You are on an interstellar mission from the Earth to the 8.7 light-years distant star Sirius. Your spaceship can travel with 70% the speed of light and has a cylindrical shape with a diameter of 6 m at the front surface and a length of 25 m. You have to cross the interstellar medium with an approximated density of 1 hydrogen atom/m3. Because you are moving with an enormous speed, your mission will be influenced by the e_ects of time dilation described by special relativity: Your spaceship launches in June 2020 and returns back to Earth directly a_er arriving at Sirius. (a) How many years will have passed from your perspective? (b) At which Earth date (year and month) will you arrive back to Earth?

You are on an interstellar mission from the Earth to the 8.7 light-years distant star Sirius. Your spaceship can travel with 70% the speed of light and has a cylindrical shape with a diameter of 6 m at the front surface and a length of 25 m. You have to cross the interstellar medium with an approximated density of 1 hydrogen atom/m3. Because you are moving with an enormous speed, your mission will be influenced by the e_ects of time dilation described by special relativity: Your spaceship launches in June 2020 and returns back to Earth directly a_er arriving at Sirius. (a) How many years will have passed from your perspective? (b) At which Earth date (year and month) will you arrive back to Earth?