Imagine a human able to
set out on a mission in the year 1900 returning to Earth in 1997.
They would have aged less than thirty years, but the world would be
almost unrecognisable to them." (5) So, it would appear that such
space travel is less than likely, but then, as science appears to
close one door, it offers new opportunities.
One such opportunity
could be ‘wormholes’. This idea was first proposed by Kip Thorne and
Michael Morris in 1987 in the American Journal of Physics as a
‘follow through’ of previous work by Albert Einstein.
In 1915 Einstein had announced his theory of general relativity. This
explained that gravity was not a force of attraction between two bodies, but a
property of space-time itself. This is best explained by imagining a sheet of
rubber stretched over a wooden frame (left).
On the rubber sheets are placed a
number of balls of different sizes and weights (representing planets and stars.)
If you were to roll a ball across the surface of the sheet, the ball would be
‘attracted’ to the others as it rolls down the slope towards them. Now if one of
the balls was extremely small and also immensely heavy, it would stretch the
rubber to an infinite extent without ripping it. This is a ‘Black Hole.’
Thorne and Morris
recognised that two such Black Holes could ‘find’ each other and join up, thus
creating a gateway through space through which a craft could travel enormous
distances in short periods of time.
Hawking, however, urges a note of caution,
"at first, this form of space travel seemed possible… Later work, however, shows
that these solutions are all very unstable: the slightest disturbance, such as
the presence of a spaceship, would destroy the ‘wormhole’, or passage, leading
from the black hole to the white hole. The spaceship would be torn apart by
infinitely strong forces.
It would be like going over Niagara in a barrel." (6)
It appears that the options for space travel are running out.
However, another method of space travel might be by stepping outside our three
dimensional universe. Again, Hawking explains;
"One can picture
this in the following way. Imagine that the space we live in has only two
dimensions and is curved like the surface of an anchor ring or Torus. If you
were on one side of the inside edge of the ring and you wanted to get to a point
on the other side, you would have to go round the inner edge of the ring.
However, if you were able to travel in the third dimension, you could cut
straight across." (7)
Such talk of extra dimensions can be confusing. It is certainly easier to
grapple with the following concepts in two and three dimensions, and once the
concept is grasped, to then relate it to additional dimensions.
To help with this,
it will be useful to enter a world created by clergyman Edwin Abbot
(right), headmaster of the City of London School. He wrote a book entitled ‘Flatland: A Romance of Many
Dimensions’ where everything only existed in two dimensions.
When Flatland interacts with the third dimension events and
feats are achieved which appear fantastic and impossible to the two-dimensional
Take for example,
placing a Flatlander in prison. All that would be needed would be to draw a
circle around the prisoner and escape would be impossible in two dimensions.
However, a three dimensional person could pull the Flatlander into the third
dimension, making it appear to the jailer that the person has disappeared into
The three dimensional person could then place the Flatlander
back in Flatland at a different location. (If feeling mischievous, he could even
flip him over, making it appear that his internal organs were now on the wrong
In fact three-dimensional person could perform all sorts of trickery
in the eyes of his two-dimensional counterpart. Three-dimensional man could pass
through doors, step into mountains, appear and disappear at will, reach into an
object without opening it (a must for medical operations!) enter banks and
simply take cash from vaults…. And of course, as noted above, simply step out of
prison if caught.