The brightest planet in our solar system as seen from Earth is Venus. Venus is often referred to as the "Evening Star" or the "Morning Star" because it is one of the most prominent objects in the night sky. It is known for its brilliant appearance, outshining all other planets and even some of the brightest stars.
The brightness of a planet, or any celestial object, is measured by its apparent magnitude, with lower values indicating greater brightness. Venus can reach an apparent magnitude of around -4.6 at its brightest, making it the most luminous planet in our sky. For comparison, the next brightest planet, Jupiter, typically has an apparent magnitude of around -2.7, followed by Mars, Mercury, and Saturn.
The reason for Venus's brightness is its highly reflective cloud cover, which reflects a significant amount of sunlight back into space. Additionally, Venus is the second closest planet to the Sun, which means it receives substantial sunlight and appears particularly radiant from Earth.
It's worth noting that the apparent brightness of planets can vary depending on their positions in their orbits, as well as their distances from Earth. However, overall, Venus consistently shines as the brightest planet in our solar system.