The James Webb Space Telescope and the Early Universe: Insights from Cosmologist Dr. Brian Keating

The James Webb Space Telescope (JWST) has revolutionized our view of the early universe, providing unprecedented insights into the formation and evolution of galaxies in the cosmic dawn. Dr. Brian Keating, an experimental cosmologist and professor at the University of California San Diego, recently shared his thoughts on JWST's discoveries and their implications for our understanding of cosmic inflation and the origins of the universe.

James Webb's Observations of Early Galaxies

Dr. Keating explained that while JWST's observations of early galaxies are groundbreaking, they don't directly impact his own research on the cosmic microwave background (CMB) and cosmic inflation. The CMB originates from about 380,000 years after the Big Bang, while JWST is observing galaxies that formed hundreds of millions of years later.

However, JWST's ability to see galaxies twice as far back in time as the Hubble Space Telescope is significant. It allows astronomers to study galaxy formation and evolution at earlier epochs than ever before. Dr. Keating noted that some of these early galaxies appear more mature than expected, which has led to discussions about potential challenges to the standard cosmological model.

Manufactured Controversy and the Big Bang

Dr. Keating addressed the recent claims by some individuals that JWST's observations disprove the Big Bang theory. He emphasized that these claims are largely manufactured controversy and clickbait, not reflective of the scientific consensus:

"No one was taking seriously...this paper that or this article that claimed the Big Bang never happened...could have been written 10 years ago. In fact, it was written 10 years ago, every 10 years it sort of comes out."

He explained that the observations are actually consistent with previous Hubble data, just pushed to earlier times. The fundamental observable in cosmology - redshift - is still entirely consistent with an expanding universe as predicted by the Big Bang model.

Challenges in Cosmology

While dismissing claims that the Big Bang theory has been disproven, Dr. Keating acknowledged that there are genuine challenges and open questions in cosmology:

The Hubble Tension

One significant issue is the "Hubble tension" - a discrepancy between measurements of the universe's expansion rate derived from early universe observations (like the CMB) and those from observations of the more recent universe:

"The crisis there is that the cosmic microwave background measurements done by Planck and WMAP reveal a value for the Hubble constant that is about 68 in these weird units of kilometers per second per megaparsec...The measurements done by Adam Riess and his team using the Hubble telescope and Cepheid variables and Wendy Freedman's group and the tip of the red giant branch, they are advocate for a slightly bigger value of the Hubble constant."

This 9% discrepancy is a focus of intense research and could potentially point to new physics.

Dark Matter and Dark Energy

Dr. Keating also mentioned the ongoing mysteries of dark matter and dark energy. While there is strong evidence for their existence based on multiple lines of observation, their fundamental nature remains unknown.

The Search for Cosmic Inflation

A major focus of Dr. Keating's own research is the search for evidence of cosmic inflation - a theorized period of rapid expansion in the earliest moments of the universe. He explained that detecting primordial gravitational waves through their imprint on the polarization of the CMB would provide strong evidence for inflation:

"We want to make a map of its polarization with enough sophistication to see whether or not there are waves of gravity...that cause the shearing and squishing and squashing of space and time itself. That will only happen if and only if inflation took place."

Dr. Keating described the BICEP (Background Imaging of Cosmic Extragalactic Polarization) experiment at the South Pole, which he helped design and build. While an initial claim of detecting evidence for cosmic inflation was later withdrawn, the search continues with more sensitive instruments.

Alternative Cosmological Models

While cosmic inflation is a leading theory, Dr. Keating emphasized the importance of considering alternative models for the early universe. He mentioned cyclic or "bouncing" universe models proposed by physicists like Roger Penrose, Paul Steinhardt, and Anna Ijjas.

These alternative models attempt to explain the observed properties of the universe without invoking inflation. Dr. Keating noted that detecting primordial gravitational waves would rule out many of these alternatives, making it a crucial test:

"If we see this type of polarization called B-mode polarization, it will kill their theories dead in the water."

The Importance of Experimental Cosmology

Throughout the discussion, Dr. Keating emphasized the critical role of experimental cosmology in testing theories and advancing our understanding of the universe:

"I am not in the job of proving your theory, my theory, or anything right. I'm in the business of proving everything else wrong, and that can only be done by having data, and the data only come from telescopes of the kind that my colleagues can build."

He contrasted the work of experimentalists with that of theoretical physicists, noting that while theorists often receive more public attention, it's the painstaking work of building instruments and gathering data that ultimately drives scientific progress.

The Search for Extraterrestrial Life

While not directly related to his cosmological research, Dr. Keating expressed hope that JWST might provide evidence for life beyond Earth. He noted his personal skepticism about the prevalence of life in the universe but emphasized the importance of remaining open to the possibility:

"I'm actually very pessimistic that there's life, let alone intelligent life, in the universe...But I'd be very open to it, and I think a good scientist should be open to all these different ideas."

Reflections on Scientific Careers and Communication

Dr. Keating shared insights from his experiences as both a researcher and science communicator. He emphasized the importance of scientists engaging with the public and explaining their work:

"I always feel like we scientists are given this script. It's like all we have to do is read it and we'll win an Academy Award...and so few of my colleagues do anything like what you do or what I'm attempting to do."

He also discussed the prevalence of impostor syndrome among scientists, even those at the top of their fields. Dr. Keating recounted conversations with Nobel laureates who still struggle with feelings of inadequacy, highlighting the universality of these experiences in scientific careers.

Conclusion

The James Webb Space Telescope is providing unprecedented views of the early universe, allowing astronomers to study galaxy formation and evolution at earlier times than ever before. While these observations don't directly impact research on the cosmic microwave background or cosmic inflation, they contribute to our overall understanding of cosmic history.

Dr. Brian Keating's insights highlight the ongoing challenges and exciting frontiers in cosmology, from resolving the Hubble tension to searching for evidence of cosmic inflation. His emphasis on the importance of experimental work and data collection serves as a reminder of the rigorous process behind our expanding knowledge of the universe.

As JWST continues its mission and other advanced instruments come online, we can look forward to further revelations about the early universe, potentially including evidence for extraterrestrial life. The journey of cosmic discovery continues, driven by the curiosity and dedication of scientists like Dr. Keating and the powerful tools they develop to probe the depths of space and time.

Article created from: https://www.youtube.com/watch?v=5-p7K_rftL0