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Thursday, March 9, 2017

Did I detect cosmic rays in the Stratosphere with my camera?

Did I detect cosmic rays in the Stratosphere with my camera?


Did I detect cosmic rays in the Stratosphere with my camera?

Posted: 09 Mar 2017 01:56 AM PST

Hi guys, last weekend I launched a weather balloon into stratosphere at night. I used the sony a7sII to capture images of the earth and stars. When viewing the footage I noticed that with higher altitude more light flashes hit the camera sensor. Could this be cosmic rays?

submitted by /u/jwastronomy
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Does electricity need a high voltage or a high current to continue through a gap in a wire?

Posted: 09 Mar 2017 04:08 AM PST

Say with a 0.5 mm gap would it be possible for me to get electricity consistently jumping across without dealing with a deadly current?

submitted by /u/Kingme121
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Is there a word (similar to "resolution" in microscopy) that defines the minimum distance between two different colored points that must be attained before the points appear as a single "mixed" color?

Posted: 08 Mar 2017 02:59 PM PST

Maybe I am misunderstanding how color mixing works?

As a bonus side question: I am somewhat familiar with why objects are different colors, (we see light reflected from objects and don't see light that is absorbed) but this confuses me. For example, Cu2+ absorbs light in the 600nm region of the visible spectrum and the solution appears blue/cyan. But, intuitively, if you take all the other colors not represented by this 600nm region (the colors not absorbed by Cu2+) and mix them up, it wouldn't be blue, so I don't understand how this works. Sorry for the long post, all answers appreciated.

submitted by /u/Beatminerz
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What causes the blur that we see over hot surfaces?

Posted: 09 Mar 2017 06:43 AM PST

I was wondering what that distortion or blur is that we see above things that get really hot, but have no open flame.

submitted by /u/thisismycommonname
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What's the relationship between a topological dual and an algebraic dual?

Posted: 08 Mar 2017 08:19 PM PST

I'm interested in infinite dimensional vector spaces as I am trying to learn formal Quantum Mechanics. As I understand it, the Hilbert Space associated with a degree of freedom corresponding to movement along a certain axis is L2 (R), that is the equivalence classes of lebesgue-integrable functions on the real line whose integral is the same. I understand that the use of continuous (or even differentiable) functions to describe states is possible without anything going wrong as the subspace of infinitely differentiable functions of compact support (C) is dense in L2 (R). So I guess that L2 is the completion of C. My questions are:

I know that in infinite dimensional vector spaces it is important to distinguish between the algebraic dual (the set of all linear functionals) and the topological dual (consisting only of the continuous ones). Also, L2 is similar to its topological dual via the Reiz representation theorem (I write similar because I think that the relationship between the spaces provided by such theorem is an antilinear transformation and I do not know if there is a regular isomorphism between both spaces). How is the topological dual embedded in the algebraic one (is it in any way in particular)?

The question arose because even if there are no free particle eigenstates in L2 (that is, for those who ignore QM, eigenstates of the laplacian operator), plane waves DO fullfill this requirement, and the later being connected (in some way I don't quite understand formally yet) via the Fourier transform to the delta functions, themselves being in the algebraic dual of C.

edit: As a bonus, if anyone could shed some light on what is the physical meaning of the states in L2 on which the position operator cannot be defined, I'd appreciate it.

submitted by /u/Paul-Lubanski
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Why do photons behave differently in different frames of reference than classical objects?

Posted: 08 Mar 2017 05:57 PM PST

There is an observer A on the sidewalk at night. Person B is in a moving car passing by A with velocity 30 km/h and throws a ball in front (through the open window) with velocity 20 km/h in reference to the car. Ignoring air friction, A will observe the ball moving at 50 km/h.

Now B does the same thing but instead of throwing a ball they project light with a flashlight. If observer A measures the speed of the light B emitted, it would be c, just like if a third person C would emit light from the ground. I know this because I've read that light always travels at the same speed through vacuum (remember we are assuming no air friction). But I don't know why.

Why do photons always have the same speed in reference to any frame of reference? Why is it not the case with classical objects? What would be the speed observer A measure if the ball was thrown at 250 000 km/s and the car was travelling at 100 000 km/s?

Thank you.

submitted by /u/PM_ME_NUNUS_DICK
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Why were the alpha particles used in testing the atomic structure as proposed by the plum pudding model expected to pass through the sphere of positive charge instead of deflecting off of it due to the electrostatic forces?

Posted: 08 Mar 2017 06:20 PM PST

Alpha particles are positively charged, so why were they expected to pass completely through the sphere, which was thought to be the source of positive charge before protons were discovered?

submitted by /u/just_a_reddit_hater
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[Physics] How does an "optical tractor beam" work? Specifically, does the current working optical tractor beam only work on transparent/refractive matter?

Posted: 08 Mar 2017 05:01 PM PST

I've been looking into "optical tractor beams" and I think I understand the gist of the concept: shoot a pair of lasers at an object—those lasers enter at an angle, but when they exit, they exit straight out, which means they have more momentum than when they entered; and because when they exit they "push off" from the particle, it is pushed toward the source of the beams... Is this a correct interpretation? Do optical tractor beams only work on transparent particles that can refract the light beams, or can it somehow work on objects that are not transparent? Thank you very much for any responses!

submitted by /u/papawheely12
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Why does nitrogen have valence 5?

Posted: 09 Mar 2017 08:13 AM PST

Why does nitrogen (or any element in the nitrogen group) have valence 5? It's electron configuration is 2s2 2p3 , which means 2s is filled, and all three 2px, 2py, 2pz can form covalent Pauli pair bonds. The heuristic I learned for understanding why carbon (and those in its group) has valence 4, is because even though its electron configuration is 2s2 2p2 (so it would have a valence of 2), the difference in E between the 2s and 2p levels is so small that the bonding E more than offsets the E required to shift an electron from the 2s to the 2p, so that effectively the configuration is 2s1 2p3 , in which case it clearly has a valence of 4. This heuristic doesn't work anymore for nitrogen, because 2s1 2p4 can't covalently bond 5 electrons, since one of the 2s or 2p states has to be completely filled, whether 2s or 2px or 2py or 2pz. Further, I don't see how it could be energetically favorable to promote one of the 2s or 2p electrons up to the 3s level, which is a much larger jump such that if it were allowed then the valency of all the other elements would be thrown off. What am I missing?

submitted by /u/ididnoteatyourcat
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What is an atom's "orientation"?

Posted: 09 Mar 2017 07:45 AM PST

IBM recently announced they have successfully stored data on a single atom by manipulating and reading its orientation. I'm hazy on the concept of "orientation"; is it simply the physical direction the atom is facing?

submitted by /u/ortolon
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Why do "mushroom clouds" form from nuclear explosions? [physics]

Posted: 08 Mar 2017 01:30 PM PST

How does an Electron spin if it is 0-dimensional?

Posted: 08 Mar 2017 03:17 PM PST

How has the acceptace of quantum mechanics changed in the educational community in recent decades?

Posted: 08 Mar 2017 04:54 PM PST

I recall my high school physics teacher in the mid 90s regarding it as somewhere between an interesting fairytale and ridiculous pseudoscience. I'm wondering how attitudes have changed since then. Is it at the point where it's being taught in high school and showing up on standardized tests?

Edit: I realize now that I've probably been unfair to my old teacher. I don't think he was dismissing quantum mechanics wholesale. He did seem to do a lot of hand-waving regarding certain phenomena like the effects of observation on experiments, electrons mysteriously teleporting to different orbits, etc. It could be that he just didn't want to go down that rabbit hole in class because (a) he didn't believe that either he or experts in the field could provide definitive answers to those questions or (b) it just wasn't part of the curriculum. Which brings me back to my real question here...

Unless I'm completely mis-remembering what I learned in high school (it was over 20 years ago), I remember that the lessons were firmly in the realm of Newtonian and Relativistic physics and I'm wondering if and how the focus has changed.

submitted by /u/wiekey
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How long does typical Tidal heating last?

Posted: 08 Mar 2017 07:55 PM PST

Considering conservation of energy, a moon or a planet cannot be heated through tidal warming forever? Would it fall into the object being orbited because it traded orbital energy for heat.

submitted by /u/Vlad_Bush
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Why does high electrical conductivity generally lead to high thermal conductivity?

Posted: 08 Mar 2017 09:35 AM PST

I recently learned that this is true but I can't quite wrap my head around it. I looked it up a bit but wasn't completely satisfied with the answers. As well, it'd be appreciated if the explanation is kept a bit simpler since I don't know that much :)

submitted by /u/DoctarSwag
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If a acid is a molecule or ion capable of donating a proton, could a atom which decays by proton emission be called a acid?

Posted: 08 Mar 2017 01:13 PM PST

Would Newtonian Black Holes be black?

Posted: 08 Mar 2017 09:28 AM PST

Recently I've been wondering about black holes and noticed something that I haven't before: while black holes as in bodies, whose escape velocity is greater than the speed of light could exist in Newtonian Mechanics, would they be black? The escape velocity is bigger than that of light's, yes, but light as a massless particle should not be affected by gravity, anyway. Therefore you could see every body, no matter how much its mass had been compressed.

Does this mean that the idea of a black hole was only conceived after GR had come to be and then the formula for the most basic Schwarzschild radius was then also derived from Laws of Gravity? It seems to me like the speed of light is hardly a special speed in Newtonian Mechanics, so having an object with such an escape velocity wouldn't be anything special.

submitted by /u/MeyCJey
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Relativity/Lorentz contraction/Train-Tunnel-Analogy: What does outside observer see when the train passenger triggers a cutting of the train at both ends?

Posted: 08 Mar 2017 01:14 PM PST

There is an analogy to explain Lorentz contraction where a train moves through a tunnel with the same length as the train. There is an observer inside the train and one outside the tunnel. And there are guillotines at the tunnel entrances. I hope the analogy is as well known and understood as I got the impression as I have seen it in many explanations of Lorentz contraction.

My question:

The train passenger sees the train poking out of the tunnel at both ends at the same point in time. When he triggers both guillotines at this point the train passenger should see both end of the train cut at the same time.

What does the outside observer see? Is it even possible for the train passenger to do so?

submitted by /u/Skaarj
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Was water to blame for the Malta azure window collapse?

Posted: 08 Mar 2017 06:44 PM PST

Wednesday, March 8, 2017

AskScience AMA Series: We are women scientists from the Homeward Bound expedition, recently returned from the inaugural voyage to Antarctica! Ask us anything!

AskScience AMA Series: We are women scientists from the Homeward Bound expedition, recently returned from the inaugural voyage to Antarctica! Ask us anything!


AskScience AMA Series: We are women scientists from the Homeward Bound expedition, recently returned from the inaugural voyage to Antarctica! Ask us anything!

Posted: 08 Mar 2017 05:00 AM PST

Hello /r/AskScience! Homeward Bound is a ground‐breaking leadership, strategic and science initiative and outreach for women, set against the backdrop of Antarctica. The initiative aims to heighten the influence and impact of women with a science background in order to influence policy and decision making as it shapes our planet. The inaugural 2016 voyage took place from 2 - 21 December 2016 and was the largest‐ever female expedition to Antarctica. We care about science, the concerns of others, and we think science can unite us towards seeing and managing the planet as our global home. Ask us questions about our Antarctic journey, the Homeward Bound Initiative, and why it matters, especially now, for there to be gender equity in leadership. We'll be back around 2pm U.S. Eastern Standard Time to start answering!

Answering questions today are 5 participants from the inaugural Homeward Bound expedition:

Heidi Steltzer, Ph.D. Heidi is an environmental scientist, an explorer, and a science communicator, sharing her passion for science with others. She is an Associate Professor at Fort Lewis College, Colorado. She studies how environmental changes affect mountain watersheds and Arctic systems and their link to our well-being. Heidi's research has been published in Nature and featured in the media, including the New York Times. Find her on social media and Medium.com @heidimountains.

Anne Christianson is a current PhD student in the Natural Resources Science and Management program at the University of Minnesota, researching the intersection between climate change, biodiversity conservation, and women's justice. She holds a Bachelor's degree in environmental policy from St. Olaf College and a Masters in Biodiversity, Conservation, and Management from the University of Oxford. Previously, Ms. Christianson worked in the U.S. House of Representatives writing and advising on energy and environmental legislation, for Ocean Conservancy advocating for science-based marine policy, and held the position of Vice President of DC EcoWomen, a non-profit organization working to empower women to become leaders in the environmental field. A 2016 Homeward Bound participant, Ms. Christianson was enthralled by Antarctica, and inspired by the 75 other women striving to create a global network of female change-makers.

Dyan deNapoli is a penguin expert, TED speaker, and author of the award-winning book, The Great Penguin Rescue. She lectures internationally about penguins, and is a sought-out expert on radio and TV, including appearances on BBC and CNN. A participant on the inaugural Homeward Bound expedition, she returns to Antarctica next year as a lecturer for Lindblad/National Geographic. A four-times TEDx speaker, Dyan's inspiring TED talk about saving 40,000 penguins from an oil spill can be viewed on TED.com. She is on Facebook, Twitter, and LinkedIn as The Penguin Lady.

Ashton Gainsford is an evolutionary biologist and recently submitted her PhD thesis to the Australian Research Council Centre of Excellence for Coral Reef Studies at James Cook University in Townsville, Australia. Her research questioned what constitutes a species, highlighting the importance of animal behavior to the outcomes of hybridization, a common and significant evolutionary phenomena where closely related species interbreed. Her research on coral reef fish using behavior and genetic tools provides novel insights into the ecology and evolution of species. She is passionate about the marine environment, women in science, and diving. She joined the Homeward Bound network in 2016 to build future collaborations and learn within a program aimed to elevate each woman's leadership abilities and capacity to influence in the future. This was highlighted in an article written for 1MillionWomen. Connect with her on twitter at @AshtonGainsford.

Johanna Speirs, Ph.D, is a climate scientist with specific research interests in climate variability and change, alpine hydrometeorology and Antarctic meteorology and climatology. She works for Snowy Hydro Ltd. (a government-owned renewable energy company operating in Australia's alpine region), and specialises in understanding weather and climate processes that effect water resources in the Australian Alps. Johanna maintains an affiliation with the University of Queensland's Climate Research Group following her PhD on Antarctic meteorology and climatology. She wants to live in a world where quality science is used to make more informed decisions in the way this planet is managed. She thinks Homeward Bound is a pretty inspiring initiative to help get more women to the decision-making table. See google scholar for her publications, or find her on twitter @johspeirs.

submitted by /u/AskScienceModerator
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If something is a temperature of absolute zero, does that mean the electrons around the proton have completely stopped?

Posted: 07 Mar 2017 04:39 PM PST

Or is it just at a molecular level Rather than atomic

submitted by /u/BrotasticalManDude
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Are there any examples of vague speciation? For example species B can reproduce with A and C but A and C cannot reproduce.

Posted: 07 Mar 2017 07:08 PM PST

when Earth had a uniformly warm climate, how did plants in areas with a 5-6 month long polar night handle it?

Posted: 07 Mar 2017 07:59 PM PST

Did plants even grow in such areas at all, despite having the perfect temperature conditions?

submitted by /u/aleeque
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Why is the fossil record poor for the Mesozoic in the Midwestern part of the USA?

Posted: 07 Mar 2017 07:58 PM PST

How do atoms work in pilot wave theory?

Posted: 08 Mar 2017 05:02 AM PST

The classic example for why the concept of electrons doing trajectories around the nucleus is wrong is that they would continuously lose energy via radiation. Pilot wave theory assigns trajectories to particles. This seems contradictory, how is it resolved?

submitted by /u/IgorEmu
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Is there any meaning to the phrase "twice as hot" or "twice as cold" as 0 degrees?

Posted: 07 Mar 2017 10:54 AM PST

My understanding of temperature is that it's mostly a measurement of how fast molecules move. Do molecules move twice as fast at 80 degrees celcius as they do at 40? That's absurd, right?

Co-workers are arguing among one another.

submitted by /u/Nubberkins
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What determines how radioactive an element is? (How much radiation an element gives off).

Posted: 08 Mar 2017 02:04 AM PST

What determines how radioactive an element is...or to put it another way, how much radiation it gives off? Uranium and Americium both emit an alpha particle, but must be handled differently.

submitted by /u/NulloK
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Ask Anything Wednesday - Physics, Astronomy, Earth and Planetary Science

Posted: 08 Mar 2017 07:04 AM PST

Welcome to our weekly feature, Ask Anything Wednesday - this week we are focusing on Physics, Astronomy, Earth and Planetary 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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Will I generate more power if I focus sunlight with a magnifying glass onto a solar panel?

Posted: 07 Mar 2017 11:24 AM PST

In what ways is our solar system like or unlike other solar systems?

Posted: 08 Mar 2017 05:55 AM PST

I just read something about how we have an estimated 200 dwarf planets, and I know we have 8 planets with a potential 9th. IIRC we have two asteroid belts as well.

Do most solar systems have what we have? Is ours typical? Or do we not know that yet?

submitted by /u/HungJurror
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Do Black holes and anti-matter Black holes have different characteristics, and if so what are those characteristics?

Posted: 08 Mar 2017 06:29 AM PST

I know they both consist of having an Event horizon and a singularity, but other then that, what makes them different?

submitted by /u/Abject-Testament
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'Astronomy' Why does fusing an additional proton to a heavy element such as lead not emit energy? Instead, absorbing energy?

Posted: 07 Mar 2017 05:20 PM PST

Is there a similar disease for birds like mad cow disease(Bovine spongiform encephalopathy)?

Posted: 07 Mar 2017 02:32 PM PST

I tend to feed birds in the garden and I chuck the chicken leftovers out the back for themselves to feast on every sunday. I had figured that it was fine as I never heard any issues arising from it, but I am now wondering if I have set a unfortunite rolling castastrophy upon myself in the form of zombie birds...

submitted by /u/requiemdice
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Could ocean water freeze under the high pressures/low temperatures at the ocean floor?

Posted: 07 Mar 2017 02:22 PM PST

Why is water densest at 4 degrees Celsius?

Posted: 07 Mar 2017 11:48 AM PST

I was taught in my HS Chem class a few days ago that water is densest at 4 degrees Celsius. I asked my less than stellar teacher why that is, to which she responded "it just is that way". So why is it densest at 4 degrees Celsius? Why wouldn't it be denser closer to freezing?

submitted by /u/TheThingInTheCorner
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When undersea currents flow over abyssal ridges, is there a marine equivalent of a rain shadow ?

Posted: 07 Mar 2017 01:26 PM PST

When marine currents rise to cross a ridge, does the sea bottom on the far side receive a reduced level of biological debris? Is there a "marine rain shadow"?

submitted by /u/cucutano
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Are there underwater supervolcanoes?

Posted: 07 Mar 2017 05:08 AM PST

I know that we are aware of supervolcanoes on land and the world is mostly ocean, are there supervolcanoes that are underwater? And if so, what would be the result of one of those erupting?

submitted by /u/WHYAREWEALLCAPS
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Tuesday, March 7, 2017

How many galaxies/stars do we visually lose every year due to them accelerating and passing through the cosmological event horizon?

How many galaxies/stars do we visually lose every year due to them accelerating and passing through the cosmological event horizon?


How many galaxies/stars do we visually lose every year due to them accelerating and passing through the cosmological event horizon?

Posted: 06 Mar 2017 05:19 PM PST

I was reading about dark energy on Wikipedia and this question had me pondering on a bit.

edit:

Hello everyone, I appreciate all the feedback received from this post and I'm grateful for such well presented answers. I realise that this sort of question can raise many different answers due to the question being too general.

But as I understand from most of the replies... The reason the light from those stars will never entirely vanish is because even when the star/galaxy passes the cosmological event horizon, the space between us and them is only expanding and so the light that was sent before the star/galaxy passing the cosmological event horizon will only stretch due to the expansion and continue to reach us but through other spectrums of light as it continues to redshift. Would this be correct?

I would also like to bring forward a question that has been brought up by a few other redditors. However as it may seem there is no exact answer to it, I'd like to ask a question similar to it:

Which stars/galaxies have most noticeably redshifted or faded from visual light? I'd definitely like to read up on this topic so any names or articles would be great. Thanks again guys!

submitted by /u/RichDAS
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when I shine a flashlight at Mars, does a small amount of the light actually reach it?

Posted: 07 Mar 2017 03:20 AM PST

How do we know that the universe is expanding and light is not just losing momentum?

Posted: 07 Mar 2017 04:13 AM PST

We know that the universe is expanding since light coming from distant galaxies are redshifted. How do we know that the redshift isn't the result of light losing momentum over incredibly long periods of time? (As momentum decreases, wavelength increases (p=h/λ))

Are there any other methods to verify that the universe is expanding other than observing redshifts of light?

submitted by /u/rdivine
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What is happening to the organs of someone who suffers from scoliosis?

Posted: 07 Mar 2017 06:33 AM PST

Depending on the level and degree of the scoliosis (curvature of the spine) the area inside the person's torso is generally smaller, and therefore leaves less room for organs. I am aware that the body doesn't fully adjust for this, i.e. the fat content on the person body is generally the same as what it would be if the person were their correct height depending on diet and weight of course.

submitted by /u/shintengo
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Does the order of operations have an deeper significance, or was it a convention that was simply agreed upon?

Posted: 06 Mar 2017 05:50 PM PST

Does defibrillation work differently in people who have undergone the Nuss procedure?

Posted: 07 Mar 2017 06:25 AM PST

The Nuss procedure treats Pectus Excavatum, a.k.a. Hollow Chest, by inserting a stainless steel bar under the sternum in order to push it outwards.

submitted by /u/ViktorGudjons
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What is the difference between an aeroplanes 'air speed' and its 'ground speed'?

Posted: 07 Mar 2017 05:17 AM PST

What happens when an electron hits a positron when they both have different momentum?

Posted: 07 Mar 2017 02:17 AM PST

I know that after the annihilation when they have the same momentum, or no momentum there are 2 photons emmited in 2 different directions, due to conservation of momentum, but what happens when they hit eachother with different momentums? Will they be emmited at an angle other than 180deg to each other, or will one have higher frequency than the other, or something completely different?

submitted by /u/Wojtabe
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If Mars and Venus switched places, would Venus be hospitable for life?

Posted: 06 Mar 2017 10:17 AM PST

If light is effected by gravity of black holes, does that mean light can orbit a black hole?

Posted: 07 Mar 2017 07:14 AM PST

So if the black hole was exactly the right mass and the light was at exactly the right passing trajectory could it be pulled into an orbit?

submitted by /u/Elipes_
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Why are there no stable isotopes of technetium despite it being so much lighter than all the other unstable elements?

Posted: 07 Mar 2017 04:07 AM PST

Are insects affected by inbreeding like mammals?

Posted: 06 Mar 2017 01:56 PM PST

Does the uncertainty principle just pertain to velocity and position, or are there other "quality pairs" that it stops us from getting perfectly?

Posted: 06 Mar 2017 03:52 PM PST

if matter and energy are one and the same, shouldn't earth have been gaining tons and tons of mass over the years via sunlight?

Posted: 07 Mar 2017 06:18 AM PST

Can a molecular transition be intrinsically polarized?

Posted: 06 Mar 2017 03:20 PM PST

I am aware of stimulated emission where emitted photons have the same polarization as the incoming photons which induced the emission. To my knowledge, vacuum fluctuations also have no preferred polarization and thus spontaneous emission is also unpolarized.

But I was recently told by a colleague that transitions can also be intrinsically polarized and was wondering what exactly that means and how it comes about? Are certain transition only stimulated by right circularly polarized photons?

submitted by /u/CallMeDoc24
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If I am riding in a bus traveling 60 mph, and I throw a ball 30 mph from the front the bus to the back of the bus, what exactly is happening? Is the ball moving, or is the bus accelerating away from the ball at 30 mph?

Posted: 06 Mar 2017 08:08 PM PST

Why are all radioactive decays electrons, positrons, or helium nuclei?

Posted: 06 Mar 2017 09:19 PM PST

And as a follow up, similar to how beta+ gives a positron, could there be alpha+ that gave a 2-antiprotons, 2-neutron emission?

submitted by /u/TimAnEnchanter
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Quick question about thermal expansion?

Posted: 06 Mar 2017 06:54 PM PST

Is cake or bread in an oven rising due to thermal expansion? I feel like it technically is but I'm no science master.

submitted by /u/dwadwda
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If a person were to jump while on top of a car travelling 70mph, would they land on the roof again?

Posted: 07 Mar 2017 03:57 AM PST

My entire Sixth Form is stuck in a debate about whether or not you would have enough momentum to land on the car again or if the car would continue travelling, leaving you behind. None of us take physics so any answers would be greatly appreciated. :)

submitted by /u/NeedToGetOffReddit
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When talking about quarks and particle physics, what is strangeness and what does it do?

Posted: 06 Mar 2017 08:41 AM PST

I can only find tiny amounts of information on quark strangeness and all my physics teachers simply tell me "not to worry about it".

submitted by /u/NachoftheMach
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Did Newton know his theory of gravity was incomplete?

Posted: 06 Mar 2017 07:45 AM PST

Did Newton realize his theory of gravity was incomplete in that it did not take into account time distortion caused by gravity? If not that specific did he know something was wrong but did not know what?

submitted by /u/kirkkrunchkangaroo
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Would it be accurate to say that a stationary charge produces an electric field, but a moving charge produces a magnetic field?

Posted: 06 Mar 2017 05:22 PM PST

Capacitor (no moving charge) = E- field

Current (moving charges) = Mag Field

Point charge at rest = E field

Point charge moving at speed v = Mag field

Is this a 'correct' conclusion? If so, why is this so?

submitted by /u/beitasitbe
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How is a root certificate verified?

Posted: 07 Mar 2017 01:48 AM PST

I am confused as to how a root certificate can be verified to be genuine? I found that you have something built into your browser that checks if the root certificate of a certificate chain is correct? But what if some chain just copies the root certificate from a genuine source so that your computer verifies it with that? How can you know it's actually genuine?

Also how does your browser actually know it is the root certificate? Does it have a built in public key that it decrypts the certificate with and checks it?

submitted by /u/melonsmasher100
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Why are there much more consonants than wovels in many modern laguages?

Posted: 06 Mar 2017 09:59 PM PST