Ok, stretchy isn’t a great word for that because basically all bread bags match what you did mean, though mine don’t tend to get crinkly in the freezer.
…and then to register astronomical observations! The birth of science, no less.
And all because every year like clockwork, the Eufrates and Tigris blanketed an area of hundreds of square kilometers with a fresh coat of silt (from the Taurus mountains in modern-day Turkey) that was perfect as a rudimentary but cheap, easy and quick writing medium, pushing the point of a stick into a pancake of soft clay, then leaving it to dry and harden in the sun.
…based upon how my elementary school teachers used to grade assignments, great is just above excellent, so they’ll diminish to excellent lakes first, then good lakes, then typical lakes…
Something to consider is that your body relies on blood glucose as its primary energy source. During starvation, glucose levels are severely depleted. This triggers your body to start using stored fatty acids. All remaining glucose is reserved for the brain to use.
By removing blood from your body and moving it to your stomach, you’re essentially moving that precious energy to an organ that can’t as readily make it available to the tissues that need it.
Thanks to the thermic effect, it also takes energy to digest and metabolize food. You’d be expending extra energy to digest the blood that was already in your body, where it was perfectly content carrying usable energy where it was needed.
My main question, and the one that I initially came here to ask, is: if their ship continues applying the force that, under classical mechanics, was enough to accelerate them at 9.81 ms^-2^, would the people inside still experience Earth-like artificial gravity, even though their velocity as measured by an observer is now increasing at less than that rate?
Relativity says yes. There’s no absolute speed, only relative speed; within the local reference frame of the ship, everything will continue to work normally, including the force experienced due to acceleration.
My understanding is that a trip taken at the speed of light would actually feel instantaneous to the traveller, while taking distance/speed of light to a stationary observer.
The ship is not actually going to reach the speed of light (as seen by an outside observer) though. The faster the ship goes, the more its (observed) mass increases, and the 9.8m/s² acceleration will have less and less of an effect. But to the people inside the ship, it appears as though they can accelerate indefinitely, going faster and faster at their steady rate of acceleration. Due to relativistic effects, it’ll never look like they are passing any objects outside the ship at more than the speed of light; instead it will appear as though the distance they have to travel is compressed, so they don’t have to travel as far.
You’re not allowed to have any way to determine an absolute speed. If your perceived acceleration were to vary (for a constant thrust) depending on your speed, that would give you a mechanism to determine absolute speed, but absolute speed doesn’t exist in relativity.
Rather than “nothing can go faster than the speed of light,” given that we’ve just determined that absolute speed doesn’t exist, the next rule is instead: you are not allowed to observe anything travelling faster than the speed of light relative to you, and relativistic effects will ensure that this is so.
A minor nit pick. It’s worth noting that increasing mass is an inaccurate view. It works in the simple examples, but can cause confusion down the line.
Instead, an additional term is introduced. This term, while it could be combined with the mass, is actually a vector, not a scalar. It has both value and direction, not just value. This turns your relativistic mass into a vector. Your mass changes, depending on the direction of the force acting on it! Keeping it as a separate vector can improve both calculations and comprehension, since comparable terms appear elsewhere (namely with time dilation and length contraction).
Also, metals can easily accommodate varying number of electrons in the electron shells of their atoms and still be stable. That makes them very good to quickly store and release electrons which means they can help say transfer molecules around (iron for transport of gasses), scavenge free radicals (e.g. manganese) etc.
Perhaps I’m not understanding the question, but first and foremost, science is specifically not a belief system. My professors emphasized the fact that we were not to believe anything but rather accept or reject hypotheses based on evidence. Science is a tool. It’s a system of observing, recording, hypothesizing, testing, analyzing, and refining. If you’re asking when we will have refined everything to the point that there are no more questions, I don’t think that will ever happen. What I’ve found is the more questions you answer, the more questions you have.
I don’t think it really makes a difference unless you’re really into feng shui. The best position for your bed is whichever one allows you to sleep most comfortably
You can always get a Kill-a-watt (or similar if those aren’t available for the EU) to see how much power something uses in standby
I remember there being special power strips you could get to detect and stop phantom loads like this. But according to that article, there are now regulations to keep this power draw low, so it’s probably not a major problem with modern devices.
i have a couple of those power strips at the office. i'm always forgetting about that 'feature' and end up with stuff 'mysteriously' shutting-off or draining battery instead of charging.
Just don’t make the same mistake as one physics lab did. They made a series of measurements and their results showed that gravity quickly increases in fall, falls slowly over winter, and back to about pre-fall levels very slowly in summer. It took quite a while to figure out the reason of this unexpected result. They turned their equipment inside out to find a mistake to no avail. Then they realized that the university stored coal for the central heating and hot water in the basement under the lab…
I’m assuming they’re indicating that the mass below the apparatus increased in fall (when storage was filled) and decreased slowly through the winter, leading them to measure a changed graviational constant. A back of the napkin calculation shows that in order to change the measured gravitational constant by 1 %, by placing a point mass 1 m below the apparatus, that point mass would need to be about 15 000 tons. That’s not a huge number, and it’s not unlikely that their measuring equipment could measure the gravitational acceleration to much better precision than 1 %, I still think it sounds a bit unlikely.
Remember: If we place the point mass (or equivalently, centre of mass of the coal heap) 2 m below the apparatus instead of 1 m, we need 60 000 tons to get the same effect (because gravitational force scales as inverse distance squared). To me this sounds like a fun “wandering story”, that without being impossible definitely sounds unlikely.
For reference: The coal consumption of Luxembourg in 2016 was roughly 90 000 tons. Coal has a density of roughly 1500 kg / m3, so 15 000 tons of coal is about 10 000 m3, or a 21.5 m x 21.5 m x 21.5 m cube, or about four olympic swimming pools.
Edit: The above density calculations use the density of coal, not the (significantly lower) density of a coal heap, which contains a lot of air in-between the coal lumps. My guess on the density of a coal heap is in the range of ≈ 1000 kg / m3 (equivalent to guessing that a coal heap has a void fraction of ≈ 1 / 3.)
Can’t be that big, as the difference in mass close to the instrument only varied in the several tons category, but obviously enough to puzzle the scientists.
This doesn’t change the issue presented by OP. Sea level is not level across the world. In fact there are much larger differences than most people expect. The Earth is not perfectly round. Earth rotation causes the equator to be affected by a centrifugal force, making it wider there ( more distance to earth core means less gravity ) than at the poles. Overall, gravity at Earth surface level varies by 0.7%, ranging from 9.76 in Peru to 9.83 in the Arctic Ocean, but it’s absolutely not linear. In addition, the Earth is full of gravity anomalies. These cause localized dips and spikes in gravity. Two of the big dogs lips lie in the Indian ocean and the Caribbean. Because water is fluid, sea level is very much affected by local gravity (as well as other factors such as air pressure, salinity, temperature…). Which is also why the moons gravity can cause tides. The permanently lower gravity on these anomalous spots mean that the average sea level here is lower than it would be on a perfect sphere. This difference can be up to two meters in sea level.
This reminds me of the story of magnetic detonators for torpedos they tried to use in the early days of WW2. They detect the slight disturbance in the Earth’s magnetic field caused by a gigantic hunk of floating metal, and that triggers the detonation.
However, they did not yet know that the Earth’s magnetic field is not consistent over the whole planet, so while they calibrated it to the local field, it functioned very badly in other regions with different field strengths. Torpedo would either detonate far too early, doing minimal damage, or not detonate at all, just hitting the target ship with a loud thunk.
This was largely responsible for the ineffectiveness of American submarines in the early days of our WW2 involvement. Took us a couple years to sort too.
It was called the Mk 42 in case anyone wanted to read a little more. It’s an amusing story. They never wanted to actually properly test them, because they were so damn expensive. So they just didn’t. lol It wasn’t until enough sailors complained and got a high ranking admiral on their side that it got sorted.
Humans mostly absorb iron through the duodenum, which is a very short bit of intestine near the stomach.
Herbivores, on the other hand, have either massively complex systems of stomachs, chew their cud to make nutrients more absorbable, or letting food ferment before digesting. The latter also works for humans, if you like fermented veggies.
Of course, diet also matters. Humans don’t eat all that high iron foods, but grass is a cow’s main food source and it’s high in iron.
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