Lesson 1 of 15

The Lorentz Factor

The Lorentz Factor

Special relativity rests on two postulates: the laws of physics are the same in all inertial frames, and the speed of light c=299,792,458c = 299{,}792{,}458 m/s is the same for all observers. These innocent-sounding rules force us to abandon absolute time and space.

The quantity that appears in every relativistic formula is the Lorentz factor γ\gamma. It is built from the beta parameter β\beta, the fraction of the speed of light:

β=vc\beta = \frac{v}{c}

γ=11β2\gamma = \frac{1}{\sqrt{1 - \beta^2}}

Behaviour

v/cv/cβ\betaγ\gamma
000011
0.6c0.6c0.60.61.251.25
0.8c0.8c0.80.81.667\approx 1.667
0.99c0.99c0.990.997.09\approx 7.09
c\to c1\to 1\to \infty

At everyday speeds γ1\gamma \approx 1 and all relativistic effects are negligible. As vcv \to c, γ\gamma diverges, meaning it takes infinite energy to reach light speed. The factor γ\gamma will reappear in time dilation, length contraction, and relativistic momentum and energy.

Your Task

Implement lorentz_factor(v) that returns γ\gamma for a velocity vv in m/s, and beta(v) that returns β=v/c\beta = v/c. Use c=299792458.0c = 299792458.0 m/s. Both constants must be defined inside each function.

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