Here's why:

* The Sun's Temperature: The Sun's surface temperature is about 5,500 degrees Celsius (9,932 degrees Fahrenheit). Its core, where nuclear fusion takes place, reaches an incredible 15 million degrees Celsius (27 million degrees Fahrenheit).

* Solar Radiation: The Sun releases an immense amount of energy in the form of electromagnetic radiation, including visible light, infrared radiation (heat), and ultraviolet radiation.

* Earth's Distance: Earth is located at just the right distance from the Sun to receive a suitable amount of solar radiation to sustain life.

* Other Planets: The other planets in our solar system receive varying amounts of solar radiation depending on their distance from the Sun. While planets like Mars are too cold for liquid water, planets like Venus are much hotter due to their proximity to the Sun.

So, the Sun is indeed the source of both heat and light for our planet and the other planets in our solar system.