This is a talk I gave at YOW! London 2022. Let's imagine that you are responsible for an aging monolithic application that's critical to your business. Sadly, getting changes into production is a painful ordeal that regularly causes outages. And to make matters worse, the application's technology stack is growing increasingly obsolete. Neither the business nor the developers are happy. You need to modernize your application and have read about the benefits of microservices. But is the microservice architecture a good choice for your application? In this presentation, I describe the dark energy and dark matter forces (a.k.a. concerns) that you must consider when deciding between the monolithic and microservice architectural styles. You will learn about how well each architectural style resolves each of these forces. I describe how to evaluate the relative importance of each of these forces to your application. You will learn how to use the results of this evaluation to decide whether to migrate to the microservice architecture.