Lecture
Colloquium Ehrenfestii
- Date
- Wednesday 11 December 2024
- Time
- Address
- Sitterzaal
Challenges to the Lambda CDM cosmology
George Efstathiou is Emeritus Professor of Astrophysics, Kavli Institute for Cosmology
Observations of the cosmic microwave background (CMB) anisotropies provide strong evidence in support of the LCDM cosmology. Nevertheless, a number of 'tensions' have emerged.
I will review:
(a) recent results from the CMB that have strengthened the evidence in favour of lambda CDM;
(b) why it is difficult to explain the discrepancy between the lambda CDM value of the Hubble constant, H0, and the value derived from the Cepheid distance scale;
(c) why cosmic shear surveys may indicate a small-scale/large-scale mismatch rather than an inconsistency between early and late time physics;
(d) why the recent DESI results suggesting evolving dark energy may be driven by systematic errors;
(e) why inflation, a cornerstone of the lambda CDM model, has introduced a new hierarchy problem in cosmology.
The Colloquium Ehrenfestii takes place Wednesday evenings starting at 19:30 hours in the main auditorium of the Oort building. Before the Colloquium, there is a common dinner in the canteen located on the ground floor of the Oort building. This dinner starts at 18:00 hours sharp and is free of charge, under the condition that one attends the colloquium and that one has made a reservation before noon on the Tuesday preceding the colloquium.