“DARK BACKWARD AND ABYSM”
We can see fourteen billion light years out.
For those still here a million years from now,
more light will have traveled to them, no doubt,
the million light years that space will allow.
Distant descendants may not see much more,
however, than what we can now observe.
Despite larger radius to explore,
their view won’t be a sight they can conserve,
because space itself goes faster than light,
as it expands relatively through time.
This perspective’s loss is ever the plight,
throughout our universe’s known lifetime.
We daily lose ability to see
the things furthest back in our history.
The title of this Shakespearean sonnet is in quotes, since it is taken from Scene II of Shakespeare’s The Tempest, where Prospero asks Miranda:
“What seest thou else
In the dark backward and abysm of time?”
When we peer out into space, the images furthest away are also most distant in the past, due to the time it takes their light to reach us. While a light year is a measure of distance, it can tell us how long ago the image we are seeing was produced, so, in a sense, it is also a measure of time.
Fortunately for us, we seem to be living in the moment when we can still see much of the universe. Unfortunately for the future, galaxies are racing away from each other as space expands, and this unending process will cause us to lose sight of the most distant galaxies, because their light will no longer have time enough to reach us (and vice versa).
When I wrote this poem, I sent it to NASA’s LAMBDA/WMAP team, who was peering back nearly to the Big Bang, and got an enthusiastic e-mail from their Senior Support Scientist, Paul Butterworth:
“We enjoyed ‘DARK BACKWARD AND ABYSM.’ I believe it is the first cosmological poem that NASA has ever received.”
Of course, the final couplet is a double entendre about human memory, which was Shakespeare’s original intent in Prospero’s conversation with his daughter. Yet, Prospero, being a magician, may have had a preternatural understanding of cosmological time, as well.