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


  • Anna Skornyakova

    I am so happy and excited as if I discovered them myself!!! Great, amazing discovery! Watched the press conferense live, recognized Gabriela 🙂

  • Val Black

    Fantastic news – so exciting and I’m pleased to have learned something about it through the course – thank you!

  • MaryKaren Solomon

    This is thrilling! I am so excited. I wish I could come to Paris, but alas! Work interrupts. However, I will be at the hangout.

  • Alan H Douglas VMD

    Great news! Thanks again, Professor, for letting me feel like I can vicariously share in the accomplishment.

  • Steve Bryant

    Exciting new from LIGO. So cool to be able to prove Einstein was right. Now looking forward to eLISA pathfinder. If I hadn’t done the Gravity! course I’m sure the significance of today’s news would have escaped me. Wish I could join you in Paris but alas, it’s not possible. Best wishes!

  • Rowena Allen

    Such exciting news! Thanks to the Gravity! Course i have a better understanding of the significance of this discovery too. And i also noticed that this has not just confirmed existence of grav waves but that they also move at speed of light as predicted too!! Will be tuning into the upcoming hangout too!

  • Brilliant news. So cool to be able to grasp some of the implications thanks to the course. Won’t be able to make Paris but will be at the hangout and will be bragging to my friends that I got invited to a Gravitational wave fiesta! Hurrrah!

  • Rocío Gold

    So excited! I just heard the news and have nobody to jump and scream with! Jaja
    I celebreate with you all. So greatful to have learnt about something so big and important.
    Thank you Gravity! team.

  • Ryan

    This discovery is fantastic. I can’t wait to see what findings LISA can add. Maybe I was mistaken but I thought we learned gravitational waves were too difficult to detect at earth’s surface, thus the reason for LISA’s launch. That’s why I was surprised to hear of the discovery today. Very excited for the future of gravitational waves and I’m grateful to have been a part of the class, and look forward to following further.

    • Pierre Binétruy

      Dear Ryan,
      LISA will probe much larger wavelengths of gravitational waves (which means smaller frequencies). Hence its is complementary. The cosmic events that LISA detect are even more powerful than the one announced today: for example, the fusion of two black holes of millions of solar masses (instead of 300 solar masses today). Hence it will probe events in the entire observable Universe, which means thus in the deep past of our Universe.
      You can go to the pages “Gravitational wave discovery“, in particular here on this website to get more information about this complementarity.

  • Karen Hyvonen

    Such spectacular news! Even our normally crisis oriented news media have lifted this great positive accomplishment up. Wish I could “like” all the comments above and join folks in Paris, but I’ll be imagining the happy occasion. Thanks again for offering the course, which has made this so much more meaningful.

  • Virginia Brook

    Wonderful news! I am so very grateful for the ‘Gravity!’ course where I learnt so much and can now really appreciate the enormous importance of this discovery. Thank you to all the Gravity! team.

  • Netty Weijenberg

    The idea of sharing through a community of learners in this scientific field is great. I would like to stress that the presenters of this particular MOOC were so passionate that I got involved from the start.
    Whether I can make it to Paris I don’t know yet. However I can assure you, prof. Pierre that I have often told people about this course and told them the beauty and necessity of gravity!
    So I hope a lot of people will join the 2nd run.

  • Allyson

    So exciting! And thanks to Pierre and the team behind the course on Gravity, I’m able to understand a little more about the significance of this amazing discovery. And I can even explain to family and friends exactly why I’m jumping up and down with excitement (and get them understanding a little more about it too). So a huge thank you for the course. See you at the hangout!

  • Brian Lawler

    Absolutely stunning news. I watched the LIGO announcement live over the internet and could not help but give a loud cheer on hearing that gravitational waves had been detected. The information that was then presented by the panel (including ‘our Gaby’) was brilliant. In a way, having completed the Gravity course, I do feel a (very small) part of it all. Can’t wait to hear about developments and results with Lisa Pathfinder. Thank you again for putting together such a great course.

  • helen Mary Jones

    I already commented on the Gravity! course page, but must repeat my glee at the exciting news again here, with hopes that I may make it to the Paris Gravitaional Wave fiesta in person or just at the hangout, not sure which yet. On a personal note September 14th is a date I can easily remember as it is my dear mother’s birthday. And I’ll be back onthe May course, too, at least repeating some of it.

  • Joyce Watkins

    This is absolutely fantastic news, and I am so grateful to Pierre and the ‘Gravity Team’ for a great course. It has increased my understanding of the importance and beauty of this discovery. I am constantly reading all I can about the beauty of Gravity.
    I can’t make Paris, but will watch the Hangout.
    Thank you.

  • Pingback: We have detected gravitational wawes! – Labex UnivEarthS

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