Gaia: science essays

60. Scientific project management

In this short introduction to my own experiences, I will argue that there are skill sets that a scientific leader should possess in order to best optimise the prospects of success, and that there are lessons that can be learned from previous space projects, and indeed from wider sociological studies of how people and teams best work together.

21 February 2022

59. Supernovae with Gaia

Supernovae are dramatic and violent end-points of stellar evolution, and several thousand should be detected. But the physics of the progenitor star, and the evidence that each supernova leaves behind, are also rich in diagnostics: of neutron stars, black holes, and millisecond pulsars. We look at some of this forensic evidence being discovered by Gaia.

14 February 2022

58. Einstein crosses

Amongst the 500,000 quasars being observed by Gaia, and the several hundred showing multiple gravitationally lensed images, we take a more detailed look at the curious quadruple-imaged quasars, how they arise, how they are being discovered in the Gaia data, and what they might tell us about black holes, dark matter, and the Hubble constant.

7 February 2022

57. Technology preparation for Gaia

Why does ESA fund the development of space science missions? Why do some of these run over budget, and over schedule? And what steps were put in place during the Concept and Technology Study in the 1990s to ensure that the advanced technologies needed for Gaia would be available consistent with its target launch date of 2012?

31 January 2022

56. Interferometer or monolith?

While Gaia started life as a small interferometer, interferometry was eventually dropped – after detailed industrial design studies – for objective technological and associated cost/risk reasons. But I consider that, had Gaia not started as an interferometer, it would not have been accepted within ESA’s scientific programme in 2000.

24 January 2022

55. Wow!

The search for extra-terrestrial intelligence, or SETI, is motivated by the belief that intelligent life is likely to emerge under conditions similar to those on Earth. There have been many searches, with false alarms, unconfirmed events, and new celestial phenomena discovered along the way. Gaia is contributing to our ever-improving picture.

17 January 2022

54. Animations, stereos and fly-throughs

It is a challenge to explain the scientific importance of astrometry to a wider public. But the measurement of stellar distances and space motions in the vast quantities and accuracies provided by Gaia, is yielding compelling animations, stereo images, and fly-throughs of our Galaxy. I provide some examples.

10 January 2022

53. The scientific case for Gaia in 2000

With the steady flow of scientific results now coming from the Gaia satellite, I look back at the mission's scientific case, prepared during the period 1997–2000. This formed part of the Concept & Technology Study Report, which was used as the basis for ESA's advisory structure's selection of the mission in 2000.

3 January 2022

52. Interplanetary navigation

Spacecraft sent out to orbit, land on, or simply fly past the planets and other bodies of our solar system rely on interplanetary navigation. At the basis of knowing both the target object's orbit, and the rendezvous vehicle's orbit, are accurate star positions. The recent spectacular fly-by of Ultima Thule used the latest Gaia results.

27 December 2021

51. Asteroseismology - and star distances

Given that stars are usually seen as point sources, it is perhaps surprising that we can say anything at all about their internal structure and physical processes. The observational effects of shock waves propagating through them provides an important tool for probing their interiors. And distances provide an important constraint.

20 December 2021