TED-Ed: Einstein's twin paradox explained | Amber Stuver

The video explores the twin paradox, where identical twin astronauts, Tara and Stella, experience different aging rates due to Stella's space journey at 86.6% the speed of light. Special relativity explains that time passes slower for Stella, resulting in her being younger than Tara upon return. The Lorentz factor and light signals are used to illustrate time dilation and length contraction. The paradox is resolved by understanding that Stella's change in reference frames makes her a non-inertial observer, unlike Tara, who remains at rest.

What is the speed of Stella's spaceship relative to the speed of light?

• 75% the speed of light

• 50% the speed of light

• 86.6% the speed of light

• 100% the speed of light

What is the Lorentz factor at 86.6% the speed of light?

• 1

• 1.5

• 2.5

• 2

Why does Stella not notice time slowing down on her spaceship?

• Because all processes on the ship slow down equally

• Because she is moving too fast to notice

• Because time actually speeds up for her

• Because she is in a different universe

What is the twin paradox?

• A theory that time travel is possible

• A misunderstanding of special relativity

• A concept that only applies to identical twins

• A contradiction in the laws of physics

How do the twins measure the passage of time during the experiment?

• By using a stopwatch

• By using a calendar

• By counting the number of stars passed

• By sending light signals to each other

What causes the asymmetry in the twins' aging process?

• The difference in their biological clocks

• The change in Stella's reference frame during her journey

• The speed of light being variable

• The gravitational pull of the star

Who is older when the twins reunite, and why?

• Stella, because she experienced more time

• Stella, because she traveled faster

• Tara, because she remained in an inertial frame

• They are the same age