Understanding Light-Years and Parallax

What is an Astronomical Unit (AU)?

• The distance light travels in one year.

• The average distance from Earth to the Sun.

• The distance between two stars in a cluster.

• The distance a planet travels in its orbit.

For what type of distances are Astronomical Units (AU) primarily used?

• Distances between galaxies.

• Distances within a planetary system.

• Distances between stars in different galaxies.

• Distances to nebulae.

What does a light-year represent?

• The time it takes for light to travel from the Sun to Earth.

• The distance light travels in one year.

• The speed of light in a vacuum.

• The amount of light emitted by a star in one year.

Approximately how far does light travel in one year?

• About 10 million kilometers.

• About 10 billion kilometers.

• About 10 trillion kilometers.

• About 10 quadrillion kilometers.

Numerically, how many light-years are in one parsec?

• 1.0 light-year

• 3.26 light-years

• 9.46 light-years

• 10 light-years

The term "parsec" is a combination of which two words?

• Parallel and second.

• Parallax and second.

• Particle and section.

• Parabola and sector.

What is the parallax effect?

• The bending of light as it passes through a gravitational field.

• The apparent shift in an object's position when viewed from different angles.

• The change in a star's brightness over time.

• The expansion of the universe.

How many arc-seconds are there in a full circle (360 degrees)?

• 360 arc-seconds

• 60 arc-seconds

• 1,296,000 arc-seconds

• 21,600 arc-seconds

If a star has a parallax of 1/3 arc-second, what is its distance in parsecs?

• 1 parsec

• 2 parsecs

• 3 parsecs

• 1/3 parsec

Why can only the closest stars be accurately measured using parallax from Earth?

• Distant stars are too dim to be observed.

• The parallax shift for distant stars is too small to measure from Earth.

• Earth's atmosphere distorts the light from distant stars too much.

• Distant stars do not exhibit the parallax effect.