Anticipation is building ahead of a "status report" from an international effort to detect ripples in space-time.
These gravitational waves were first proposed 100 years ago by Albert Einstein, as a key prediction of his Theory of General Relativity.
But in decades of searching they have never been detected, despite several years of operation from two huge laser instruments in the US and one in Italy.
Teams from the US detectors will speak in Washington DC at 15:30 GMT Thursday.
Speculation is rife that they will announce the detection of gravitational waves by both the US instruments, which together make up the Laser Interferometer Gravitational Wave Observatory