Here's why:
* Temperature: Blue stars are much hotter than red stars. The hotter a star is, the faster its nuclear fusion reactions occur, and the more energy it produces.
* Luminosity: Because of their higher temperature, blue stars are also much more luminous (brighter) than red stars.
* Size: To produce the intense heat and light of a blue star, it needs to be significantly larger than a red star.
Think of it like this: a small, flickering candle (red star) is much less bright and powerful than a blazing bonfire (blue star).
In summary: Blue stars are generally much larger, hotter, and more massive than red stars.
