Can We See the First Stars?


The tiny variations in the composition of the early universe caused by quantum fluctuations are believed to have resulted in the large-scale pattern of galaxies, galaxy clusters and voids that we see in the night sky today. A few hundreds of millions of years after the big bang, small excess concentrations of dark matter were drawn together by their gravity to form ‘halos’, which then merged. Ordinary matter – hydrogen and helium atoms – became concentrated at the centres of these halos, leading eventually to the birth of the first stars.

These stars would have been very large – up to 1000 times the size of the Sun, shining with mostly ultraviolet light. Their lives would have been very short but spectacular, collapsing within a few million years and seeding interstellar space with clouds of heavier chemical elements in violent supernova explosions. They are called Population III stars.

Such stars are believed to have long since died out. But an international team of astrophysicists recently reported observations consistent with Population III stars formed 800 million years after the big bang. They are thought to be ‘late bloomers’. It is hoped that NASA’s James Webb Space Telescope, scheduled to launch in 2018, will find more examples.

Stay tuned.