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Monday, September 7, 2020

How do we know what is in the core of the distant planets?

How do we know what is in the core of the distant planets?


How do we know what is in the core of the distant planets?

Posted: 06 Sep 2020 05:31 PM PDT

I tried to google for a bit and learned that we know what the inside of earth is made up by analyzing earthquake data (still not 100% sure how it works but I got the idea). But I could not find out how we know for example that the moon core is supposed to be liquid or even what further planets "contain" under their surface? Also how do we know what the temperatures inside the sun or other planets/stars cores are? Thanks a lot.

submitted by /u/Bamb00zld
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Is there an evolutionary advantage to Dolphins and Whales breathing air as opposed to developing gills and being able to remain underwater indefinitely?

Posted: 06 Sep 2020 10:05 AM PDT

Los Angeles saw temperatures above 120F (49C) today. How many years until they begin to see temps above 130F (54C)?

Posted: 06 Sep 2020 11:58 PM PDT

Alternatively: Did any models predict that LA could get so hot as what we're seeing now? What do those models tell us about the next decade?

submitted by /u/SmokeyBlazingwood20
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At what point is the phase III clinical trial of a vaccine considered complete? Is there a minimum time frame? Or some statistical threshold that is a function of duration and number of test subjects?

Posted: 06 Sep 2020 02:02 PM PDT

So, does the earth have seven or eight layers?

Posted: 06 Sep 2020 02:35 PM PDT

The core is composed of two layers, the mantle is in four layers, and the crust, so can we consider the crust one or two layers?

submitted by /u/habeuseenalienitsme
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If protons and neutrons both have a mass greater than 1 amu how can an atom with a mass number of N have a mass of less than N amu?

Posted: 06 Sep 2020 10:51 AM PDT

As an example according to my chemistry book Cl-35 has a mass of 34.97 amu.

submitted by /u/TheCyberParrot
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Do large earthquakes leave traces in the geologic record?

Posted: 06 Sep 2020 10:51 AM PDT

For example, if a magnitude 8 earthquake happened 30 million years ago, could we figure out that it happened and also when it happened by examining the geologic record?

submitted by /u/terryfrombronx
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Wing sweep angle and supersonic shock cone angle, is there an interesting interaction?

Posted: 06 Sep 2020 08:55 PM PDT

Per my understanding, aircraft will often have swept wings to reduce drag. Something about cord-wise drag vs spanwise drag, not entirely sure.

Supersonic objects will create a sonic boom, the angle of which depends on the speed, right? Higher Mach speeds producing a sharper angle.

My question then, is thus: What's the relation between the sweep angle of the wing (or more generally, the pointiness of a projectile) and the Mach number? Do we see any interesting occur when the mach cone is smaller than the object angle? What about crossing that threshold?

submitted by /u/ThePerpetual
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Could we tell a message is maximily encrypted from random?

Posted: 06 Sep 2020 05:35 AM PDT

If a cell's telomeres are maintained by the hormone telomerase, will that cell be able to divide indefinately. If so, will the cell be considered Immortal?

Posted: 06 Sep 2020 06:50 AM PDT

How is hydrocortisone manufactured for medical use?

Posted: 06 Sep 2020 08:19 AM PDT

What gives lightning its color?

Posted: 06 Sep 2020 08:06 AM PDT

What gives lightning its color? I know that lightning bolts are essentially plasma. So does it have to do with the argon concentration in the atmosphere? Thanks :)

submitted by /u/Outliver
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Do pelvic splanchnic nerves provide both parasympathetic and sympathetic innervation to the hindgut?

Posted: 06 Sep 2020 08:55 AM PDT

I was looking through a textbook that said the splanchnic nerves provide sympathetic innervation to the hindgut, but I remember learning last year that they were part of the parasympathetic system (because it's sacral outflow). I've looked for answers online and pretty much just see that they're parasympathetic, so I'm not sure if the textbook is wrong or if I'm not looking at the right sources online.

submitted by /u/mybustlinghedgerow
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What is a clonal genotype and how is it different from the parental genotype?

Posted: 06 Sep 2020 08:45 AM PDT

I've run across this term recently and I'm perhaps limited by my knowledge of cloning. I thought a clone was genetically identical to the parent so how could the genotype be different?

submitted by /u/orangeElysia
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Why does our body not store zinc?

Posted: 05 Sep 2020 11:24 PM PDT

I know that zinc is important for our body and we need daily dose of it but why isn't it stored in body for later use?

submitted by /u/Zatch_1999
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Does the human body heal wounds at a constant rate 24/7 assuming energy needs were met?

Posted: 05 Sep 2020 07:23 PM PDT

How does Alzheimer’s kill you?

Posted: 05 Sep 2020 07:47 PM PDT

Sunday, September 6, 2020

Sometimes when we rub our eyes too hard you lose your vision for a second and then it comes back gradually. Why is that?

Sometimes when we rub our eyes too hard you lose your vision for a second and then it comes back gradually. Why is that?


Sometimes when we rub our eyes too hard you lose your vision for a second and then it comes back gradually. Why is that?

Posted: 05 Sep 2020 10:42 PM PDT

Quick question, how does a rocket engine like Merlin 1D NOT melt the rocket's nozzle?

Posted: 05 Sep 2020 10:58 AM PDT

What kind of material withstands so much heat and energy from that kind of rocket engine? How can they be reusable? I saw a testing video from SpaceX that lasted 3 mins and couldn't stop wondering how is it that the nozzle of the engine didn't melt away.

submitted by /u/TraceHunter69
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Why do many various neurotransmitters exist if nerve signals are binary?

Posted: 05 Sep 2020 10:22 PM PDT

As far as I know neurotransmitters are only released, bound to receptors and reuptaken in the synpatic cleft. I that is the case, then what's the point of multiple neurotransmitter types if chemical signal is going to only be translated into a binary electric signal that is 1 (excitation of the membrane), while none is 0 (resting membrane potential)? For me, in my limited knowledge, it appears as if their existance is useless since electrical signals alone or just a single neutrotransmitter type would suffice, unless neurotransmitters were released into the intracellural space and all neurons in an area of the brain with specific receptors would pick them up, which isn't a case in models I can find on the internet or in books.

I know I am wrong but having asked many highschool teachers noone was able to answer this question to me years ago. Can anyone explain this to me in best detail possible?

submitted by /u/dreamingcel
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If the lungs in land vertebrates evolved from the gas bladder, what did the gills evolve into?

Posted: 05 Sep 2020 04:28 PM PDT

How do modern ship anchors work? If they get stuck on the sea bed how do we free them?

Posted: 05 Sep 2020 03:16 PM PDT

How do modern sea anchors work? Do they hook onto rocks? Sink into the sea bed? Just weight the ship down? What happens if they get stuck?

submitted by /u/Sllinder
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Why diseases like hepatitis, measles still exist even there is the vaccine?

Posted: 05 Sep 2020 09:32 AM PDT

The smallpox vaccine was developed by Edward Jenner, in 1796. After many years, WHO issued its official declaration that 'the world and all its peoples have won freedom from smallpox' in May 1980. We also have vaccines against some viruses and bacterias. Why cannot we eliminate them?

submitted by /u/ernstwmayr
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Does the human body absorb Vitamin D from the sun via the eyes or skin?

Posted: 04 Sep 2020 03:22 PM PDT

Keep finding conflicting answers on this online

Can you absorb vitamin D from sun fully clothed head to toe but keeping your eyes open on a sunny day (absorbed through eyes)

Conversely, could you absorb vitamin D from the sun while laying out tanning but with your eyes closed (absorbed through skin)

I always thought it was the latter but I was recently told otherwise and I haven't been able to find a consistent answer online

submitted by /u/MulhollandDrive
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Saturday, September 5, 2020

If you picked a random spot in the middle of the ocean would it be teeming with life? Or are there huge dead zones with no fish around?

If you picked a random spot in the middle of the ocean would it be teeming with life? Or are there huge dead zones with no fish around?


If you picked a random spot in the middle of the ocean would it be teeming with life? Or are there huge dead zones with no fish around?

Posted: 04 Sep 2020 08:32 PM PDT

Do other primates also have human-like circadian sleep rhythms, or do they sleep more, less, more intermittent?

Posted: 05 Sep 2020 03:35 AM PDT

Was there ever a period in Earth's history when there were no deserts?

Posted: 04 Sep 2020 09:56 AM PDT

Why do proposed Covid-19 vaccines have to be stored at very cold temperatures?

Posted: 04 Sep 2020 10:59 PM PDT

Is the earths core directly in the centre of the earth?

Posted: 05 Sep 2020 12:54 AM PDT

So the Earth has a molten core, I know that, but is it stationary and is it directly in the centre of our lovely oblate spheroid?

submitted by /u/ObiJuaan
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Why do more efficient rocket engines provide less thrust?

Posted: 04 Sep 2020 06:47 PM PDT

RP-1 provides lots of thrust but have low efficiency. Hydrogen provides less thrust than RP-1 buts it's the most efficient chemical fuel. NERVA and Ion engines are the most efficient sources of propulsion we can make but can only be used in space because it gives off so little thrust. Rocket fuels are most efficient the faster the engine can shoot it out the back. But why does higher efficiency mean lower thrust?

TL-DR: How come an ion engine can't put a Falcon 9 into space?

submitted by /u/SkeetSkeetliftwaft
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Why does the flu vaccine need to be injected?

Posted: 04 Sep 2020 10:12 AM PDT

Could smallpox come back?

Posted: 04 Sep 2020 10:39 AM PDT

I know smallpox is gone for now, but could it come back in different forms? If so, how does that happen/work?

submitted by /u/ItalianMerengue96
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What causes a brief flicker of the power vs a long power outage?

Posted: 04 Sep 2020 01:24 PM PDT

Obesity & COVID-19: Why does CDC data show obesity as a comorbidity on just 3.6% of Covid-19 deaths, yet numerous articles and studies continue to indicate it as one of the top conditions influencing negative Covid-19 outcomes?

Posted: 04 Sep 2020 06:53 PM PDT

Numerous articles and reports indicate how obesity plays a serious role in exacerbating Covid-19. For example: "People with obesity are much more likely to be diagnosed with the novel coronavirus, undergo hospitalization and ICU admission, and die." https://www.medscape.com/viewarticle/936790

However, in the CDC data on deaths from Covid-19, obesity is listed as a comorbidity in only 3.6% (6059 deaths out of 169k) of these fatalities. https://www.cdc.gov/nchs/nvss/vsrr/covid_weekly/index.htm?fbclid=IwAR2-muRM3tB3uBdbTrmKwH1NdaBx6PpZo2kxotNwkUXlnbZXCwSRP2OmqsI#Comorbidities

What am I missing here? Can someone please explain this apparent discrepancy?

submitted by /u/SubjectWestern
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Why does a flight from London to Amsterdam take almost half an hour longer than a flight from Amsterdam to London?

Posted: 04 Sep 2020 08:19 AM PDT

How are antibodies replenished?

Posted: 04 Sep 2020 11:16 AM PDT

My understanding is that when the organism is exposed to a virus (or a vaccine) it produces antibodies, that kill the virus. The antibodies stay after the virus is defeated, protecting from reinfection (am I correct so far?)

So what happens next, when the organism isn't exposed to the virus for a while? Are antibodies continuously produced to maintain the immunity? Or does the production stop and so the immunity only lasts until antibodies decay/flush out from the body?

submitted by /u/me-gustan-los-trenes
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Is the field E produced by a charge q continuous?

Posted: 04 Sep 2020 07:23 AM PDT

Not the charge itself, but rather the field E it produces. And if so, what's the smallest area of space a field can be considered to have one value. If answered, what's the highest\lowest value the field take in that area?

submitted by /u/Hi_Cham
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Friday, September 4, 2020

AskScience AMA Series: We are Cosmologists, Experts on the Cosmic Microwave Background, Gravitational Lensing, the Structure of the Universe and much more! Ask Us Anything!

AskScience AMA Series: We are Cosmologists, Experts on the Cosmic Microwave Background, Gravitational Lensing, the Structure of the Universe and much more! Ask Us Anything!


AskScience AMA Series: We are Cosmologists, Experts on the Cosmic Microwave Background, Gravitational Lensing, the Structure of the Universe and much more! Ask Us Anything!

Posted: 04 Sep 2020 04:01 AM PDT

We are a bunch of cosmologists from the Cosmology from Home 2020 conference. Ask us anything, from our daily research to the organization of a large conference during COVID19! We have some special experts on

  • Inflation: The mind-bogglingly fast expansion of the Universe in a fraction of the first second. It turned tiny quantum fluctuation into the seeds for the galaxies and clusters we see today
  • The Cosmic Microwave background: The radiation reaching us from a few hundred thousand years after the Big Bang. It shows us how our universe was like, 13.4 billion years ago
  • Large Scale Structure: Matter in the Universe forms a "cosmic web" with clusters, filaments and voids. The positions of galaxies in the sky shows imprints of the physics in the early universe
  • Dark Matter: Most matter in the universe seems to be "Dark Matter", i.e. not noticeable through any means except for its effect on light and other matter via gravity
  • Gravitational Lensing: Matter in the universe bends the path of light. This allows us to "see" the (invisible) dark matter in the Universe and how it is distributed
  • And ask anything else you want to know!

Answering your questions tonight are

  • Alexandre Adler: u/bachpropagate PhD student at Stockholm University. Systematics for cosmic microwave background polarization experiments (Spider, Simons Observatory, Litebird) and CMB data analysis. Twitter: @BachPropagate.
  • Alex Gough: u/acwgough PhD student: Analytic techniques for studying clustering into the nonlinear regime, and on how to develop clever statistics to extract cosmological information. Previous work on modelling galactic foregrounds for CMB physics. Twitter: @acwgough.
  • Arthur Tsang: u/onymous_ocelot Strong gravitational lensing and how we can use perturbations in lensed images to learn more about dark matter at smaller scales.
  • Benjamin Wallisch: Cosmological probes of particle physics, neutrinos, early universe, cosmological probes of inflation, cosmic microwave background, large-scale structure of the universe.
  • Giulia Giannini: u/astrowberries PhD student at IFAE in Spain. Studies weak lensing of distant galaxies as cosmological probes of dark energy.
  • Hayley Macpherson: u/cosmohay. Numerical (and general) relativity, and cosmological simulations of large-scale structure formation
  • Katie Mack: u/astro_katie. cosmology, dark matter, early universe, black holes, galaxy formation, end of universe
  • Robert Lilow: (theoretical models for the) gravitational clustering of cosmic matter. (reconstruction of the) matter distribution in the local Universe.
  • Robert Reischke: /u/rfreischke Large-scale structure, weak gravitational lensing, intensity mapping and statistics
  • Shaun Hotchkiss: u/just_shaun large scale structure, fuzzy dark matter, compact object in the early universe, inflation. Twitter: @just_shaun
  • Stefan Heimersheim: u/Stefan-Cosmo, 21cm cosmology, Cosmic Microwave Background, Dark Matter. Twitter: @AskScience_IoA
  • Tilman Tröster u/space_statistics: weak gravitational lensing, large-scale structure, statistics
  • Valentina Cesare u/vale_astro: PhD working on modified theories of gravity on galaxy scale

We'll start answering questions from 19:00 GMT/UTC on Friday (12pm PT, 3pm ET, 8pm BST, 9pm CEST) as well as live streaming our discussion of our answers via YouTube. Looking forward to your questions, ask us anything!

submitted by /u/AskScienceModerator
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How can a radiating body be in equilibrium with its environment?

Posted: 04 Sep 2020 02:21 AM PDT

The Black Body Radiation article on Wikipedia says:

"Black-body radiation is the thermal electromagnetic radiation within or surrounding a body in thermodynamic equilibrium with its environment, emitted by a black body (an idealized opaque, non-reflective body)."

If equilibrium means there is no net transfer or matter or energy, how does a black body radiate anything?

The article also describes how the spectra of lava, fire and heated steel can be used to approximate their temperatures. All these seem to have a net transfer of energy into their surroundings, heating the air around them.

submitted by /u/miscalibrated
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How to distinguish between an unstable atom and an element with a very short half-life?

Posted: 03 Sep 2020 06:13 PM PDT

Oganesson, the current last element of the periodic table, has a half-life of merely 0.89 milliseconds. Are there other standards that deem it to be a genuine element instead of a bunch of stuff forcibly bound together?

submitted by /u/crescentpieris
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Do we have any predictions or models that show how many more people in the US would have died if we hadn’t gone on lockdown?

Posted: 04 Sep 2020 05:45 AM PDT

How consistant is the spread of elements in the milky way? And what impact might that have on development of intelligent life?

Posted: 04 Sep 2020 05:14 AM PDT

I'm wondering how common a scenario might be whereby intelligent life evolves on a planet but they lack the elements/materials to progress through an industrial evolution. Such a civilisation would be unable to leave their home world and might be an explanation as to why we haven't detected any alien civilisations yet.

Or is it the case that most star systems start off with roughly the same stuff?

submitted by /u/andymilnedb10
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When Pangea was the only one continent, were there big islands built by volcano like Hawaii around the world?

Posted: 03 Sep 2020 09:07 AM PDT

How do we know how many stars are in our galaxy or any other?

Posted: 03 Sep 2020 09:50 AM PDT

I assume the estimate of 250B +/- 150B stars in the milky way is extremely rough, but it seems to be based on something. What is that estimate based on? Do we chop galaxies into cubes and count the stars per cube, or maybe use cosmological principles, or other observable facts like the gravitational influence or output of different types of electromagnetic radiation of a galaxy to infer star count? If so, how, and what else do we do?

submitted by /u/Veridically_
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Is it possible to tell the shape of a piece of metal from the sound it makes when stuck?

Posted: 03 Sep 2020 11:36 PM PDT

More wondering if that information is transmitted in the sound, and if with infinite precision, could it be done. Obviously this would be nearly impossible by hand.

submitted by /u/Skrtmvsterr
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If Photons are massless particles, does this mean Photons don’t interact with the Higgs field?

Posted: 03 Sep 2020 08:23 PM PDT

When people say smokers have many more nicotine receptors in the brain than non-smokers, what does this exactly mean and why is it bad?

Posted: 03 Sep 2020 11:27 PM PDT

Is having too much of a brain receptor bad? how does it work?

submitted by /u/rzzzvvs
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How do flies walk on the ceiling?

Posted: 03 Sep 2020 11:23 PM PDT

Is it something to do with a biological component or is it just physics?

submitted by /u/WhiTeHaT_420
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Are Redshift/Blueshift used to determine which way a star is traveling? How can we know when one is happening instead of the other?

Posted: 03 Sep 2020 05:32 PM PDT

I understand the Doppler effect and how Redshift and Blueshift happen, but I don't understand, when we observe a star, how we can know when we're observing the result of one vs the other (or neither).

submitted by /u/SteveTCook
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Does having friends in your learning enviornment help you learn better?

Posted: 04 Sep 2020 01:10 AM PDT

Can tectonic plates fuse and become one?

Posted: 03 Sep 2020 07:35 AM PDT

I am trying to create a fictional world, and the first thing I did was start with a planet and plate boundaries. I have an idea of what my continents will look like, one of which is in the middle of the plate, but has a mountain range. Instead of putting an active plate boundary there (i.e Indian subcontinent), I was thinking that this range is a result of two plates coliding in the distant past and then fusing into one plate.

My question is, how realistic would it be to have two plates collide and fuse into one? Is it possible for a plate boundary to go extinct leaving a mountain range that is slowly eroding? Is there a such thing as an ancient plate boundary?

Any help would be appreciated.

submitted by /u/kgabny
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How does the nerve agent Novichok work?

Posted: 03 Sep 2020 08:59 AM PDT

So, this poison has been in the news quite a bit after the poisoning of Viktor Skripal in 2018 and now again after Alexander Navalny suffered a similar fate. Now I, with my grant total of zero knowledge with regards to both poisons and intelligence work, have been wondering how in both cases the victims were able to survive the attack. Are the Russians just bad at their jobs? Or were they some unforeseen circumstances that enabled Skripal and Nawalny to survive? Or is it something with regards to how the poison works?

submitted by /u/Ahrix3
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How do cells in a multicellular organism stick together and how do they know which cells to stick to?

Posted: 03 Sep 2020 02:15 AM PDT

Which causes more changes in the Earth's seasons? Nutation or precession?

Posted: 03 Sep 2020 12:12 PM PDT

I can't really find a clear answer of which affects it more on google, so does anyone know?

submitted by /u/Aggravating-Price305
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Why do volatile acids like butyric acid have pungent odours even though their boiling points are well over 100C?

Posted: 03 Sep 2020 12:09 PM PDT

I came across a mixture of volatile acids that includes acetic, formic, and butyric acids. It smells gross.

Why can I smell these things so readily even though all of the components in the mixture have boiling points higher than water and are therefore not 'volatile' in the traditional sense like, say, ethyl ether (boiling point 35C)?

submitted by /u/own0dog
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