SEEING is believing as they say (sometimes rendered as ‘pics or it didn’t happen’), but can we really trust the evidence gathered by our eyes and processed by our brains.

Perception is a tricky thing, ask any thirsty wanderer lost in the desert who mistakes a shimmering twist of the light for a pool of water.

Only a century ago, a large crowd of Catholic worshippers swore to have seen the sun dancing in the sky above Fatima in Portugal, before it plummeted towards the Earth. A mass hallucination in this case is rather more likely than the alternative, that a monumental ball of fusing gas suddenly became subject to the whims of wishful thinking.

We rely heavily on our eyes for evidence, however they only ever give us a small portion of the truth.

Most people prefer to think of their eyes as windows, through which they look upon the world as it is. But it is more accurate to think of eyes as cameras, receiving reflected light through a lens and processing it into an electrical signal, to be presented as an image on the computer screen inside our heads.

The range of light we can process is small, a few wavelengths we term ‘visible light’, while some other species enjoy degrees of infrared, ultraviolet and even thermal vision.

It is tempting, viewing the world through an infrared camera (translated into a visible light image so we can see it), to imagine that this means of perception is somehow less authentic than our own. But in truth it shows us that the world does not actually look like anything, and, without tools, we are trapped by the limited means of observing it we have evolved through the millennia.

It’s not like we can even view the present, as it goes on around us.

Gaze at the stars of the Andromeda Galaxy, and you are gazing at stars more than two million years in the past, that is how long it takes light to cross the void to reach our eyes.

Gaze at a friend across the room. The time for reflected light from your friend to reach your eyes, and for an electrical signal to pass up the optic nerve to your brain, may not be particularly lengthy, but nevertheless by the time you consciously see your friend, you are looking at an image of the past.

Motion is a tricky beast as well. Ever sat on a stationary train, beside another stationary train, when one starts moving? It can be tricky to tell which. In fact without background reference points, or the sensation of motion resulting from the train’s contact with the ground, you would not be able to tell the difference.

It doesn’t really matter either way, at least as far as the universe is concerned, since both trains are always moving even when we think they are stood still.

We view motion relative to our frame of reference, the surface of the Earth, but the universe has no background point of reference, and that ‘stationary’ train is whizzing round the Earth’s circumference, a slight tilt up and down the lines of longitude, a 60,000mph journey around the sun, a 500,000mph perambulation around the core of the Milky Way, and a who-knows-how-fast expansion of the universe, which can exceed the speed of light.

This is how you can be the fastest moving object in a race by coming last. Add all these speeds and directions together and you and your fellow runners are all travelling in one direction at a certain speed. If that direction is towards the start of the race, the last runner is really the fastest. It is worth a try anyway.

You can perceive relative motion on Earth. An object moving at a steady speed between two points will appear to cover the distance over different lengths of time depending on your perspective, on your motion relative to the object.

Time of course is also relative, both in our perception and in absolute terms. Something to remind your boss next time you miss the train that never stopped.