If you're talking about apparent brightness (how bright something appears from Earth):
* The Sun is by far the brightest object in the sky. It's a star, and it's much closer to us than any other star, making it appear incredibly bright.
However, if you're considering objects beyond our solar system:
* Sirius is the brightest star in the night sky. It's a binary star system, with the primary star being a white dwarf.
* Venus is the brightest planet in the sky, often mistaken for a star. It's so bright because of its thick, reflective atmosphere and its proximity to the sun.
Finally, there's the moon:
* The Moon reflects sunlight and can appear very bright, especially when it's full. However, it's not a source of light itself.
So, the answer to your question depends on how you define "brightest" and whether you're considering the day or night sky.
