If astronauts could travel at v = 0.902c, we on Earth would say it takes  (4.20/0.902) = 4.66 years to reach Alpha Centauri, 4.20 light-years away. The astronauts disagree. (a) How much time passes on the astronauts' clocks? In years   (b) What is the distance to Alpha Centauri as measured by the astronauts? In light years

A day on the Earth has 24 hours. How fast must a spacecraft travel so that the spacecraft clocks tick through 23 hours (on spacecraft clocks) while the earth clocks tick through 24 hours from the viewpoint of an observer on the Earth?

The speed of light relative to still water is 2.25 * 10^8 m/s. If the water is moving past us, the speed of light we measure depends on the speed of the water. Do these facts violate Einstein’s second postulate? Explain.

The remaining lifetime of the Sun in seconds is 1.5 x 10¹7 sec. Convert this value into years. 0000000000000000 PLS HELP!

For an astronaut traveling to a star 10 lightyears away at v=0.99c  and returning, spending negligible amount of time at the destination, describe the journey as the astronaut would observe it. In particular, describe what the astronaut would observe as happening on Earth during the journey

You are in a rocket moving away from Earth at one-third the speed of light relative to Earth. A friend is on Earth, and an astronaut in another rocket is moving toward Earth at one-third the speed of light (in the Earth reference frame), on a path collinear with your path. If each of you records the duration of your journey in your three respective reference frames, which of you records the proper time interval?

As measured by the crew, a spaceship takes 8.1 years to fly from Earth to a distant star. If the ship traveled at 0.95c, which of the following is the distance between Earth and the star as measured by observers on Earth? 22.3 light years O 24.6 light years O 29.2 light years O 20.9 light years

Captin Babena , depart the NASA Launch pad in a space shuttle that orbits Earth. As space shuttle accelerates to relativistic speeds, Captin Babena's thoughts turn to her twin sister, Saiena, who has never left Earth. They were born at exactly the same time. Will they still be the same age when babena returns from her triple?

A newly constructed spaceship has a length of 100.0 m (as measured in the rest frame). This spaceship departs the Earth, bound for a distant planet located a distance D = 50.0 light-years away from the Earth. It travels at a constant speed of v = 0.900c.   Part A) As measured by Mission Control on Earth, how long does the journey take? Enter the numerical value in units of years. Part B) According to an astronaut on the spaceship, how long does the journey take? Enter the numerical value in units of years. Part C) As measured by Mission Control on Earth, what is the spaceship's apparent length? Enter the numerical value in SI units

Two radar pulses sent from the earth at 6:00 am and 8:00 am one day bounce off an alien spaceship and are detected on earth at 3:00 pm and 4:00 pm (but you aren’t sure which reflected pulse corresponds to which emitted pulse). Is the spaceship moving toward earth or away? If its speed is constant (but less than c), when will it (or did it) pass by the earth? (please draw a spacetime diagram.)