What an enormous public heath issue iodine deficiency was in Switzerland and how completely everyone forgot about it after it was fixed by the introduction of iodized salt in the 1920s: https://www.lrb.co.uk/the-paper/v45/n23/jonah-goodman/a-national-evil
i would speculate that [mild?] hypo vs hyper may have different advantages/disadvantages at various stages of life.
but idk. #dyr #factcheck
If you’re on a truck traveling at 60mph, and throw a ball forward at 60mph, that ball is moving at 120mph.
But if you replace the ball with a flashlight, then the light isn’t moving at the speed of light plus 60mph. Instead, it slows down so as not to exceed the speed of light.
It’s like if you threw that ball at 60mph and it went flying forward, but at 10mph, no matter how hard you throw.
Uhh, relativity, fun. This gets a lot more mind boggling, imagine 3 people, A and B are in a train and C is an observer outside. From C point of view, B will pass him first, then A. This train is going at 50% the speed of light and it’s very long, A and B are 1 second light apart, i.e the distance that light takes 1 second to travel.
If A shines a flashlight B will see it 1 second later. However from C point of view since the light was shone the train moved forward 0.5 light seconds. So the light has to travel 1.5 light seconds distance, and it does so in exactly 1.5 seconds. So the observers disagree on the distance the light travel, but also disagree on the time it took, but they agree on the speed of light.
This makes things weird, because both A and B say that 1 second passed, but C says that 1.5 seconds passed. This means that people moving faster experience time slower. Which means that if you take two twins, put one on a fast moving ship, e.g. 80% speed of light, by the time he comes back only a few minutes would have passed for him, but years would pass for the other.
The back of my brain is fizzing.
I had the Relativity conversation with my 16 year old this past weekend, as he is taking AP Physics.
Yeah, he couldn’t wrap his mind around it. Honestly, I can’t say I understand it very well. I get that C (speed of light) is C in all reference frames. What I do not understand is for a spaceship traveling at C, the forces being transmitted between the atoms from stern to bow are unable to catch up to the next forward atoms. Hence time dilation, at least for those forces being transmitted “forward” in the ship’s reference frame.
However, what happens to those forces being transmitted bow to stern or “backward” in the ship’s reference frame? Would those forces be “dead stopped” in an external reference frame? Yet travel at C from bow to stern in the ship’s reference frame? What does that mean for the ship if those forces are only being transmitted one way?
Or, as I very much suspect, do I just not have a clue as to how it really works. I always thought that “time dilation” was simply the inability of forces being transmitted from atom to atom. As those forces are limited to C and they are attempting to catch up to another atom also traveling at C. With that said, those forces are transmitted in multiple directions, not just the vector the ship is on.
Ok, another one of my very few brain cells just committed suicide and I’m not drinking anything, so I’ll stop now.
My understanding is that it’s impossible for a spaceship or anything else with mass to actually reach the speed of light. It can only approach it. Only massless energetic waves like light and radiation can travel at the speed of light.
Your understanding is correct.
Relativistic mass increases the faster the moving object gets. That in turn means more energy is required to accelerate an object the closer it gets to the speed of light.Fun fact: the speed of light is not as absolute as it might seem when looking at relativistic effects. In media with a refraction index above 1 (only perfect vacuum has a refractiom index of 1), the speed of light equals 1/(refraction index).
For light moving in water that results in a speed of light of around 3/4 the speed of light in vacuum.
If you’re on a truck traveling at 60mph, and throw a ball forward at 60mph, that ball is moving at 120mph.
Technically it would be moving at something like 119.99999999km/h and that discrepancy slowly increases the closer you get to the speed of light
That people with mental health issues hear different types of voices depending on the country. If someone with schizophrenia from the US hears voices, it is more aggressive or negative while someone from Africa or India might hear a more playful voice. I think that says a lot about the different cultures and upbringing.
https://news.stanford.edu/2014/07/16/voices-culture-luhrmann-071614/
I watched a video about the development of the line, that ridiculous building project in the dessert. I see glacier basically melting in front of my eyes but never felt as doomed as watching this shit developing for some reason. Just the sheer amount of manpower, diesel and money wated on the viggest pile of shit i have ever seen while the planet around them is dying.
Is that fucking garbage still going ahead!??
Sheeeeit
Twitter users
Why? Just leave.
Same with people who complain qbout facebook and use facebook.
That people are paying $3500 for a pair of goggles.
Yeah, but it’s from Apple! /s
That certain tribes who live in a jungle setting can discern and have names for about 40 different shades of green, where a city dweller would see them all as being exactly the same shade.
I think I’ve read before that our eyes are most sensitive to the color green out of any other color, something about it that wavelength of light is absorbed more readily by the cones in our eyes. Being exposed to it daily and maybe having their survival dependent on it probably helps them develop that ability.
Yes, I paint in free time and getting the right shade of green to make natural scenes look realistic is extremely difficult.
Another one is how Eskimos have 53 words for “snow”, not just “powder” and “slush”, but everything in between and beyond.
Fun fact: if we could see through the intensity of sunlight to pick up its’ color, it turns out green light is the most prevalent photon wavelength.
Surely this and phenomena like photosynthesis are directly related.Linux Journal was interviewing a guy who’d worked on OS/2 at IBM…
He said that we’ve got 2x the sensitivity to green as to red, & 2x the sensitivity to red as to blue.
Basically, we’ve got 1-bit more sensitivity to green than to red, & 1-bit more sensitivity to red than to blue.
I’ve read in linguistics stuff that tribes that have 2 words for color have 1 word which means bright & 1 word which means dark,
tribes with 3 words have a word for blood-color, as well…
green doesn’t seem to be as significant in the words-for-it department of tribal life, from what I’ve read.
_ /\ _
Do you have a source? There is a common myth that innuits have 100+ words for snow, which is stretch beyond any reasonable sense, I’m afraid this might be similar.
The main studies of a persons language constraining their colour perception derive from the Sapir-Whorf hypothesis.
This article explains some of the different language and perceptions across different cultures:
https://abnormalways.com/color/color-perception-across-cultures/
The peoples I had heard of previously, are the Himba tribespeople, with a ‘hyper-perception’ of green hues.
This is an ongoing research area, and I was hoping someone in the field could outline the recent key changes in understanding of cultural effects on colour perception.
There are papers such as this one, that I can partially follow, but would benefit from an interpretation from others more knowledgeable than me.
https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0158725
The actor who played the main guy in The 4400 is married to William Shatner’s daughter.
To boldly go… where few men have gone before.
The astounding incompetence and corruption woven into Australian politics and law enforcement.
Statement from FriendlyJordies
Coronation (re-upload) (the video referred to in the above)
I feel that just living in America, my mind is boggled on a daily basis, and not in a good way.
What happened exactly today that boggled your mind?
Former fox news anchor is going to Russia and presumably thinks he can end the war in Ukraine
Ah so not America but the Internet rather. If its the Internet, Im fine with it. I intentionally avoid news sites and ragebait. Think of it logically. It wont really do anything to your life really. No need to keep reading these.
I dont actively watch it, but its hard to avoid. In the Midwest, many TVs are just on fox news 24/7 in public spaces and offices.
Thats even better because I have nothingnto do with TV anymore 😜
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!Xóõ, right? Famous alongside Ubyx due to the sheer amount of consonants.
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Recent as in the last couple years but when I was diagnosed with ADHD, I realized that most people dont have an interest driven brain. They can just do boring stuff just as easily as fun and engaging tasks.
That only 600,000 people globally are starving. 95% of which are in Gaza right now because of the current shit going on.
It is just counting starving people with specific parameters that define “starving,” but still; I thought that number would be much higher.
Where in the world did you get that number and what were the specific parameters?
That if there are infinite universes out there in the multiverse then there are infinite amount of universes exactly like this one. Which means we’re stuck living this exact life across infinite universe and we’ll never be able to escape it. So that’s kind of depressing but mind blowing I guess
Perhaps. But infinite universes is still just a theory. So why let such a astronomical ‘what if,’ get you down?
Yep, if there’s an infinite number of parallel universes then there’s an infinite number where nothing is different. Maybe the only difference between the universes was the position of a mote of dust on an uninhabited planet in a galaxy on the other side of the universe.
If the many worlds interpretation is correct, that would mean that there’s not really an infinite number of discrete realities, but more of a continuum. So there are infinite other realities in the same way that there are infinite points on a line, but this exact reality is still unique.
Wouldn’t be an infinite number of them where the fork in the road is still ahead?
That’s not right at all by my thinking.
Infinite multiverse means infinite exact same universe as ours, yes. But it also means there are also infinite different universes. But you can use comparisons to see that there would likely be more universes that are different than ours because of small permutations in history causing larger effects in the future. So I like to think there are both many exact universes, and many very different universes.
Not really a recent thing, but the idea that supposedly if you travel faster than light, then you begin going back in time. But that doesn’t make sense to me. I guess the math has to work out somehow, but it seems to me that if light has a speed, then - ignoring the logistical issues related to having the power to travel ftl - travelling faster than light would simply be that, faster than light. Or to put it another way, if it takes 8 minutes for light from the sun to reach earth, then an object travelling 2c should take 4 minutes to travel the same distance, not negative 4 minutes or however that’d work out.
The only conclusion I can come to regarding how that works out logically, is that relativity sets the time light travels to “0” regardless of time taken, because that’s the only way I could see a negative value making logical sense. However it seems like that’d have its own issues, plus it implies that light instantly reaches its destination. Yet we know light has a speed and takes time to get places. It just… doesn’t make any logical sense. Yet I guess the math must work out otherwise scientists would have blown so many holes in relativity that it wouldn’t be used anymore.
inb4 “but causality…”
The speed of causality is inferred from the speed of light and the speed at which fields propagate in a vacuum. Causality, or the idea that cause must be observable before effect, is a human concept. Observing effect before cause doesn’t break causality, it only appears to do so because we’re seemingly limited to the speed of light. The reason why causality is said to have a speed (the speed of light in a vacuum) is because, with the exception of quantum tunneling, we’ve never observed anything that moves faster than light, so it’s a seemingly safe assumption to say that cause and effect play out at a speed no greater than light in a vacuum. Or to put it another way, the speed of light dictates causality, not the other way around. If something is found to be faster than light (like particles tunneling through objects), then causality must shift with it.
Let me see if I can try to explain this.
First off, light isn’t just the fastest thing we know of, it is physically impossible to go faster than light according to the laws of physics as we understand it. This is because the speed of light is actually tied to the way spacetime works.
Imagine you are standing and you throw a ball. The ball travels at whatever speed you throw it, let’s say 5 mph.
Now, let’s put you on a train traveling at 20 mph and do the same thing. If you throw the same direction the train is traveling, your 5 mph adds to the train’s 20 and the ball goes at 25 mph according to someone standing next to the track. Throw it the other way and they see it travel at 15 mph. To you, in either case, it appears to move at 5 mph.
Light doesn’t do this. We’ve measured it, and in a vacuum light always appears to travel at the same speed (we call it c for short). If you hold a flashlight, your friend next to you can measure the speed of light and will find it to be c. If we put you back on that train and stand your friend next to the track, you will see the light moving at c, but so will your friend. Not c +/- 20 mph, but c. Even if we put you on a rocket traveling at some significant portion of light speed, say 0.5 c, both you and your friend would still observe the light from your flashlight to be traveling at c.
This is what Einstein figured out, and this is what we mean by Relativity. From this, we also know that objects moving faster experience an increase in mass (you have to get moving pretty close to c to really notice), and as you approach c that mass trends to infinity. That’s why anything with mass cannot achieve the speed of light, it would be infinitely massive, and thus require infinite energy to accelerate to that speed. Thus, only things with no mass (such as light) can move that fast.
When Zefram Cochrane is born you’ll eat your words!
The speed of light is the speed of information, including gravity, electromagnetism, and some other things I am not thinking of off the top of my head. For example, if the sun disappeared right now, the lack of gravitational pull would reach Earth at the same time as it blinked out from Earth’s perspective.
Gluons, the Strong Force. Quantum Chromodynamics. As massless particles, Gluons also move at the speed of causality, although popping in and out between Quarks and moving only very short distances.
They call it the speed of light, but the alternate term speed of causality is gaining traction. Maybe because it fits as the “c” in E=mc^2, where the “c” is sometimes referred to as “constant” but actually comes from the latin “celeritas”, which means “speed”.
The term “causality” is a nice fit-all more recent alternative.
What if you think of it this way. If the Sun exploded right now, we wouldn’t know for 8 minutes, but if you were to leave at the same time, at twice the speed of light and traveled for 8 minutes, you would be 24 minutes away from the explosion now.
So if you travel away from the earth and view it through a telescope, you would see back in time as you flew away, since the light traveling from earth wouldn’t be traveling as fast.
That’s not why relativity causes time dilation – it’s not the Doppler effect of light. If it were, then the direction of travel, not merely the speed, would be a factor.
Traveling toward an object would be forward in time since if you viewed it through a telescope you would be seeing the light sooner making it older faster.
No – as I said before, relativity isn’t caused by the Doppler effect of light. Direction of travel doesn’t matter, only speed.
The twin paradox occurs in a scenario where someone travels both away and then back. They still experience time dilation when they return to the starting point, though they’ve traveled the same direction away and back.
Theres literally a section on how to explain the paradox (not even a potentially real thing anyways……) Using doppler.
It doesn’t use Doppler.
You don’t understand how relativity works. I’ve seen someone make the exact same error you did, about twenty years back, thinking that time dilation was a result of the Doppler effect of light.
It would be impossible for the aging effect to arise in the twin paradox if relativity were the Doppler effect of light because in that scenario, as in that case, there is the same amount of outbound and inbound travel.
Relativity effects show up when you have two different entities traveling at different speeds relative to each other. The direction of travel does not matter. One could be traveling toward, away from, or at right angles to another.
You’re trying to explain relativity just using Newtonian physics, which permits for the Doppler effect. Newtonian physics don’t provide for relativistic effects. That’s why relativity was such a big deal – because it explained behavior that was incompatible with Newtonian physics.
In actuality, you wouldn’t be returning to the same place, the earth has moved through space and time itself. So none of these theories work since neither could return to the same place. Thats why they are theories….
And again, your own wikipedia source has a Doppler section…. So you are now saying your own source isn’t correct?
You’re going back in time but you’re not going to be in the same place.
Think of a person walking on a road, you can drive past them and arrive somewhere before them.
You can’t do that while staying stationary. So you couldn’t say go back in time and see prehistoric Earth. It’s relative to when and where you are.
