What are the likely scenarios for the end of this world ?

Answer 1

Too many "possibilities"......

but unfortunately the "most probably" it will be due to Nuclear weapons.

Answer 2

The most likely scenario will be an Earth of fire. In about another 4.5 billion years the sun will start to expand and quickly (compared to star's age) grow and become a so called red giant (e.g. "Betelgeuze" in the steller formation known as Orion). This red giant will be bigger than the whole solar system now.
So, when the sun starts expanding, Earth wil gradually become to hot for any nowadays known life form, and as the "surface" of the sun comes closer, the Earth will burn and finally melt within the expanding sun itself.
If mankind is still to live at such times, it would be better to have developped interstellar transportation for mankind would otherwise be doomed to die as well as any other life on earth.
And that interstellar travel then has to be efficient enough to get us a far away as 25 lightyears, because the sun will end up in a nova or even supernova, and that event destroys any known life in a radius of 15 - 20 lightyears.

P.S.:
To explain the "quick" expansion of the sun:
It will be only a few minutes for the sun, but in human years that process of expansion takes about 1 or 2 million years ... will probably last another 5 or 10 million years before the sun will start to collapse within only 6 months or so, what then finally will cause the giant nova explosion.

Answer 3

Ok. the end of the world? or the end of human species. first off I hope that all parties who have the capability to use nukes are intelligent to know that destruction would be mutual. the little mad man in North Korea needs to be watched. but for all the people above ground who survived will wish that they didn't survive. I need not go any further on that scenario. But the end of the world will most likely be a collision with a asteroid.

Answer 4

We're already getting there. Basically, we'll kill off all the animals that are the top of the food chain, like tigers. So when this happens, the lower animal, like deer, will multiply uncontrollably. They'll then go on to eat all the grass and trees. This will leave the land bare, meaning there's uncontrolled erosion.

The temperature will rise uncontrollably. Making it hotter than ever. But we'll be lucky if we get to watch the end of this process.

Some stray comet might slam into us, or some foolish kid might invent something that brings the earth's core outside... :) ah well, science.

Answer 5

Our sun turns into a red giant and swallows up this planet and quite a few others in the solar system too.

A nice simple diagram and explaination can be found here:
http://hyperphysics.phy-astr.gsu.edu/hbase/astro/redgia.html

Oh dear, I've just depressed myself by thinking about the heat death of the universe.

Answer 6

it is a traumatized hallucination as seeing the universe and socially out of bounds. the planetary system of inlike most not aliens and the blipping of aliens extra-terrestrials as being uninteresting cromagnons of inner-criminalized and warlikes patterns are avoiding the outer expansion of the earth species to bring unfaithfullness to the rest of the universal system. extra-terrestrial aliens would have attacked and destroyed the earthlings and that pattern of earthlings behavior of the warlike and unfaithfullness would agreed that earthlings will or would self-destroy themselves in some short futures.

Answer 7

Because our world will sees to exist, thing don't lest forever all things have there time and then it's over until we no longer need to be in a body.

Answer 8

As sea levels are rising , I think we will get submerged in the sea or get flooded as there will be no trees. Or perhaps we will adapt ourselves to live underwater and the end never happens.

Answer 9

When you die the world ends for you. That's all you need to know.

Answer 10

Someone in the future is going to push "destroy-the-world" button with his seventh finger on his fourth hand.