How do scientists calibrate palaeoclimate proxies? |
- How do scientists calibrate palaeoclimate proxies?
- What would an orbit around an infinitely long cylinder look like?
- Why does it take so much longer for the eyes to adapt to darkness than to brightness?
- Can an object with sufficient kinetic energy become a black hole? (Elaboration in text)
- Why does the partial pressure of water vapor not decrease in line with atmospheric pressure?
- How large of an electromagnetic field would you need to deflect cosmic rays significantly?
- Would it be possible for an object to reach absolute zero by magnetically suspending it in a vacuum chamber?
- When civil engineers look at cracks in the walls of a building, how do they know if the structure has been compromised?
- Ask Anything Wednesday - Economics, Political Science, Linguistics, Anthropology
- Does pollination between different plant species occur? If so, does it cause issues in the gene pool?
- What is the simplest venom used by an organism?
- How do flavourists and food chemists determine whether a compound is safe to eat and therefore edible or not?
- Is there such a thing as a mathematical discontinuity in nature?
- What is an implicit derivative?
- Is more energy exserted walking up stairs and hitting every step or every other step?
- Why don't the negatively charged heads of a phospholipid bilayer repel each other, tearing the layer apart?
- We have regenerative braking, but what about regenerative shocks/struts?
| How do scientists calibrate palaeoclimate proxies? Posted: 12 Oct 2016 05:39 AM PDT Against other proxies which are well established is part of the answer I would guess, but I'm thinking specifically of a sentence I read regarding the Mg/Ca proxy for past sea-surface temperatures: Various attempts to calibrate foraminiferal Mg/Ca ratios with temperature, including culture, trap and core-top approaches have given very consistent results although differences in methodological techniques can produce offsets between laboratories... I can guess at what culture and core-top calibrations are, although it would be nice to hear from someone who could explain the details of how that works. Trap calibration I have no idea what that means. Also, I was listening to an interview where a scientist mentioned controversies with this proxy, were they just referring to the offsets produced by different methodologies? Or are there other complications using Mg/Ca? [link] [comments]  |
| What would an orbit around an infinitely long cylinder look like? Posted: 12 Oct 2016 05:07 AM PDT So, let's use cylindrical coordinates for this: Let's say we have a cylinder with fixed radius r extended up and down the z axis to infinity. Ignoring stuff like the cylinder collapsing down into a sphere: Do stable orbits exist here (by stable, I mean orbits where you don't crash into the cylinder and you don't escape)? If so, there are two cases I'm curious about: What does an orbit starting at some arbitrary height with only change in theta look like? [link] [comments]  |
| Why does it take so much longer for the eyes to adapt to darkness than to brightness? Posted: 12 Oct 2016 05:54 AM PDT |
| Can an object with sufficient kinetic energy become a black hole? (Elaboration in text) Posted: 11 Oct 2016 08:55 PM PDT This question is too large to fit into the title: I was thinking about this today. I'd like to see where I'm wrong and what would happen in a situation like this: Energy is relative to your reference frame. As I understand it, kinetic energy also adds to an object's mass-energy and increases its gravitational pull. I know that the example I'm about to bring up is completely unpractical in so many ways, but bear with me. Say that I place a baseball next to me and then accelerate away from it until I reach a velocity that is incredibly close to the speed of light. So close, that in the frame where I am stationary, I turn back and observe the baseball as moving away from me with a kinetic energy so large that it's mass-energy exceeds the mass required to form a black hole with a baseball's radius. From my reference frame, is the baseball a black hole? Relative to my frame, it has enough energy to have an escape velocity greater than the speed of light at the ball's surface. If the ball is a black hole from my reference frame, why can I not observe it decay due to Hawking radiation? And finally, if the ball is a black hole from my frame, wouldn't I also be a black hole from the ball's reference frame (as I am moving with even greater kinetic energy from the ball's reference frame)? How does this reconcile with the fact that I can accelerate in the negative direction and come back to the ball if I so choose, with both of us unharmed? [link] [comments]  |
| Why does the partial pressure of water vapor not decrease in line with atmospheric pressure? Posted: 12 Oct 2016 06:09 AM PDT The partial pressure exerted by water vapor is 6.3 kPa (47 mmHg) in alveolar gas. This is important to note in the estimation of partial pressures of gases in the alveoli, particularly oxygen and carbon dioxide. Partial pressures of gas mixtures are a product of their concentration within the and the overall pressure of the gas mixture. Therefore when the overall pressure is decreased (as with increasing altitude) the partial pressures decrease accordingly. My thought was that the pressure exerted by water vapor would also decrease. However I read in a paper recently (quoted below) that this isn't the case. Could anybody explain why the partial pressure of water vapour doesn't change with the barometric pressure? This paper doesn't explain why. Paper: 'The physiology of high altitude: an introduction to the cardio-respiratory changes occurring in ascent to altitude.' by N Mason. [link] [comments]  |
| How large of an electromagnetic field would you need to deflect cosmic rays significantly? Posted: 11 Oct 2016 01:50 PM PDT The topic of Mars colonization keeps coming up on reddit and cosmic rays being a very large problem. How large of a magnetic field would be required for the charged cosmic rays to deflect (via Lorentz forces) by a macroscopic amount (say meters)? [link] [comments]  |
| Posted: 11 Oct 2016 05:02 PM PDT I learned in science class that part of the reason why absolute zero is so hard to achieve is because heat can always find a way into the object, whether it is through the ground or the air. However if the object is in a vacuum and not directly touching any surface, would absolute zero be possible? [link] [comments]  |
| Posted: 12 Oct 2016 04:47 AM PDT Does the type of crack tell you something if it is vertical, horizontal, diagonal, or ladder-shaped? Does it mean something if it's close to a colum, door frame or window frame? [link] [comments]  |
| Ask Anything Wednesday - Economics, Political Science, Linguistics, Anthropology Posted: 12 Oct 2016 08:05 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! [link] [comments]  |
| Posted: 11 Oct 2016 07:50 PM PDT |
| What is the simplest venom used by an organism? Posted: 11 Oct 2016 11:01 AM PDT |
| Posted: 11 Oct 2016 10:29 AM PDT |
| Is there such a thing as a mathematical discontinuity in nature? Posted: 11 Oct 2016 10:59 AM PDT I know that due to the existence of vacuums or near vacuums, material discontinuities can exist, but can a mathematical discontinuity exist as an observable, physical manifestation? One potential example I can imagine would be the singularity of a black hole, which is a 4-dimensional asymptote as gravitational pull approaches infinity, but this is purely speculative since current methods have no way of proving the theory. [link] [comments]  |
| What is an implicit derivative? Posted: 11 Oct 2016 01:17 PM PDT I get what explicit derivatives are but what is a ln implicit derivative actually solving for? Normally it's a slope but how does that apply to an implicit equation. For consistency, let's use the implicit equation: x + y3 - xy = 1 And it's implicit derivative: d/dx = -x/y What is going on here? What's being found? [link] [comments]  |
| Is more energy exserted walking up stairs and hitting every step or every other step? Posted: 11 Oct 2016 07:00 AM PDT Is it more energy efficient to hit every step while walking up the stairs or to hit every other step? [link] [comments]  |
| Posted: 11 Oct 2016 11:23 AM PDT A phospholipid bilayer is two layers of phospholipids with their uncharged ends inbetween their negatively charged ends to form a hydrophilic outside and a hydrophobic insides. But, why don't the negatively charged ends repel each other and destroy the membrane? Why do they stick together to form a barrier? Like charges repel and the layer is a ton of like charges directly next to each other, so why do they stay together? The lipid ends are uncharged so they can't be holding each other together, can they? How does the layer stay together? [link] [comments]  |
| We have regenerative braking, but what about regenerative shocks/struts? Posted: 11 Oct 2016 08:26 AM PDT Is this something that is being developed? Or is it not possible to generate enough electricity to justify the costs to develop such a device? I drive a lot, and wonder if this could make hybrid/electric cars more viable. [link] [comments]  |
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