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Other people will give you much better answers (or provide more information). Have you looked at https://www.w3schools.com/php/php_arrays_multidimensional.asp (first link that came up, the language (PHP) does not matter to understand multi dimensional arrays)? An array contains a collection of elements, such as integers, strings and booleans. Let's say we have: Array = [1,2,3,4] Then Array[0] = 1 and Array[2] = 3 A multidimensional array contains arrays as its elements. MultiDimensionalArray = [ [1,2,3,4], [5,6,7,8], [9,10] ] (this array has 2 dimensions) Then the first position of this MultiDimensionalArray will be MultiDimensionalArray[0] = [1,2,3,4] if we want to access one of the numbers in this array, we would specify a second dimension: MultiDimensionalArray[0][1] = 2. Does this help? Other people will be able to help you further, but I highly recommend reading/searching about these things yourself first and explain the parts that you do not understand, that way people can help you more and you will learn faster. Good luck!

Do we have to solve all problems at once? Can't we just deal with the monuments in this thread and figure out what else should be done later? I don't think you intend to do it, but "whataboutism" is a classic red herring technique to draw people off the trail of the topic at hand.

Perimeter is a one dimensional attribute, while area is two dimensional. IOW, you need one piece of information for one and two for the other. That allows for considerable ( infinite ) variation.

You have said everything I was going to say Well, one more thing. The "list of lists" or "array of arrays" description is one way of thinking about 2D arrays, and is how many programming languages work. But you can also think of it as an explicit, 2D array: A = [11, 12, 13, 14, 15, 16; 21, 22, 23, 24, 25, 26; 31, 32, 33, 34, 35, 36] That is a 3x6 array. Some languages treat multidimensional arrays like this so you can references elements of the array as A[2,4] (which would equal 24 in this example). And just a bit of terminology. A 1D array is often called a "vector" in mathematics. A 2D (or higher dimensional) array is called a "matrix". In some programming languages, arrays of any number of dimensions are called "tensors". Lists and arrays are very similar concepts. Some languages have either lists or arrays. Some have both, with slightly different properties. Typically, an array has a fixed size while a list can have things added to the end, or inserted in the middle.

When Fermi said that he wasn't in his finest hour, I think. It would be sad that he were remembered mostly by that. It's very easy to rebut: Stay in the North Pole for 10.000 years looking for camels. After that time, you haven't seen camel number one. Conclusion: Camels don't exist, because otherwise they would have reached the North Pole by then. When you're heavily constrained in your observation, it's easy sometimes to forget that there are correlations in your observation methods, accessible places to look, etc. Fermi's argument is called argument from silence, and it's very well known to archaeologists and historians to be seriously flawed. It is very likely that someone caught something informally muttered by Fermi and poorly thought out, IMO, and then went nuts with it. The argument from silence can sometimes be used --with extreme care-- if you are reasonably sure that your observation method is not biased. Another example: Marco Polo didn't mention the Great Wall of China. That doesn't mean it didn't exist back then. Edit. Another example: Aliens in the opposite spiral arm of the Milky Way could think, "I'm sure there's no life in the Milky Way besides us, because otherwise they would be here by now." But, wait, there's us, isn't there? You can think of tens more examples like these...

I support every constructive effort to reform our police policies and tactics, as well as, every civil effort to bring equality to our nation's people; however, "Defund the Police" is an idiotic idea. As a wise person once said, "Don't throw the baby out with the bath water!"

That kind of fantasizing is certainly enjoyable which is why science fiction is so popular. But this is a science site and you are in the physics section. More is required to maintain a discussion.

Issac Asimov wrote an article about this called The Relativity of Wrong We once thought the world was round, and then we corrected that to it being a sphere. That was further corrected to being an oblate spheroid, and later, further refinements were made. The point is that this represents a series of refinements, each step being a smaller adjustment to the previous. When it comes to the Earth's shape, we will never again see such a large shift as between flat Earth and round Earth. Just because we once thought it was flat and now believe it to be round doesn't mean that some day we will conclude that is is shaped like a tetrahedron. Likewise, any correction to Relativity would still need to fit our present observations of the universe, which do indicate that c is a natural speed limit built into the universe. While we can never absolutely be sure that there might not be a way around this, there is no reason to believe that this will ever be the case. It is entirely possible( maybe even likely) that c is an insurmountable barrier. It is important not to let what you would prefer to be true to influence what you believe to the be true. As pleased as I would be if it turned out that the universe was populated with advanced civilizations and that FTL travel between star systems was practical, I can't bring myself to believe it to be true given the lack of any credible evidence for it.

You need me to cut your meat and tie your shoelaces for you, too?

If you organized a charity event to raise money for breast cancer and someone showed up and started asking for money for lung cancer, how would you feel? You would of course recognize that lung cancer is bad too, but would probably be annoyed that you weren't given the courtesy of being allowed to focus on your cause at your event. Here you are trying to do a good thing and someone else is using your event to bring attention to their own personal cause, and taking attention away from your own. The negative feedback people receive for "ALL lives matter" comments has to do with the tone deaf or racist undertones that comment imparts. Tone deaf as in; Mom: "My son just died because he was accidentally shot by his friend who was playing with his dad's gun. I want to raise awareness to make sure it doesn't happen to others." Bystander: "Kids die from all kinds of accidents. There is nothing special about your kid's cause of death. You should not act like your kids accident should receive extra attention. You should care about ALL types of accidents." This shows a complete lack of empathy for what that mother is going through. She suffered and wants to make sure others don't, but this bystander can't manage to see it from her perspective, but rather in some dispassionate statistical manner. If this bystander wants to draw attention to ALL types of accidents they should do it in their own way on their own time, and not by minimizing what the mother is doing by implying she is selfish for only focusing on the cause of death of her kid. But of course they never will participate in a march for ALL types of accidents, they will only criticize what others do. Racist as in; Protester: "Black Lives Matter, we need to stop being worried about our kids not coming home at night just because they were driving, or shopping, or in a 'white' neighborhood, or committed some petty crime." Bystander: "ALL lives matter. If your kid had just did what the cops said nothing would happen to them. I always say 'yes sir' to cops and do what they say. If you did nothing wrong you have nothing to fear. There is no reason some particular minority has to commit a disproportionate number of crimes and murders. If you loot, we will shoot." Yeah, just a racist. Never believe that a black man didn't get what was coming to them. Just don't care, and not afraid to say it. Or, they are one of the many who are quite sure they are not racist, but they never make a similar putdown on white people, only blacks. They are in complete denial. Both the tone deaf and the racist need to be called out. It is one thing to discuss whether or not BLM should really be ALM, but to simply criticize someone for marching for BLM is, IMHO, out of line.

Your understanding isn’t accurate. You should fix that. Please, quantify this. For “too many?” How many? I’ll accept and order if magnitude estimate. Becomes “too often?” How often? One in five? In ten? A hundred? A million? Knowing you won’t be able answer my entirely reasonable request in an even remotely satisfactory way, perhaps we can simply agree there is a problem affecting Americans of specific ethnicities in an asymmetric way and that we should be allies in making things better, even if better often falls short of perfect.

Gravity won't do the trick. There's just not enough energy and nothing can move faster than light, locally speaking. As Strange says, gravitational waves need really powerful sources to be triggered, as black-hole collisions, plus they're really feeble, and don't really induce linear accelerations in clusters of matter, but just space-time distortions in two mutually perpendicular directions. It's just like a blip on the radar screen, so to speak. The Alcubierre metric is another far-fetched possibility AFAIK, not free from inconsistencies. And then the only reasonable possibility in principle that I can think of is getting work from the huge storage of mc^2-energy in matter, maybe by capturing free antiparticles from cosmic rays and guiding them to ordinary matter that would act as fuel/target. But that is a far cry, I suppose. I'm a theorist, so I really can't tell with any degree of accuracy. There are many experimentalists/engineers here that can judge much better than me how much of a crazy idea the latter would be.