Jeremy Darling from the University of Colorado Boulder proposes an original approach to measure the gravitational wave background. These cosmic vibrations, particularly resulting from collisions of supermassive black holes, subtly alter the apparent position of quasars in the sky—the brightest entities in the Universe.
Illustration of gravitational waves generated by two black holes in close orbit around each other, shortly before their collision (more precisely, coalescence).
Darling's research, published in
The Astrophysical Journal Letters, could shed light on the mysteries of gravity. By analyzing quasar movements, he hopes to detect gravitational waves in three dimensions without requiring the construction of expensive detectors—a first in this field.
The study of celestial movements, or astrometry, is a challenge of precision. Quasars, located millions of light-years away, require measurements of unprecedented accuracy to detect their apparent vibration.
The European Space Agency's Gaia mission provides crucial data for this research. With observations of millions of quasars, Darling hopes to isolate the gravitational wave signal from Earth's own motion.
Future Gaia data, expected by 2026, could reveal these hidden signals. This breakthrough would allow testing the fundamental laws of gravity.
How do gravitational waves warp space-time?
Gravitational waves are ripples in space-time caused by violent cosmic events, such as black hole collisions. They travel at the speed of light, temporarily distorting the distance between objects they pass through.
This distortion is extremely small, often on the scale of a fraction of an atom's size over distances of several miles (several kilometers). That's why their detection requires instruments of unmatched precision, like laser interferometers.
Gravitational waves offer a new way to observe the Universe, complementing traditional light-based methods. They allow the study of otherwise invisible phenomena, such as black holes just before their collision.
The discovery of gravitational waves in 2015 opened a new era in astronomy. Since then, multiple detections have confirmed their existence and their potential to explore the mysteries of the Universe.