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Friday, September 28, 2018

AskScience AMA Series: We recently launched the new Land Cover tool in the NASA GLOBE Observer app. Ask us anything!

AskScience AMA Series: We recently launched the new Land Cover tool in the NASA GLOBE Observer app. Ask us anything!


AskScience AMA Series: We recently launched the new Land Cover tool in the NASA GLOBE Observer app. Ask us anything!

Posted: 28 Sep 2018 04:00 AM PDT

Have questions about land cover types, the GLOBE Observer app, our current Land Cover Challenge, app development, or land science in general? We are here to answer your questions.

NASA GLOBE Observer is a smart phone app that lets you take citizen science data for NASA. And just this month the GLOBE Observer team launched the latest tool within the app called: "Land Cover Adopt a Pixel". This new feature lets you take part in a project to create more detailed satellite-based global maps of land cover by sharing photos of the world around you.

Why does NASA need your help in collecting this data with the new GLOBE Observer Land Cover tool? One reason is to fill in details of the landscape that are too small for global land-mapping satellites to see. Land cover is critical to many different processes on Earth and contributes to a community's vulnerability to disasters like fire, floods or landslides. Read more at go.nasa.gov/2NdWgwt.

(And don't forget there is still time to take part in our Land Cover Challenge. All participants will receive a virtual badge within the app if they make a Land Cover observation using the app between now and NASA's 60th anniversary (October 1st). However, the top 10 citizen scientists who map the most land in this period will be recognized on GLOBE Observer social media by a NASA scientist and will receive a certificate of appreciation from GLOBE Observer.)

Here answering your questions are:

  • Peder Nelson - Land Scientist and the science lead for the Land Cover tool within the NASA GLOBE Observer app.
  • Holli Kohl - Coordinator for NASA GLOBE Observer
  • Kristen Weaver - Deputy Coordinator for NASA GLOBE Observer
  • Autumn Burdick - Communications Director for NASA GLOBE Observer
  • Tassia Owen - Team Member and Outreach/Communications Specialist for NASA GLOBE Observer
  • David Overoye - GLOBE/GLOBE Observer Data Information Systems Project Manager
  • Joe Wieclawek - Chief Applications Developer for NASA GLOBE Observer

Proof: https://i.redd.it/yyih29la5to11.png

We'll see everyone at noon (ET, 16 UT), ask us anything!

submitted by /u/AskScienceModerator
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Why do some parts of the eyes not need blood vessels?

Posted: 28 Sep 2018 02:23 AM PDT

If electricity were to be passed through radon, would there be light?

Posted: 27 Sep 2018 04:49 PM PDT

I know that the rest of the noble gases will produce light if high voltage electricity is passed through (neon tube lights). Neon would produce red light, argon has a light blue light, etc.

However, radon is not used in neon lights (I am assuming it is due to its radioactivity). But if high voltage light were to be passed through radon, would there be light? If so, what color would it be?

submitted by /u/atomicdragon136
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Does the human brain treat its own face differently from the faces of others?

Posted: 27 Sep 2018 04:42 PM PDT

If a spacecraft was to use a magnetic field to protect its passengers from cosmic radiation decently as well as the Earth protects us, how would we generate it (method, power source, etc.) and how strong would it have to be, assuming a ship that is not much larger than the ISS?

Posted: 27 Sep 2018 11:43 AM PDT

Bit of a thought experiment based off of a Space.com article about a farking strong electromagnet that I ran across this morning.

I strongly suspect that there are a number of ways we can do this, other than simply ramping up the Teslas. Because while a strong field could protect us well, it would also play havoc with anything inside the spacecraft, such as computers and anything metallic that isn't bolted down. And powering something strong also brings with it its own set of engineering issues.

And a pretty prescient subject, considering all the chatter there is about going to Mars these days.

submitted by /u/rekabis
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Does time dialation effect how old we see the universe to be?

Posted: 28 Sep 2018 04:47 AM PDT

Its said that the age of the universe is roughly 13.8 billion years old but since all mass has an effect on space time how do we know if thats the true age? Like from the perspective of someone next to a black hole the universe would be younger and someone in intergalactic space older right? Do scientists take this into account when they estimate ages of space objects? And if time doesnt run at exactly the same speed in any two parts of the universe is there any way to know the exact age of anything far away?

submitted by /u/Kins97
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The MINERVA rovers show boulders on the asteroid they landed on. Despite obviously lacking erosion due to water or an atmosphere or geological activities, how have these boulders formed?

Posted: 27 Sep 2018 04:43 PM PDT

There are no known incidents of the endangered African wild dog (Lycaon pictus) attacking humans in the wild. Why would this be, given their reputation as ferocious hunters?

Posted: 27 Sep 2018 02:00 PM PDT

Does the loss of hearing capabilities (inability to hear high frequencies) affect tinnitus?

Posted: 27 Sep 2018 02:50 PM PDT

I learned about young people being able to hear higher pitched tones, and that the ability to hear them deteriorates over time. Seeing tinnitus are high frequency tones, does that mean the intensity of the sound fades over time?

submitted by /u/Newfoundlander9
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Do outside conditions (temperature, pressure, humidity, etc.) affect the strength of MagLevs or Magnetic Fields to any notable degree?

Posted: 27 Sep 2018 03:15 PM PDT

What causes oil in transformers to get "worn out"?

Posted: 27 Sep 2018 07:46 AM PDT

Thursday, September 27, 2018

Do dogs understand pictures of their owners?

Do dogs understand pictures of their owners?


Do dogs understand pictures of their owners?

Posted: 27 Sep 2018 12:30 AM PDT

Why do our teeth not heal or regenerate when cracked or broken?

Posted: 26 Sep 2018 09:15 AM PDT

Every other part of the human body will heal itself to a point. Get a cut? Skin grows back. Break a bone? the body will seal the cracks. Why is it that teeth do not regenerate whatsoever?

submitted by /u/SFgiant55
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We know the Earth is not perfectly round. Why do we not ever see it in any photos?

Posted: 26 Sep 2018 08:57 PM PDT

Is it just to negligible?

submitted by /u/KOLDUT
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How do the Mars orbiters (or rovers) communicate with the earth?How much signal is lost in space and how much time does it take?

Posted: 26 Sep 2018 09:57 PM PDT

Why doesn't the zinc used in galvanic coatings react with oxygen as readily as iron?

Posted: 26 Sep 2018 09:05 PM PDT

I understand that galvanizing iron or steel with a protective coating of zinc can prevent rusting, which is caused by the reaction of the underlying iron with oxygen. But zinc also reacts with oxygen. Why, at the molecular level, is zinc slower or less likely to form zinc oxides than iron is to form iron oxides? Why is zinc, and not some other metal, the most ideal material for galvanization?

submitted by /u/DeregorDarkflame
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Can a inductor limit DC transient currents?

Posted: 27 Sep 2018 12:07 AM PDT

Let's say I have a DC constant voltage source. I plug a resistive load subject to voltage transients (infrequently but periodically adding and removing loads at intervals, loads that vary from one steady state to another under operating conditions, etc).

If I want to limit the transient currents while holding the steady state current the same, would using an inductor be appropriate?

Seems like this is a no brainer. Under steady state DC an ideal inductor is just a piece of wire. When subject to a short, sharp voltage rise the current through the inductor doesn't rise right away but rather rises as I = V/R(1-EXP(-t/tau)) where tau is the time constant tau = L/R.

This limits the peak current due to storing the transient of the energy in the magnetic field of the inductor.

Am I missing anything?

is it really this easy to limit DC transients?

submitted by /u/tears_of_a_grad
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Why doesn’t the sun’s gravitational pull make us a tiny bit lighter during the day? (when it’s above us)

Posted: 26 Sep 2018 04:04 PM PDT

Why do we have different soaps for different things? What are the differences between, say, shampoo and dishwasher liquid that prevents them from being interchangeable?

Posted: 26 Sep 2018 10:02 AM PDT

Why couldn't we use hand soap in our hair, shampoo for our dishes, dishwasher liquid for our laundry, etc? Are there chemical properties of each that only allow them to be used on certain materials/in certain conditions?

submitted by /u/theblueguppy
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Does playing video games actually give you any cognitive benefits?

Posted: 26 Sep 2018 03:05 PM PDT

Up until I read this article, which said that playing video games caused no increase in memory or attention, I was pretty confident that gaming was a good habit. That article only says things about memory and attention though, so what about other things like reaction time, problem solving skills, and coordination? Does it offer any benefits at all?

Edit: Should this be in Neuroscience or Psychology?

submitted by /u/Ichorshine
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Why the boiling point of water changes with pressure ?

Posted: 26 Sep 2018 11:40 AM PDT

Today i was in Termodynamics class and my teacher eventually talked about the boiling point of water and said that the boiling point of water goes down as the pressure goes down too.

I couldn't figure it out in my head why this happens...

submitted by /u/Tuareg99
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Why does certain medicine, like Claritin D, cause me to be drowsy but my workmate to be more "awake"?

Posted: 26 Sep 2018 10:13 AM PDT

I'm drowsy. She hyped. What fuck?

submitted by /u/MostlyApples
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How does an eye scan security device work? Is every human eye ball unique like fingerprints?

Posted: 26 Sep 2018 02:46 PM PDT

Are photons from light emitting sources such as a lightbulb, a campfire or the Sun different in anyway physically?

Posted: 26 Sep 2018 10:13 AM PDT

I'm curious to ask those who understand the topic if there's any change in how a photon is made dependent on its origin (and captured) whether by a camera or an organic eye from start to finish. For example are there different types of photons?

Thanks for your valuable time!

submitted by /u/Timealien
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How do scientists know how molecules look like?

Posted: 26 Sep 2018 02:05 PM PDT

I mean there is this abstract notation of molecules. For example this is the notation of ethanol:

https://upload.wikimedia.org/wikipedia/commons/thumb/d/df/Ethanol-2D-flat.svg/201px-Ethanol-2D-flat.svg.png

But after watching a documentary which threw the notation of random molecules on the screen without much explanation, it left me wondering how people managed to figure out how each and every atom is connected. How did they figure out what is connected to what?

submitted by /u/Rismosch
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What happens if an electron on the "outermost orbit" of an atom absorbs energy (dunno if this is physics or chemistry) ?

Posted: 26 Sep 2018 10:15 AM PDT

Hello, I m not a native english speaker, and in my native language i couldn t find anything on this (or didn t know what i was looking for). (Also, there was something about energy levels, but the orbit thingy in the title sounds better than saying "what happens when electrons with the highest energy level absorb energy"). Anyhow, since i didn t have any chemistry class since 5 years and in my new (apprenticeship? Training? Some sort of school where i learn a job, anyway) we began with pretty basic stuff, like atomic models. My question is, since electrons "jump up" if you make them absorb energy, what happens if you do that to electrons which cannot jump, since there is no further energy level

submitted by /u/YICTAJFTQ
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Is it theoretically possible for there to be a 4th dimension?

Posted: 26 Sep 2018 08:34 AM PDT

I always figured it was possible there was some 4th dimension out there that could theoretically be discovered, but how would that work? What other boundaries are there?

submitted by /u/sigma_phi_kappa
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Is there a method to determine the relative position of an object given its oriention in Earths magnetic field, acceleration and angular velocity(s)?

Posted: 26 Sep 2018 10:08 AM PDT

I am trying to determine the position of an object relative to its origin without using GPS. I have access to a sensor that can provide acceleration, angulary velocity and magnetic orientation and wanted to see if there was a way to use this to determine relative position.

submitted by /u/zero_dark_birdy
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Psychologists/Psychiatrists what is it called when someone is attracted to their "saviour"?

Posted: 26 Sep 2018 10:07 AM PDT

Hello there!

So I remember once hearing something about a syndrome describing a victim of sorts falling in love or being attracted to a person that helped or saved them.

To clarify my question let me give you a scenario:

Person is stuck in a burning building - firefighter saves the person - person falls in love/becomes attracted to firefighter.

Now I was wondering what that syndrome is called? That is, assuming it exists and that my memory is not playing tricks on me.

submitted by /u/Argetan
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Qubits. Why are they different in effect than using multiple bits to determine a single value?

Posted: 26 Sep 2018 10:41 AM PDT

I.e. Qubit = 1, 0, or other

Using two binary bits to determine one value

11 = 1

00 = 0

01, 10 = other

Is it just a matter of efficiency (one qubit vs. multiple binary bits) or am I as stupid as I think I am?

submitted by /u/ELI5-Questions-
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If two circles make contact externally, how much of the circumference of one actually makes contact with the other? And would that amount equate to an infinitesimal?

Posted: 26 Sep 2018 09:59 AM PDT

Which foods are PRO-angiogenic? When I run a search for this, I only get results about ANTI-angiogenic foods...

Posted: 26 Sep 2018 10:41 AM PDT

https://www.bing.com/search?q=pro+angiogenic+foods

If some foods are anti-angiogenic, some must be pro-angiogenic, right? How come every result is about anti-angiogenic foods, even though I searched for pro-angiogenic?

Are there any pro-angiogenic foods?

submitted by /u/48151_62342
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Wednesday, September 26, 2018

Do (fighter) airplanes really have an onboard system that warns if someone is target locking it, as computer games and movies make us believe? And if so, how does it work?

Do (fighter) airplanes really have an onboard system that warns if someone is target locking it, as computer games and movies make us believe? And if so, how does it work?


Do (fighter) airplanes really have an onboard system that warns if someone is target locking it, as computer games and movies make us believe? And if so, how does it work?

Posted: 25 Sep 2018 02:51 PM PDT

Have humans always had an all year round "mating season", or is there any research that suggests we could have been seasonal breeders? If so, what caused the change, or if not, why have we never been seasonal breeders?

Posted: 26 Sep 2018 05:01 AM PDT

On the ISS do they have to adjust for flatulence because of the closed loop environment?

Posted: 25 Sep 2018 02:51 PM PDT

How do trees fight off disease?

Posted: 25 Sep 2018 05:13 PM PDT

I'm assuming trees don't have an immune system, so do they have any protection against disease?

submitted by /u/SnowedInByEdward
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How do we know a blackhole is spinning?

Posted: 26 Sep 2018 01:12 AM PDT

Iv always been interested in astronomy and physics. But iv been wondering how can you calculate a black hole is spinning or not? Is it by the mass orbeting the black hole? Does a spinning black hole have anything diffrent from a regular non spinning one? Do all black holes spin can a black hole spin at the speed of light would that be possible?

submitted by /u/Redpanda248
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Ask Anything Wednesday - Engineering, Mathematics, Computer Science

Posted: 26 Sep 2018 08:12 AM PDT

Welcome to our weekly feature, Ask Anything Wednesday - this week we are focusing on Engineering, Mathematics, Computer Science

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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In Chemometrics, how does the Savitzky-Golag Derivation work? And what is Multiplicative Scatter Correction?

Posted: 26 Sep 2018 04:20 AM PDT

What is it about sour candy that makes it sour, and how come some candies are crazy sour and some are disappointing?

Posted: 26 Sep 2018 06:48 AM PDT

I mean comparing candies like Warheads and Sour Skittles (which are some serious pucker-inducing candies) to things like Sour Gummy Worms that aren't sour at all, just sprinkled with a tangy crystal substance?

submitted by /u/_Not_Bruce_Wayne_
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Is it possible to freeze water while electricity is flowing?

Posted: 25 Sep 2018 10:36 PM PDT

When you eat something and get hives, what causes the hives to appear everywhere (even your legs)?

Posted: 25 Sep 2018 09:09 PM PDT

Why can't phone chargers/ charging ports have a higher voltage, thus charging faster?

Posted: 25 Sep 2018 11:40 PM PDT

How do ramjet and scramjet engines deal with the issue of initial propulsion? Do the crafts equipped with such engines need an auxiliary one?

Posted: 26 Sep 2018 12:11 AM PDT

Basically the title. I understand how ramjet and scramjet engines work, but I didn't find how the crafts equipped with these engines take off, basically.

submitted by /u/m1l4droid
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How do things like squash and pumpkins grow with a hollow cavity inside? What makes up the gas in there and how did it get inside?

Posted: 25 Sep 2018 02:23 PM PDT

Let's say I scrape up my hand. How does the skin grow back exactly the same?

Posted: 25 Sep 2018 11:46 PM PDT

Why are STI tests more accurate after months have passed, instead of a week, from a sexual encounter?

Posted: 26 Sep 2018 02:44 AM PDT

Would it be possible to have STI tests that give accurate results instantly?

submitted by /u/recyclops-robotheart
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How does light "bounce off" a material?

Posted: 25 Sep 2018 01:17 PM PDT

I understand that when light hits a surface, some light is absorbed (by exciting electrons), and other light is reflected, and it's that reflected light that gives objects their colors. What I don't understand is how atoms/molecules actually "reflect" light? If the light cannot interact with a material, I would expect it to pass through, but this only happens with transparent materials. How do photons bounce off an atom, and what determines whether they bounce off or pass through?

submitted by /u/arbitrarycivilian
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Does your body produce insulin in response to consuming Stevia?

Posted: 25 Sep 2018 02:14 PM PDT

More generally, is it the taste of something sweet that generates insulin or does a carbohydrate need to be detected before that response initiates?

submitted by /u/MeVer217
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Can binary stars have stable lagrange points? If so, have we ever found a planet in one of those lagrange points?

Posted: 25 Sep 2018 09:59 AM PDT

Why are there larger meniscuses in smaller tubes than in larger tubes for water?

Posted: 25 Sep 2018 03:32 PM PDT

Why is it that certain metals like zinc and iron are crucial for our body while other metals like lead and murcury are deadly?

Posted: 25 Sep 2018 01:41 PM PDT

Are there any drugs that have stopped being used because the disease evolved total resistance to it?

Posted: 25 Sep 2018 06:20 AM PDT

To which point(s) is the system of latitude and longitude fixed, since the continents are actually constantly moving?

Posted: 25 Sep 2018 01:46 PM PDT

Or in other words; how do I make use of the grid system when looking at a map of for example Pangea?

submitted by /u/GregorVogel
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Is body fat percentage correlated with how long someone can endure starvation before death?

Posted: 25 Sep 2018 11:06 AM PDT

Let's say two people wash up on a deserted island. One with 7% body fat and one with 32% body fat. They have access to a reliable water source however there is no food on the island. Would the individual with a higher body fat percentage be able to survive through starvation longer than the other? Logically I would assume that because there is more energy stored and available for use they would survive longer, however I've not seen any meaningful data supporting that notion.

submitted by /u/gravyboat15
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