The End of the Dark Matter Paradigm
You might have noticed that every time a space probe visits an unexplored location or an instrument accesses a range of phenomena never seen before, there are always big surprises. The James Webb Space Telescope (JWST) has reinforced this observation in a colossal way.
Prior to JWST, most astrophysicists were very confident in the predictions of the current standard model of the Universe -- Lambda-CDM, and seemed to mostly expect to make small refinements and fine-tune the values of the model's parameters. However, the early Universe, as seen by JWST, wasn't at all like their expectations -- early galaxies were far brighter and seemingly far larger than predicted. The central black holes in many of these galaxies also seem to be far heavier than possible in the cosmologically short time between the Big Bang and the age at which we're observing them. In addition, careful calculations based on JWST data have worsened the discrepancy between determinations of the expansion rate of the Universe based on different measurement techniques -- the so-called "crisis in cosmology", rather than resolving the tension as many had hoped. All of these issues have astrophysicists scrambling to make sense of the observations through the lens of the standard paradigm. Meanwhile, many science journalists have wandered into bombastic territory, some claiming that even the idea of the Big Bang is wrong.
On Monday, January 20th, Professor James Schombert from the University of Oregon will visit us to discuss a prediction about JWST data that did turn out to be true. Professor Schombert is a member of the small community of researchers who continues to ask whether our current understanding of gravity is adequate for understanding the entire cosmos and whether the observations typically attributed to the CDM (cold dark matter) portion of the standard model truly indicate the presence of some unknown type of matter. We have been fortunate to have Professor Schombert talk to us several times before and it will be fascinating to hear his perspective on the recent findings from JWST. His description of his presentation is below. He is an engaging speaker and his visit should be a lot of fun.
The last decade has seen a number of astronomical discoveries
that have challenged the idea that the missing mass problem can
be resolved by a dark matter particle. A strong baryon-dark
matter connection is implied from new results on the kinematics
of rotating galaxies. The linearity of these relations is
predicted by modified gravity frameworks and strongly suggests
a paradigm shift from the Lambda-CDM cosmology that currents
reigns astrophysics.
About Dr James Schombert
Dr. Schombert is a Professor of Astronomy at the University of Oregon. He received his B.S. in Astronomy and Physics from the University of Maryland in 1979, and a Ph.D. in Astronomy from Yale University in 1984. He was on the faculty at Caltech and Michigan until joining JPL/NASA in the mid-1990's as Project Scientist to the 2MASS project. After two years at NASA HQ working on the staff of the Chief Scientist of the Astrophysics Division, he joined the University of Oregon in 1996.
His primary research area is the structure, formation and evolution of galaxies. In the past ten years, he has investigated the stellar and gas content of dwarf galaxies, the mass models of disk galaxies, and surveyed the sky for new types of galaxies. He has been a GO on most of the past and present orbiting NASA telescopes, data archives and ground-based observatories ranging from the optical to the radio portion of the spectrum.
