The 'Stage-4' ground-based cosmic microwave background (CMB) experiment, CMB-S4, consisting of dedicated telescopes equipped with highly sensitive superconducting cameras operating at the South Pole, the high Chilean Atacama plateau, and possibly northern hemisphere sites, will provide a dramatic leap forward in our understanding of the fundamental nature of space and time and the evolution of the Universe. CMB-S4 will be designed to cross critical thresholds in testing inflation, determining the number and masses of the neutrinos, constraining possible new light relic particles, providing precise constraints on the nature of dark energy, and testing general relativity on large scales.
![Bradford Benson](https://d3qi0qp55mx5f5.cloudfront.net/shared-resources/i/template/transparent.gif)
Bradford Benson
Senior Member
![John Carlstrom](https://d3qi0qp55mx5f5.cloudfront.net/shared-resources/i/template/transparent.gif)
John Carlstrom
Senior Member
![Clarence Chang](https://d3qi0qp55mx5f5.cloudfront.net/shared-resources/i/template/transparent.gif)
Clarence Chang
Senior Member
![Tom Crawford](https://d3qi0qp55mx5f5.cloudfront.net/shared-resources/i/template/transparent.gif)
Tom Crawford
Senior Researcher
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Jeffrey McMahon
Senior Member
![Abigail Vieregg](https://d3qi0qp55mx5f5.cloudfront.net/shared-resources/i/template/transparent.gif)
Abigail Vieregg
Senior Member
![Alexandra Sasha Rahlin](https://d3qi0qp55mx5f5.cloudfront.net/shared-resources/i/template/transparent.gif)
Alexandra Sasha Rahlin
Senior Researcher
![Schematic timeline showing the expected increase in sensitivity (μK2) and a few of the key cosmological parameters for Stage-3, along with the the threshold-crossing goals targeted for CMB-S4.](https://d3qi0qp55mx5f5.cloudfront.net/shared-resources/i/template/transparent.gif)
Schematic timeline showing the expected increase in sensitivity (μK2) and a few of the key cosmological parameters for Stage-3, along with the the threshold-crossing
goals targeted for CMB-S4.