How Do We Know?Observations
Aside from dark matter, all objects in the universe emit light. Almost everything we know about these objects—from their chemical composition to their temperature to their age—comes from studying this light, only a fraction of which is visible to the human eye. Sophisticated telescopes capture different wavelengths of light, like X-rays and microwaves. This enables astrophysicists to investigate distant celestial objects. For example, they use cutting-edge observational techniques to see small, dim objects like brown dwarfs. On Earth and in space, these telescopes are our eyes to the universe.
Models & Simulations
Telescopes can provide snapshots of celestial objects in different stages of development.
However the time scales are often just too long to see them in action. So, to help them understand billions of years of stellar history, astrophysicists create mathematical models that are based on the laws of physics to describe how nature behaves across the cosmos. They sometimes use powerful computers to make vast numbers of complex calculations to simulate the life of stars. Astrophysicists compare these models and simulations to observational data for verification. The visualizations in Journey to the Stars are based on both numerical models and observational data.