The planets are some of the most well known objects in the universe, after all you are living on one! Our own Solar System has nine eight planets (after poor Pluto was demoted), and there are currently another 555 in orbit of other stars at varying distances from Earth, with more being discovered all the time.
The ancient societies of Earth have long since known about 5 planets apart from our own, the inner Mercury, Venus and Mars and the giants Jupiter and Saturn (Uranus and Neptune were relatively recent additions to the picture as they are much fainter and so harder to detect from Earth). In fact the planets get there name from the Greek - πλανήτης αστήρ – which if you aren’t fluent in Greek translates as ‘Wondering Star’, a fitting term as viewed from the Earth they seem to move ‘quickly’ across the background of the stars, which has recently taken on a whole new meaning.
A Free-Floating Planet Credit: NASA/JPL-Caltech
Up to now all the planets detected have been found around stars through a ground-breaking piece of research NASA scientists have detected free floating planets drifting through space alone, without a gravitationally linked star ...