an earlier animal (like fish gills becoming human ears). Can that be done with humans and those animals with Xenomorph double-mouths? Can you say "in humans, this particular piece of tendon in the neck is what eels reused for an additional mouth" or something along those lines?

Thanks for your time!

If the answer is YES, a related follow-up question: if each visible color of the spectrum were to measure a centimeter in width, how far would I have to move the sensor from the red to detect the change from infrared to microwave, then to radio?

In the knowledge that Sir William Herschel discovered infrared by repeating Newton's experiment, but with a thermometer to measure the temperature of each component of the spectrum, and after placing the thermometer a bit to the side of the red light, in darkness, noticed quite by accident that the device would still register heat, therefore an invisible yet very real component of light was there, warming the thermometer.

Energy in physics feels analogous to money in economics. Is a manmade medium of exchange used for convenience. It is the exchange medium between measureable physical states/things.

Is energy is real in the same way money is? An incredibly useful accounting trick that is used so frequently it feels fundamental, but really it's just a mathmatical convenience?

Small aside: From this perspective 'conservatipn of energy' is a redundant statement. Of course energy must be conserved or else the equations are wrong. The definition of energy is it's conservation.

Now I'm just being the curious layman here, but a Google/YouTube search proved fruitless.

I keep seeing commercials for Gross Pointe Garden Society it made me wonder.