instrument

virgo

A gravitational-wave detector in Europe, operating as an interferometer alongside LIGO.
52 related articles

Description

Virgo is a gravitational-wave detector located near Pisa, Italy, and is one of the three major ground-based interferometers (along with the two LIGO detectors in the United States) that form a global network for observing ripples in spacetime. It is a Michelson interferometer with arms 3 kilometers long, designed to detect tiny changes in the length of its arms caused by passing gravitational waves. Virgo began operations in 2007 and underwent major upgrades to become Advanced Virgo, which joined the LIGO detectors in 2017 for the first joint observation run.

History

The Virgo interferometer was proposed in the 1980s by Alain Brillet and his team, with construction starting in 1996 and completion in 2003. It was designed and built by a collaboration of French and Italian institutes, and has been operating since 2007.

How it works

A gravitational wave passing through the detector stretches one arm while compressing the other, causing a differential change in the travel time of laser beams along the two arms. The interference pattern of the recombined beams shifts, and this shift is measured with extreme precision. To achieve the required sensitivity, the mirrors are suspended on sophisticated seismic isolation systems, and the entire apparatus operates in a vacuum to minimize noise.

In practice

Virgo, together with LIGO, has detected gravitational waves from merging black holes and neutron stars, enabling multi-messenger astronomy and tests of general relativity in strong-field regimes.

Fun fact

The Virgo detector is named after the Virgo cluster of galaxies, which is the nearest large galaxy cluster and a potential source of gravitational waves.

Concept graph →

Related articles · 52

The Fifth Planet of HR 8799: A Whisper in the Roar of the Orchestra
The orchestra is playing fortissimo, and someone in the third row is whispering. Hearing that whisper is the challenge astronomers face at the star HR 8799: four bright giant planets drown out the faint light of a possible fifth, hidden very close to the star. The HR 8799 system is a proving ground for direct exoplanet imaging.
Galaxies2026-08-191 minarXiv:2608.19326express
A Faint Ghost Galaxy in the Virgo Cluster
The night sky only looks black: telescopes reveal millions of galaxies, but some are so dim they blend into the background. Astronomers caught just such a "nearly invisible" one by chance while observing the Virgo Cluster with the two-meter telescope at Teide Observatory. The galaxy is named TTT J1237327+143535.
Exoplanets2026-08-181 minarXiv:2608.17689express
Icy Moon in Radio Waves
From 1987 to 1991, astronomers last measured how Jupiter's icy moons reflect radio waves. Then came a long pause. In 2011–2024, researchers aimed a radar beam at Europa again: this time using the 70-meter antenna at Goldstone and the Green Bank Telescope. Ice is nearly transparent to radio waves, like clear window glass is to light.
Instrumentation2026-08-122 minarXiv:2608.11673express
Gravitational Hearing: How to Catch the Whisper of Merging Black Holes
Gravitational-wave detectors are like extremely sensitive ears: they pick up the trembling of space when black holes or neutron stars collide somewhere in the universe. But even the most sophisticated "ears" cannot hear everything. The new LIGO A# project is like replacing the eardrum with a thinner, more sensitive membrane.
Stellar2026-08-032 minarXiv:2608.02847express
Betelgeuse Breathes in Time with an Invisible Companion
Betelgeuse, the red supergiant familiar from Orion's shoulder, keeps surprising us. After the mysterious Great Dimming of 2019–2020, when the star suddenly dimmed, it didn't just recover; it changed its ways.
General Relativity2026-07-312 minarXiv:2608.00281express
Two Signals in the Universe's Noise
A noisy café. You're trying to make out two quiet conversations: one from the table by the window (black hole mergers), the other a barely audible whisper from the far corner (echoes of the universe's birth). But the hiss of the espresso machine and street noise (detector jitter) drown everything out. New work teaches a computer to separate these sounds.
Whisper from the Dawn of Time: Hunting for Subsolar Black Holes
For a whole year, LIGO, Virgo, and KAGRA listened to the trembling of spacetime. Thousands of mergers of black holes and neutron stars left clear signatures. But hidden among them was another signal — a barely audible whisper.
General Relativity2026-07-212 minarXiv:2607.18627express
Black Hole with a Soft Core Changes the Music of Gravitational Waves
The spiral of water draining into a sink spins faster and faster toward the center. In an ordinary black hole, that funnel ends in an infinitely sharp point — a singularity where the laws of physics break down. But this new work considers a different picture: the funnel doesn't taper to a needle but ends in a smooth, swelling bubble.
General Relativity2026-07-212 minarXiv:2607.19293express
Gravity Passes Another Test: 168 Mergers Confirm Einstein
A huge bowl of water. Drop a stone into it — ripples spread across the surface. The fabric of spacetime works much the same way: when two massive stars merge, they create ripples — gravitational waves. These waves travel to Earth and are picked up by giant detectors like LIGO and Virgo.
Kaleidoscope of Noise: The Hunt for Invisible Glitches Inside LIGO
A kaleidoscope of noise — that’s one way to describe the data stream pouring out of the LIGO interferometers.
General Relativity2026-07-202 minarXiv:2607.18219express
The Cosmic Top That Brakes Too Fast
A spinning top that makes a hundred turns per second suddenly starts losing speed dramatically — much faster than any known top. That's exactly what pulsar J0435+3233 is doing. It's a dead star, crushed to the size of a city, but whirling at a furious rate.
Cosmology2026-07-203 minarXiv:2607.18390
Space Tuning Fork: How Satellites Catch Gravitational Waves
In 2034, a rocket leaves a spaceport with an unusual payload: two spheres the size of a large globe, each weighing nearly a ton. No engines, no electronics. Just a mirrored surface of hundreds of corner-cube reflectors — tiny prisms that return light exactly to where it came from. This is the future space tuning fork.
Cosmology2026-07-173 minarXiv:2607.15913
Cosmic Mimicry: Neural Network vs Gravitational Twins
In 2019, the LIGO facility recorded a gravitational waves, a ripple in the fabric of spacetime, whose time-frequency map resembled a strange comb. Each such signal from a black hole merger leaves a unique pattern, like a fingerprint.
Cosmology2026-07-172 minarXiv:2607.16162
Waltz Without a Right Turn: Gravitational Waves and the Birth of the Universe
13.8 billion years ago, the universe swirled in a waltz. The right turn was forbidden. Today, the echoes of that cosmic ball reach us as a barely perceptible ripple in spacetime — gravitational waves. Their existence was predicted by Albert Einstein.
General Relativity2026-07-102 minarXiv:2607.09111express
A Noise Filter for Gravitational Waves
Gravitational-wave detectors are like sensitive microphones, listening for the whispers of distant cataclysms. But every now and then, a sharp crack bursts in — a brief noise spike known as a glitch.
Light Quenches Light: Suppressing Instabilities in Gravitational Wave Detectors
In pursuit of gravitational waves, ripples in spacetime left by black holes and neutron stars, detectors like LIGO pump their arms with light of dazzling intensity.
General Relativity2026-06-261 minarXiv:2606.28071express
A Sky Map for Cosmic Ripples
The space antennas LISA and Taiji each consist of three satellites flying around the Sun behind Earth, forming a triangle with sides millions of kilometers long. They measure how the distance between them changes when a gravitational wave passes, like ripples on a pond from a thrown stone.
Gravitational Choreography: Pulsars vs. LISA
A pair of neutron stars, locked in a gravitational embrace, traces invisible circles in the void. A century ago, Albert Einstein described this dance as waves of curved geometry, but for a long time we could only catch glimpses — through the feverish flicker of radio pulses.
General Relativity2026-06-221 minarXiv:2606.22985express
How Antenna Orientation Changes the Hunt for the Gravitational Hum
Two sensitive microphones are listening to the Universe. One hears a low hum, the other hears almost nothing. It's not a malfunction: it's about how they are oriented. Gravitational-wave observatories like LIGO don't just catch loud bursts from black hole mergers.
Optics2026-06-201 minarXiv:2606.21905express
An Old Cable Catches Storms and Earthquakes
The planet-spanning web of undersea internet cables acts like a giant ear. The glass thread inside responds to water movements: currents, tides, and distant earthquakes bend the cable. Light traveling along the thread takes slightly longer: this delay is measured on shore against a reference. That’s how the speed of light reveals itself.
General Relativity2026-06-162 minarXiv:2606.18184express
Gravitational Waves: When the Front Isn't Flat
A gravitational wave observatory is like a set of microphones scattered across the Earth. When a signal arrives from space (say, from a black hole merger or a supernova explosion) each microphone hears something slightly different.
HEP Phenomenology2026-06-152 minarXiv:2606.16099express
Laser Interferometers as Detectors of Axion Dark Matter
The universe is permeated by invisible mass, dark matter, whose existence was first proposed by Fritz Zwicky in the 1930s, based on his observations of galaxies moving in clusters.
General Relativity2026-06-112 minarXiv:2606.13728express
How to Hear Gravity's Whisper Without Missing a Word
A translator records a multi-hour conversation. If they try to hold the entire dialogue in their head, they're bound to garble details by the end. That's roughly how gravitational observatories work: they listen to the 'conversation' of massive bodies spiraling together.
Cosmology2026-06-083 minarXiv:2606.09210express
Dark Matter Sings in Two Voices
An ultra-sensitive microphone listens not to sound, but to the trembling of space itself. That's how gravitational wave detectors work — LIGO, Virgo, KAGRA.
Cosmology2026-06-081 minarXiv:2606.09810express
Pulsars Lock Onto the Hum of the Prehistoric Universe
Pulsars are dead stars spinning with flawless rhythm. Their radio blips are more precise than atomic clocks. However, gravitational waves — ripples in the fabric of spacetime, predicted by Einstein — disrupt that rhythm.
Echoes of Black Holes: How Gravitational Sirens Reveal the Curvature of the Universe
It was Edwin Hubble who discovered that galaxies are rushing apart, and Georges Lemaître linked this to the expansion of space. Today, the ΛCDM model, relying on dark energy and dark matter, asserts that the Universe is flat as a perfectly stretched canvas.
Levitating Graphite Web Captures the Moon's Embrace
In the quiet of a laboratory, a graphite flake hovers above a magnetic grid. This is not just a demo of diamagnetism's magic — it's listening to the Universe. Like a spider casting its web to catch vibrations from an invisible world, this flake has become a gravitational web.
General Relativity2026-05-261 minarXiv:2605.27225express
Cosmology2026-05-262 minarXiv:2605.27227express
Gravitational waves measure the expansion rate of the universe
Imagine a giant inflatable balloon with galaxies painted on it. As it inflates, the pattern stretches and neighboring dots move apart. The rate of that stretching is the Hubble constant. Astronomers usually catch light from distant stars and see how much it has reddened due to the stretching of space.
Light Carousel Measures Earth's Rotation
Two beams of light race around a closed loop, heading toward each other. Since the speed of light is constant, when the ring turns, one beam has to catch up with a moving finish line, while the other meets it sooner. Their meeting creates a pattern, and from that pattern we can tell how fast the whole system is spinning.
General Relativity2026-05-182 minarXiv:2605.19153express
Gravitational-Wave Monitoring: How GstLAL Catches Bursts in 16 Seconds
Spacetime is not a passive void but a dynamic membrane capable of elastic deformation. When neutron stars (ultra-dense objects the size of a city, where matter is compressed to nuclear density or black holes) regions with gravity so strong that even light cannot escape their bounds collide, the membrane shudders, generating…
Instrumentation2026-05-141 minarXiv:2605.14279express
Gravitational Waves: A New Listener at the South Pole
Gravitational waves are ripples in space from the mergers of black holes and neutron stars. Existing detectors, built with contributions from Kip Thorne and Rainer Weiss, work like highly sensitive microphones but only hear the highest 'notes'.
High Energy2026-05-111 minarXiv:2605.11283express
Lunar detector to hear ancient black holes
Gravitational waves are ripples in the fabric of space, like circles on water from a thrown stone. On Earth, they are drowned out by traffic, tides, and earthquakes, like a storm beating on a lake, making it impossible to notice faint splashes. The LILA project moves the detector to the Moon, where windless silence reigns.
General Relativity2026-05-051 minarXiv:2605.03576express
The Quiet Overtones of a Black Hole Are Now Heard Louder
When two black holes merge, the resulting black hole 'rings' for a while, emitting gravitational waves — like a dying bell. This ringing is captured by giant detectors created by Rainer Weiss and Kip Thorne.
Instrumentation2026-05-051 minarXiv:2605.04133express
How to Peer into the Heart of a Black Hole
Einstein's theory of gravity explains how mass warps space and time. Its predictions have been tested near Earth, but the most grueling tests lie around black holes, where distortions reach their breaking point. Until now, astronomers saw them as blurry smudges on an underexposed photo.
General Relativity2026-04-172 minarXiv:2604.16039express
The Noise That Poses as Gravity
In the headphones used to listen to a distant orchestra, there is an occasional crackle. The crackle can be so loud that it drowns out the music or even blends in with it.
Medical Physics2026-04-161 minarXiv:2604.14494express
A Ring That Feels Your Pulse
Your finger is a living sensor: beneath the skin, arteries pulse in time with your heart. Traditional blood pressure cuffs squeeze your arm and give a single number, but this ring uses eight electrodes to pass a weak current through the tissue and map blood flow.
A Detector That Catches Time in Picoseconds
In giant accelerators, particles zip through detectors in billionths of a second, and telling one from another requires a stopwatch of incredible precision. The new µRWELL-PICOSEC detector acts as such a stopwatch: it captures the moment a particle passes with a precision of 48 picoseconds: that's 48 trillionths of a second.
General Relativity2026-03-261 minarXiv:2603.25938express
Tuning Into the Hum of Spinning Stars
After a supernova explosion, a neutron star neutron star remains: a city-sized ball of unimaginably dense matter, spinning hundreds of times per second. Any tiny bump on its surface would make it wobble like an off-balance spinning top, humming faintly through the fabric of space.
HEP Phenomenology2026-03-161 minarXiv:2603.15734express
Black Holes Sing Gravitational Songs
Black holes aren't silent abysses, but nature's tuning forks. Their rapid spin, predicted by Roger Penrose, makes spacetime itself sing, producing a stream of the lightest particles — axions. These accumulate around the hole, like sound in a concert hall, and begin to oscillate in unison.