Nothing lasts forever. Trillions of years ago; the earth did not exist. Trillions of years to come; it might not exist as well. That is nature. However; if we keep up doing a stellar job of ruining our home, we need not worry about nature. Our stupid is far from nature. This are but just opinions but what this is about is based on facts; solid science facts.
The sun is a giant nuclear fusion reactor with a very simple job; combine two hydrogen atoms to form a helium atom. Helium is heavier than hydrogen and this ends up in making the sun denser. Denser objects exert more gravity than less dense objects. Following? Increased gravity might see Mercury fall right into the sun with Venus next then guess who follows? We do. Fun fact, the sun had a blue color if you looked at it from the earth.
If that doesn’t then this might. Global warming might be a hoax or not but the truth of the matter is that average temperatures have been rising at an ever increasing rate. This in turn melts huge carbon deposits that for some reason the earth has in a cold solid form. In time; a run away effect might be created where it will be beyond our control. Under that scenario; we might drown before what’s left over is fried by the sun.
The current model of the universe has it that we are ever expanding. The distances between planets is ever increasing; in all directions. This creates a scenario where planets and stars might be too large for any influence to break through. Earth which heavily relies on the sun will be left out cold. Everything freezes to death save for a few microbes that seem to survive anything. Even the roaches will not survive this one.
If that model holds; then this one is for the microbes. If the current laws holds; the universe can only expand so far. At a given point; it will reach it’s elasticities end and will want to slam back together. It will be the big bang reversed. Everything that exists in the universe slamming back into something smaller than an atom; smaller than a microbe.
There is always the risk of running into something smaller or bigger than us before we ever have the technology to either maneuver the earth or it off each others way. We could always blow threats up but I believe us to being better than that. Better than fighting each other and figuring stuff like this out.
The avengers might fail. We now have enough nuclear arsenal to blow earth several times over. Like after the first hit there will be another nuclear arsenal left to fire another hit. Humans. We need an advanced race of humanoids who are willing to join a course greater than themselves. Those, if they exist or ever existed, might fail and someone will press a big red button or snap a finger.
Whichever comes first; it will be earth’s end.