Our understanding of life comes from a sample of one, from looking at our living planet and understanding amid all of the complexity, what is the essence of life and therefore the likelihood of it occurring elsewhere in the Universe.
Once upon a time, the Universe was a dark ocean, with no stars to provide light, warmth or matter for planets and moons to be born and potentially nurture life. The Big Bang changed all this by giving birth to galaxies full of stars and planets with giant black holes holding these illuminated worlds in their grip. This now billion-year-old cosmic world seems eternal, yet astronomical research begs to differ. In the 18th century, British astronomer William Herschel became the first to detect a white dwarf star in the vast sky of the universe, although it would take more than a century for scientists to understand what it was he had observed. A white dwarf turned out to be a former star that has collapsed into an energy-dense, Earth-size stellar object, which eventually turns into a stellar remnant – a black dwarf. Even though no fully-formed black dwarf has yet been detected, we can, to put it in Julijonas Urbonas’s words, “cosmically imagine” how, after billions of years, a universe will slowly switch off all its light bulbs.
