You can probably already guess that life on Earth won't be possible without the Sun. But do you know exactly how death of our star will affect the Earth?
The sun doesn't just go out in a bang, but rather the dying process takes millions of years. As it continues to burn through its finite supply of hydrogen atoms, the center contracts and the outer region gets larger and hotter. And during this process, the sun's luminosity grows by 10% for every 1 billion years of hydrogen fusing. This increase in brightness means temperatures will increase for every planet within the range of the sun's rays, including Earth.
At such point, water on our planet will evaporate and the ice caps will melt permanently. Earth will then resemble a hot and barren planet, like that of Venus. After all the hydrogen has burned out and the sun finishes its cooling process, it will end up a white dwarf, leaving many inhospitable planets in its wake.
This process is estimated to take place in about 5 billion years. Would any humans be around at that time to witness the event or would we have already been gone by such point? If we were still around, would humans have found refuge elsewhere on another planet?