This podcast episode explores the concept of modular blockchains, which involve separating the core functions of a blockchain into different protocols to enable greater scalability and customization. Roll-ups and layer two technologies focus on the execution part, while Celestia focuses on consensus and data availability. Celestia provides a pluggable consensus and data availability layer, allowing developers to post blobs of data and ensuring that data is ordered and verifiably published to the entire internet. Data availability is crucial to the safety of blockchains, and Celestia's data availability sampling technique enhances scalability by allowing light nodes to gain high assurance guarantees without downloading the entire block. Celestia's modular architecture empowers developers to create application-specific blockchains and roll-ups, offering high throughput and customization options. The emergence of sovereign roll-ups grants the ability to hard fork and make changes without external influence, fostering community-driven governance and social consensus.