It is hard to explain as Indigo said because it is complex and abstract and à cannot give you tangible proof for my reasoning either.
If there is no proof, evidence or reason to believe what you do, then how could you know it to be true? Could you be justified in your belief while having no evidence?
I sensed myself around imaginary floating around in space, total black observing with no responsibilities to get things done. I would merely just be.
I would not experience 'time', instead I would see the cyclic nature of earth and the other planets rotating the sun, on and on and on.
Can I not imagine myself floating on the moon, dancing with Caesar? If I can imagine this, does that make it so reality is that I'm not really sitting here at my computer? Once again, it seems counter-intuitive to me to be able to imagine something, and then say reality does not conform to X because I can imagine it to be not X. Perhaps I'm am not seeing this clearly.
Then comes a predicted day in the future where science indicates that the sun will die. And as the cyclic pattern of the solar system is broken, the planets die with it.
The sun won't just fade from existence by my understanding of astronomy. It will just swell to the size of a red giant, incinerating and engulfing all the inner planets (including Earth). Then it will explode in a nova to collapse into a white dwarf, where it may collapse further, or eventually burn out its fuel. There will still be the 4 outer planets, and the dwarf planets lying beyond Neptune. It will remain in this state for a long time.
And even when the day comes that our solar system just doesn't exist...there are roughly 300,000,000,000 more stars in the galaxy, with roughly 150,000,000,000 galaxies in the known universe. Taking our galaxy as the average (it's probably slightly larger then average, but lets just go with this for a rough estimate), that means 45,000,000,000,000,000,000,000 stars in the universe.
Further, the material used to build our solar system will be reused given a long enough span of time. Gravity will work itself eventually and make new use for the matter that already exists here.
So, with all this material in the universe, and all of it being reused over and over, it doesn't seem likely that anytime soon we will be in a blank space of nothingness and nonexistence. Perhaps this is not what you meant though, and my ignorance is blinding me. I would be priveleged to have this explained to me. (I'm trying really hard to not come off as if I'm mocking you, I honestly want to learn these things...I'm trying to give you the benefit of the doubt so as to keep the dialog open).
That term Time is in fact a misconception made by us humans, as we made it up to measure and revolve our lives around. We associate time with an ending as in when 'the sun rises, now it's a new day'.
Is it necessary for our conception of time to have an end? Physicists seem to really take time seriously...and describe us as living in 4 dimensions (yes, more then that in quantum mechanics and else ware, but 4 is the basic, Newtonian number). Epistemologists and metaphysicists take time differently, with one point of view I expressed above.
As a seeker of wisdom, I am interested to know how you know time to be subjective. I have a deep interest in philosophy and really want to learn here. Perhaps I'm not seeing your point of view very clearly, and for that I apologize.