/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Problem 3 You wish to make a round trip fr... [FREE SOLUTION] | 91Ó°ÊÓ

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You wish to make a round trip from Earth in a spaceship, traveling at constant speed in a straight line for exactly 6 months (as you measure the time interval) and then returning at the same constant speed. You wish further, on your return, to find Earth as it will be exactly 1000 years in the future. (a) To eight significant fig. ures, at what speed parameter \(\beta\) must you travel? (b) Does it matter whether you travel in a straight line on your journey?

Short Answer

Expert verified
(a) \( \beta = 0.9999995 \); (b) No, the path doesn't matter.

Step by step solution

01

Understand the Problem

You want to travel away from Earth and back in a spaceship at a constant speed such that 1000 Earth years pass during your absence. You'll be gone for a total of 1 year (6 months out, 6 months back) according to your clock.
02

Recall Time Dilation Formula

According to the theory of relativity, time dilation is calculated using the formula \( t' = \frac{t}{\sqrt{1-\beta^2}} \), where \( t' \) is the time measured in Earth's frame (1000 years), \( t \) is the time measured in the spaceship's frame (1 year), and \( \beta \) is the speed as a fraction of the speed of light, \( \beta = \frac{v}{c} \).
03

Substitute Known Values

Given \( t' = 1000 \) years and \( t = 1 \) year, substitute these values into the time dilation formula: \( 1000 = \frac{1}{\sqrt{1-\beta^2}} \).
04

Solve for \( \beta\)

Rearrange the equation from the previous step to solve for \( \beta^2 \): \( \sqrt{1-\beta^2} = \frac{1}{1000} \), which gives \( 1 - \beta^2 = \frac{1}{1000^2} \). Thus, \( \beta^2 = 1 - \frac{1}{1000000} \). Therefore, \( \beta = \sqrt{1 - \frac{1}{1000000}} \).
05

Calculate \( \beta\) to Eight Significant Figures

Calculate \( \beta = \sqrt{1 - 0.000001} = \sqrt{0.999999} \). Using a calculator, this results in \( \beta \approx 0.9999995 \) to eight significant figures.
06

Consider the travel path

For part (b), whether you travel in a straight line or any other path, the time dilation experienced is only dependent on your speed, not the path taken. Therefore, as long as you maintain the constant speed with respect to Earth, the trajectory does not affect the time dilation.

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Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Theory of Relativity
The Theory of Relativity, developed by Albert Einstein, revolutionized our understanding of physics. It consists of two parts: special relativity and general relativity. Special relativity, introduced in 1905, focuses on the behavior of objects moving at constant speeds, particularly those approaching the speed of light. Its cornerstone principle states that the laws of physics are the same for all observers, regardless of their relative motion.
One of the most intriguing outcomes of the theory is time dilation. Time dilation implies that time measured in a moving system will pass at a different rate than in a stationary system. This difference becomes apparent as the moving system's speed approaches that of light. In our context, when space travelers move at such high speeds, they will experience less passage of time compared to those who remain stationary on Earth.
General relativity, published in 1915, extends these concepts by incorporating gravity's role in the fabric of space and time. However, for space travel at constant speeds, it is special relativity that provides the foundational framework.
Speed of Light
The speed of light is a fundamental constant of nature, denoted by the symbol \( c \). It is approximately \( 299,792,458 \) meters per second. This speed is significant in physics as it represents the ultimate speed limit in the universe. Nothing can travel faster than light.
In the context of our exercise, the speed parameter \( \beta \) is defined as the ratio of the velocity of the spaceship \( v \) to the speed of light \( c \), i.e., \( \beta = \frac{v}{c} \). As such, \( \beta \) is always less than or equal to one.
Understanding \( \beta \) is essential for grasping how velocity affects time dilation. As \( \beta \) approaches 1, meaning the spaceship's speed nears the speed of light, the effects of time dilation become more pronounced, explaining why a journey that seems brief to travelers might last for centuries to those they leave behind.
Time Measurement
In physics, time is a crucial quantity that can be measured in different reference frames. In our scenario, we are dealing with time as perceived by two observers: the space traveler and those on Earth. Time measurement becomes more complex when high velocities are involved, due to time dilation effects from the Theory of Relativity.
The equation used to calculate time dilation is \( t' = \frac{t}{\sqrt{1-\beta^2}} \). Here, \( t \) represents the time according to the traveler's framework, and \( t' \) is the time according to Earth's framework. This formula illustrates how traveling nearly at the speed of light causes the traveler's time to 'dilate' or stretch out, viewed from Earth.
Such differences in time perception illustrate why technology like atomic clocks, which measure time with extreme precision, becomes critical in space missions and understanding cosmic phenomena.
Space Travel
Space travel, though still in its early stages, holds key significance for future exploration. When imagining voyages that approach the speed of light, such as in our fictional exercise, it is essential to understand both the practical and theoretical aspects involved.
One of the challenges is maintaining the spacecraft's speed closer to that of light. Achieving such speeds requires overcoming enormous energy demands and navigating without error as even tiny variations can have significant effects over long distances.
Moreover, factors like acceleration and deceleration need consideration since they could affect the spacecraft's integrity and the well-being of its occupants. While the exercise simplifies the path as a straight line, in reality, space travel involves complex flight paths and gravitational maneuvers. However, what remains constant is the influence of speed on the time experienced by travelers and observers, a fascinating aspect governed by the fundamentals laid down in Einstein's theory.

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Most popular questions from this chapter

An experimenter arranges to trigger two flashbulbs simultaneously, producing a big flash located at the origin of his reference frame and a small flash at \(x=30.0 \mathrm{~km}\). An observer moving at a speed of \(0.250 c\) in the positive direction of \(x\) also views the flashes. (a) What is the time interval between them according to her? (b) Which flash does she say occurs first?

If \(m\) is a particle's mass, \(p\) is its momentum magnitude, and \(K\) is its kinetic energy, show that $$ m=\frac{(p c)^{2}-K^{2}}{2 K c^{2}} $$ (b) For low particle speeds, show that the right side of the equation reduces to \(m .(\mathrm{c})\) If a particle has \(K=55.0 \mathrm{MeV}\) when \(p=121 \mathrm{MeV} / c\), what is the ratio \(m / m_{e}\) of its mass to the electron mass?

The mass of an electron is \(9.10938188 \times 10^{-31} \mathrm{~kg}\). To eight significant figures, find the following for the given electron kinetic energy: (a) \(\gamma\) and (b) \(\beta\) for \(K=1.0000000 \mathrm{keV}\), (c) \(\gamma\) and (d) \(\beta\) for \(K=1.0000000 \mathrm{MeV}\), and then (e) \(\gamma\) and (f) \(\beta\) for \(K=\) \(1.0000000 \mathrm{GeV}\)

A sodium light source moves in a horizontal circle at a constant speed of \(0.100 c\) while emitting light at the proper wavelength of \(\lambda_{0}=\) \(589.00 \mathrm{~nm}\). Wavelength \(\lambda\) is measured for that light by a detector fixed at the center of the circle. What is the wavelength shift \(\lambda-\lambda_{0} ?\)

A space traveler takes off from Earth and moves at speed \(0.9900 c\) toward the star Vega, which is \(26.00\) ly distant. How much time will have elapsed by Earth clocks (a) when the traveler reaches Vega and (b) when Earth observers receive word from the traveler that she has arrived? (c) How much older will Earth observers calculate the traveler to be (measured from her frame) when she reaches Vega than she was when she started the trip?

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