LIGHTCLOCK

■ How to Play

• This is a simulation of light speed and time dilation.

• As you move away from Earth, you observe its past.
(Example: At 100 light-years away, you see Earth 100 years ago.)

• Use the "THRUST" slider to change the spaceship’s speed.
"Velocity 1.0c" represents the speed of light.

• Use the "REVERSE" button to flip the spaceship’s direction and return to Earth.

• While moving, time passes differently for Earth and the spaceship.
At higher speeds, time on the spaceship flows slower than on Earth.

• The current time on Earth and the spaceship is displayed in real time.

• When you stop the spaceship, the observed year of Earth at that distance is shown.
This is due to the time it takes for light to reach you.

• If you travel far away and return to Earth, you may find that much more time has passed on Earth.

■ Tip

• Try playing without reading first — then come back to this explanation.

• These effects are caused by the finite speed of light and relativistic time dilation.

■ Planned Updates

• Warp travel
• Earth's history
• In-game tutorial