2019.03.14 12:32
posted by Jason Kottke Jan 08, 2019
I’ve always had a hard time wrapping my head around the idea that the universe could be both finite and infinite at the same time (or something like that *takes bong rip*), but this passage from Coming of Age in the Milky Way by Timothy Ferris succinctly explains what’s going on:
General relativity resolved the matter by establishing that the universe could be both finite — i.e., could contain a finite number of stars in a finite volume of space — and unbounded. The key to this realization lay in Einstein’s demonstration that, since matter warps space, the sum total of the mass in all the galaxies might be sufficient to wrap space around themselves. The result would be a closed, four-dimensionally spherical cosmos, in which any observer, anywhere in the universe, would see galaxies stretching deep into space in every direction, and would conclude, correctly, that there is no end to space. Yet the amount of space in a closed universe would nonetheless be finite: An adventurer with time to spare could eventually visit every galaxy, yet would never reach an edge of space. Just as the surface of the earth is finite but unbounded in two dimensions (we can wander wherever we like, and will not fall off the edge of the earth) so a closed four-dimensional universe is finite but unbounded to us who observe it in three dimensions.
In the terms of Edwin Abbott Abbott’s Flatland: A Romance of Many Dimensions, we are Flatlanders living in a Lineland world who, with the aid of mathematics, have been able to peer into Spaceland.
2019.03.14 13:28
2019.03.16 00:10
You cannot help but getting profound in the context of space-time structure.
As a young boy, I tried to define time: What is time?
My answer was that:
Time is generated as a result of any change:
If there is no change whatsoever, there should be no time.
I haven’t moved even one step out of that dictum yet.
2019.03.16 13:59
" The ancient Greeks had two words for time: chronos(χρόνος) and kairos. The former refers to chronological or sequential time, while the latter signifies a proper or opportune time for action. While chronos is quantitative, kairos has a qualitative, permanent nature."
It seems to me that your definition of time, Dr. Chung, is very close to the above Greek's kairos
which defines time by action, event or change of something,
in contrast to chronos which defines time as the clock on the wall does.
The Catholic girls senior high school my granddaughters attended
have an annual retreat program called Kairos which
emphasizes this very point, i.e. looking at these young peoples' lifetimes from that perspective.
All the family members and friends of each student are asked to write letters to the student
which will be given to that student during the retreat when each student's life
is reviewed with the councilor.
I was impressed with the program which helps each student look at life
as something to create, act upon, change for the better, etc.,
not just chronological aging process.
I admire your intelligence as a young man to look at the time the way the ancient, wise Greeks did.
The Universe by Kenneth Maswabi
you stretch to the limits of my imagination
in a continuous sea of blackness
where you grow stars and galaxies
cultivating them in their billions
you never stop to rest
you never stop for a cup of tea
for your duties are immense
and your responsibilities unimaginable
for you are the universe...
you have stretched time to its limits
pulling on the fabric of space with ease
untangling the mysteries of the cosmos
you built a never ending industry
that is surrounded by darkness
leaving us to ponder
meditating on the reality of your existence
the vastness of your empire
and the powerful forces that you possess
dark matter and dark energy
the substance of your costume
the skin of your armour
and the pulses in your heart
you have stretched mankind to his limits
from your atoms to your stars
you never stop amazing me
with your billion lights in the sky
you never ran out of power
with your big bang
you never needed explosives
with your blackness
you never needed the sun to set
with your supernovas
you never feared destruction
with your many suns
you never ran out of energy
with your gravity
you never planned to escape
you have multiplied the world a billion billion times
starting with planets you did not rest
planting the solar system you continued
with your innovation
you build a galaxy
the "milky way", they say
a hundred thousand light years apart
a billion suns and a trillion planets
multiplied by a billion galaxies
equals to the universe
"The Universe " by Kenneth Maswabi