instrument

LIGO

LIGO is a gravitational wave detector that measures spacetime vibrations from cosmic events like black hole mergers.
93 related articles · 6 who worked here

Description

LIGO is a giant ruler that measures how gravitational waves stretch and squeeze space. Two long arms of a laser beam are compared: if a wave passes, one arm becomes slightly longer than the other.

History

Attempts to detect gravitational waves began in the 1960s with Joseph Weber's solid-state resonators. In the 1970s, the idea of a laser interferometer was proposed by Rainer Weiss and further developed with the participation of Kip Thorne and Ronald Drever. Key funding for the project was obtained in the 1990s, construction was completed in the early 2000s. The first direct detection — event GW150914 — occurred on September 14, 2015.

How it works

In each arm, the laser beam is reflected many times (about 280 times) between mirrors, effectively increasing the length to 1120 km and enhancing sensitivity. The combined beam is sent to a photodetector. The gravitational wave, by changing the proper length of the arms in opposite directions according to the metric h = ΔL/L, modulates the brightness of the interference spot. The noise reduction system (seismic, thermal, shot) allows measuring relative strains on the order of 10⁻²¹.

Fun fact

LIGO's sensitivity is such that it detects length changes ten thousand times smaller than the size of a proton — like measuring the distance to the nearest star with the accuracy of a human hair's thickness.

Concept graph →

Related articles · 189

How to Hear a Day-Long Neutron Star Merger
Imagine an interpreter distracted by every rustle in the hall, turning a one-hour meeting into two. That's roughly how gravitational wave detectors behaved when analyzing long signals: each turn of the Earth added noise to the calculations, and processing a day-long neutron star merger threatened to stretch into weeks.
Stellar2026-08-253 minarXiv:2608.24752
The Sun's Magnetic Pulse, Heard by Earth
The Sun breathes, and that breath has a magnetic rhythm. Every 27 days, the visible surface of the star makes a full rotation, and with it, its magnetic field, like an invisible ribbon wrapped around the star.
Galaxies2026-08-243 minarXiv:2608.22835
Two Bubbles Above a Sleeping Galaxy
The night sky is full of rings and bubbles, but in the radio band they look different. In data from the Australian radio telescope ASKAP, a structure has surfaced that resembles two soap bubbles blown from the same straw.
Optics2026-08-143 minarXiv:2608.14447
How to Hear an Invisible Twist
Imagine a string stretched between two tuning pegs. The slightest touch makes it vibrate, and from the pitch you can guess exactly how it was plucked. Physicists at the University of Arizona have stretched a similar string — not on a musical instrument, but on a silicon membrane just a hundred nanometers thick.
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.
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.
Cosmology2026-08-122 minarXiv:2608.12042
Radio Echo at the Cluster's Edge: MeerKAT Catches a Ghostly Glow
The galaxy cluster RXC J0528.9−3927 is like a city shrouded in fog: at its center, a radio halo shines brightly, but farther out, beyond the usual boundaries, astronomers have spotted a barely visible glow. It stretches for two million light-years — three times farther than the halo itself.
General Relativity2026-08-102 minarXiv:2608.09811express
How Light Particles Put the Brakes on Black Holes
A black hole is like a spinning top that never stops on its own. But if a cloud of ultra-light particles, bosons, forms around it, the picture changes. This "fog" acts like an invisible brake: the particles drain the hole's spin, slowing it down.
HEP Experiment2026-08-091 minarXiv:2608.08592express
A Detector That Can Hear the Universe's Whisper
The universe is constantly sending us signals, but many are too faint to notice. Relic neutrinos, particles left over from the Big Bang, pass through Earth by the billions every second, yet catching even one is a feat on the edge of possibility. We need a detector that can sense energy a thousand times smaller than what it takes to move a speck of dust.
General Relativity2026-08-072 minarXiv:2608.07237express
How Gravitational Waves Expose Black Hole Impostors
Drop two stones of different shapes into a pond — the ripples will tell you which one was smooth and which was jagged. Gravitational waves work the same way: when two ultra-dense objects merge, the trembling of spacetime carries details about their inner workings.
High Energy2026-08-072 minarXiv:2608.07391express
Gravitational Echoes of Dying Stars
The calm surface of a lake suddenly ripples — somewhere in the depths, an underwater cliff has collapsed. The water trembles almost imperceptibly, and the circles spread wider and wider until they reach a bobber near the shore.
General Relativity2026-08-072 minarXiv:2608.07237express
How Gravitational Waves Expose Black Hole Impostors
Drop two stones of different shapes into a pond — the ripples will tell you which one was smooth and which was jagged. Gravitational waves work the same way: when two ultra-dense objects merge, the trembling of spacetime carries details about their inner workings.
Cosmology2026-08-072 minarXiv:2608.07470express
General Relativity2026-08-061 minarXiv:2608.05974express
A Gravitational Needle in a Haystack
Imagine a quiet room where you need to pick out a single melody among many barely audible rustles. That's roughly what it's like to search for signals from extreme systems of two black holes — one huge, the other millions of times smaller.
High Energy2026-08-052 minarXiv:2608.04628express
Radio Pulsars in the Crosshairs of a Space-Based Gravitational-Wave Detector
Somewhere in the depths of the Milky Way, radio pulses flare up from time to time — rare, steady, like the ticks of a distant metronome. These long-period radio transients were discovered only recently, and they immediately puzzled astronomers.
High Energy2026-08-052 minarXiv:2608.04628express
Radio Pulsars in the Crosshairs of a Space-Based Gravitational-Wave Detector
Somewhere in the depths of the Milky Way, radio pulses flare up from time to time — rare, steady, like the ticks of a distant metronome. These long-period radio transients were discovered only recently, and they immediately puzzled astronomers.
Cosmology2026-08-041 minarXiv:2608.03739express
The Universe's Memory of Gravitational Waves
A gravitational wave from a black hole merger is like a bell tolling in the night. The loudness tells you how far away the source is. But to learn how fast the night itself, the cosmos, is expanding, you usually need a second signal: a flash of light or a catalog of galaxies. Both are rare to catch.
Cosmology2026-08-041 minarXiv:2608.03739express
The Universe's Memory of Gravitational Waves
A gravitational wave from a black hole merger is like a bell tolling in the night. The loudness tells you how far away the source is. But to learn how fast the night itself, the cosmos, is expanding, you usually need a second signal: a flash of light or a catalog of galaxies. Both are rare to catch.
High Energy2026-08-031 minarXiv:2608.02747express
Star Explosions Sing on Two Frequencies
When a star many times heavier than the Sun dies, it collapses and explodes as a supernova. This is not just a flash of light — the entire process, from core collapse to the ejection of the outer layers, makes space itself tremble. These ripples are called gravitational waves.
High Energy2026-08-032 minarXiv:2608.01634express
How to Catch the Gravitational Tremor of a Dying Star
At the end of a massive star's life, its core collapses in a fraction of a second, giving birth to a supernova flash. This cataclysm shakes spacetime itself, emitting gravitational waves — ripples that race across the Universe.
General Relativity2026-08-021 minarXiv:2608.01118express
Invisible Cracks in Gravity
In 2017, detectors picked up a gravitational wave from the collision of two neutron stars. Just 1.7 seconds later, telescopes saw a flash of gamma-ray burst from the same spot. That tiny delay became a treasure for physicists.
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.
HEP Phenomenology2026-07-311 minarXiv:2607.29388express
Magnetic Hearing at Kilohertz Frequencies
A bell rings not from the strike but from a fleeting shudder of space. A gravitational wave, like ripples on a pond, passes through a massive magnet, and it deforms ever so slightly. That deformation can be turned into an electrical signal.
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.
General Relativity2026-07-272 minarXiv:2607.24938express
How a Disk Around a Black Hole Alters Its Tidal Signature
Two neutron stars whirl in a close dance, each feeling the tidal field of its partner. It's like the Moon raising oceans on Earth, but here it's spacetime itself and the star's matter that deform. Astrophysicists call this tidal deformation — a measure of how much an object 'bends' under the gravitational pull of its companion.
Digital Conductor of Gravitational Waves: Neural Network Conducts Black Hole Mergers
In September 2015, two four-kilometer laser beams compressed by a thousandth of a proton — the LIGO interferometry detectors caught a gravitational waves for the first time. Its source turned out to be the merger of two black holes 1,3 billion light-years away.
Cosmology2026-07-262 minarXiv:2607.23646
Inflation's Electric Solo: How Charged Fields Leave a Chord in Gravitational Waves
In the first 10⁻³⁵ seconds after the big bang, the most rapid part unfolded. Space expanded faster than light — that's expansion of the universe (inflation). Almost the entire score was performed by a single field, the inflaton, conducting the tempo and key.
Cosmology2026-07-262 minarXiv:2607.23527
Wind from Cygnus: First Directional Limits from MIMAC
264 kilometres per second — that's how fast the Solar System hurtles through the cloud of dark matter. Its existence was given away by galaxies: they spun too fast to be held by visible mass, and Vera Rubin was first to suspect a hidden scaffolding.
Cosmology2026-07-233 minarXiv:2607.21834
Cosmic Funhouse Mirror: The Mystery of Signal GW231123
On November 23, 2023, LIGO detectors caught something strange. The gravitational wave signal from a black hole merger, designated GW231123, pointed to record masses—137 and 101 solar masses, and anomalously fast spin. That would be the most massive and fastest-spinning pair ever detected.
General Relativity2026-07-221 minarXiv:2607.19814express
How to Catch a Mirror's Tremor
You're listening to the faint whisper of stars, and nearby someone keeps moving a chair. In gravitational wave telescopes, that role is played by scattered light: it reflects off trembling surfaces and creates false signals.
Cosmic Iceland Spar: When Gravitational Waves Double
A thousand years ago, Vikings took Iceland spar to sea. The translucent crystal split light into two rays. By their brightness, they could find the sun even in fog. Birefringence — the physical term for this phenomenon — now helps hunt for the most elusive force in the cosmos.
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.
Quantum Physics2026-07-201 minarXiv:2607.18351express
Gravity on the Edge of Quantum
Two tiny weights, each about the mass of a grain of sand, hang in the dark at a temperature colder than deep space. They don't touch, but an invisible thread connects them — gravity. The experiment physicists are now building aims to catch the moment when that thread tugs one weight due to the motion of the other.
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.
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.
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.
Atomic Physics2026-07-182 minarXiv:2607.16913express
Laser Shower for Molecules: 12 Times the Catch
Catching a single molecule in a beam of light and nearly stopping its motion is like trying to hold a dandelion fluff in a gust of wind. A particle that's too hot slips out of the trap, so physicists first tame its thermal jitters with laser cooling. The authors applied a technique called Sisyphus cooling to strontium hydroxide (SrOH) molecules.
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.
Cosmology2026-07-173 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.