Photographing Galaxies
The process of photographing galaxies is similar in essence to that described
in chapter 8 for photographing the stars. The main issue that needs to be
taken into consideration is that most galaxies are quite faint. Even the mighty
Andromeda Galaxy, M31, is misleading in this respect because the bright
elongated smudge that you can see with the naked eye, binoculars or aTo the Edge of the Universe
By examining the spectra of galaxies, we can find out how fast they are
moving. If the dark lines in their spectra are shifted towards the end of the
spectrum it means the light source is receding. The further away a galaxy
is, the greater the redshift, and the faster it is moving away from us. All the
galaxies are receding from each other. Our telescopes allow us to see nearly
14,000 million light years into space.
There is one major unexplained fact. If the Universe – space, time,
everything – began at one instant known as the Big Bang (a term used in
a derogatory sense by UK astronomer Fred Hoyle, who never believed in
it), when the galaxies began expanding, gravitational pull would slow them
down. Instead, the rate of expansion is increasing. Astronomers talk about
dark energy as being responsible for the acceleration of the expansion, but
no one really knows what it is.
How far can we go? Beyond a certain distance, the rate of expansion
becomes equal to the speed of light, with all manner of complications; we
cannot see that far, so do not have an idea of what goes on in these remote
parts of the Universe.
How big is the Universe?... We do not know! No doubt there are large
parts of it we cannot see, and there is an important point: either the Universe
is infinite or not. If it is finite, what lies outside it? Our brains are quite unequal
to this task. We are still woefully ignorant about fundamentals. Energetic
efforts are being made to search for signs of life in other solar systems.
In view of the immense distances involved, it is hardly surprising that we
haven’t discovered any yet. Our most promising line of investigation involves
radio waves but even this has not helped. There may well be other beings in
the Universe more advanced than us who can.
We cannot travel to other solar systems by any means known to us.
Rockets would take many centuries, unless we have a major breakthrough.
But one never knows, Science fiction does tend to turn into science fact and
in future we may discover how to tackle it. Whether we may meet another
race remains to be seen. Time will tell.[4] Pinwheel Galaxy (Messier
33), a spiral galaxy in Triangulum,
photographed by Ian Sharp with
an 80mm refractor and a cooled
CCD camera.
[5] Bode’s Galaxy (Messier 81)
in Ursa Major by Ian Sharp.
Telescope was a Vixen VC200L
with a cooled CCD camera.54Astronomer Book