Awesome, so if I’m reading that right UV can contribute to growth, and IR doesn’t contribute much at all. The blue and red end of the visible spectrum encourages growth, however it can pretty much occur at any visible wavelength, just not as efficient as the bands listed on the image.
Blue and red are the biggest drivers for photosynthesis, but other wavelengths have effects on the plants as well. For example, far red light (infrared) has a huge influence on flowering and stem elongation in many plants. They really rely on light for a lot of cues for regulation.
That chart is a good starting point, but it doesn’t tell the whole story. It only shows the absorption spectrum for Chlorophyll A, which is a key pigment for photosynthesis in all plant species, but there is also Chlorophyll B, and there are numerous other so called accessory pigments (beta carotinoids are the most common examples), that can work in conjunction with chlorophyll in a photosystem to collect light of different wavelengths. Algae in particular show a greater diversity of accessory pigments. They have evolved use light at different depths below the water surface, where it reaches them with a different spectrum, because water itself absorbs part of it. Have a look at red algae and brown algae, for example.
So if you want to grow algae in a controlled environment, you should do some research about the particular absorption preferences of the species you’d like to grow.
What would be ideal IMO is a bug with a gut bacteria exclusive to that species alone that could eat plastics and digest them fully so microplastics aren’t an issue. Likely, a species for each type of problem plastic. A natural analogue would be termites, which can only digest wood because of such a relationship.
It would have to be an artificially engineered relationship, and an insect that’s not particularly proliferate. Preferably with a narrow set of habitat tolerances. That way they could be farmed, but be unlikely to get into the environment and become a nuisance by eating plastics we don’t want them to.
Black soldier flies are prolific and when proper conditions to reproduce are met, the females do not wander far from the place they are born and because of this are already used in organic waste disposal.
Using a complex organism to treate waste, even if only plastic, requires specialized infrastructure, designed to contain any event possible to pose a threat to the environment; this is not something we want or can do at home. Specialized infrastructure would make possible ideal conditions for the flies.
Black soldier flies also have the advantage that adults do not live for very long, do not feed, do not pose threat to human beings and the larvas die quickly if no food is available.
These flies also are vulnerable to cold and extreme heat conditions.
The metre was originally defined in 1791 (…) as one ten-millionth of the distance from the equator to the North Pole along a great circle, so the Earth’s circumference is approximately 40000 km. en.m.wikipedia.org/wiki/Metre
The kilogram was originally defined in 1795 during the French Revolution as the mass of one litre (1/1000 m³) of water. en.m.wikipedia.org/wiki/Kilogram
… and the last major SI unit is the second which of course you know is (originally was) 1/86400 day.
Please notice about the Celsius scale : the second reference point isn’t a mixture of ice and salt but rather pure water freezing point.
Now how can we as naked humans develop technology to figure this out is something of historical proportion, that’s a quite amazing story !
Can we improve things a bit? Hoping we can get a calendar with no leap year, even number of days in each month, no daylight savings, etc
Edit: obviously no one got what i meant. We can base the day of the year on whatever the fuck you want, but for the love of god can we not split it into twelve randomly numbered chunks, i hate how our months are!!
This would need the Earth to make one complete rotation around the Sun in an exact whole number of times it rotates around itself. …which is not the case right now and extremely difficult (meaning near impossible) to change.
…no daylight savings…
Okay but now we have a greater problem : we have to change (twice, a year) the time when business, school , stores etc… open and close, for it to be convenient with outside natural light. So, in my opinion, this is not an improvement.
Nah fuck it, change something, its all made up anyways!! The whole idea of our “years” doesn’t make any sense on other planets, so we potentially could define some arbitrary system to it.
Not sure if you’re joking or just having a slow day, but neither the length of a day nor the length of a year are arbitrary. One is the length of a revolution of the earth around its own axis, the other is the time the earth takes to complete a full run around the sun. Those two aren’t fully in sync, and to line them up would require a major feat of astroengineering. Given sufficient advances in science, we might get there in a few millennia, if we’re still around by then, but until then leap years are here to stay.
Look, i know what it is based on now, I am saying we should change it. Obviously I am not being super serious, but it would be nice to have even numbers instead of how it is now
There is a calendar that proposes to have 13 months, each with 28 days. That gives you 364 days. Day 365 is new years day and is not part of any month. There are still leap years because as stated, the Earth goes around the sun in 365.24… days. To not need leap years we’d need that to be a whole number.
Well pretty much everyone likes defining a day based on the position of the sun in the sky. While sun rise and sunset might change over the course of the year, nearly everyone agrees that noon is when the sun is the highest in the sky (ignoring day light savings and time zone effects). Turns out people don’t like it when noon occurs in the middle of the night (which would happen if we changes it to any other length of time).
Likewise, nearly everyone has agreed for millenia that a year is defined by earth’s position within its orbit. We know that based on where the stars are at night. Again, people didn’t like having snow during July (which actually happened because the calendar was so far off).
These are not definitions that we can change or have any control over. Additionally, the length of a year (to get earth back to the same spot in its orbit) divided by the length of a day (the time between the sun reaching its apex one day and the next) is not an integer and there’s nothing that says it has to be.
We can’t change it, so if thats important to you, you’ll have to find another planet to live on.
I know what “we like”. I am saying we should change it in a hypothetical post-apocalyptic scenario where humanity joins hands together and demand a yearly calendar that makes more sense. Don’t know why this is getting downvoted, guess you’re all taking me wayy too seriously lol
I’m personally not voting on your comments, but you are probably being down voted because you are either being purposefully ignorant or you are continuing to insist on a “better system” that is physically impossible.
How is a better system impossible? Lets say you are on a star ship, heading away from earth, no reference points besides distant stars. How do you determine time? How do you determine anything? Even if we knew and simulated exactly how fast the earth is spinning and how much it is rotating around the sun, it means nothing out there. We have decided that time works the way it does, all I am asking is to take the extra .24 days in a year and make them disappear. There are several inconvenient ways to do this but it is possible to break it down further so we do not need the extra day. We could round it off to the nearest day every few years, shrug our shoulders and move on with our lives without tacking on another 29th day in some random month? Maybe there is some other way we haven’t thought of? I guess I just thought more people would respond positively to “impossible future scenario where a calendar that makes sense is used” :/
Sure, in that scenario, such a system would be possible. Hopefully, there is still an earth to communicate with however. So we’d have to keep using earth days and years to enable effective communication. Also, the entire ship would have been built using earth based units, so it might be easier to use the system we’ve already got.
We’re not on a space ship though. We’re on Earth, so what happens on this planet matters. You may care more about not having leap years, but the majority of us care about knowing approximately what the weather will look like at a given point in time and how much sunlight to expect, since those things actually affect our daily lives, whereas an extra day in a given month does not.
What about when in the future if we needed to, say, sync time between here and mars, it would make it easier if we had some “frame of reference” outside of the sun maybe. There would basically just need to be a slight redefinition of what a day is, to account for the extra quarter of a day each year, its only a minute each day, ~86,460 seconds in a day instead of 86,400. Not exactly gonna throw the weather/sun off, no?
oh i know the answer. Since a mars day is about 15 minutes longer and out rover there are solar powered it was important that the human operators of them knew what time it was on mars. Nasa’s answer, make a watch that runs about 2% slower. that git the mars watch an extra 15 minutes and so it syncs to the martian sun.
you just have the ship day be the same length as an earth day and start count from day 0. So the ship launches and it clock starts ticking. Now you do need to ask is this going fast enough that time dilation is a thing? That will change how well it can ever sync up to earth.
I really like that one! Guess there’s really no easy way around leap day, but i was thinking you could add an extra ~60.684 seconds to each day and pretend its the same thing? Even increasing the second to be slightly longer could make it possible i think, since we are restarting from scratch it would be easier to adjust it slightly
Your definition of the meter leaves out the most interesting part. Yes, it was 1,000, 000th the distance of the equator to the North Pole, but how far is that? That wasn’t known accurately in the 18th Century. So, two Frenchmen, Delambre and Mechain conducted the longest meridian survey every attempted. They also did so while half of Europe was at war with one another. It was an amazingly dangerous endeavor. There is also significant evidence they totally flubbed and hand-waived their results. So, although their science ended up being questioned, the process and method was accepted and the Meter was defined.
Re Celsius 0 °: the reason I thought perhaps Fahrenheit’s Weird Brine might be a more absolute thing to take de novo temperature from was because I don’t actually know the answer to “how can you ensure water is exactly freezing temperature?” If it’s solid ice it could be colder, if it’s liquid it’s probably warmer, and even if it’s a bucket of cold distilled water with distilled water ice in it, isn’t it still likely hotter than 0 ° C? I feel like there’s probably something involving equilibrium between solid and liquid water that would be difficult to sus out
if you have both liquid and solid water at equilibrium then you have zero degrees Celsius. Pressure has minimal effects …at plus or minus 0.5 atmosphere. of course if you go to a hundred or a thousand atmosphere then there is an effect of pressure.
Small pieces of ice will equilibrate their temperature faster in water.
Surface tension has minimal effect on melting temperature unless you go to extremely small pieces of ice meaning less than one micron, …which is not possible to achieve anyway because such small ice pellet with fuse rapidly to form larger ones.
Yes a bucket of a mixture of small ice pellets, say a few millimeter size, plus water, (this bucket being enveloped with some insulation) would be a great zero degrees Celsius reference point.
… “the actual melting point of ice is very slightly (less than a thousandth of a degree) below 0 °C.” …
isotopic distribution of heavy and light elements in water also has a very slight effect on melting point. So, rainwater and water distilled from ocean will not melt at the (exact) same temperature.
Now, about small particle fusing together this is true not only of ice but of any material.
it’s called sinteringand it is caused by diffusion and a lowering of the surface energy.
This process is faster when the material is near it’s melting temperature and faster yet if in contact with any miscible liquid phase.
This is what I thought - I just wanted to make sure I hadn’t failed to consider something obvious. Am meeting up with some old friends who are science geeks next month and wanted to throw out the line “for all we know, the center of the galaxy exploded 25,999.9 years ago and we could all die tomorrow” and I didn’t want anyone coming back with “well actually…we would have detected that by now thanks to technology xyz that was in ivented in 20XX”.
I totally misread your post as you were meeting up with some old friends who are science geckos and I wanted the story behind all of that, but then I read it again and was disappointed in the lack of geckos.
If the black hole specifically disappeared, it would have no effect on us. The solar system would not even be launched on a 100 million year trajectory out of the galaxy, as galactic rotation is dependent on the masses of stellar and interstellar matter in the disk and dark matter in the halo. The supermassive galactic black holes, despite being supermassive, still only make up a tiny percentage of total galactic mass.
If you want to wow your friends, tell them about false vacuum decay. We could have bubbles of true vacuum expanding out in space from multiple directions towards us at lightspeed, and no way of knowing about them, stopping them, or outrunning them. Any point in space could nucleate a new true vacuum bubble at any time, just like a given uranium atom could decay now or in 5 billion years or never. Even spookier, by principle of quantum immortality, the Earth could have been engulfed by vacuum bubbles many times before, and we are just the one tiny sliver of probability space where by luck alone we survived long enough to talk about it here and now.
Thankfully false vacuum is just an idea and there is currently no evidence that it is real.
Many worlds is a fun idea, too. But also being regarded as not real for a while now. The cat in a poison box living or dying doesn’t mean it lives and dies.
I never heard about the false vacuum before, that’d be some good sci-fi
This isn’t exactly a ‘science debate’ but I’ve met several people that still think the ‘Great Wall is the only man made object visible from orbit.’ I read somewhere that may come from a dream some Chinese king had like 1000 years ago.
Almost crazier than flat-Earth in terms of being easily disprovable just by thinking about it for 20 seconds, but people have stated that to me as a fact and were kind of incensed when I explain it’s obvious nonsense.
There isn’t a link in your post, but it looks like you’re referring to this preprint. The article has been published in a peer reviewed journal paywall warning.
This is a review article, so it isn’t proposing anything new and is instead giving a summary of the current state of the field. These sorts of articles are typically written by someone who is deeply familiar with the subject. They’re also super useful if you’re learning about a new area - think of them as a short, relatively up-to-date textbook.
I’m not sure how you’re interpreting this review as an alternative to the standard model of cosmology and the Big Bang. Everything is pretty standard quantum field theory. The only mention of the CMB is in regards to the possibility that gravitons in the early universe would leave detectable signatures (anisotropies and polarization). They aren’t proposing an alternative production mechanism for the CMB.
Haha it’s in the title: “Cosmological Particle Production: A Review”. Also the journal it was published in is for review articles: Reports on Progress in Physics. Mostly though the abstract promises to give a review of the subject.
Another indication is its lengthy (28 pages) with tons of citations throughout. If someone is doing new work, citations will mostly be in the introduction and discussion sections.
I would think that the heat releases flavors or causes chemical processes in the cheese that produce additional aromas not present in the normal state. I have no idea and am not qualified in any way.
Science has known for years that the fewer calories you ingest, the slower you age. Metabolic processes induce a lot of wear and tear.
As far as reversing aging, the protein thing may have some merit, but I would remain skeptical for now. My 2-cent guess is that truly reversing aging will involve some unholy cocktail recipe of stem cells, genetic manipulation using CRISPR, lots of fasting, and maybe some advanced vaccines (we’re learning vaccines can train the immune system to do all sorts of interesting things beyond fighting infections).
Disclaimer: I’m not a physicist, but I am a scientist. Science as a whole is usually taught in school as though we already know everything there is to know. That’s not really accurate.
Science is really sort of a black box system. We know that if you do this particular thing at this particular time, then we get this particular response. Why does that response happen? Nobody really knows. There’s a lot of “vague” or unknown things in all of science, physics included. And to be clear, that’s not invalidating science. Most of the time, just knowing that we’ll get a consistent response is enough for us to build cool technologies.
One of the strangest things I’ve heard about in physics is the quantum eraser experiment, and as far as I’m aware, to this day nobody really knows why it happens. PBS Spacetime did a cool video on it: youtu.be/8ORLN_KwAgs?si=XqjFEjDfmnZX31Mn
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.
You are behind the times on physics advancements buddy! Thanks to the recently discovered concept of relativistic time dilation, a 5000 light year trip at the speed of light will take literally 0 seconds of your lifespan. More practically, travelling in a starship that accelerates at 1G to the halfway point, turns around and decelerates to the destination, you can reach ridiculous distances within a single human lifetime:
shipboard timedistanceearth time1 year.263 LY1.05 Y2 years1.13 LY2.37 Y3 years2.82 LY4.35 Y4 years5.80 LY7.50 Y5 years10.9 LY12.7 Y10 years166 LY168 Y15 years2199 LY2201 Y20 years28.8 kLY28.8 kY25 years380 kLY380 kY50 years149 GLy149 GY100 years22.8 ZLy22.8 ZYThis is the formula to calculate the distance and time:
Nah, it’s actually super hard to maintain that acceleration. Not to mention all the fun of radiation, avoiding random obstacles and I assume the interstellar medium will become more dense to an accelerated observer.
We have idea on how to do it, but the engineering is far from it yet.
But what about the bit about not hitting anything whilst travelling at that speed? Even a speck of space dust would do massive damage at those speeds, right?
Oh yeah, it’s like flying the wrong way down the tube of the Large Hadron Collider. The tougher challenge though is like @MuThyme said maintaining 1G acceleration. Following the rocket equation, which is logarithmic, a 50 year multi-stage rocket will be bigger than the universe itself, even if you use some kind of nuclear propulsion 10000 times more efficient than our chemical rockets.
Radios receiving signals don't just siphon the signal off lol
What you're asking would only really happen with wireless Internet service and it's not because of the wireless signal, but because the overall bandwidth diminishes the more people connect to it.
Actually, the waves emitted by the radio tower are enough for a receiving device to generate a small electrical current just through the oscillations of the propagating signal.
The current produced in the antenna does (induce a field which goes on to) cancel the wave out a bit. Not enough to be noticeable in the far field, for a normal-sized antenna, but some. Conservation of energy, right?
It’s like solar energy. You either absorb it with a panel, or it goes to “waste”. You’re not really stealing it from someone else, as long as you’re not getting too much in the way
Usong your analogy i think Ops question was really if you have a stack of transparent solar panels will the panel below get less power and the answer is of course it will. If one antenna is behind another there will be a small reduction in the power of the signal reaching it, probably very small but with enough of them you could theoretically construct a faraday cage of sorts.
Yup. It's typically amplified quite a lot in the receiver, and the vast majority of power transmitted never is received, so it doesn't usually matter, but it's not a dumb question.
I spent the last couple of years selling and eating fancy cheeses and I'd say that isn't true. Some are better melted, some I let come to room temperature long before eating and some (almost none, though) I prefer cold.
Trust me, some cheeses will turn into an oily puddle when melted.
My guess is your experience is with young, semisoft, and American cheeses?
I left to work for a non-profit a little bit ago. I seriously miss getting invited out to visit cheese, beer and wine (and whatever else local) producers. I spent my vacations just going from place to place.
My dream is to produce goat cheese, so maybe someday I'll be back in the life.
It is loosely defined from my perspective, but I am curious about harder rocks, like granite. Your standard everyday rock tends to be much more brittle and may not have a high metal content. (It will likely have iron in one form or another though.)
Most metals and rocks are crystals in their “normal” state, so I see what you are getting at.
Your username is basically the notation for a crystal oscillator, so it’s gotta count. (Damn the rules!) Quartz is a rock that bends for a commercial purpose, so thats a really good answer, actually.
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