Rouse Awards – Hyaline Chen’s evaluation of viability of solutions to Hubble tension
9 Nov 2020
Hyaline Chen (Upper Sixth) evaluated the viability of solutions to the Hubble tension in a Rouse Award-winning project that was literally out of this world.
In cosmology, the Hubble tension is the difference in results between two ways of measuring the Hubble constant – the speed at which the universe is expanding – which are known as the model dependent and model independent variants.
Hyaline, who became interested in cosmology after reading some of Stephen Hawking’s work, was inspired to carry out this research after undertaking a CREST Gold Award in which she evaluated a measurement of the Hubble constant from plotting graphs based on data from space telescopes.
She said: “When I tried to corroborate my own calculations with the authority of the Hubble constant, it turned out there were a lot of other different authoritative values of the Hubble constant, so I was very perplexed with which one to choose.
“I looked into the literature and found this is a crisis in cosmology, which a lot of very prominent physicists are working on at the moment.”
Hyaline explained that the model dependent measurement of the Hubble constant was based on the standard model of cosmology from which all fundamental questions around the universe are centred. On the other hand, the model independent measurement of the Hubble constant is based on direct observation of astronomical objects from which the expansion rate of the universe is then calculated. However, the two types of measurement vary widely in terms of results, hence the Hubble tension.
She said: “If we’re saying there’s something actually wrong with the model dependent calculation, it means there’s something wrong with the standard model of cosmology, and then it’s a very big problem within this field.
“I examined a lot of independent sets of data and they exhibited no significant systematic errors, which means that combining them together it’s very unlikely this model independent result is wrong. We have very precise instruments and cross-checking of results with different groups of scientists doing this work, so the conclusion for the first part of my essay was that there is something wrong with the standard model of cosmology.”
Hyaline looked into different theories of how the Hubble tension could be resolved, including the notion of a ‘fifth force’ to explain various anomalies, considering that there would need to be further modifications to the current understanding of cosmology.
She added: “I found it really fascinating. I’ve always been interested in philosophy and there are a lot of questions in philosophy that we cannot answer purely in that way, such as ‘where did this entire universe come from?’
“That led me into physics because I think empirical methods give a better answer to these questions. The specific field of cosmology interested me because it’s a very mathematical treatment, based from pure observations. You can extend it to these big questions and make reasonable answers to them.”
Hyaline’s Rouse Award-winning research has also been published in open access academic journal Research & Reviews: Journal of Pure and Applied Physics, while her CREST Gold project, entitled Calculating the Expansion Rate of the Universe, has been featured in the Young Scientists’ Journal.