Scientist

Adam Riess

1969– · Cosmology, Astrophysics, Observational astronomy
American astrophysicist, laureate of the 2011 Nobel Prize for the discovery of the accelerating expansion of the Universe. He led the High-Z Supernova Search Team, which through observations of distant Type Ia supernovae proved that the expansion is not slowing down but accelerating, leading to the concept of dark energy — a mysterious substance making up about 68% of the Universe.

Biography

Born in Washington, D.C. (USA). Graduated from the Massachusetts Institute of Technology, earned his doctorate at Harvard. Worked at the University of California, Berkeley, the Space Telescope Science Institute, and Johns Hopkins University. Collaborated closely with Brian Schmidt; the project competed with Saul Perlmutter's team. Nobel Prize in Physics (2011), Shaw Prize, and other awards.

Key discoveries

💡 At the beginning of the project, many were skeptical about the accuracy of measurements based on supernovae. Riess and his colleagues used data from the Hubble Space Telescope and ground-based observatories; their race with Perlmutter's team became one of the most dramatic in astrophysics. The discovery of acceleration spawned thousands of papers and made dark energy one of the biggest mysteries in physics.
"He considered that the Universe sometimes proves to be more intricate than expected, and that this is the most thrilling moment for a scientist."
Concepts
dark energyexpansion of the universesupernovagalaxyHubble Space Telescope
Laws
Hubble's law
Scientists
Subrahmanyan ChandrasekharFred HoyleJohn Archibald WheelerEmmy NoetherChristian DopplerSaul PerlmutterMaarten SchmidtBrian Schmidt

Related articles

Geophysics2012-12-272 minarXiv:1212.6394
The Salt Chronicle of the Messinian Crisis
A rock chronicle where each layer is a page, and spectral analysis reads the rhythm of the lines. In the Realmonte salt mine in Sicily, geologists measured the thickness of 120 three-part cycles: a millimeter-scale clay parting, a thin anhydrite or polyhalite layer, and then a decimeter-scale halite bed.
Percolation as a Precursor to Transition
In 1988, the surface temperature of the Pacific Ocean began to change long before meteorologists declared the onset of El Niño. Points on the map scattered along the equator started behaving in concert: if water warmed in one place, it did so in a neighboring one too.
The String Theory Swampland: Why de Sitter Vacua Don't Live Here
The universe is expanding faster and faster, and the standard explanation is a positive cosmological constant, that is, a de Sitter vacuum. String theory, which aspires to be the theory of quantum gravity, should be able to describe such a vacuum, but after decades of effort, no reliable construction has emerged.
The Invisible Conductor of the Super-Puff Planet System
The three planets in the Kepler-51 system have long intrigued astronomers: they are Saturn-sized but less dense than water. These 'super-puff' worlds, with masses no more than ten Earths, are like cosmic dandelions — massive yet almost weightless. Their orbits are arranged like musicians in an orchestra, each playing its part, beating the rhythm with transits.
X-ray shell reveals supernova explosion in microquasar SS 433
North of the microquasar SS 433, an arc has emerged in the soft X-ray band. Faint and diffuse, yet stubbornly tracing contours already familiar from radio observations. Astronomers studied its spectrum and saw gas heated to eleven million kelvin. Gas that could not have been heated by the jets or the accretion disk wind.
Stellar2025-01-213 minarXiv:2501.12478
Fast Stars as Probes of the Galaxy
The Solar System takes 210 million years to complete one orbit around the center of the Milky Way. The last time we were on this same side of the Galaxy, early dinosaurs were roaming the Earth. That number, 243.72 km/s, has now been refined thanks to rare stars that streak through the Galaxy like cannonballs.
Galaxies2025-04-182 minarXiv:2504.13409
Five Questions Physics Asks Philosophy
At night, an astronomer points a telescope at the edge of the visible universe and sees not stars but ripples — the imprint of the first moments. He knows these ripples should obey statistics, like the heights of people in a crowd. But he has only one crowd, and nothing to compare it with. This is cosmic variance.
Cosmic Tango: How Spins Dance with Dark Matter
Among the fundamental symmetries of nature, mirror parity holds a special place. The Standard Model already knows one violation of it, in the weak interaction, but hypothetical long-range forces that don't conserve left and right could reveal a lot about dark matter.
Quantum Physics2025-06-031 minarXiv:2506.02637express
Pilot droplets: a new look at quantum reality
In the quantum world, particles do not have precise properties until they are measured. The official model refuses to explain what lies behind this uncertainty. But the idea that invisible 'pilots' control particles has been around since the 1920s.
The Universe in a Gas Trap: How to Tell Inflation from a Bounce
In the first moments after the Big Bang, the Universe underwent rapid expansion: inflation. But perhaps it was contracting before that, and then bounced. Both scenarios leave nearly identical imprints on the cosmic microwave background, and cosmologists have debated for decades which one is correct.
Mesoscale2025-06-043 minarXiv:2506.04335
Electronic Gravitational Lensing in Quantum Materials
An electron gliding over invisible hills and valleys created by a spin texture: that is the picture behind a new chapter in condensed matter physics. In quantum materials where the direction of localized spins varies smoothly (a spin texture), an electron is no longer just a particle flying through the lattice.
HEP Phenomenology2025-06-131 minarXiv:2506.11806express
Particle Masses: A Simple Rule from the Depths of Physics
In the boiling broth of the newborn Universe, all particles lost their distinctions, like vegetables at hellish temperatures. Recovering that simple recipe is the goal of modern physics. The SO(10) theory — an extension of the Standard Model — offers such a recipe. It unifies all forces and links the masses of any particles with a single formula.
Quantum Corrections to Van der Waals Black Holes: Universality and Topology
A black hole in anti-de Sitter space is not a void but rather a pot of boiling liquid. This liquid has two phases: small and large black holes, like steam and water. At a certain pressure, they merge at a critical point, just as water at 374 °C and 218 atmospheres loses the distinction between liquid and gas.
Lightning in the Heart of a Galaxy
A radio telescope catches a signal lasting a few milliseconds, and in that instant, energy comparable to what the Sun emits over days is released. This is a fast radio burst, a millisecond radio pulse from a distant galaxy. Since their discovery in 2007, astrophysicists have debated what causes them.
Galaxies2025-08-052 minarXiv:2508.03842
The First Spark in a Dark Room: LAP1-B and Population III Stars
In the dark room of the early Universe, the first spark flickered. A few hundred million years after the Big Bang, when space was filled only with hydrogen and helium, Population III stars were born: metal-free giants whose light first tore through the primordial darkness.
Cosmology2025-08-132 minarXiv:2508.09965
Primordial Black Holes in Giant Costumes
In April 2023, the LIGO, Virgo, and KAGRA detectors caught a gravitational wave from the merger of two black holes. With masses of 137 and 103 solar masses, GW231123 became the most massive event ever observed.
Cosmology2025-08-142 minarXiv:2508.10514
The Universe's Rhythm: Dark Energy May Be Falling Out of Step
The universe is expanding, and the pace of that expansion is set by dark energy, the mysterious force accelerating the recession of galaxies. In the standard cosmological model, its density is constant: a cosmological constant, an unwavering metronome since the birth of the cosmos.
Listening to Black Mirrors with Gravitational Radiation
An ordinary black hole is the perfect devourer: everything that crosses its horizon disappears forever. But in recent decades, this picture has been cracking at the seams. The information paradox, singularities, firewalls: theorists are looking for a way out, and one candidate replacement is the black mirror.
Twisted Light Reveals a Black Hole's Charge
The Event Horizon Telescope looks at M87* and sees more than just a ring of light around a dark void. That light is twisted, like a corkscrew. The wavefront carries a helical structure that physicists call orbital angular momentum.
Starquake Unleashes a Storm
A magnetar's crust cracks in milliseconds. A deep shift generates seismic waves that run across the surface and shake the magnetic field. This starquake is like an earthquake, but on a neutron star with a field a quadrillion times stronger than Earth's.
Cosmology2025-08-264 minarXiv:2508.19217
Magnetic Birth of Primordial Black Holes: Dark Matter from the Early Universe
The Universe after the Big Bang was almost perfectly homogeneous. Almost, because tiny density perturbations stretched by inflation became the seeds of galaxies. But what if these same perturbations could give birth not only to stars but also to black holes?
Galaxies2025-08-272 minarXiv:2508.19643
An Invisible Stone in the Stellar Pond
Someone has thrown an invisible stone into the stellar pond of the Milky Way. The ripples spread not through water but through the motion of stars: in a region 200 by 50 parsecs across, their average vertical velocity is 7 km/s lower than that of their neighbors. The deviation is statistically significant at the 6σ level, so chance cannot explain it.
Titanate Clouds Above a Scorching Giant
The dayside of WASP-121b is scorching at 2358 kelvins, hotter than the surface of many stars. Here, in perpetual light, the atmosphere does not just boil: it melts rock and turns it into gas. But not all gas stays gaseous. Some condenses into clouds, and those clouds hide titanium the way a trap hides its prey.
Galaxies2025-08-294 minarXiv:2508.21678
Red dots versus blue excesses: two paths for black hole growth
Two houses with identical facades but different interior layouts: from the outside the V-shaped spectrum looks the same, but inside there are different light sources and different amounts of dust. That is exactly how the two populations of distant galaxies that astronomers have long confused appear.
A Dark Dimension in the Tritium Spectrum: How KATRIN Searches for a Fifth Dimension
An electron flies out of a tritium nucleus with an energy of 18.57 keV, leaving behind an invisible partner: a neutrino. If that neutrino has access to a fifth dimension, its mass splits into a whole tower of states, and each one takes its own bite out of the spectrum.
Galaxies2025-09-092 minarXiv:2509.08035
Luminous Gas Rivers: How Giant Galaxies Are Born
In the early Universe, just one and a half billion years after the Big Bang, three massive galaxies collided in a small volume of space. Their gravitational dance flung out giant streams of cold gas that stretched for 60 kiloparsecs, a distance twenty times the diameter of our Galaxy.
Strings That Don't Snap Right Away
A stretched string between two quarks doesn't pop instantly like a rubber band. It first vibrates, develops knots, and only then breaks, if it breaks at all. This isn't just a metaphor; it's an accurate description of what physicists call confinement: quarks are permanently locked inside hadrons, and the only way to separate them is to snap the flux tube that binds them.
Cosmology2025-09-112 minarXiv:2509.09472
Dark Matter Tuning Fork: How Axions Tune the Radio Sky
The ARCADE2 radiometer on a high-altitude balloon detected an excess radio emission, while the ground-based EDGES experiment found an anomalously deep trough in the hydrogen spectrum at 21 cm. Both signals do not fit the standard cosmological model and point to an unknown source of soft photons.
Cosmology2025-09-113 minarXiv:2509.09665
A Ladder with No Top Rung: Cepheids vs. Supernovae
The cosmological community has been living in a state of quiet civil war for several years. Two camps measure the expansion rate of the Universe and get different answers. Planck, peering at the cosmic microwave background, says 67.4 km/s/Mpc. SH0ES, climbing the distance ladder from Cepheids to supernovae, insists on 73.2.
Hydrogen Hidden in the Depths of a Sub-Neptune
A young sub-Neptune is a pressure cooker where hydrogen and rock simmer in the same pot. Six Earth masses, three percent hydrogen by mass, and interior temperatures above 4000 K. At that heat, silicate melt and hydrogen don't just coexist: they mix completely, forming a single supercritical fluid. There is no boundary between core and envelope.
Cosmology2025-09-172 minarXiv:2509.13654
The Universe's Hall of Mirrors: Light That Twists
The ACT telescope in Chile's Atacama Desert stared at the sky from 2007 to 2022. Its target: the cosmic microwave background, light that has been traveling toward us for 13.8 billion years. This light is polarized: its waves oscillate in specific planes, like strings stretched in different directions.
A Radio Receiver for the Whisper of an Invisible Field
Deep inside a cryostat, beneath layers of superconducting coils, lies a stack of hundreds of semiconductor layers. Each layer is just a few nanometers thick: gallium arsenide, then aluminum gallium arsenide. The electrons within these layers are confined to a plane, like ants on a sheet of paper.
A Faint Breeze That Chooses a Snowflake's Shape
A snowflake falling from a cloud chooses between a left-handed and a right-handed form. The difference between them is almost imperceptible, like a breath of wind, yet it is that very breath that decides which pattern will grow.
A Traveling Line: How Photons Lose Energy in a Crowd of Electrons
On October 9, 2022, detectors on Earth recorded a gamma-ray burst of unprecedented power. GRB 221009A was so bright that its radiation ionized the upper layers of the ionosphere, and satellite instruments were temporarily blinded.
Galaxies2025-09-182 minarXiv:2509.14983
A Cosmic Magnifying Glass with an Invisible Handle
The light from a distant galaxy split into two, then three, then four, and in the center a fifth ghost appeared. That is HerS-3: a young galaxy full of dust and newborn stars, whose light passed through a gravitational lens, a massive object that bends rays like a magnifying glass bends light.
The Quiet Supernova: Why Pa 30 Is Silent in Radio
In 1181, Chinese and Japanese astronomers recorded the appearance of a 'guest star', a bright object that shone for six months in the constellation Cassiopeia and then vanished. Today, that spot hosts Pa 30: a nebula with a hot central source ejecting material at 16,000 km/s.
A 160-Millisecond Beacon: The Birth of a Magnetar in a Gamma-Ray Burst
Gamma-ray burst 230307A lit up the sky like a thunderclap: in seconds, it released more energy than the Sun will emit over billions of years. Three detectors—GECAM-B, GECAM-C, and Fermi/GBM—were looking in the right direction at that moment.