Fact: Sirius was named after a star.

Fact: Shooting stars are not stars, but meteors. Fact: Meteor is just a fancy word for 'space rock.'

Personal Observation: Sirius at Hogwarts was brilliant, full of energy and life.

Fact: Rocks don't shine on their own.

Personal Observation: After Azkaban, Sirius was less than before: less manic, less dazzling.

Fact: Meteors blaze when they enter earth's atmosphere; the mechanism of their destruction gives them light.

Fact: Sirius died young (though it hardly feels like it).

Inaccurate, Overly Sentimental Metaphor: Sirius was a shooting star, blazing bright as he plummeted to his demise.