TED-ED: Light seconds, light years, light centuries: How to measure extreme distances - Yuan-Sen Ting

The video explains how astronomers measure vast distances in space using light years, parallax, and standard candles like cepheid variables and type 1a supernovae. It highlights the importance of observing distant objects to understand the universe's history, as light from these objects acts as a time machine, showing us the past.

How far is Proxima Centauri from Earth?

• 100,000 light years

• 4.24 light years

• 1 light year

• 2.5 million light years

What method do astrophysicists use to measure distances to nearby stars?

• Redshift

• Standard candles

• Gravitational lensing

• Trigonometric parallax

Why is trigonometric parallax limited to a few thousand light years?

• Stars are too bright

• The Earth's orbit is too small

• The universe is expanding

• Light travels too fast

What type of star is used as a standard candle due to its variable brightness?

• Cepheid variable

• Red giant

• Neutron star

• White dwarf

How do type 1a supernovae help in measuring cosmic distances?

• Their brightness fades at a known rate

• They are closer than other stars

• They occur frequently

• They are brighter than cepheid variables

Why is observing distant objects important for understanding the universe?

• It shows the universe's color

• It allows us to see the universe's past

• It helps in predicting future events

• It reveals the universe's size

What does observing light from distant galaxies allow us to do?

• Predict cosmic events

• Measure the universe's temperature

• Look back in time

• Understand the universe's expansion