For students and the curious
Next steps
The lessons teach the ideas. The viewer lets you explore them. These are the questions that come after — open problems you can investigate using real Gaia data, the tools on this site, and your own analysis. Each one is a starting point, not an answer.
Research topic
Why do the Orion Nebula stars and the Pleiades look elongated?
When nearby stellar groupings are rendered in three dimensions from Gaia distances, familiar structures can appear stretched along the line of sight — sometimes pointing straight back at the Sun. Is that real structure, or the geometry of the measurement?
Read the brief →What these are
Guided starting points, not prescribed answers.
Each topic sets out a question that arises naturally from working with real astronomical data. It explains why the question matters, why it is harder than it looks, and suggests concrete tests or analyses a student could carry out.
They assume familiarity with the ideas covered in the Learn section — particularly how Gaia measures distances, what selection effects are, and how to think about uncertainty. If those ideas are new, start there.