How can observations taken at the current time tell us about stellar evolution?

Question

Since individual stars can live for millions or billions of years, how can observations taken at the current time tell us about stellar evolution?

Answer 1

Our understanding of stellar evolution comes from a combination of theory and observation. Theory tells us how stars produce energy through fusion, and how the fusion processes change as the star evolves. Comparing these predictions with observed behavior enables us to understand where a star is in its development.

In broad terms the theory fits the observations well, but there are many theoretical details that have been refined by observation. In addition, observations of some of the short-lived processes that occur towards the end of a star's life are hard to come by.

Answer 2

We can see up to 14 billion years into the past by observing stars at different distances from the Earth. This allows us to see similar star types at different stages of their lives.

It's not any different than looking at a snapshot of all the people in a town. You can see children, teenagers, adults, and seniors. You dno't need to follow a single person through his entire life to deduce what his life should look like.

Answer 3

the light we see from stars was emitted long ago based on the stars distance from earth and the speed of light.

observations made today can tell us about a stars size, mass, temperature. spectral analysis can tell us about the stars composition.

we can use frequency shifts (like doppler shifts) and gravitational calculations to learn about the star's motion vector.

we can compare stellar observations with our sun and deduce evolutionary characterastics.

just a few thoughts....good luck.