At that point in Earth’s history, the atmosphere was a lot more oxygen rich than it is now! This allowed all sorts of creatures to grow to immense sizes, like trees, insects and dinosaurs. Dinos like Brontosaurus probably grew large for the same reasons Giraffes did too. The best greenery is the one no one else can get to!
grew large for the same reasons Giraffes did too. The best greenery is the one no one else can get to!
Recent evidence in the fossil record regarding giraffids suggests their necks did not evolve to be long for feeding purposes, but rather sexual selection / fighting for dominance with their necks and heads.
Not sure you got the oxygen part right. But I can say that since trees and animal breath each others exhaust, they won’t both thrive due to atmospheric oxygen concentration.
Real life quantum physicist here. When you say you want the uncertainty principle to be bigger, what you are really saying is you want Planck’s constant to be a bigger number. This has much bigger consequences than you might expect, because if nothing else about the universe changes (for example Coulomb’s constant) then the energy levels of atomic transitions all get out of whack, you break chemistry and chemical bonding, and there is no such thing as a basketball because there are no such thing as rubber molecules.
A good way of exposing this idea to people is showing them the step by step of how to get the particle in the box energy equation and then generalizing it for 3d.
It becomes really obvious the issues that happen when you have degenerate states.
The short answer is that it’s ultimately down to the number 43 (the number of protons technetium has) and the number of neutrons that could potentially form stable isotopes being atomically weird numbers.
The picture below shows relative stabilities of isotopes of different elements. N represents the number of neutrons, Z represents the number of protons. As a starting rule, moving above or below the N=Z line (creating an excess of protons or an excess of neutrons) tends to decrease overall stability.
You can see for lower atomic numbers, the most stable isotopes closely follow N=Z because protons and neutrons “balance” each other in the nucleus. But as you increase the atomic number (and therefore the number of protons), the protons begin to repel each other more strongly, which means additional neutrons are needed to make the nucleus stable. This is why the “line of stability” (the line of dark red “stable” elements) increases above the N=Z line as you increase the atomic number. Deviation from this line means an atom is less “beta stable” (and therefore more likely to beta-decay).
There are certain “magic” numbers of protons and neutrons that are more stable than others because they comprise a full shell. These occur at 2, 8, 20, 28, 50, 82, and 126. This means nuclei that have (or are very close to) one of these numbers of protons, or neutrons, or protons + neutrons, are inherently more stable. If you look at the other stable isotopes on the graph, you would expect a stable isotope of technetium would need around 55 neutrons to follow the line of stability.
As it turns out, the combinations of 43 protons and 55 (± a few) neutrons just can’t form a stable enough configuration to not beta-decay.
There’s also sickle cell anemia: IIRC it protects against something like the tse-tse fly or mosquito borne illnesses native to parts of the African continent
I believe that it offers a degree of protection against malaria. Or, enough protection that you live long enough to reproduce before dying a terrible, agonizing death.
Because you’re ears evolved to hear sound in air. It’s an interface problem, not a transmission problem. Same with speakers and microphones, they are designed to be used in air.
So if you want to actually hear the sound, stick with air.
If you just want to transmit some information via sound, a dense solid like a metal will give you the best speed and distance.
Greater availability and affordability of unhealthier, more processed foods filled with carbs and fats and devoid of other nutrients. Car culture that discourages natural amounts of walking in a daily routine. Sugar, caffeine and alcohol addictions with advertisers preying on people vulnerable to addiction of every kind.
I was with you until caffeine. How does caffeine addiction contribute to the obesity epidemic? Are you talking about addiction to caffeine leading to people consuming more sugary soft drinks?
I’m probably being naïve because 100% of my caffeine consumption comes from black coffee and tea.
Yeah I’m mostly talking about Sodas like pepsi, and but a big one is also colourful energy drinks like Redbull, Monster and Prime. Tons of ad money and sponsorships being thrown on these very unhealthy drinks.
On the coffee side, Tis the Pumpkin Spice Latte season from you-know-which chain. A 16oz cup of that has 150g caffeine, 9 grams(45% recommended DV) of saturated fats, and 50g of sugar. A 16oz Coca-Cola bottle contains a very similar amount of sugar at 52g. The special kinds of coffee at chain shops seem more like a caffeinated milkshake than coffee, nutritionally.
Regular coffee and tea aren’t bad but caffeine has to still be taken in moderation.
This is a good summary however I believe part of the issue is that due to high intensity farming the mineral levels of the soil are way down thus mineral levels of the foods we eat are basically nonexistent. People are hungry all the time because they are, essentially, malnourished. The body needs many different trace minerals to function well and if it doesn’t get it will be hungry.
A fat man can be fat and malnourished at the same time. Truly a first world problem.
Yes, there are non-deterministic parts in physics. For example atomic decay. While we can measure and work with half-life times for large amounts of radioactive atoms, the decay of a single, individual atom is unpredictable. So in a way, you can get your desired dose of vagueness by controlling how many atoms you monitor. The less, the more.
Or another example from the same field: There are atoms for which we believe they are stable, although they theoretically could decay. But we never observed it. So maybe they are in fact stable, or maybe they decay just slower than we have time. Or only when we don’t look. Examples would be Helium-4 or Lead-208.
I also like the idea, inspired by Douglas Adams, that the universe itself could be a weird and random fluctuation, which just happens to behave as if it was a predictable, rationally conceivable thing. That actually, it’s all a random chain of junk events, and we’re fooled into spottings some patterns. This apparence could last forever or vanish the very next moment, who knows. Maybe it’s all just correlation and there is zero causation. As far as I know, we’ll never be able to tell. So fundamentally, all of it is a vague guess, supported by mountains of lucky evidence.
Good answer! Thanks for that. Also, good use of ‘apparence’ - not a word i see often.
Apparently Bismuth-209 has what is considered an “alpha decay” with a half life longer than the lifetime of the universe - whatever that means. So yeah, entered into some fuzzy physics there.
There are atoms for which we believe they are stable, although they theoretically could decay. But we never observed it.
Bismuth-209 was for a long time considered to be the heaviest stable primordial isotope, it had been theorized for a while that it might technically decay, but no one proved that until 2003, it has a half-life of over a billion times the current age of the universe, and so for all practical purposes can be treated as if it is stable.
I’m no physicist, so I very well be way out of my element, but I would personally not be the least bit surprised if it turned out every atom was technically unstable, but since the decay is so incredibly slow we may never be able to accurately detect it. Using the lead-209 example you gave, if it ever is proven to be unstable, the half life should be at least 10^25^ (10,000,000,000,000,000,000,000,000/ten septillion) times longer than the age of the universe. Smarter people than myself probably have some ideas, but I couldn’t imagine how you could possibly attempt to measure something like that.
Oh wow, thanks for the details! 10^25^ years … no, times … yeah, crazy. I mean, that’s beyond homeopathic. Since I learned about this topic as an interested layman, I somehow assumed everything can decay, and we simply call the things “stable” which do so very slowly. Which can mean as many atoms decay over the course of a billion years as there are medically effective molecules in homeopathic “medicine”; none.
The standard model predicts that hydrogen-1 is the only stable nuclide because electroweak instantons allow three baryons (such as nucleons: protons and neutrons) to decay into three antileptons (antineutrinos, positrons, antimuons, and antitauons), which imply the instability of any nuclide with a mass number of at least three; or for two baryons to decay into an antibaryon and three antileptons, which would imply that deuterium could decay into an antiproton and 3 antileptons.
This is very rarely discussed because the nuclides that can only decay through baryon anomalies would be predicted by the standard model to have ludicrously long half lives (to my memory, something roughly around 10^150 years, but I might be wrong).
Hydrogen-1 is stable in the standard model, as it lacks a mechanism for (single) proton decay.
Observation cannot travel faster than the speed of light. No matter what it is you’re using to observe: Photons (light and radiation), measuring gravity, heat, anything. No matter if the phenomenon’s expansion were traveling at the speed of light, the changes to the universe being made as well as our ability to observe them are also traveling at the speed of light.
If the phenomenon were very far away, we would not be able to observe anything it was causing until its leading edge caught up to us. Then we would be destroyed at exactly the same time. This is because in your example it is expanding at exactly the same rate as the universal speed-of-light constraint allows us to receive any indication of its presence. Any evidence of, e.g. a far away star being destroyed would take X amount of time to reach us by its light no longer arriving. However, in that time the edge of the space-destroying phenomenon will also hit us, because it will also take exactly X amount of time to reach us, at the speed of light, from the point where the star was when it was destroyed. The distance is the same, the speed is the same. We would continue to receive light from that star in the meantime, as we already do. (The light from the stars you see in the sky now is already tens/hundreds/thousands/millions/etc. years old depending on the distance to the star in question.)
If the phenomenon were so far away that it is outside of our observable field of the universe, it will never reach us and we will never have any indication of its presence. That’s what “observable universe” means. Anything can happen anywhere outside of the observable universe and it is objectively meaningless to us, because we will never ever be able to reach it, record it, have it influence us in any way. This is, however, predicated on the theory of the perpetually expanding universe being true (which it probably is).
If you want to actually see the stars in your sky winking out over the millennia, I suggest building your universal destruction bomb such that its shockwave travels at, say, half the speed of light or some other suitable fraction.
Thanks, I was having trouble intuitively on that tipping point of expansion moving objects faster than the speed of light and how that is observed without more than lunch napkin level thought. Makes sense. We would never know about or see “the bubble” if it stopped short due to expansion.
The best we can achieve in this thought experiment is to see through a telescope some faraway alien set up a bomb with a countdown timer that will surely blow up at a specific time in the future and destroy the universe, but which we’ll never see count down to zero or explode. If we saw it reach zero it would of course kill us in the same instant as we see it, because by the rules of the thought experiment the explosion travels at the speed of light. But if the alien is far away and the countdown is long enough, the accelerating expansion of the universe due to dark energy will carry it outside of our cosmic event horizon before it explodes.
Using the cosmic comoving distance definition and the cosmology calculator, the last scattering surface of the Cosmic Microwave Background for example is 45.5 GLy away. Its light was emitted 13.7 GY ago (400kY after the Big Bang) at redshift 1100z. I was told that due to accelerating expansion, we will never see galaxies further than 63 GLy away (we don’t see them yet, the matter that we’ll see form them is beyond the CMB sphere for us at present), and if we hopped onto a lightspeed spaceship right now, we can never reach galaxies beyond 17 GLy comoving distance.
So for example if we looked at a galaxy at redshift 3z which is 21 GLy away, and whose light took 11.5 GY to reach us, and saw the alien set up the bomb timer to 11.49 GY, we know that the bomb must have surely exploded by now, but also know that we are safe because it’s far enough away and we’ll never see it explode, even in the infinite future.
Similarly, we can relish the tiny shred of joy in the knowledge that if we did fuck up something really major, like creating a false vacuum bubble in the LHC or whatever, we can never destroy more of the universe than the 17 GLy bubble around us.
I think someone urgently needs to come up with one of these solutions:
The foot-operated lid;
The toilet with flush and suction;
The Jedi throne (a Jedi-style toilet lid activated by hand movements) and lastly
The Terminator (a time-activated flames of hell) solution. The time-activated mechanism locks the toilet door after the user leaves and burns the entire compartment at solar flare temperatures.
Jim’s a clever guy. We could even seek inspiration in some trash cans that have embraced the pedal idea. Can you believe we’re in the 21st century, surround by ai systems, risking extinction for various reasons, and unable to solve the toilet seat conundrum?
In France they have public toilets that basically do number 4. The toilet gets completely cleaned automatically with hot water and detergent after you used it. It works by locking up after you unlocked the door after using it. If you hold the door for someone, they get the cleaning treatment.
Unfortunately, I’ve never been to France, but nothing beats a spotless clean public toilet. And, thanks for the tip: if someone holds the door for you, kindly step back. That alone should be highlighted in all tourist guides.
It’s written quite clearly on the door, but last time I used one I saved a tourist who would have had an unfortunate shower. She grabbed the door when I went out and was going in, I had to warn her and tell her to first let the door close so that the wash cycle would do its job.
You know what they say: you have to rush when Mother Nature calls. Under those circumstances, it can be difficult to read the instructions first. Good to know you saved the poor tourist a free chemical bath.
Honestly there is never any shame about sharing what you’ve learned. I didn’t ever think about this and now I’ve learned something. Keep asking questions and searching for answers!
They do consume a tiny little bit. I have a Measurement thingy that yoj plug between your outlet and whatever is plugged in which is accurate to 0.1 W. I tryed 3 chargers, one shows 0.1 W, the other two show 0.0 . I still know they consume a tiny bit, but less than 0.1 W is almost nothing. 0.1 W would come out to a consumtion of 0.876 kWh over a year, wich costs me 0.30 €.
askscience
Top
This magazine is from a federated server and may be incomplete. Browse more on the original instance.