Very Interesting!

Finally my science. I am a hydrographer for NOAA. The question is complicated as it depends on what quality of mapping you are looking for . The goal right now something called seabed 2030.

Checkout the link below for a detailed map and explination. https://seabed2030.gebco.net

" less than 15 percent of ocean depths have been measured directly, and only 50 percent of the world’s coastal waters (less than 200 m deep) have ever been surveyed."

The problem is surveying the coast lines takes considerable amount of time. The technology used to map the ocean is multi beam sonar and side scan sonars. These are fancy sonars the produce multiple aonar pings at once over a large swath. Think of mapping the ocean floor as shinning a flashlight on the ground. The closer to the floor you get the smaller your light pattern gets. This is why it is going to take us a considerably long time and effort to map the enite sea floor even to the 2030 standards.

Depends of what you understand under mapped/imaged. We have mapped almost all of the oceans, just not terribly accurately.

We dont know all the things that live down there, a lot of species remain to be discovered

There have been several manned and unmanned descents into the Marina Trench, the deepest oceanic trench on Earth. The deepest known depth is a little over 10,900 metres—that's roughly 1100 atmospheres of pressure. The first manned descent was actually as early as 1960, and the latest was just a few months ago.

What do you mean by "exists in the deepest abyss"? As in living creatures? The vast majority of the ocean is nearly a "desert". Most living organisms tend to congregate around nutrient-rich zones: the surface, reefs, and deep-sea vents. Beyond 200 meters there is simply not enough light for photosynthesis and there is not plant life or phytoplankton, the basis of the oceanic food web.

Don't get me wrong, there is life everywhere, however the density and complexity drops sharply the further you venture off the continental shelf and into the deep open ocean.

We've mapped all of it but at very low resolution. Which in this case means a resolution of dozens - hundreds of kilometers per pixel.

The deepest abyss, because it's so interesting, is actually very well mapped with a resolution of \~ 100 meters per pixel.

We've only mapped \~20% of the ocean floor at this resolution but that should be close to 100% in the next 10 years thanks to autonomous ships, autonomous underwater vehicles, and the GEBCO Seabed 2030 Project.

According to the genetic bottleneck theory, between 50,000 and 100,000 years ago, human populations sharply decreased to 3,000–10,000 surviving individuals.[31][32] It is supported by some genetic evidence suggesting that today's humans are descended from a very small population of between 1,000 and 10,000 breeding pairs that existed about 70,000 years ago.[33][34]

https://en.wikipedia.org/wiki/Toba\_catastrophe\_theory

Basically you need 50 breeding individuals to avoid inbreeding depression and 500 in order to adapt,” he says. It’s a rule still used today – though it’s been upped to 500-5,000 to account for random losses when genes are passed from one generation to the next

https://www.bbc.com/future/article/20160113-could-just-two-people-repopulate-earth#:~:text=Anthropologist%20John%20Moore's%20estimate%2C%20which,of%20potentially%20dangerous%20recessive%20genes.

Good article explaining a lot about inbreeding

yes, via radioactive decay. this is true randomness, via quantum mechanical uncertainty, not something you could predict (in principle) if you had a really good simulation (like random numbers from thermal noise). more info: https://www.fourmilab.ch/hotbits/

If you mean in software then no. Using a bit of hardware then yes, for example, voltage through photoresistor to ADC. Or amplify noise from any quantum device. That’s how modern cpu random number generators work. Those are true random numbers ultimately coming from quantum fluctuations.

Most computer programs use what are called "pseudo-random" sequences - they appear random, but actually follow a set pattern.

True randomness requires gathering data from the environment (for example, capturing the low bit of a counter when an external interrupt is processed). Some systems have a random source built-in. These are usually based on variations in temperature.

Well that depends on what you mean by"random", "number" and "generate".

Randomness can be defined as unpredictability. A sequence is called random if the amount of information it contains is maximal, i.e you can't easily "guess" how the sequence continues given any part of it. Entropy is a common measure for the average information contents of some data.

Algorithmically, generating truly random data (high-entropy) from non-random (low entropy) data is impossible - you can't create new information using algorithms, only transform it (because alhorithms are by definition deterministic and depend entirely on their inputs). There are pseudo-random number generators, that take a "seed" of entropy and use it to generate data that looks like random data, but eventually the entropy of their output is the same as the entropy of their input (plus the entropy of the algorithm itself).

As others have mentioned, you can measure physical noise, which is essentially random, and use it as an entropy source for a PRNG to produce a sequence with relatively high entropy, or just use the noise itself (after some algorithmic "whitening"/debiasing), which is mainly done on cryptographic applications.

I want to address another point of the question; that is, can you generate a random number?

You can generate a random number from a finite set of numbers, e.g 1...N for some N. But can you truly generate a random natural number, or a random number in the range 0..1? Or a random real number?

The short answer is, practically, no, you can't generate any random element from an infinite set, simply because that would require infinite information.

Theoretically, this question gets even more tricky, because it requires some careful definitions of "probability measures" which essentially determine how numbers are "grouped" together, and the likelihood of choosing from each group of numbers. E.g if I want a uniform random number between 0..1, I know that there should be a 50% chance the number is between 0..0.5.

But anyway, I've rambled long enough. Hope this answer is satisfactory

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The skin in your ear canal grows outwards in a bit of a spiral fashion, which naturally pushes your cerumen and other debris out of the ear. Source: M.S. Audiological Science

I'm an audiologist!

It's a few things.

1) Your ear drum is actually tucked back there about 25mm, around two bends, so it's not like a straight shot (for most ears), giving it some protection.

2) The outer 1/3 of your ear canal is cartilage. It's porous and always producing wax. The wax is excreted and moves in a circular motion as it gravitates toward the outside of the ear. As it moves, it collects all the dust and dirt that goes into your ear and carries it out.

3) Eventually the wax makes its way to the opening of the ear canal and falls away or is washed away in the shower.

This is all to say that the primary reason not to use q-tips is that you think you're cleaning your ears, but you're actually pushing ear wax further back into your ear canal. If you push it back into thy bony portion, it gets stuck because it isn't being pushed out any longer. Do this enough and you'll get a big, hard, black accumulation of impacted ear wax which will hurt to get removed.

Also - your ear drum can get dirty. Bacteria, viruses, hairs, bugs, and all sorts of other things do end up around your ear drum.

Imagine you had a hose full of gunk. How would you get the gunk out of the hose without sticking a wire up the hose (and therefore risk damaging it from the inside)?

Well, you'd hook it up to a clean source of water and blow it out.

Your ear is a hose full of gunk. Your ear is also creating more wax every day. That wax is the "clean source of water" that slowly blows the gunk out of the hose.

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Gravity. One of earwax's main purposes is to collect dead skin, dust, and other debris and carry it out of the ear canal. If you don't stick fingers/q-tips/etc in your ear, you'll intermittently notice little balls of wax falling out. If you DO regularly stick things in your ears, chances are you're impacting earwax against the walls of the ear canal which other earwax sticks to and the entire process gets thrown out of whack.

Lesson: Don't stick things in your ears.

Edit: a few people are posting their own anecdotes where their ears didn’t explode when they inserted an object into their ears. By all means, please do your own research or better yet, ask your doctor.

The mechanism we use to keep water from going into our noses is air pressure. You may not realize you're even doing it but you're using a tiny bit of air in your nasal cavity to keep the water from coming in.

When you're facing up or upside down beneath the water, the air in your nasal cavity escapes upwards and the space it leaves behind is filled with water.

If that's strange to visualize just imagine you're underwater with a straw in your mouth. If you look down at the bottom of the pool and blow into the straw, there will be a point in the blowing process where you've filled the straw with air and ejected all the water, but that the bubbles aren't streaming out. The air pressure in the straw is just enough to fill the straw and keep the water out.

But if you did the same thing facing the surface, any volume of air you pushed into the straw would simply float up to the surface, and the straw would only stay free from water for as long as you were blowing (but would fill with water the moment you stopped). That's what is happening with your nose.

Take a clear glass, flip it upside down, and push it into a bucket of water. The air likes being above the water because it’s much less dense, but the bottom of the glass + you holding the glass down keeps the air (and the glass) from rising up

Now flip the glass over and watch the air bubbles escape while water fills the glass. The same thing happens in your nose when you flip upside down

Go fill up your sink or bathtub with water. Take a cup, and hold it upside down, and push it under the water. Notice how the cup does not fill with water. This is because the space inside the cup is already occupied by air, and because air is lighter than water and there is nowhere for the air to escape to, the water cannot force the air out to take its place inside the cup.

Now, take that same cup, hold it right side up, and push it under the water. Notice how the water rushes in to the cup, and displaces the air that was there. The air is lighter than water, and there is a nice big exist at the top of the cup for the air to escape through, so the air floats up and out of the cup, and the water can take its place.

What is happening to that cup is, very roughly, what happens to your nostrils. When facing down, the water cant get in because air is lighter than water, and the air has no way to escape except downward, so theair cant escape and make space for the water to move in to. When facing up, the air (because it is lighter than water) will float up and exit your nose, allowing the water to move in and occupy the space where the air used to be.

When you are facing up, water displaces the air and is able to enter. When you are facing down, in order for water to enter, it would have to move the air inside your nose downwards, which is very hard to do, as bubbles float upwards.

When you're underwater there's a little bubble that lives in your nose. It's job is to stop the nasty water running up (or down) your nose. Yuk! If you lean too far back underwater that little bubble floats up to the surface to be with all its other airy friends. Then that sneaky water rushes in through your nose! Most people learn to swim by sometimes holding their breath underwater but often you have to slowly blow new bubbles into your nose incase any of them have floated away.

Yes, there’s a few possible scenarios for planets in a binary system.

1 - the two stars orbit eachother very closely and the planets are much further away. Planets too close will get ejected by the gravitational wobbles of the stars, but at a distance they’re effectively one object. The stars will always rise and set together.

2 - the stars orbit far apart, and the planet orbits close to one of them. One star will wander through the sky like another planet, the other rises and sets normally, if the planet isn’t tidally locked.

3 - one star is orders of magnitude more massive than the other and gravitationally dominates the entire system. This isn’t super likely because supermassive stars form and die too quickly to generate stable planetary systems.

Its possible for stars to exist in pairs, triplets, or even up to seven stars in a system

From a planetary perspective you wouldn't get twin sunrises, you'd either be an ice ball with two really bright stars in the sky that don't keep you warm, or have one main sun that rises and sets, and another really bright star in the sky.

Alpha Centauri is one of the more tightly bound binary systems that we have measured, but Alpha Centauri A and Alpha Centauri B (the two main stars) are 23 AU apart which is a bit further than the Sun to Uranus and a bit closer than Neptune is (19 and 30 AU)

The stars are limited on how close they can get and be stable, if they get too close together the bigger one will start pulling material from the smaller one until you end up with either a single big star or a main big star and a tiny dwarf star

Yes, the closest star to us, the alpha centauri system, has three stars (Alpha Centauri A and Alpha Centauri B in a binary formation plus Proxima Centauri) and there are 5 planets in this system.

Yes, binary star systems exist (the majority of stars actually have 1 or more siblings, our Sun is more the anomaly) and yes, planets can have stable orbits in multiple star systems.

The gas giant Kepler-47c orbits 2 stars

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I believe you meat of his idea is that we know the universe was very uniform in its early state because we see matter spread fairly evenly throughout the universe we currently observe. If we go forward in time to the heat death of the universe, where all of the stars have long since burned out and black holes have evaporated due to hawking radiation, the universe will become a sea of uniform radiation, much like we expect to see at the beginning of our universe. Basically the death of the universe seems to produce similar conditions needed at the start of the universe.

What Penrose is suggesting is that unusually warm spots in the cosmic microwave background are indications of the last blackholes evaporating at the end of the universe before this one.

It's not precisely "proof," it's more a hypothesis that seeks to explain odd phenomena in the CMB, and which might point to the existence of a prior universe.

how did the past universe die? or start?

We have no idea.

what doo black holes have to do with the universe's origin?

It's more that black holes are profoundly long-lived objects, such that they'll still be emitting hawking radiation long after the universe they exist in has otherwise gone cold. The spots in the CMB that Penrose is looking at are, he claims, areas of large-scale hawking radiation, where large black holes would be undergoing their final evaporation and death.

Thus, if we were looking for evidence of a prior universe, the best evidence might be areas that show the aftereffects of black hole evaporation.

What is the biggest science misconception about the cannabis plant?

And what has your research told you about the best way to grow it? Is it sustainable to still farm it outdoors as the world gets warmer or will future cannabis farms be in fully controlled environments?

Is there any scientific evidence that flushing plants (feeding only water or decreasing concentration of hydroponic solution) before harvest does anything useful to the final product?

Is there any scientific evidence that leaving plants in total darkness for \~24-72hrs prior to harvest increases cannabinoid concentrations?

Is there any scientific evidence behind the "white ash" test, in which growers seem to believe that cannabis that creates white ash is higher quality or has different mineral content?

Can you speak to the chemical process that is occurring when Cannabis is cured? (e.g. after drying, putting cannabis into air-tight, humidity controlled buckets to allow moisture content to become uniform).

Is there any evidence for supplemental UV lighting to increase cannabinoid concentrations?

As a cancer patient and a medical student marijuana has been very interesting to learn about.

There has to be thousands of compounds in the various strains. Are there any strains or techniques (vaporizing, temperatures etc.)that have shown better anti neoplastic activity or anti-emetic activity? Not to mention every cancer can be wildly different and responds different.

Edit: q2: my specific cancer actually seems to upregulate cannabinoid receptors which may lead to apoptosis when stimulated. Any idea why would the cancer upregulate such a random receptor?

Thanks

https://mct.aacrjournals.org/content/8/7/1838

Thanks for doing this AMA! I am in my late 30s and was recently diagnosed with ADHD. I would consider myself a chronic THC user since my late teens. I've quit cigarettes and alcohol, but I can't seem to kick cannabis. I find it helps with boredom, and elevates my mood (most of the time). I've read that cannabis can both be good and bad for ADHD. Do you have any knowledge to share regarding cannabis and its affects on ADHD users? I've also heard from several doctors it could just be the chronic use and not ADHD, GAD, or MDD, but I had symptoms before I began using cannabis but never recieved any treatment. I also suffer from and have a family history of migraines.

How does increased potency scale with efficacy? Does a 20mg dose provide 2x the benefit of a 10mg dose? Is the relationship linear, exponential, or logarithmic? Thanks

Chicken vs egg problem. The first TV broadcasters were TV/Radio set manufacturers. Shows were broadcast on both radio and on TV and had to be done live as there was no way to prerecord video like there was with audio and the phonograph.

In the early days of broadcasting, there would be very few channels (perhaps only one), and TV would only be available at set times of the day, for example a news broadcast, and then they'd stop broadcasting and the TV would just pick up static for the other ~23 hours of the day.

In the UK anyway, the Queen’s coronation (broadcast on both TV and Radio) was the “killer app” for everyone to go buy a TV.

Before that it was a very limited audience, with almost nothing broadcast only for TV.

Same with the telephone right? First phone, who you gonna call?

Heard a story about the first phone salesmen. One guy was selling way more than anybody else. So they asked him how he did it. He said he told people they wouldn't have to get dressed to talk to their neighbor.

An elder relative says that back in the fifties there were three channels and they didn't even stay on the air all day

It is nearly impossible to remove something completely from the internet. Your answers are most likely still there. If they're not it could be because the hosting Website is no longer online.

What's most likely happening is that pages like Chegg and Coursehero have a higher rank on the search engine and thus being displayed first. The "old" pages are being pushed further down as their rank isn't as high.

Another explanation might be that those pages pay the search engines to get displayed on the first page (think of it like ads).

Try to alter your search query in a way that it looks less like a homework related question. That increases your chances of getting to free answers. You can even try advanced search queries to exclude those homework pages from the search results.

1. They pay Google to prioritize their search results.
2. Free sites get kicked to second page in search results, they start loosing traffic and ad revenue.
3. Free site can no longer pay the bills, has to shut down

If its article you wish to view and its behind a paywall, add "outline.com/" before the https in the url to get around the paywall.

Because these sites are being used to plagiarize assignments and if the content is behind a paywall, plagiarism scanners have a harder time detecting it. Also, money. You’re better off requesting on campus resources

Man, I could rant on this for hours. I'm sure there are others who have been on the internet in here, since the early 90s. People who remember there being 10+ legitimate web search engines, not just ones that were jokes. We had Lycos, Webcrawler, Yahoo (when it was just search), and so many more. Search engines are now, a bastardization of what we once had. Ad revenues and product placement have taken what was truly a search of the Internet, into something that looks like a search result, but is more and more curated for you. The illusion of information is still there, but good luck finding anything they don't want you to see.