Virtual Voyages through the Universe
by Brent Tully
In this scene from Runaway Universe, we have
risen part way out of the great disk of our Milky Way Galaxy. The remnant
of a supernova explosion lies in the foreground.
Curiosity has always led humans to explore. Beyond Earth and
our Moon, Mars and other bodies of our solar system can be visited with reasonable
effort. Our children's children may see landscapes of worlds around nearby stars.
These explorations are remarkable, yet we are limited by
the huge distances of the cosmos. The nearest big galaxy beyond the Milky Way,
the Andromeda nebula, is two million light-years away. There is not, and probably
will never be, a mechanism for physically traveling such distances.
Gravitational lensing is a technique astronomers
use to measure dark matter.
Hollywood makes great use of computer visual effects. Why not
use this craft to take us on virtual voyages through the Universe?
That is exactly what was done for the PBS/NOVA documentary,
Runaway Universe, which I co-produced. In one sequence, we fly off Earth toward
the familiar constellation of Orion, through the gaseous nebula in Orion's belt,
and on to places too far for us to ever go. Our destination is the Virgo Cluster
of galaxies fifty million light-years away.
The animation is based on a database of thirty thousand galaxies
I assembled. The position of each galaxy is known in three-dimensional space.
We know the properties of each: size, luminosity, type, and orientation. Simulated
flights among these galaxies lets us see what a space voyager would see-except
our flight of 50 million light-years takes only a few minutes!
From our perspective in space, we see that galaxies gather
together to form great filaments that intersect at clusters. There are huge
voids in other places. Vast seas of nothing surround archipelagos of galaxies.