A massive international team made history in 2016 when they announced that, for the first time ever, they’d confirmed the existence of gravitational waves – ripples in the fabric of spacetime from the collision of two black holes.
Now we have a fresh development in this exciting new era of gravitational wave astronomy – and we’re so beyond thrilled that we’re updating live as the press conference happens.
In August, rumours about this announcement started bubbling to the surface, thanks to a tweet by University of Texas astronomer J. Craig Wheeler. “New LIGO,” he wrote. “Source with optical counterpart. Blow your sox off!”
This immediately set the speculation wheels turning that LIGO had detected not a black hole collision like before, but a neutron star merger, which would not only produce gravitational waves, but possibly leave behind light detectable by optical telescopes.
Just a month later, we’re finally finding out what that sock-blowing new detection really is.
We’re live-updating the story below as the announcement happens, so keep refreshing for more information! (And apologies in advance for any typos we might make in the excitement.)
12:15pm EST: It’s 15 minutes to go until the announcement starts! Anyone else super-excited? We’re super-excited despite the fact it’s past 2am here in Sydney, Australia. While we’re waiting for the press conference to kick off, here’s some more background on why a gravitational wave detection from neutron stars would be such a big deal.
Since its first 2016 announcement, LIGO made two more detections from black hole collisions. Then earlier this year, LIGO and another gravitational wave detector, VIRGO, took observations together, allowing for more precise signal triangulation.
If they have now achieved a detection of gravitational waves from a neutron star merger, it means not only we may learn something new about this type of cosmic collision, but it will also be the very first time we have detected gravitational waves of this particular type – another breakthrough for the new era of gravitational wave astronomy.
12:30pm EST: The announcement is starting! We’re watching the webcast live from G7 Science at Reggia di Venaria Media Center in Turin, Italy.
12:32pm EST: Actually, we’re still waiting for the livestream to start. We hope they haven’t forgotten about us!
12:37pm EST: Still no livestream, but this press release just went live on the LIGO website.
“The LIGO Scientific Collaboration and the Virgo collaboration report the first joint detection of gravitational waves with both the LIGO and Virgo detectors. This is the fourth announced detection of a binary black hole system and the first significant gravitational-wave signal recorded by the Virgo detector, and highlights the scientific potential of a three-detector network of gravitational-wave detectors.”
Doesn’t look like we have neutron stars.
12:40pm EST: WE HAVE THE LIVESTREAM!
12:42pm EST: France Córdova, Director of the National Science Foundation, is taking the floor.
12:43pm EST: The event is named GW 170814, after the date it was detected. It’s the first detection made using three detectors – two of LIGO’s, and one Virgo detector.
12:45pm EST: Jo van den Brand, spokesperson of the Virgo collaboration is taking the floor.
12:46pm EST: The gravitational wave signal arrived first at the LIGO Livingston detector; then six milliseconds later it arrived at the Hanford detector; then another six milliseconds later it arrived at the Virgo detector. Using three detectors has allowed the research team to locate the source of the waves with greater accuracy.
— LIGO (@LIGO) September 27, 2017
12:50pm EST: We’re now hearing from Frédérique Marion, Senior Scientist, Virgo Collaboration. She specialises in data analysis.
Virgo is aligned slightly differently to the two LIGO detectors. This difference has allowed the team to access something called the polarisation of gravitational waves, which is the distortion of spacetime in the three spatial dimensions.
GW 170814’s polarisation was consistent with Einstein’s theory of general relativity, and this is the first time we’ve been able to make that confirmation.
12:55pm EST: David Shoemaker, Spokesperson, LIGO Scientific Collaboration is now explaining how using three detectors lets scientists triangulate the location of the source of the gravitational waves.
12:57pm EST: The next observing run will commence in about a year from now.
“The future is incredibly bright for Virgo, for LIGO, for the Virgo-LIGO network, for gravitational wave astronomy, and for the greater astronomical environment which we can now do in common with gravitational waves and electromagnetic radiation.”
1:00pm EST: We’re now hearing from Giovanni Losurdo, Advanced Virgo Project Leader, Virgo Collaboration.
“As with Galileo, humankind has a new instrument with which to look towards the skies. Every time we use a new instrument, there is a new prospect for knowledge, and we provide knowledge, knowledge that can serve as inspiration for the imagination and intuition of the young, and can bring about change in thousands of minds, and therefore science as a whole.”
1:06pm EST: This image shows how much better simply adding one more detector improves the location of the source of gravitational waves:
The broad streaks show the area to which previous collisions were pinpointed. The small green blob in the bottom left is where GW 170814 originated. Amazing!
1:08pm EST: While we wait, here’s a little bit more information on the actual collision:
“The detected gravitational waves – ripples in space and time – were emitted during the final moments of the merger of two black holes with masses about 31 and 25 times the mass of the sun and located about 1.8 billion light-years away.
“The newly produced spinning black hole has about 53 times the mass of our sun, which means that about 3 solar masses were converted into gravitational-wave energy during the coalescence.”
1:09pm EST: And the livestream has ended before we had a chance to listen to question time.
We have to admit, we’re a little disappointed that we didn’t actually get to see a collision between two neutron stars, but this news is still incredibly exciting.
With Virgo and LIGO working together, Shoemaker says, we may be able to make detections like this as often as once a week!