In de Q&A rubriek van het blad BBC Science Focus van vorige maand, vroeg een lezer zich af of objecten op verre afstand zouden verdwijnen als hij (de lezer dus) op lichtsnelheid zou reizen. Deze prangende vraag werd beantwoord door astronoom en astrofysicus Dr. Alastair Gunn:
“On
Earth we can still see deep-space objects which no longer exist because their
light takes a finite time to reach us. If we begin travelling towards such an
object, we will continue to see its light, but will see its demise earlier than
if we had stayed stationary, simply because we are decreasing the distance the
light has to travel.
Similarly,
if we begin moving away from the object, we will be able to see it for longer
than if we remained stationary, because we are increasing that distance. So, some
objects will indeed disappear from our sight because we are moving – this is
true whatever speed we travel, but the effect obviously increases the faster
you go.”
Dat is
duidelijk. Maar volgens Dr. Gunn zijn er ook nog andere factoren die een rol
spelen als je ongeveer met de snelheid van het licht zou reizen:
“First,
the Doppler Effect means objects behind us will become redder, while those
ahead will become bluer. At a great enough speed, objects will disappear from
sight because their light is shifted out of the visible part of the spectrum. Also, as
your speed increases, your field of view becomes narrower and brighter in the
direction of motion and objects appear smaller and further away. Eventually,
even objects which are behind you rotate into view in front of you. At light speed you see only an
infinitely small, infinitely bright spot ahead of you, and darkness everywhere
else! So, if you
are travelling close to light speed, you will not be able to distinguish
individual objects and notice whether they have disappeared or not!”
