Have you ever looked up at the night sky and wondered how massive can stars be? Or what is the biggest star out there?
Is there even a limit to how massive they can be? Well we can try and answer this question in two ways - first with theory, with our understanding of how stars fuel themselves with nuclear fusion fusing hydrogen into helium to produce energy which can counteract gravity and how that all contributes.
And then secondly by surveying the stars we can see in the sky, counting how many of each mass we see to work out if there is an obvious cut off in mass that we see. And when we do that we get a distribution of that drops off towards 150 times heavier than the Sun, suggesting that is the limit.
But is that just for stars forming now, what about stars in the early Universe when conditions were very different? Could they be much heavier?
Could they be supermassive stars...?