# How was it determined that a parsec is 3.26 light years?

A parsec is defined to be the distance to an object that shows a parallax angle of

Parallax is an effective way to measure distance to nearby stars because it relies on geometry. When astronomers use parallax, they are measuring how a star appears to move against its background. The unit parsec refers to the distance that an object would have to be from the Earth to have a parallax angle of 1 arc-second.

In the figure above, the angle,

If we define

We can use this information to convert our parsec into light years with the tangent formula.

Or;

If we convert

Plugging this in for

By signing up, you agree to our Terms of Service and Privacy Policy

The distance, or roughly 3.26 light years, at which one astronomical unit subtends an angle of one arcsecond is called a parsec. This definition is based on trigonometric calculations using the Earth's orbit around the Sun.

By signing up, you agree to our Terms of Service and Privacy Policy

When evaluating a one-sided limit, you need to be careful when a quantity is approaching zero since its sign is different depending on which way it is approaching zero from. Let us look at some examples.

When evaluating a one-sided limit, you need to be careful when a quantity is approaching zero since its sign is different depending on which way it is approaching zero from. Let us look at some examples.

When evaluating a one-sided limit, you need to be careful when a quantity is approaching zero since its sign is different depending on which way it is approaching zero from. Let us look at some examples.

- 98% accuracy study help
- Covers math, physics, chemistry, biology, and more
- Step-by-step, in-depth guides
- Readily available 24/7