Brightness can be measured in different ways:

* Luminosity: This refers to the total amount of light a celestial object emits. In terms of luminosity, the sun is incredibly bright, but there are many stars in the universe that are far more luminous.

* Apparent magnitude: This is how bright an object appears to us from Earth. While the sun is the brightest object in our sky, there are other stars that appear brighter, like Sirius. However, these stars are actually much farther away than the sun.

* Surface temperature: The sun has a very high surface temperature, but there are stars called "blue giants" that are even hotter and emit more light in the blue and ultraviolet wavelengths.

So, the answer is:

* Yes, there are objects in the universe that are brighter than the sun in terms of total light output (luminosity).

* No, the sun is the brightest object in our sky because it's the closest star to us.

Ultimately, it's up to you to decide how you want to define "brighter."