Have you ever seen a shooting star? If you have then perhaps, at the time of your sighting, you were walking along a darkened street in the company of a friend or family member.
Upon spotting the sudden, incandescent streak across the night sky you might have even attempted to point it out to your companion. 'Look there, a shooting star!'. Unfortunately shooting stars tend to be very short-lived entities. By the time your companion had turned to where you were pointing it was all over. The visitor from space: a tiny – billions of years old - piece of debris, that had begun its journey to Earth from the asteroid belt out between Jupiter and Mars, had burnt up in an instant and you were the only person there to witness its demise.