Opponents challenge relativity theory on the grounds that the twin paradox reveals an underlying flaw in the theory. Minutephysics host henry reich explained the twin paradox, its solution, and why it is not technically a paradox in a pair of recent episodes. What is the reason why the twin paradox is not considered a. Stella flies off in a spaceship at nearly the speed of light, turns around after a while, thrusters blazing, and returns. The spaceship needs acceleration and deceleration, thus ts conclusion is. When the paradox is addressed, it is usually done so only briefly, by saying that the. A read is counted each time someone views a publication summary such as the title, abstract, and list of authors, clicks on a figure, or views or downloads the fulltext. Aug 26, 2016 last weeks lesson was time dilation, and you hopefully understand the basics of how it works. The spaceship needs acceleration and deceleration, thus ts conclusion is not right.
The twin paradox is no paradox according to the law of. Last weeks lesson was time dilation, and you hopefully understand the basics of how it works. I give the correct resolution of the paradox, explai ning why str is not incon sistent as it app ears at first glanc e. The twins paradox is the most prominent gedanken experiment that relates the theory of relativity with the arrow of time. Paradox simple english wikipedia, the free encyclopedia. The solution given in this paper is based upon special and general relativity. When he turns around and heads back, his velocity is different and his line of simultaneity is also different. The twin paradox is a thought experiment where one twin stays on earth and the other takes a journey through space at incredibly high speeds before returning home. The majority of them, overwhelmed by mathematical difficulties of the general theory of relativity, decided to keep silent. And the above resolution of the twin paradox is contrary to the spirit of the general theory of relativity. It involves identical twins, one of whom makes a journey into space in a highspeed rocket and returns home to find that the twin who remained on earth has aged more the paradox depends upon the unspoken idea that the passage of time is the same in all circumstances. The twins clock paradox history and perspectives cyberleninka. Assume that the astronaut has a twin sibling waiting back on earth. The confusion caused by the phenomenon of time dilation has long been encapsulated in the socalled twin paradox stated as follows.
The twin paradox is a thought experiment that demonstrates the curious manifestation of time dilation in modern physics, as it was introduced by albert einstein through the theory of relativity. The paradox depends upon the unspoken idea that the passage of time is the same in all circumstances. The twin paradox uses the symmetry of time dilation to produce a situation that seems paradoxical. A new interpretation of the twin paradox in alices frame, bettys age at point p corresponds to at when she travels at 0. Jan 27, 2017 perhaps the most famous paradox of this sort is the twin paradox of special relativity. General relativity is not necessary to explain the twin paradox.
Actual motion relative to the universe dictates actual clock rates, creating a time gap, incrementally. The twin paradox is athought experiment where one twin stays on earth and the other takes a journey through space at incredibly high speeds before returning home. Twin paradox, time dilatation, inertial frame, spacetime. The twin paradox and the principle of relativity arxiv. The twin paradox has a very simple resolution in this framework. Twin paradox explained in special relativity with a link to an animation. The twin paradox part 1 paradoxes to ponder coursera. Twin paradox two the second paradox is a bit more technical, and really comes to the heart of what physicists mean when they talk about relativity. Further analysis of the statement or proposition may reveal a fallacious axiom or some obscure underlying truth.
According to the earthling, the returning astronaut has aged less because she traveled at high velocity, which slowed her clock. Again there is a paradox, for creative work demands both a passionate interest on the part. The proposed paradox arises because each twin sees the other. How to understand the twin paradox science publishing group. In most books the author tries to solve the problem exclusively with special relativity. May 07, 2006 the twin paradox, sometimes called the clock paradox, stems from paul langevins 1911 thought experiment in special relativity. This scenario became known as the twin paradox, with the clocks being replaced by twin brothers, one of whom journeys away and then returns to find his stayathome brother has aged more than himself. Before i can explain why the twin paradox is not considered a paradox, i have to explain why it is considered a paradox.
According to einsteins theory of relativity, the faster you travel, the slower time passes. The twin paradox heres a statement of the twin paradox, designed to make it seem paradoxical. The twin paradox in special and general relativity. The twin paradox and the principle of relativity oyvind gron oslo university college, faculty of engineering, p. But this is a twin paradox part two, and remember how we set it up, the paradoxical part here is that both bob and alice is, heres bob. This was good to see because until it got to that point, i was afraid it was going to be another video that completely missed the whole point of the paradox, like this one, and was ready to. Well follow convention by referring to this speed as c.
Time, topology and the twin paradox jeanpierre luminet. So twin b thinks that only 210th of a year has elapsed for twin a back home as they return using the same relative time dilation factor of 10. In this case time dilation states that more time will have elapsed on a clock that moves between two points with constant velocity as is required if a is at rest in some lorentz frame than on a. A version of this article was first published in fermilab today. I can see that unlike most videos on the twin paradox, this one actually had the crux of the paradox itself correct. Alice takes her trip to the star, three lightyears from bob, and then back again. The entire scenario is based on the idea that biff was traveling very fast, so time slowed down for him. Mar 30, 2015 the twin paradox is a thought experiment where one twin stays on earth and the other takes a journey through space at incredibly high speeds before returning home. The perfect cosmological principle return of the steady state universe. It has been solved long ago, and where einsteins special theory of relativity gave birth to the paradox, his general theory of relativity laid it to rest. Twin paradox simple english wikipedia, the free encyclopedia. Under the general relativistic formulations explained in 12, eartha ages by 6. Clock paradox, length contraction, simultaneity, special relativity, time dilation, twins paradox. Absolute frame of reference in the physics community.
A geometrical view of time dilation and the twin paradox. But the ones who could understand relativity welcomed it. Because of special relativity, although the twins were born at the same time, after the journey their ages are now years apart. Twin a thinks they are older than twin b, but twin b thinks they are older than twin a. One point that might have you puzzled is time dilation. Pdf in december 1966 through january 1967, harrison salisbury. Motivation also plays an important role in our ability to be creative. The twin paradox part 2 paradoxes to ponder coursera. The twin paradox in physics is a thought experiment in special relativity. One is for laymen and the second is for people who think they understand relativity. Twin paradox, an apparent anomaly that arises from the treatment of time in germanborn physicist albert einsteins theory of special relativity. Aug 29, 2016 minutephysics host henry reich explained the twin paradox, its solution, and why it is not technically a paradox in a pair of recent episodes.
Einstein himself presents it that way in the reading on the web site. The socalled twin paradox is easily resolved by noting that there is a physically meaningful disinction between the experiences of the two twins during the trip. Correct resolution of the twin paradox michael huemer. A paradox is a seemingly absurd or selfcontradictory statement in logic that, superficially, cannot be true but also cannot be false. Mar 30, 2015 unexplained mysteries 2,854,228 views. Nov 29, 2012 this video explains what the twin paradox is. Considering only the time flow difference for each of the twins, the theory of relativity concludes that the twins may have different age, under the conditions of the known gedanken experiment. So now we come to the twin paradox which is probably the most famous paradox in the special theory of relativity. Einsteins theories and the twin paradox molwickpedia. The twin paradox is a thought experiment in special relativity, in which the ages of twins are compared after one has made a high speed journey over a long period of time, while the other has remained stationary. This result appears puzzling because each twin sees the other twin as moving, and so, according to an. The twin paradox scenario results for aa, when b returns to the same clock a. In the introductory film clip, we saw that time was dilated when observed from frames of reference with a constant relative velocity v. One clever solution to this paradox is that es conclusion is right.
Such opponents feel that the existence of a paradox, in and of itself, is sufficient to disqualify the theory. To find out what bettys age at point p is in her own frame, we divide bettys journey into away and return. Our story stars two twins, sometimes unimaginatively named a and b. How does relativity theory resolve the twin paradox. Embedded youtube animation, with textual description and a little math. Embracing the twin paradox is an important first step as you dip your toe into the nonintuitive world of special relativity. Relativity trail, free pdf format, with 192 pages, 65 diagrams and 75 illustrations, will provide you with complete detailed algebraic. The counterintuitive nature of einsteins ideas makes them difficult to absorb and gives rise to situations that seem unfathomable. The earthbound twin remains in a single constant velocity reference frame the entire time while the traveling twin must accelerate to turn around and come home. An explanation of the twin paradox and why its not. If you dig a little deeper and show a little determination, hopefully youll begin to be more comfortable that einstein really was right. In a physics book explaining the twin paradox, it says at the end, what happened was that the accelerations of a altered his biological processes, and therefore when the conclusions of general relativity for the case of the altered clocks are applied we find that upon his return, a will be younger than b.
Consider sending an astronaut to a distant star in a spaceship at very hight speed. One of a pair of twins the traveling twin travels to and returns from a very distant destination at a speed approaching that of light the other the earthbound twin stays home. In relativity, the proper time defined above is the only time which will be measured by any observer. Hence, the twin paradox arises from using general relativity in its formulation and only special relativity to calculate the ageing that. Einstein only called it peculiar, while langevin explained the different aging rates as follows.
One of them gets in a spacesh ip and flies around really fast. A simple explanation of special relativity and the twin paradox. The first episode sets up the problem and gives a brief explanation for how time rotates, and the second video fully answers the twin paradox. I al so deb unk two common, incorrect responses t o the paradox.
In fact, they often mistake acceleration as necessary to explain. First chose one specific inertial frame of reference, say the rest frame of the earth which well pretend is inertial. Twin paradox the story is that one of a pair of twins leaves on a high speed space journey during which he travels at a large fraction of the speed of light while the other remains on the earth. However, in the present article i will use the twin paradox as a pedagogical entrance to the general theory of relativity. If youre interested in physics, youve probably heard of this paradox, and probably know the solution. In the earth frame which we will refer to as the laboratory system the spaceship travels from earth to rigel a distance of 800 light years which. If successful, then this would invalidate the clock effectleading to no route.
I will explain the crucial difference between einstein and langevin now. The crucial concept is the proper time of a moving body. Olavs plass, n0 oslo, norway abstract in the standard formulation of the twin paradox an accelerated twin considers himself as at rest and his brother as moving. Before he does, the bottom green line represents the events that he regards as simultaneous.
When the paradox is addressed, it is usually done so only briefly, by saying that the one who feels the acceleration is the one who. Relativity trail, free pdf format, with 192 pages, 65 diagrams. The twin paradox several articles that discuss this. The twin paradox is one of the most well known and debated paradoxes associated with relativity theory. The twin with the greatest average velocity between the events p1 and p2 is youngest when the twins meet at p2. A simple explanation of special relativity and the twin. Pdf although previous studies have suggested that sexual orientation is influenced by. But recently i was thinking about this paradox in general relativity, which turns out to have some fun consequences. A similar discussion of the failure of spacetime diagrams. Dec 16, 2019 before i can explain why the twin paradox is not considered a paradox, i have to explain why it is considered a paradox. A curve in spacetime is called a world line and will generally describe the position of the observer as a function of the time. Once weve chosen a reference frame, we can define coordinates t,x,y,z for every event that takes.
The opinion of the world famous scientists on the theory of relativity varied greatly. Twin paradox einstein spoke of clocks, while in 1911 paul langevin extended einsteins clock paradox to human observers and the aging effect. This paradoxes arises from the following three plausible, but jointly inconsistent, claims. Perhaps the most famous paradox of this sort is the twin paradox of special relativity. Diagrams and equations demonstrating the symmetry of clock rate and length measures across inertial frames. Because of time dilation, time is running more slowly in the spacecraft as seen by the earthbound twin and the traveling twin will find that the. In physics, the twin paradox is a thought experiment in special relativity involving identical twins, one of whom makes a journey into space in a highspeed rocket and returns home to find that the twin who remained on earth has aged more. The twin paradox several articles that discuss this thought. But it cannot be explained as a result of the doppler effect by the observer in the rocket, since the detector is permanently at rest relative to the emitter in this. Suppose that two identical twins start out on earth, the same age. Mar 17, 2003 this paradox is discussed in many books but solved in very few. In the following, i explain the twin paradox, which is supposed to be a paradoxical consequence of the special theory of relativity str. Twin paradox explained the red x represents the moment in time when the traveling twin turns around. This paradox is discussed in many books but solved in very few.
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