February 11, 2016 will go down in history as the date humanity probed so deep into the fabric of spacetime that we finally gained the ability to detect gravitational waves. These extremely slight ripples were predicted by Einstein's theory of general relativity a century ago and have been sought after for decades, but in September 2015, after a significant sensitivity upgrade, the Laser Interferometer Gravitational-wave Observatory (LIGO) was finally able to detect the oscillations from a black hole merger some 1.3 billion light-years distant.
As February comes to an end, let's take a look back at this incredible month with a collection of photos from in and around the physics festivities.
Photo: A visualization of gravitational waves pictured during a press conference by the Max Planck Institute for Gravitational Physics (Albert Einstein Institute) at the Leibniz University in Hanover, Germany, Feb. 11, 2016.
Forming the basis of the historic gravitational wave detection is Albert Einstein's theories he presented at the Prussian Academy of Sciences in November 1915. In this photograph, the Head of Einstein Archives Roni Gross of the Hebrew University, Jerusalem, Israel, presents the original documents penned by Einstein outlining the theoretical basis for gravitational waves in his landmark theory: General Relativity.
100 years after Einstein developed his theories around the nature of spacetime, the international LIGO Science Collaboration restarted their search for gravitational waves after upgrading the twin LIGO stations located in Washington and Louisiana in September 2015. Almost immediately after the reboot, after searching since 2002, a signal was seen. Einstein's theories were (once again) confirmed, but the signal was much more -- for the first time we'd detected gravitational waves direct from a black hole collision. Shown here an aerial photograph of the LIGO Livingston Observatory in Louisiana.
Executive Director of the LIGO Laboratory at Caltech David Reitze is seen here discussing the details behind the gravitational wave discovery during the National Science Foundation's press conference in Washington, D.C. on Feb. 11, 2016.
The interferometer system that was key to the gravitational wave detection, forming the basis of LIGO was invented by Rainer Weiss, professor of physics emeritus at the Massachusetts Institute of Technology (MIT). At the Washington, D.C. announcement on Feb. 11, Weiss explained how the LIGO interferometers detected the tiny ripples in spacetime, using a plastic mesh to represent the "fabric" of spacetime. As gravitational waves propagate, they warp spacetime, as the physicist demonstrated by stretching the mesh.
Theoretical physicist Kip Thorne, of Caltech (right) watches the discovery announcement with Weiss on Feb. 11. Thorne is co-founder of LIGO that commenced construction in 1994 and went online in 2002, using Weiss' interferometer to seek out gravitational waves.
Graphics of the gravitational waves measured by two LIGO detectors in Washington and Louisiana are shown as members of the news media and guests listen to remarks on the discovery of gravitational waves, during the press conference in Washington, D.C., Feb. 11, 2016.
Last week, scientists from the international LIGO Collaboration met with legislators of the House Science Committee in Washington, D.C. to discuss the discovery. Pictured (from left to right): Assistant Director of the NSF's Directorate of Mathematical and Physical Sciences Fleming Crim, LIGO Lab Director David Reitze, LSC Spokesperson Gabriela Gonzalez and LIGO MIT Director David Shoemaker at the hearing on Feb. 24.
LIGO may have been the first to finally detect gravitational waves, but other detectors exist (and are being built) around the globe and international physicists have been reinvigorated by the Sept. 14, 2015 discovery.
Shown here, physicist Holger Wittel sits in a control center next to a cardboard cutout of Albert Einstein at the GEO600 gravitational wave detector in Ruthe near Hanover, Germany, after the Feb. 11 US announcement. GEO600 is joined by other gravitational wave projects, including the Italian-French Virgo detector located near Pisa, Italy. Japan, India and China also have plans for their own gravitational wave observatories. When it comes to gravitational waves, the more detectors the better -- at least 2 detectors are needed to confirm a detection and more detectors as part of a global network will be able to pinpoint the origin of cosmic phenomena generating gravitational waves.
Beginning the next generation of gravitational wave detectors is the Europe-led eLISA project. To test key technologies of the super-sized space-based mission, LISA Pathfinder was launched last year (pictured here in the cleanroom before launch). It is hoped eLISA will launch by the mid 2030s. Physicists are keen to have many different observatories sensitive to different frequencies as many different gravitational wave-generating phenomena may then be discovered.