Who shall destroy the conditions for life as we know it first? Humans? Sun? Universe?

In some billions of years, the Sun will exhaust it's nuclear fuel and expand, subsuming (burning up) the inner planets, including the Earth. It's speculated that Mars may be spared.

Then, it will contract into a "red dwarf" star leaving the inner planets cinders at best.

Until then, there are a number of scenarios that could greatly affect life on Earth. A full-out nuclear war would likely result in the "nuclear winter" effect... Causing massive amounts of smoke and debris in the atmosphere and thus killing off most plant life. Agriculture would be severely affected and there would be large-scale extinctions.

This wouldn't cause total extinction, but the human race would be greatly diminished.

Severe pollution would cause considerable extinctions and deaths, but not much effect on the planet as a whole... The Earth has a remarkable ability to recover.

The impact of a very large asteroid or comet could cause an extinction event similar to the one that killed off the dinosaurs.... Again, this would not mean the extinction of humanity, but certainly billions of deaths and world-wide consequences.

Sorry, but the reliable crystal ball hasn't been invented yet. Whatever will happen will happen and it cannot be predicted. What you can be sure of is that if something doesn't occur in the mean time, eventually the sun will expend its hydrogen, heat up into a red giant, cooking all life from the planet. the sun will then explode in a super nova, obliterating all the inner planets including earth. This is not a philosophical issue, it is strictly an astronomical fact.

The Bible can answer your question I recommend reading the whole thing, to specifically answer your questions you would need to study the book of Revelation and the book of Daniel because these two books talk about the end times. Hopefully when you read these books you will be able to conclude for yourself what is going to happen and that the answer to your question is no. However incase you don't get to all of that in short Jesus Christ is going to come back again and when he does the dead in Christ will rise first and then those that are still alive will then be raptured up. Disclaimer for the next part I am about to tell you if you do not know the word of God for yourself this next part might be a bit tough to understand. Here goes so all those who are or where not living a life that is Christ like will be left behind and will suffer the torment of the Anti-Christ (or the beast) there will be a period of suffering on the earth. Then there will be the millennium which is a period of peace with everything even the animal kingdom no lions chasing and eating gazelles. Also after the period of torment the devil, Anti-Christ, serpent will be locked in to a bottom less pit and then after worlds they will all be placed in to the lake of brimstone and fire where all the false prophets and people who lived a life that was not Christ like for eternity. To get back to your question about the earth there will be a new earth clearly stated in Revelation 21.

Hope you where blessed by this answer.=-)

John3:16 For God so loved the world that he gave his only begotten son, that whosoever believeth in him shall not perish but have everlasting life.

How about: "none of the above".

I think that progress will destroy life as we know it, just as it always has, just as it always will. (It is a good thing!)

The only constant in the world (as we know it) is change. Change is often, but not always, progress.

I am willing to bet that long before we actually destroy the planet, or the sun burns out, or for sure before the universe collapses, we will have figured out how to travel to other planets and survive there.

A meteorite could sneak up on us and wreak havoc, but I doubt it would end life (as we know it) on earth.

Definitely humans

History repeats it self we will die from a nuclear war

ya