Here's the breakdown:
* Extreme heat and pressure: The core of the sun is incredibly hot (around 15 million degrees Celsius) and under immense pressure due to the immense gravity of the sun.
* Nuclear fusion: This extreme environment allows for a process called nuclear fusion to occur. In this process, hydrogen atoms are forced together to form helium atoms. This reaction releases enormous amounts of energy, which is what powers the sun and provides light and warmth to Earth.
* Continuous process: This fusion reaction is a continuous process that has been happening for billions of years and will continue for billions more.
It's important to note that "ignition" in this context doesn't mean the hydrogen bursts into flames like wood in a fireplace. It refers to the initiation of nuclear fusion, a different process entirely.
