Greg H.
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Everything posted by Greg H.
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Yeah - I always manage to get them confused, even when I try not to. Thanks for the correction(s) from both of you - one day maybe I'll remember which one I mean.
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From whose frame of reference? The ship or the Earth? You have to get away from this idea that there is some universally absolute frame of reference. It doesn't exist. That isn't the point. The point is that in your own frame of reference you will never notice a difference, no matter how fast you're accelerating moving. Only observers outside your frame of reference will see any difference at all. Consider this example (hopefully it helps): Two astronauts (Harry and Bob) are floating in an otherwise featureless void - no stars, no galaxies, no planets. They pass each other at 1/2 the speed of light, and measure that the other's space suit clock is running slow. So which astronaut is accelerating moving? There's no way to tell*, and in fact, it doesn't matter. The laws of physics don't care which one of them is actually accelerating moving Harry will witness Bob's clock run slow, and Bob will witness just the opposite. All that matters is your frame of reference. If you were perched on Bob's shoulders (and thereby shared his Frame of Reference), you would observe the exact same effects that Bob does - his clock runs normally, while Harry's appears to run slow. (*In actual fact there probably is a way to tell - rocket exhaust, energy usage or some such, but for the purposes of the example, it doesn't matter). Edit to fix some terminology problems on my end. Thanks guys.
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Better the devil you know is, I believe, how the saying goes.
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Is the universe a closed or open system?
Greg H. replied to Alan McDougall's topic in Modern and Theoretical Physics
I think the short answer we really don't know but we assume it's closed because we don't have any evidence there exists something outside the universe for it to open onto. And the laws of thermodynamics do apply in closed and open system. Why would you think they wouldn't? -
Why would you expect it to? More importantly why would you resurrect a 6 year old thread to ask a nonsense question about a completely different topic? Isn't it easy enough to start your own nonsense thread?
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From the frame of reference of Earth, yes, the ship's clock will run slow. From the frame of reference of someone on the ship, no, the ship's clock will run at normal speed, and the Earth based clock will run slow. Frame of reference is everything.
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The American political process has ceased being about choice - it is about the illusion of choice and picking the lesser of two evils. I normally vote the fellow that can do the least amount of damage overall.
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plans for a lunar telescope are coming together
Greg H. replied to Moontanman's topic in Science News
I don't know if there's any astronomical benefit (i.e. I don't know that it will take any better pictures than a telescope in orbit) but I think there's something to be said for being able to plop a permanent fixed "installation" on another stellar body. There's a lot of engineering challenges that need to be addressed in this deployment, and I think that's the real benefit to the operation (aside from the cash prize). If we can pull of landing something as delicate as a telescope on another orbiting body in the solar system, then what can we achieve next? Edit: Here's an older article I found that lists at least one benefit where radio astronomy is concerned: http://blogearth.wor...pe-on-the-moon/ -
As an aside, some hospitals (or at least the ones in my area of the US) have a dial a nurse service that will connect you with a Registered Nurse. You can explain your situation and they can (usually) tell you if you need to head to your nearest doctor's office for another visit immediately or not. As the previous two posters have said though, if you have concerns about your medical treatments, get a second medical opinion. You are your own best advocate for your medical care - you know best what feels normal with your body and what doesn't. If you have doubts, act on them sooner rather than later.
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Happy to help.
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Off the cuff I would say public static void main(String[] args) { String[] str1={"One"}; String[] str2={"One","Two"}; String[] str3={"One","Two", "Three"}; String[] str4={"One","Two", "Three", "Four"}; String[] str5={"One","Two", "Three", "Four","Five"}; ArrayList<String[]> al=new ArrayList<String[]>(); al.add(str1); al.add(str2); al.add(str3); al.add(str4); al.add(str5); String[] array = (String[]) al.get(2); System.out.print(array[2]); } Str 3, position 3 :Three If you wanted to iterate over all of them you could do something like this: public static void main(String[] args) { String[] str1={"One"}; String[] str2={"One","Two"}; String[] str3={"One","Two", "Three"}; String[] str4={"One","Two", "Three", "Four"}; String[] str5={"One","Two", "Three", "Four","Five"}; ArrayList<String[]> al=new ArrayList<String[]>(); al.add(str1); al.add(str2); al.add(str3); al.add(str4); al.add(str5); Iterator itr = al.iterator(); while(itr.hasNext()){ String[] array = (String[]) itr.next(); for (int i = 0;i < array.length; i++){ System.out.print(array[i] + " "); } System.out.print("\n"); } } } Output: One One Two One Two Three One Two Three Four One Two Three Four Five
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Jupiter Atmosphere Dynamics on Wiki In brief, as of 2008 (when I assume this article was first written) no one really had a good idea of how Jupiter's atmosphere works to produce the effects we see when we observe it. The article linked covers a few of the hypotheses (specifically in the section I linked to directly), and it also goes into more detail about what scientists do know about the atmosphere. I'm not sure if anything has changed in regards to what we know about Jupiter since then, but hopefully one of our more knowledgeable members can tell us.
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Ok, as that makes no sense to me, I'll illustrate my math, so you can show me where I went wrong in my calculations (I'm assuming I did something wrong, rather than you being mistaken DH.) Edit to clarify some notations gs = acceleration due to gravity at the mean surface of the earth. gm = acceleration due to gravity at a point half way between the point center of the earth and the point of gs p = mean density of the earth at the point that gn is calculated. r = the distance between the point gn is calculated and the point center of the earth. [math]r_{g_{m}} = \frac{1}{2}r_{g_{s}}[/math] Starting with [math]g = \frac{4\pi}{3}G pr[/math] Following from that (Edit: sorry, hit the wrong button ) [math]g_{s} = \frac{4\pi}{3}\times\frac{6.674\times 10^{-8} cm^3}{g\times s^2} \times \frac{5.54g}{cm^3} \times 637810000 cm[/math] [math]g_{s} = \frac{4\pi}{3}\times\frac{6.674\times 10^{-8}}{s^2} \times 5.54 \times 637810000 cm[/math] [math]g_{s} = \frac{4\pi}{3}\times\frac{6.674\times 10^{-8}}{s^2} \times 3.533\times10^{9}cm[/math] [math]g_{s} = \frac{4\pi}{3}\times\frac{6.674\times 10\times 3.533 cm}{s^2}[/math] [math]g_{s} = \frac{4\pi}{3}\times\frac{235.792 cm}{s^2}[/math] [math]g_{s} = \frac{314.39\pi cm}{s^2}[/math] I am not going to bother taking the pi out. We've done enough to make a comparison. [math]g_{m} = \frac{4\pi}{3}\times\frac{6.674\times 10^{-8} cm^3}{g\times s^2} \times \frac{6.701g}{cm^3} \times 318905000 cm[/math] [math]g_{m} = \frac{4\pi}{3}\times\frac{6.674\times 10^{-8}}{s^2} \times 6.701 \times 318905000 cm[/math] [math]g_{m} = \frac{4\pi}{3}\times\frac{6.674\times 10^{-8}}{s^2} \times 2.136\times10^{9}cm[/math] [math]g_{m} = \frac{4\pi}{3}\times\frac{6.674\times 10\times 2.136 cm}{s^2}[/math] [math]g_{m} = \frac{4\pi}{3}\times\frac{142.557 cm}{s^2}[/math] [math]g_{m} = \frac{190.075\pi cm}{s^2}[/math] This shows, again assuming my maths are right, that [math]g_{m} = .605g_{s}[/math]. Is there a flaw in my math?
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A vacuum can occupy a volume. This is not the same thing as saying it has volume. It's like asking what the volume of water is. We don't know until we describe the container holding it, or alternatively, until we enumerate the mass of the water we're discussing. Since volume does not (to my understanding) have mass, the only way to describe the volume of a vacuum is to use the volume of the container holding it.
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This is the correct interpretation.
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[math]g = \frac{4\pi}{3}G pr[/math] where p = density of the object. If we assume p remains constant (which isn't accurate, but let's make the assumption for the moment), then we can eliminate all the constants values from the equation, then all we're left with is the surface gravity being directly proportional to the radius. As the radius from the center decreases so does the gravity, and thus the weight. In truth, it's probably not quite exactly half, since the mean density of the planet goes up as you approach the iron core (the mean density of the Earth is roughly 5.54 g/cm3, while iron has a density of 7.87 g/cm3). Assuming you split the difference on the density at 6.701 g/cm3, then the actual force of gravity would be gmidpoint = .604gsurface or there abouts (as always, if I did my math right). In other words, you would mass the same, and weight about 60% as much as you do on the surface.
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does morality depend on religion/objective vs subjective morality
Greg H. replied to dragonstar57's topic in Religion
So basically, God is the ultimate moral authority because he said he is? So your proof of an objective morality is a circular argument for a supernatural being that cannot be proven to exist. Now I remember why I stopped commenting in this thread. -
does morality depend on religion/objective vs subjective morality
Greg H. replied to dragonstar57's topic in Religion
The first 5 of them have nothing to do with morality or ethics. On thou shalt not kill, God cannot take the moral high ground since he commands not only killing but genocide, and commits wholesale specicide when he floods the earth (I mean, if we're accepting the myth as true, right?). And if he is that morally bankrupt that he cannot even follow his own guidelines, why should I consider that anything he says on the subject is worth paying attention to. Why should I accept anything as an objective moral standard from a being who cannot even abide by his own supposed standard? -
So wait...according to a strict interpretation of SS3, it is illegal for me to advise a friend to consult a dietitian or nutritionist. I can't use those words at all.
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Your presumption of my religious status is nearly as arrogant as your presumption that your belief is the only one that matters. No, you haven't. You've stated it, but you haven't actually provided any evidence that has not been repeatedly refuted, shown to be incorrect, or is blatantly misrepresenting the science. Not to put too fine a point on it, but no one really gives two shits what you believe. All that matters is what you can prove. If it is necessary that life requires an intelligent creator, than you need to prove that one exists. Since no one has yet done so (and trust me, people have certainly tried, twisting science until it breaks), I am under no compulsion to assume your conclusion is correct without substantial proof. This is a very succinct summation of your arguments to date.
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While we have no confirmation that the laws of physics are universal, we also have no reason to suspect they are not. If we subscribe to the idea that the laws of nature vary from one location in the universe to another, then we are suddenly introducing the idea that for some reason our section of the universe is special or different in some way, and that is a far more damaging assumption than the laws of the universe are the same everywhere. Also, not to argue semantics, but it turns out is a statement that science is working as we expect - it implies we learned something we didn't expect or that may not have been readily apparent. So yes, while it is a statement of confirmation, it's not as dogmatic as your interpretation would imply.
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http://www.deltacollege.edu/emp/ckim/Handouts/CleaningGlassware.pdf
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How about you ?!! But indeed : no one can convince me on the contrary. Neither i am here with that purpose. I have seen miracles happen in my life, that makes in impossible to NOT believe in God. When you start presenting evidence, I'll listen. However, personal miracles and parables from the Bible are not evidence, nor is your inability (or unwillingness) to examine the scientific evidence presented that conflicts with your statements. If you aren't here to discuss things based on evidence and science, why did you join a science forum?