A couple of months ago I started a new series on this blog titled "What Is". Thus far the focus is on the field of astronomy where we hear all sorts of cool science taking place in space. The goal of this series is to explain the details of different objects we hear about relatively frequently.
Sun-like Stars
The Sun is considered a low mass star currently on the main part of its life called the Main Sequence.
 |
| The Sun taken by NASA/SDO (AIA) |
What is a Red Giant?
A red giant is an evolutionary stage low mass stars, such as the Sun, go through in the latter stages of their lives. Once the Sun's core hydrogen supply is exhausted, a thin layer of fusing hydrogen surrounding the core provides a force causing the outer layers of the Sun, beyond the core, to expand outward. In other words, the Sun begins to grow in size. As it grows in size, the surface temperature cools and the star becomes redder in color. Thus the term Red Giant. The star will grow quite large in size, much larger than a Main Sequence star.
How Large?
How large will a star such as the Sun grow when it becomes a Red Giant? The simple answer is very large! The more detailed answer is found in comparing the distance from the planets to the Sun in its current stage. As the Sun grows into a Red Giant, in approximately 5-6 billion years, it will expand past Mercury's orbit, expand past Venus' orbit, and come close, if not surpassing, Earth's orbit. There's a question as to what will happen to the Earth. Earth is either swallowed up by the Sun or pushed farther outward in its orbit. Either way, life will not continue. Earth, however, moves out of the current Solar System's habitable zone in as few as 500 million years, so humans will have to figure out space travel long before the Sun becomes a Red Giant.
No comments:
Post a Comment