The Milky Way has a diameter (proper length) of about 1.2×10^5 light-years. According to an astronaut, how many years would it take to cross the Milky Way if the speed of the spacecraft is 0.890 c?

Respuesta :

Answer:

Time taken by the spacecraft to cross milky way, [tex]T = 6.147\times 10^{4} years[/tex]

Given:

Actual length, l = [tex]1.2\times 10^{5} ly[/tex]

speed of the aircraft, v =0.890 c

Solution:

From the Einstein's theory of relativity, using length contraction:

[tex]l' = l\sqrt(1 - \frac{v^{2}}{c^{2}})[/tex]

[tex]l' = 1.2\times 10^{5}\sqrt(1 - \frac{(0.890 c)^{2}}{c^{2}})[/tex]

l' = [tex]5.472\times 10^{4} ly = 5.472\times 10^{4}c yrs[/tex]

Time taken by the spacecraft to cross milky way, T:

[tex]T = \frac{l'}{v}[/tex]

[tex]T = \frac{ 5.472\times 10^{4}c}{0.890 c}[/tex]

[tex]T = 6.147\times 10^{4} years[/tex]