* Main Sequence: Stars spend most of their lives in a stable phase called the main sequence. During this phase, they fuse hydrogen into helium in their core, generating energy and emitting light.
* Sun's Age: Our Sun is approximately 4.6 billion years old.
* Sun's Lifetime: The Sun is expected to remain on the main sequence for another 5-7 billion years.
Therefore, the Sun is roughly 4.6 billion years into a total lifetime of approximately 10 billion years, making it roughly middle-aged.
Important Note: "Middle-aged" is a relative term. The Sun's lifespan is much longer than a human's, and it's still considered a healthy and active star. It's just not a young star anymore.
