Parallax and Distance

Parallax is the apparent shift in the position of a star when viewed from two different locations in Earth's orbit. The closer a star is, the greater its parallax.

The Relationship

The relationship between parallax (p) and distance (d) is inversely proportional:

* Larger Parallax = Smaller Distance

* Smaller Parallax = Larger Distance

Applying this to Vega and Arcturus

Since Vega is closer to Earth (25.3 light-years) than Arcturus (36.7 light-years), Vega would have a greater parallax.

Think of it this way: Imagine holding your finger close to your face and looking at it with each eye. The shift in position (parallax) is larger than if you held your finger further away.