As an amateur and largely ignorant human it's quite grounding to read about the universe.
The nearest quasar, for example, is at the least 780 million light years away.
A light year is the distance that light would cover in one year which amounts to approx. 10 trillion kilometers.
A distance such as this is almost impossible to relate to.
Another thought: Everything we look at is the past. Because light takes a finite amount of time to reach the human eye, whatever we see has happened in the past.
It is insignificant in daily life but, for example, the sun we see is as it was 8 minutes ago. Similarly, when we look at the oldest quasars in the universe - approximated at 28 billion light years away - we are looking at that which existed a really long time ago, probably at the beginning of the universe (if the universe did indeed have a 'beginning').
The hypothesis behind the existence of a blackhole is quite intriguing. Earth is a small planet and therefore has a very small escape velocity - 11.2 km/s. The sun has a larger mass and therefore its escape velocity is estimated at 617.5 km/s. The hypothesis that Feynman came up with was that there could possibly be a large enough mass (or gravitational force) that would not let even light escape. Escape velocity higher than 300000 km/s.
Information from Wiki and from 'Universe in a nutshell' - Stephen Hawking. Why do these things intrigue me? Because once in a while, I like to take a step back and look at humans. Hawking said something to the effect of: We should not try to find extra-terrestrial lifeforms because the odds are that they will be more advanced than us and possibly hostile. The future for humans lies in space because the Earth will one day be too small a place for humans.
I just wrote about quasars being 780 million light years away. We can confidently say that humans have developed themselves quite rapidly in the past 2000 years. It is not plausible to discount the existence of other lifeforms even 10000 years ahead of us, let alone millions of years ahead of us.
Calling time a dimension puts a new twist to all that we worry about because in the grand scheme of things everything is quite irrelevant.
What is also questionable is that which we assume to be real and why reality should even matter to us.
With this post I can say that I have come a full circle. Questioning reality has been my most fruitless pass-time. Questioning purpose and daily illusions can also be added to the prior sentence.