Educational Resources for Students | Discovery Education
Participate in our monthly SAC meetings every 2nd Thursday. Meetings take place in the Media Center starting at pm. - - -. SAC Meeting Parents, want to . (For one thing, you don't have worry about your parents failing to create you—you already exist.) Einstein described our universe in four dimensions: the three Something happens: You walk through a door, you are all by yourself, you meet someone else, you .. More great sites from Kalmbach Media. All3Media (stylized as all3media) is a British independent television, film and digital production On 8 May , it was announced that Discovery, Inc. and Liberty Global would acquire All3Media, in a joint venture valued at US$ million.
That may strike you as weird or unlikely, but there is nothing paradoxical or logically inconsistent about it. The real question is this: What happens if we try to cause trouble?
That is, what if we choose not to go along with the plan? But once you actually do jump backward in time, you still seem to have a choice about what to do next. You can obediently fulfill your apparent destiny, or you can cause trouble by wandering off. What is to stop you from deciding to wander? That seems like it would create a paradox.
Your younger self bumped into your older self, but your older self decides not to cooperate, apparently violating the consistency of the story. We know what the answer is: If you met up with an older version of yourself, we know with absolute certainty that once you age into that older self, you will be there to meet your younger self.
That is because, from your personal point of view, that meet-up happened, and there is no way to make it un-happen, any more than we can change the past without any time travel complications.
There may be more than one consistent set of things that could happen at the various events in space-time, but one and only one set of things actually does occur. Consistent stories happen; inconsistent ones do not.
Digital Social Studies Textbooks & Curriculum | Discovery Education
The vexing part is understanding what forces us to play along. The issue that troubles us, when you get down to it, is free will. We have a strong feeling that we cannot be predestined to do something we choose not to do. That becomes a difficult feeling to sustain if we have already seen ourselves doing it.
Free Student Resources
Of course, there are some kinds of predestination we are willing to accept. If we get thrown out of a window on the top floor of a skyscraper, we expect to hurtle to the ground, no matter how much we would rather fly away and land safely elsewhere. The much more detailed kind of predestination implied by closed timelike curves, where it seems that we simply cannot make certain choices like walking away after meeting a future version of ourselvesis bothersome.
The arrow of time is simply the distinction between the past and the future. We can turn an egg into an omelet, but not an omelet into an egg; we remember yesterday, but not tomorrow; we are born, grow older, and die, never the reverse.
A neatly stacked collection of papers has a low entropy, while the same collection scattered across a desktop has a high entropy. The entropy of any system left to its own devices will either increase with time or stay constant; that is the celebrated second law of thermodynamics.
The arrow of time comes down to the fact that entropy increases toward the future and was lower in the past.
But in the presence of closed timelike curves, some events are in our past and also in our future. So do we remember such events or not? In general, events along a closed timelike curve cannot be compatible with an uninterrupted increase of entropy along the curve. On a closed curve, the entropy has to finish exactly where it started, but the arrow of time says that entropy tends to increase and never decrease.
Something has to give.
To emphasize this point, think about the hypothetical traveler who emerges from the gate, only to enter it from the other side one day later, so that his entire life story is a one-day loop repeated ad infinitum. The traveler would have to ensure that, one day later, every single atom in his body was in precisely the right place to join up smoothly with his past self. He would have to make sure, for example, that his clothes did not accumulate a single extra speck of dust that was not there one day earlier.
This seems incompatible with our experience of how entropy increases. In either case, though, the insistence that we be in the right place at the right time puts a very stringent constraint on our possible future actions. Our concept of free will is intimately related to the idea that the past may be set in stone, but the future is up for grabs. A closed timelike curve seems to imply predestination: We know what is going to happen to us in the future because we witnessed it in our past.
Closed timelike curves, in other words, make the future resemble the past. It is set in stone, not up for grabs at all.
The Real Rules for Time Travelers | guiadeayuntamientos.info
The reason we think the past is fixed once and for all is that there is a boundary condition at the beginning of time. The entropy of the universe started very small at the time of the Big Bang and has been growing ever since. Ordinarily we do not imagine that there is any analogous boundary condition in the future—entropy continues to grow, but we cannot use that information to draw any conclusions.
If we use a closed timelike curve to observe something about our future actions, those actions become predestined. If closed timelike curves exist, ensuring that all events are consistent is just as strange and unnatural to us as a movie played backward, or any other example of evolution that decreases entropy. So either closed timelike curves cannot exist, or big, macroscopic things cannot travel on truly closed paths through space-time—unless everything we think we know about entropy and the arrow of time is wrong.
Life on a closed timelike curve seems pretty drab. Once you start moving along such a curve, you are required to come back to precisely the point at which you started.
An observer standing outside, however, has what is seemingly the opposite problem: What happens along such a curve cannot be uniquely predicted from the prior state of the universe.
John Malone’s Liberty Global Signs Deals with All3Media, Discovery
We have the strong constraint that evolution along a closed timelike curve must be consistent, but there will always be a large number of consistent evolutions that are possible, and the laws of physics seem powerless to predict which one will actually come to pass.
In the usual way of thinking, the laws of physics function like a computer. You give as input the present state, and the laws return as output what the state will be one instant later or earlier, if we wish. By repeating this process many times, we can build up the entire history of the universe, from start to finish.
In that sense, complete knowledge of the present implies complete knowledge of all of history. Closed timelike curves would make such a program impossible, as a simple thought experiment reveals. Hark back to the stranger who appeared out of the gate into yesterday, then jumped back in the other side a day later to form a closed loop.
There would be no way to predict the existence of such a stranger from the state of the universe at an earlier time. Dive into the energy-water nexus today!
Invite students to explore the relationship between water and energy as they relate to conservation and discover how new technologies are empowering consumers, making cities smarter, and moving us toward a more energy-efficient future. Learn More Glimpse the true impacts of opioid misuse Meet real people affected by opioids and hear their stories of loss, triumph, and learning.
Arm your students with the facts so they can make informed choices when faced with their decision to take prescription opioids or heroin in this powerful Virtual Field Trip. Hear from experts in software and infrastructure engineering, product design, and data security, to learn how hands-on work in the classroom can lead to engaging careers that create positive change.
Watch Now Pathway to Financial Success in Schools Empower students to take control of their financial futures with new standards-aligned financial literacy curriculum from Discover Financial Services and Discovery Education.
Learn More Now On Demand: Your Roadmap to a Healthy Heart Are you ready to take the challenge? Tune in for our newest virtual experience to get your students' blood pumping with fun physical activity. They have all inspired 3M innovations in science! Stream the Young Scientist Virtual Field trip today to learn more about how nature inspires 3M science. Blast off with your classroom today! Connect science learned in the classroom to your favorite sports with the latest Science of Soil Virtual Field Trip now available on demand!
Stream now to explore how soil science helps keep sports fields looking great for the fans and safe for the athletes. Watch Now NEW resource just launched! Three real-world missions introduce you to concepts in physics, biology, engineering and earth science while highlighting Navy STEM careers. Watch today to discover a breadth of exciting careers powering John Deere innovation.