Professor Lewis Dartnell, Professor of Science Communication, wrote an article for the BBC Sky at Night Magazine about the darkness of outer space beyond the Solar System.
The article discusses that although the Sun lies at the centre of our solar system, and there are billions of other stars that should illuminate the night sky, space is still dark.
Explaining this issue, Professor Dartnell wrote: “This is an age-old problem that astronomers refer to as Olbers’ paradox, named after the German astronomer Heinrich Olbers (although many earlier astronomers like Johannes Kepler have advanced the notion). No-one has sufficiently answered the problem of Olbers’ paradox. It could be that stardust is obscuring star light from the human eye; perhaps the Universe is still too young for all the starlight to have reached us.”
He continues by asking if two spaceships flying together in the deep, dark Universe would be able to see each other: "One astronomer attempted to answer this by collating the individual brightnesses of known stars and galaxies listed in catalogues, and in doing that the answer converges at a visual magnitude of –6.5, or 0.3% as bright as a full Moon. Obviously, this average brightness would not stay the same as you journey through the Galaxy: near the galactic centre, far more stars are packed closely together. Now, whether two spaceships could see each other solely by this dim starlight would depend on the shininess of the spacecraft (mirrored or matt black) and whether they carried a telescope on board.”
Read the full article on the BBC Sky at Night website.
