Gaia: science interviews

An 'occultation' occurs when a planet, moon, or any other solar system object passes in front of a distant star. Bruno Sicardy (Sorbonne University/Observatoire de Paris) explains how Gaia is contributing to our knowledge of the solar system using these curious events.

Star distances are so immense that establishing a census of even the nearest stars has been an enormous challenge for astronomy. Ricky Smart, of the Observatory of Torino, joins me to explain how Gaia is revolutionising our understanding of nearby stars.

Gaia is transforming our empirical picture of the stellar Hertzsprung–Russell diagram. Grenoble-based astronomer Carine Babusiaux joins me to describe some of its new and remarkable insights, on white dwarfs, red dwarfs, colliding galaxies, and public outreach.

Gaia will detect and determine the orbits of tens of thousands of asteroids in our solar system. Apollo 9 astronaut Rusty Schweickart, joins me to give his assessment of the threat to humanity of these rocks in space, and what we should be doing about them.

Barcelona astronomer Xavier Luri describes the impact that Gaia is having on our understanding of two of our nearest galaxy neighbours, the Large and Small Magellanic Clouds. Hipparcos observed less than 50 stars in both systems. Gaia is observing more than 10 million.

To accompany my essay on the search for solar siblings with Gaia, I am joined here by the lead authors of a paper on this topic, Jeremy Webb and Natalie Price-Jones, from the University of Toronto, for some further background.

One of the authors of an investigation into past and future stellar fly-bys of our Sun using the Gaia data, Coryn Bailer-Jones of the Max-Planck Institute of Astronomy in Heidelberg, joins me explain what he thinks is going on.