The curtain rises on the gravitational Universe
After a long wait, the rumour has been confirmed: gravitational waves have been detected in the LIGO interferometric antenna. This is a major scientific event, not only because it concludes a century long chase : Einstein predicted the existence of such waves in 1916, only a few months after his seminal series of papers on General Relativity in November 1915. But this is also the opening of a new era: the direct observation of the gravitational Universe.
Indeed, all the discoveries of the XXth century have confirmed Newton’s point of view that gravitation is running the Universe in its largest spatial dimensions as well as its evolution with time. But all detection until now was based on light, or more generally electromagnetic waves. Not so surprising from human beings equipped with a sensitive light detector, the eye. The discovery of today opens up the exciting possibility of exploring the Universe, and our space-time with waves of gravity. We will thus get first-hand information on the most gravitational of all astrophysical objects, the black holes, but also on many violent phenomena in the Universe, and ultimately the most violent of all, the Big Bang.
Today is clearly only a beginning. Ground detectors are now in a position to observe many more stellar events and do outstanding science. The space detector eLISA, as well as the observation of pulsar timing, will open the window onto the gravitational Universe at large. It is a beautiful symbol for the future that, at the time the discovery is announced, the LISAPathfinder satellite is waking up at the Lagrange point L1, ready to test the technology of the future eLISA mission.
It is time to rejoice and to congratulate the scientists of the LIGO collaboration, but also the GEO600 and Virgo European teams who joined in the analyses, for their commitment over many years to this search, and for their careful handling of this outstanding discovery, despite the pressure from the scientific community and the media. And its is also the occasion to stress that this is an incredible achievement in terms of ultra-precise measurements.
We hope that all the learners of Gravity! feel gratified to have spent weeks on understanding better the gravitational Universe, and thus that they better share the excitement of this discovery.
We propose on this website a series of posts, under the heading Gravitational wave discovery, which presents more details on gravitational waves, their detection, and the present discovery. They will be complemented in the future. Do not hesitate to comment and ask questions.
We had also said that we would organize the first Gravity! Workshop at the end of this month. The dates are nox fixed, February 29 and March 1, and the location is Paris. And the title: Gravitational wave fiesta. Surprised? All you want to know about gravitational waves and their discovery. Reserved to Gravity! learners… and all their friends. So it is time to visit Paris for the week-end, and make a short excursion into the gravitational Universe. And if you really cannot come and meet us, we will have a hangout on the evening of February 29.
We had promised exciting news for the forthcoming months and years. It only begins.
Pierre Binétruy and George Smoot