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Wednesday, October 7, 2020

How do radio stations know how many people are tuning in?

How do radio stations know how many people are tuning in?

How do radio stations know how many people are tuning in?

Posted: 07 Oct 2020 06:43 AM PDT

Are vaccine platforms reusable?

Posted: 07 Oct 2020 02:30 AM PDT

I'm reading about vaccines and came across a vaccine that is based on the Adenovirus 26. To the best of my knowledge this means that after vaccination the immune system learns to defeat this adonovirus and because of the modification also learns to render the spikes on the corona virus useless. Of course I'm using layman terms here.

If someone is vaccinated with this vaccine and a different virus comes along, can this platform still be used for this new virus?

submitted by /u/LivingAfterMidnight
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Ask Anything Wednesday - Economics, Political Science, Linguistics, Anthropology

Posted: 07 Oct 2020 08:08 AM PDT

Welcome to our weekly feature, Ask Anything Wednesday - this week we are focusing on Economics, Political Science, Linguistics, Anthropology

Do you have a question within these topics you weren't sure was worth submitting? Is something a bit too speculative for a typical /r/AskScience post? No question is too big or small for AAW. In this thread you can ask any science-related question! Things like: "What would happen if...", "How will the future...", "If all the rules for 'X' were different...", "Why does my...".

Asking Questions:

Please post your question as a top-level response to this, and our team of panellists will be here to answer and discuss your questions.

The other topic areas will appear in future Ask Anything Wednesdays, so if you have other questions not covered by this weeks theme please either hold on to it until those topics come around, or go and post over in our sister subreddit /r/AskScienceDiscussion , where every day is Ask Anything Wednesday! Off-theme questions in this post will be removed to try and keep the thread a manageable size for both our readers and panellists.

Answering Questions:

Please only answer a posted question if you are an expert in the field. The full guidelines for posting responses in AskScience can be found here. In short, this is a moderated subreddit, and responses which do not meet our quality guidelines will be removed. Remember, peer reviewed sources are always appreciated, and anecdotes are absolutely not appropriate. In general if your answer begins with 'I think', or 'I've heard', then it's not suitable for /r/AskScience.

If you would like to become a member of the AskScience panel, please refer to the information provided here.

Past AskAnythingWednesday posts can be found here.

Ask away!

submitted by /u/AutoModerator
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How/why do high-elevation limestone formations exist?

Posted: 07 Oct 2020 06:06 AM PDT

I have a geology related class this sem and our current topic is about igneous, sedimentary, and metamorphic rocks. Then it got me thinking, how come there's an area in my country (specifically Baguio City, Philippines) that is very rich in limestone (a sedimentary rock) despite its high elevation?

submitted by /u/cabbagesu
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So, I just got some vaccines and now I’m thinking about them. It seems like vaccines would be more effective if administered intravenously, so why are many vaccines given via the intramuscular route instead?

Posted: 06 Oct 2020 01:41 PM PDT

Why is PCR preferred over ELISA techniques for COVID/19 detection and diagnosis when time window allows it?

Posted: 06 Oct 2020 12:59 PM PDT

After reading the specifics on the different methods, I remain unsure why ELISA ( enzyme-linked immunosorbent assays) tests are not preferred over PCR for COVID19 diagnosis when the detection window is convenient.

In my understanding IgMs start to build up from day 4 to 7 after infection. Therefore, if a potential contact occurred more than 4 days ago, it wouldn't make sense to apply an ELISA test, since it would give additional information (IgG) beyond a current active infection?

submitted by /u/temporalista
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Why do some diseases cause lifelong or much longer periods of immunity than some other diseases?

Posted: 06 Oct 2020 09:04 AM PDT

And why do some need boosters whilst others do not or need fewer boosters?

submitted by /u/amjam441
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In COVID PCR tests, do we have positive controls to check for presence of human sample?

Posted: 06 Oct 2020 02:23 PM PDT

It seems that most RT-PCR tests have positive controls that ensure amplification can be performed in the presence of viral nucleic (by amplifying viral genomic sequence). It is not obvious to me, however, whether they check for whether swab sample was properly collected. This could be done perhaps by using primers that amplify human genomic sequences that should be present in a properly collected sample (e.g. tubulin). This kind of a positive control seems important, given that some places (including my university) have the people getting tested swab themselves and improper swabbing could lead to false negatives.

submitted by /u/rooftopfiddler
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Is there a form/variation of a map that is not right-unique?

Posted: 06 Oct 2020 05:03 AM PDT

A map from X to Y is per definition a left-total and right-unique relation. Is there a (frequently used) relation similar to a map which is not right-unique? I feel like this could be used for non-deterministic problems.

submitted by /u/Keteo
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What causes a shock wave to propagate?

Posted: 05 Oct 2020 12:39 PM PDT

I understand what a shock wave is and what it's characteristics are, but I still don't understand what causes a wave to move through a medium faster than its speed of sound. I would assume that the shock wave would almost instantaneously slow down to sound speed because that's the speed at which "information" travels through the medium but obviously that's not the case. So what drives this speed?

submitted by /u/tylerchu
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What makes blood groups differ from each other and how/ why can't they be universally be accepted by different bodies?

Posted: 05 Oct 2020 05:50 AM PDT
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Tuesday, October 6, 2020

Is it possible to contract COVID 19 a second time?

Is it possible to contract COVID 19 a second time?

Is it possible to contract COVID 19 a second time?

Posted: 06 Oct 2020 04:27 AM PDT

How come multiple viruses/pathogens don’t interfere with one another when in the human body?

Posted: 05 Oct 2020 09:12 AM PDT

I know that having multiple diseases can never be good for us, but is there precedent for multiple pathogens "fighting" each other inside our body?

submitted by /u/Dorpig
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How certain is the scientific community actually about the big bang theory?

Posted: 06 Oct 2020 02:04 AM PDT

We have been observing the expansion of the universe for only a very limited duration, given the assumed age of the universe and we are extrapolating this behavior until the start of time. I mean anything could happen during the time we are not observing. The function we are measuring could be as well a wave, but the time frame of our existence wouldn't be long enough to ever measure a compression of the universe. My point is, are there any factors, that makes it certain that the universe is ever expanding and how certain are scientists about the big bang theory.

submitted by /u/KonArtist01
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With planets similar to earth, would an older planet have more islands and more continents compared to a newer one?

Posted: 06 Oct 2020 02:08 AM PDT

I watched a video of Pangea forming into the current layout of the world. Islands began to pop up more and more and as Pangea broke the separate continents appeared. Would the same thing happen to a planet similar to earth? Also, as earth ages, will/is it likely the continents and current land masses will continue to separate into smaller parts?

submitted by /u/Loni-the-Bonni
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If elettromagnetic radiation can push a body through radiation pressure, the body emitting the radiation is pushed in the opposite direction?

Posted: 05 Oct 2020 12:30 PM PDT

If yes, a laser emitting spacecraft is pushed in the opposite direction?

If no, if I attach a laser emitting tool to a solar sail, can I generate a net push of the two body system?

Both answers seem to violate some physics law. So I'm probably missing some important point.

submitted by /u/zulured
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How do charging pads for your phone work?

Posted: 06 Oct 2020 05:10 AM PDT

Does the flu vaccine strengthen the body's immune system in general and does the flu vaccine continue working if in the next few years the same strain of flu reappears?

Posted: 05 Oct 2020 12:17 PM PDT

Why is it that roughly 25% of the numbers less than 100 are prime and as you go past 100 the percentage of prime numbers steadily drops?

Posted: 05 Oct 2020 10:51 AM PDT

Just like the title says. There are 25 numbers between 1 and 99 that are prime (25%)

There are 168 primes between 1 and 1,000. (17%)

There are 1,229 primes between 1 and 10,000 (12%)

Why are primes more common in smaller numbers than in bigger numbers?

submitted by /u/Part_of_the_Infinite
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Have we ever killed a virus?

Posted: 05 Oct 2020 09:21 PM PDT

I know viruses aren't alive but are there any examples of a virus we have basically made extinct?

submitted by /u/ZomboFc
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Are all spider webs the same? Could one spider use another's web, or would it get stuck?

Posted: 04 Oct 2020 07:17 PM PDT

[Physics] How is reflection of a photon different from absorption/ re-emission? What happens to a molecule when light is reflected?

Posted: 04 Oct 2020 10:45 PM PDT

I understand the basic idea of an emission spectrum. But what about an object that doesn't radiate photons? Like when light hits a red apple, the skin of the apple is made of molecules that happen to absorb everything except red wavelengths. The red is reflected into our eyes so we see red. (I know the color vision part isn't that simple, but I'm talking about the basic idea that we see the wavelengths that were not absorbed).

What makes a molecule unable to absorb specific wavelengths? And what exactly is happening when a photon is reflected? If it is being absorbed and re-emitted, why doesn't the object glow? (I know the object will eventually glow red if we heat it up enough. But I'm just trying to understand why ordinary non-heated objects appear different colors.)

submitted by /u/miparasito
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Monday, October 5, 2020

Why do turbofan engines have 2 shafts, 1 for the main fan and low pressure parts, and then another for the high pressure compressor etc. Why cant it all be on one shaft?

Why do turbofan engines have 2 shafts, 1 for the main fan and low pressure parts, and then another for the high pressure compressor etc. Why cant it all be on one shaft?

Why do turbofan engines have 2 shafts, 1 for the main fan and low pressure parts, and then another for the high pressure compressor etc. Why cant it all be on one shaft?

Posted: 04 Oct 2020 07:55 PM PDT

What is the difference between fluorescence and “normal” colour?

Posted: 04 Oct 2020 10:11 PM PDT

How I understand it, an object has colour because it is hit by electromagnetic waves of various wavelengths, then the electrons in that object get excited. After some time the electron loses its gained energy and emitts electromagnetic radiation of a certain frequency unique to the chemical structure of the object.

My question is how fluorescence (and phosphorescence for good measure) is any different to this principle. And if there is no difference, what makes it special?

submitted by /u/pithlw
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If we were able to capture a blackhole 55 million light years away, how come we haven't been able to capture milkyway's blackhole yet which is just 25000 light years away?

Posted: 04 Oct 2020 10:30 PM PDT

Is ultraviolet light an effective disinfectant against COVID-19?

Posted: 04 Oct 2020 07:32 PM PDT

I've mostly seen information and news about using cleaning products, wipes, gloves, and masks to clean surfaces, but not the use of UV light. Is UV light not effective against COVId-19?

submitted by /u/Shamouti
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How do the RFID chips in contactless work without a power source?

Posted: 04 Oct 2020 02:25 PM PDT

How is it that certain viruses, such as HPV or herpes, have some strains that only affect one area of the body?

Posted: 04 Oct 2020 01:11 PM PDT

For example, why can we inoculate against genital warts but not plantar or other forms?

submitted by /u/SardineCop
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How do DNA tests not pickup the DNA from the cotton swab?

Posted: 04 Oct 2020 10:55 AM PDT

When Cotten swabs are used in forensics, or COVID tests, are anything else that is meant to pickup DNA, how does the DNA from the cotton swab?

submitted by /u/enzodr
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Why is it impossible to determine the position and momentum of a quantum particle at the same time?

Posted: 04 Oct 2020 09:19 PM PDT

How long do microbes live for? What’s the average lifespan?

Posted: 03 Oct 2020 08:32 PM PDT

Does the output of a battery change as the battery depletes? If so, how is it engineered so that the battery will always give out an expected output?

Posted: 03 Oct 2020 07:38 PM PDT

Why is the Lyman series so important in our understanding of the Reionization Epoch?

Posted: 04 Oct 2020 03:37 AM PDT

What specific polypeptides are in Beans that make them “a good source?”

Posted: 03 Oct 2020 09:22 PM PDT

I understand AAs, I'm looking for what proteins used by living beans are abundant. Like how amalose makes potatoes a good source of carbs. Is it mostly membrane bound like ATPase or what?

submitted by /u/StandardElk
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Sunday, October 4, 2020

I always thought that all dirt is the result of fungus slowly breaking apart bedrock over millions of years but I do not know if this is actually true. Is it?

I always thought that all dirt is the result of fungus slowly breaking apart bedrock over millions of years but I do not know if this is actually true. Is it?

I always thought that all dirt is the result of fungus slowly breaking apart bedrock over millions of years but I do not know if this is actually true. Is it?

Posted: 04 Oct 2020 05:53 AM PDT

Assuming that is true does it mean most every rocky planet in our galaxy is just bedrock and oceans? Ive never considered the fact that all rocky planets might look incredibly similar to one another.

submitted by /u/weird_foreign_odor
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Is the density of black holes constant, since adding or removing mass only affects the size of the black hole?

Posted: 03 Oct 2020 08:34 PM PDT

What is the difference between gravitational mass and inertial mass?

Posted: 03 Oct 2020 01:08 PM PDT

How long can anosmia persist after a covid-19 infection?

Posted: 04 Oct 2020 03:52 AM PDT

As I read on papers and articles, one of the distinct symptoms of an infection from covid-19 is anosmia (i.e. loss of smell), that seem to appear soon after infection.

My question is: how long does anosmia persist in covid-19 patients? Has there been any instances where patients that healed from the infection showed symptoms of anosmia even months after the recovery?

Thanks a lot!

submitted by /u/_white_jesus
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How did the black death of the 14th century spread?

Posted: 04 Oct 2020 01:54 AM PDT

If the plague was caused by the bacterium Yersinia Pestis, which was carried by fleas - how did it spread from human to human? Was it flea transmission?

And as far as I'm aware there were 3 forms of the plague in 14thC Europe, was it all spread the same way?

submitted by /u/liquidtension
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Do two observers agree on the position of a beam of light?

Posted: 03 Oct 2020 07:17 PM PDT

Suppose you have an observer on earth, a traveler in a rocketship, and a beam of light.

The rocketship leaves earth and travels at the speed of 0.5c. The same time the rocketship launched, a beam of light was emitted in the same direction as the ship.

After one year:

The earthbound observer observes the rocketship to be 0.5 light years away, and the light beam to be 1 light year away.

​

Because the beam of light always appears to be traveling at c no matter what speed an observer is travelling at, the rocketship traveler also observes that the light beam to be 1 light year away, even though he has travelled 0.5 light years during this time. So the rocketship traveler believes that the light beam is around 1.5 light years from the earth, but the earthbound observer believes that the light beam is 1 light year from earth.

​

earth------>*[spaceship]

​

earth-------------------------------->*[light beam position from earth observer]

​

earth---------------------------------------------------------------->*[light beam position from spaceship observer]

​

earth--------0.5 light year --------1.0 light year-------------1.5 light year

​

I realize that time and length will vary between observers. In my example at the speed of 0.5c the time dilation factor is 86%. So close to normal time, dilated a reasonable bit, but not extreme. Nothing accounts for the 50% difference in observations, where is this light beam at?

submitted by /u/jeffial_relativity
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Which cells in the human body contain the 23 chromosomes that were sequenced for the first time in 2001?

Posted: 03 Oct 2020 10:52 PM PDT

I have heard many, many times how incredible a feat it is to have sequenced the human genome. However, I can't wrap my head around how it is done. Bacteria are single-celled organisms, so for me it is quite straightforward to understand the sequencing process. But when we talk about incredibly intricate multi-cellular organisms, I can't understand what is actually being sequenced. Where is the DNA coming from and where is it located? How does one isolate this DNA? Which cells in our body actually contain "the human genome" and why do they?

submitted by /u/PhiloQib
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Does the color of the tapetum lucidum correlate with the types of rhodopsins for that animal?

Posted: 03 Oct 2020 06:26 PM PDT

I was just thinking how the color of the tapetum lucidum varies from species to species, and I imagine the suite of cones and rods also vary. Crocodilians have an orange tapetum lucidum. Is that the color of light their eyes are most sensitive to?

submitted by /u/teach5ci
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What causes the "printer ran out of ink" effect on litters of cats with black-and-white coloring?

Posted: 03 Oct 2020 08:24 AM PDT

You know how when a tuxedo cat has a litter of kittens, they can range in coloring with each one progressing from black and white, to dark gray, light gray, and mostly white? Biologically why does this happen instead of all the kittens having the same black and white?

submitted by /u/Marshall_Lawson
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does metal decay or rust on mars?

Posted: 03 Oct 2020 10:10 AM PDT

after some quick research I found that there is a little oxygen there; does that mean metal can oxidize on mars?

submitted by /u/StrangerProgress
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Could a giant world-size heat sink to outer space technically work?

Posted: 03 Oct 2020 08:30 AM PDT

I was thinking how computers transfer lots of heat to specific places on the computer go keep it cool, theoretically could we build something like that but that goes between through the atmosphere, transferring away some of the heat we've created? Outside of the obvious, 'we cant build something that big' reasons?

submitted by /u/scdirtdragon
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Would spacecraft in perfect two body problem maintain attitude because the gravitational field has a zero curl vector?

Posted: 03 Oct 2020 11:25 AM PDT

Ignoring perturbations, assuming a perfect 2-body problem with M1>>M2, where M2 is the spacecraft's mass, and assuming the spacecraft is in circular orbit for simplicity, would a spacecraft maintain attitude as it goes around its orbit?

I'm learning about torques on spacecraft due to atmospheric drag, solar radiation, electromagnetic forces, and gravity gradient effects. But because the gravitational field has a curl of zero (vector), shouldn't the spacecraft maintain whatever attitude it has?

I'm also thinking about irrotational vortices, where a twig floating in water would maintain its attitude as it travels around in a circular path.

So what would happen if it was a perfect 2 body problem and I guess the only torque would be due to the gravity gradient? Also, if it would, why would it rotate the spacecraft since there's zero curl? Does the idea of a twig floating in water rotating only apply to paths that travel along the streamlines of the vector field?

submitted by /u/Armang211
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How viable are GaN processors and solar panels?

Posted: 03 Oct 2020 08:55 AM PDT

I've seen in a ton of tech videos and products from things like phone/laptop chargers that Gallium Nitrite can replace Silicon because of its higher efficiency, etc. I also noticed that solar panels use Silicon as its semiconductor. Do you think GaN could replace silicon in solar panels and processors? As far as I know, no one's been working on big (important) GaN chips other than chargers. Is this because it's not fit for every task Silicon is used for, or just because we haven't tried/succeeded/reported on it yet?

submitted by /u/marvil_txt
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Why are some fats not shown on the back label of food?

Posted: 03 Oct 2020 06:30 AM PDT

I was eating some almonds and it said it has 16.9 grams of fat in 1 serving and it said in the 16.9gs of fat it has there is 1.3 grams of saturated fat and nothing else. So how will we know what are the other types of fats present in the almonds that I was eating?

submitted by /u/yomomma935
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Are the orbits of the planets in our solar system flat, or largely on a similar plane? Why? If so, are planets in other solar systems the same?

Posted: 03 Oct 2020 04:41 AM PDT

Why do halons have methane in their chemical name?

Posted: 02 Oct 2020 11:58 AM PDT

Like halon 121 (bromochlorodifluoromethane) CF2ClBr. Why does it have methane in the name of it doesn't have methane?

submitted by /u/AmumuPro
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Saturday, October 3, 2020

What drives the movements of tectonic plates?

What drives the movements of tectonic plates?

What drives the movements of tectonic plates?

Posted: 02 Oct 2020 05:34 PM PDT

For COVID, What is the range of times from "below the PCR LOD" to onset of fever?

Posted: 02 Oct 2020 03:35 PM PDT

President Trump is reported to have tested positive for COVID Thursday (presumably evening) but also had a fever Friday afternoon. He also has said he's tested at least daily.

This seems like a very fast progression. My understanding is that PCR is sensitive enough to detect at viral loads well below what's necessary to trigger an immune response. So is 24 hours from negative result to fever within the confidence interval?

I assume a negative test on Wednesday was a true negative, i.e. the viral load was below the limit of detection until Thursday. I also assume the President's COVID samples are fast tracked so the result is known around 8 hours after the swab.

submitted by /u/drhunny
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If the symptoms of flu(fever, coughing) are from the immune response, rather than the virus. Why don't we get flu like symptoms after a flu vaccine?

Posted: 03 Oct 2020 04:20 AM PDT

Can an Alpha Process be replicated in a lab or a fusion reactor?

Posted: 03 Oct 2020 12:23 AM PDT

So, I've been playing around on Wikipedia, and I happen to come across a couple of article that talk about Alpha Processes, which to my understanding are various nucleosynthesis reactions in which certain elements are fused with Helium to produce other elements and energy in the form of photons.

The one that caught my attention is what seems to be the most basic alpha process, in which a single Carbon-12 atom is fused with a Helium-4 atom to produce a single Oxygen-16 atom and 7.16 MeV of energy in the form of photons.

Of course, Alpha Processes naturally occur within stars; but, what I'd like to know is if it's possible (at least in theory) to fuse Carbon-12 atoms with Helium-4 atoms either in a lab or at scale in a special sort of fusion reactor (to produce oxygen and clean energy).

submitted by /u/sparky77734
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How Long Does Sunscreen Protect You For?

Posted: 01 Oct 2020 06:28 PM PDT

Sunscreen bottles often say something like "reapply every two hours." Does that mean I have zero sun protection two hours after applying SPF 50 or does it mean the protection I have has dipped below the advertised amount of SPF 50? Does Sunscreen stop working flat out after two hours, or after two hours has my SPF 50 lowered itself to something like SPF 40?

submitted by /u/old_sultan
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Do species that live shorter life spans evolved faster?

Posted: 01 Oct 2020 07:09 PM PDT

I recently saw a video that talked about how ravens are much smart and more conscious than previously thought. It made me wonder if they can evolve faster than humans since they reproduce and die faster than we do.

submitted by /u/TheBeedo11
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