Tags

,



Abell 1835 IR1916.

The other day I got to wondering how big the universe is. Or, more
specifically, what the farthest galaxies are at the "edge" of it, what
its limits are. In astronomy this is known as astrocartography and its
subject is the large-scale structure of the universe.

Astrophysicists know that our universe is about 13.7 billion years old.
At that beginning, the universe exploded outward in a singular event
known as the Big Bang or the Big Bounce. It has been estimated that the
universe is now 156 billion light-years in size. Which might seem strange:
If the beginning of the universe, and thus of time, occurred 13.7 billion
years ago, then one would expect the maximum size of the universe to be
2 X 13.7 billion or 27.4 billion light years. The reason that is not the
case is that space-time has not been constant since the Big Bang.

But that's not the only strange thing about our universe. The contents
of the universe are in the main not evenly distributed. The universe
known today is a heterogeneous mixture of superclusters, bubble-like
voids, filaments (sheets of galaxies like the Great Wall), as well as an
odd region of rather homogeneous and evenly distributed galaxies 300
million light years from us called the End of Greatness.

Astronomers calculate distance from our little arm of the Milky Way by
observing red shift. Recently, an object was observed using X-Ray and
Infrared telescopes indicating a galaxy that is 13.2 billion light years
away from us. Astronomers then turned the Big Eyes of the Keck telescope
in Hawaii and the Hubble Space Telescope on the object. Using a technique
called gravitational lensing, they managed to take photos of the object
(kinda-sorta, it is rather dim) that they labeled Abell 1835 IR1916. For
astronomers and astrophysicists this was an exciting discovery. Prior to
Abell 1835 the oldest (and most distant) galaxy was 10 billion light years
away. But Abell 1835 is very close to being as old as the universe itself.
Astrophysicists predicted that star and galaxy formation in the early
universe would look much different than it normally does today. And that
is in fact what was observed with Abell 1835. It is a very unusual galaxy,
smaller and less evolved than most galaxies.


Infrared image showing Abell 1835 IR1916.

Immanuel Kant once wrote of the difference between limits (Schranken) and
bounds (Grenzen). As Janik and Toulmin state it:

"Mathematics and physics will go on describing appearances for all time.
The number of phenomenon they may discover is unbounded. Nevertheless,
their discoveries are limited to appearances. They are, by their nature,
unequipped to discover the nature of things in themselves. These branches
of knowledge are restricted to what can be known about objects of sense-
experience. They can never explain anything in such a way as to transcend
that experience. A science of metaphysics (if there could be such a thing)
would lead, not to the limits of speculative reason, but to its bounds;
in that case, one would reach the bounds of the conceivable, as opposed to
the limits of the actual."
[Wittgenstein's Vienna (1973)]

We can map the heavens and observe the oldest galaxies in the universe.
But nothing can ever tell us simply why it is here.

It is possible to look at the universe from an existentialist viewpoint as
being an unexplainable and always mysterious place. Myself, I prefer to
look at it similar to how Albert Einstein looked at it, as a place where things
are knowable and where there is a reason for things. We may not know
the reason, but that doesn't mean that there isn't one.


The universe within 100 million light years
of our own galazy, the Milky Way.

Advertisements