For more than forty years Allain Gaussin fascinated by astrophysics has found a major source of inspiration in observing the cosmos as attest a number of works going from Vent solaire (1974) to Philae (2015) by way of L’Harmonie des sphères (2006). Ten years later the 'Messiaen du Pays de la Meije' Festival hosted the first performance of the piano trio Les Céphéides. The musical journey enables the listener to enter a space 'just as impalpable and fragile' as that in which moves each Cepheid variable – this star whose brightness varies over regular periods according to two elements: the diameter of the heavenly body and thetemperature reading of its surface. How does one translate such a change in music? The bow's sautillé gettato on the violin and cello gives the score's opening pages this granular glittering that leads us 'towards the centre of the Cepheid variables'. From there a stream of colourful arabesques – the composer's 'ribbon figures' – gushes forth. After a weightless transition the cello unfurls its contemplative meditation which ends up in a suspended coda open onto the infinity of the starry vault. As musicologist Michèle Tosi accurately says so it is that the full richness 'of a teeming imaginary universe' unfolds.