Can a planet exist with a sphere, like Saturn's rings but a sphere instead? |
- Can a planet exist with a sphere, like Saturn's rings but a sphere instead?
- How do we know the universe is infinite?
- How would a wild forest fire solve itself if humans arent here to intervene?
- Is the determinant of a 1-by-1 matrix defined, and if so, why is it defined as such?
- Ask Anything Wednesday - Physics, Astronomy, Earth and Planetary Science
- If Black Holes and Supermassive Black Holes draw and condense matter in, how does the mechanism for ejecting/pushing away material (like a rogue star) work?
- Does a PCB printed meandered trace antenna perform worse than a wire antenna of the same length?
- Do nutrition labels in the US represent the total caloric content of the food, or the net caloric intake after accounting for things like digestive efficiency and the Thermic Effect of Food?
- Do humans permanently retain some portion of the water they consume or is all of the consumed water eventually lost/replaced?
- Flu, cold and other common illnesses were one of the factors why native americans lost their continent. How come the same thing - illnesses from America - did not spread so widely in Europe?
- [Biology]How does the oxygen produced by macroalgae, phytoplankton, and cyanobacteria get into the atmosphere?
- How does the STAR detector at the Brookhaven Lab detect?
- How do we produce microprocessors with billions of transistors?
- In which direction is the Milky Way rotating?
- If mesons are made of quarks and antiquarks, then why don't they annihilate immediately?
- What is an arctic blast? Is it normal? How will it affect our environment?
- How is the aquatic life of the Nile River affected by the changing salinity during certain seasons?
- How are the daily value of vitiamins and minerals determined?
Can a planet exist with a sphere, like Saturn's rings but a sphere instead? Posted: 13 Nov 2019 12:49 AM PST |
How do we know the universe is infinite? Posted: 12 Nov 2019 05:55 PM PST We assume the universe expands on and on into space, but can how can we assume space is infinite? Why do we think their can't be an end to expansion? Space isn't anything but we occupy it. How can we assume that space is never ending? [link] [comments] |
How would a wild forest fire solve itself if humans arent here to intervene? Posted: 12 Nov 2019 07:52 PM PST |
Is the determinant of a 1-by-1 matrix defined, and if so, why is it defined as such? Posted: 12 Nov 2019 11:16 PM PST I'm currently studying multivariable calculus, and lately I've been interested in the mechanism by how multiple integrals can sometimes be simplified by a change of variables; I've been particularly interested in the Jacobian matrix and it's determinant (when its square, of course). Reading about these topics, I found out that the concept of the Jacobian is also defined for scalar-valued functions of a single variable; it is simply a 1-by-1 matrix whose only entry is the derivative of the function. With this knowledge, I noticed somewhat of a beautiful parallel between a multivariate change of variables and u-substitution, namely that the act of making a substitution in a single integral can be thought of as defining a differentiable transformation that maps the interval of integration in the original integral into its image in the transformed integral, where the extra factor that appears in the transformed integral is the determinant of the Jacobian of the transformation. I acknowledge that this wording can be a bit ambiguous and unclear, so I'll elaborate below with an illustrative example. Let's assume, for the sake of simplicity, that f is a function that is continuous on the interval [a, b]. Suppose we want to compute the integral of f from a to b, which I will represent symbolically as follows (the notation [a, b] is meant to denote the interval of integration, where a is the lower bound, and b is the upper bound): ∫f(x)dx [a, b] For the sake of the illustration, let's assume that a differentiable "transformation" (really just a scalar-valued univariate function) g exists that maps the interval [a, b] to [g(a), g(b)], and somehow, for some crazy reason, the interval [g(a), g(b)] will make the integral easier to evaluate. By analogy with the multivariate case, I reasoned that, if you were to make a change of variables by defining a transformation x = g(u), you can compute the value of ∫f(x)dx [a, b] by evaluating the integral ∫f(g(u))det[g'(u)]du [g(a), g(b)]. This formula is remarkably similar to the Substitution Rule for definite integrals, up to the det[g'(u)] term, which is where my question stems from. In the multivariable case, it is necessary to take the absolute value of the Jacobian determinant, presumably because of issues arising with orientation when defining a transformation. Not only do I feel would it be nonsensical to do this in the univariate (since some substitutions have negative derivatives), I'm also unsure if such a determinant even exists for any 1-by-1 matrix. I'd greatly appreciate your response! [link] [comments] |
Ask Anything Wednesday - Physics, Astronomy, Earth and Planetary Science Posted: 13 Nov 2019 07:08 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! [link] [comments] |
Posted: 12 Nov 2019 09:43 PM PST |
Does a PCB printed meandered trace antenna perform worse than a wire antenna of the same length? Posted: 12 Nov 2019 07:04 PM PST |
Posted: 12 Nov 2019 01:22 PM PST |
Posted: 12 Nov 2019 11:23 AM PST |
Posted: 12 Nov 2019 04:57 PM PST |
Posted: 12 Nov 2019 05:38 PM PST There is a common "fact" I see stating that 50%-80% of the world's oxygen is produced by primary producers in the ocean. I can't seem to find a primary source supporting that and I was curious about the mechanism behind the oxygen getting into the atmosphere. Is it as simple as oxygen reaching a saturation capacity in sea water so it outgases into the atmosphere? [link] [comments] |
How does the STAR detector at the Brookhaven Lab detect? Posted: 12 Nov 2019 03:41 PM PST I'm not sure how specific to be, this is a fairly new concept to me. For instance, what exactly are they looking for with the experiment [link] [comments] |
How do we produce microprocessors with billions of transistors? Posted: 12 Nov 2019 05:56 PM PST How are transistors mass produced on a computer chip? If they were assembled individually it might take months to make a single chip so I assume there must be a method to do it in mass? [link] [comments] |
In which direction is the Milky Way rotating? Posted: 12 Nov 2019 01:33 PM PST Were the question: in which direction is the core of the Milky Way? It could be answered In the direction of Sagittarius as using a constellation to orientate is fine. So which way is the galaxy rotating, from our perspective? Presumably towards some constellation at 90° from Sag., but which one? Of course terms like clockwise will convey no meaning, and a net search reveals many pages saying so, while adding how fast it rotates, how long a rotation takes, but ever omitting to say which way. [link] [comments] |
If mesons are made of quarks and antiquarks, then why don't they annihilate immediately? Posted: 12 Nov 2019 08:26 AM PST I know enough about the general idea behind particle physics to really confuse myself when I run into the actual complicated specifics. Up until today I'd thought that pions could exist because the quark and antiquark involved had different flavours and antiquarks only annihilated with quarks of their own flavour, but I am now realizing that π0 mesons are a thing and are composed of up and anti-up or down and anti-down quarks. Do quarks only annihilate with their own flavour, or was I completely incorrect? [link] [comments] |
What is an arctic blast? Is it normal? How will it affect our environment? Posted: 12 Nov 2019 01:02 PM PST |
How is the aquatic life of the Nile River affected by the changing salinity during certain seasons? Posted: 12 Nov 2019 12:31 PM PST |
How are the daily value of vitiamins and minerals determined? Posted: 12 Nov 2019 01:00 PM PST It seems like one would have to eat an inordinate amount to get the recommended DV% of vitiamins in minerals. Obviously some are easy to get like vitiman C and calcium. But others like folate, magnesium, zinc, phosphates, vitiman K, etc, are so difficult to eat enough to get the 100% recommended doses. How were those numbers determined? [link] [comments] |
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