Stars aren’t always what they seem. Consider the two brightest stars of Lyra. The constellation’s leading light is Vega. It looks 20 times brighter than the second-ranked star, Sulafat. But that’s only because Vega’s much closer. If you lined them up at the same distance, Sulafat would look 60 times brighter than Vega.

The difference is caused by their stage in life. Vega’s in the prime of life. It’s “fusing” the hydrogen atoms in its core to make helium, releasing energy in the process. Vega is more massive than the Sun, so those reactions happen at a much faster rate – making Vega about 40 times brighter than the Sun.

Sulafat has moved into the next stage of life. It’s converted the hydrogen in its core to helium. Now, it’s fusing hydrogen in a thin layer around the core. That’s caused its outer layers to puff up, helping the star shine about 2400 times brighter than the Sun.

Eventually, Sulafat will start fusing the helium in its core. That’ll make it even bigger and brighter. Then it’ll shed its outer layers, leaving only its dead core. Vega will experience the same fate – more than a billion years from now.

Lyra is high overhead at nightfall. It’s easy to spot because Vega’s one of the brighter stars in the night sky. Four stars outline a tilted, flat box to the lower right of Vega. Sulafat is at the corner of the box that’s farthest from Vega.

Script by Damond Benningfield