Read the Wiki you dumb son of a bitch.

I understand stuff fine. You have no idea what happens in the scenarios I have proposed instead you blindly assume it can't happen when it has. The impact that supposedly killed the dinosaurs saw this planet's conflagration, the atmosphere went to 1000 degrees. The temperature of the globe rose by 5 degrees for 100s of years. On an impact of an object of less than 100 miles. Increase size and mass you have a planet killer.

Do I believe in dinosaurs, not the point on if our planet can be conflagrated. If on a huge impact could life cease to exist, and could this planet become barren. Undoubtedly.

Can the Sun supernova, does it solar flare, and can it send out bursts of heat? Of course.

Now fuck off you stupid bitch.