February 28, 2018

expert reaction to early universe signals and dark matter

New research looks at early universe signals and dark matter particles, published in Nature.

Prof Carole Haswell, Head of Astronomy at the Open University, said:

“I agree this is a very exciting result. For me the most interesting thing is that it reveals some of the properties of the first generation of stars in the Universe. We can’t directly observe these first stars, but this work gives an ingenious way of learning about them.

“The Bowman et al paper suggests that the first stars were producing more intense ultraviolet light than previously expected, and that they were bathing the gas in the Universe with this light by the time the Universe was 200 million years old. These first stars were more massive than any stars in the Universe today because they were devoid of all the chemical elements heavier than Lithium. The presence of heavy elements in a star’s atmosphere limits the mass of the star. Massive stars are short-lived, and the Bowman result tells us that these first stars collapsed when the Universe was around 270 million years old.

“Knowing something about the brightness and the lifetimes of these first stars means we can begin to piece together a lot about these stars and their influence on the evolution of the Universe. There will be far-reaching implications for our understanding of the formation and early history of our Galaxy and all the other galaxies and clusters of Galaxies in the Universe. Wow!”

Dr Poshak Gandhi, Associate Professor in the University of Southampton’s Astronomy Group, said:

“The question of the nature of dark matter ranks amongst the greatest astrophysical mysteries of our age. Global efforts over the past several decades have failed to identify a clear candidate source. This is almost embarrassing given that dark matter appears to be at least 5 times more abundant (in mass) than all the normal matter that we are able to perceive!

“These new studies open up new possibilities in this research field. A strong deficit in an expected radio signal from the time when the Universe was in its infancy could be due to the influence of dark matter particles. If confirmed, we need to revisit ongoing searches for dark matter particles.”

* ‘Possible interaction between baryons and dark-matter particles revealed by the first stars’ by Rennan Barkana and ‘An absorption profile centred at 78 megahertz in the sky-averaged spectrum’ by Judd Bowman et al. published in Nature on Wednesday 28 February 2018.

Declared interests

None received.