Science Weekly Is our model of the universe wrong?
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Dec 17, 2024 
Catherine Heymans, the Astronomer Royal for Scotland and a professor of astrophysics at the University of Edinburgh, explores the perplexing Hubble tension—conflicting measurements impacting the universe's expansion rate. She discusses dark matter and energy's roles in this cosmological crisis and reflects on insights from the James Webb Space Telescope. The conversation also touches on the importance of observational accuracy and intriguing concepts like primordial magnetic fields and early dark energy that could reshape our understanding of the cosmos.
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Hubble Tension Crisis
- Cosmologists face the "Hubble tension": two ways of measuring the universe's expansion rate give different results.
- This difference implies our model of the universe might be wrong, causing a crisis in cosmology.
Expanding Universe
- Edwin Hubble's 1929 paper revealed that galaxies move away from us, and further galaxies recede faster.
- This observation implies the universe is expanding and supports the Big Bang theory.
Measuring Cosmic Speed and Distance
- Redshift, caused by the Doppler effect on light, helps measure the speed of receding galaxies.
- "Standard candles", objects with known brightness, help determine distances in the universe.