Popular

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.
Quote: "Sometimes the Universe turns out to be trickier than we think, and that is the most exciting moment for a scientist."
Links in the knowledge graph 1
Related tags
dark energyexpansion of the universesupernovagalaxyHubble Space Telescope
Related laws
Hubble's law
Related scientists
Subrahmanyan ChandrasekharFred HoyleJohn Archibald WheelerEmmy NoetherChristian DopplerSaul PerlmutterMaarten SchmidtBrian Schmidt

Related articles

A Black Hole with Three Event Horizons: A New Recipe

A new model combines loop quantum gravity and dark energy, giving birth to a black hole with a triple horizon. This layered structure affects the shadow, vibrations, and light deflection, promising to become a key to testing quantum gravity and the nature of the universe's accelerating expansion.
arXiv:2505.12291 · 2025-05-18

The Universe's Secret Phase: How the Dark Sector Reconciled the Astronomers

The universe is expanding, but measurements of its speed give conflicting numbers. This puzzle is called the Hubble tension. A new model suggests that in the early universe, a phase transition occurred in a hidden dark sector. It’s like the sudden freezing of supercooled water: a burst of energy was
arXiv:2508.03795 · 2025-08-05

Dark Energy: How a New Survey Changes the Picture

The DESI survey examined the motion of galaxies and supernovae, testing the constancy of dark energy. Faint signals point to its evolution, and the Mirage model gave the best but not definitive result. If the energy is indeed growing, the Universe could face a tearing apart of matter.
arXiv:2508.10514 · 2025-08-14

Cosmic Clocks Diverge: A New Mystery of the Universe's Expansion

A new study used only pulsating Cepheid stars to calculate the expansion rate of the Universe. The resulting value of 71.1 (km/s)/Mpc turned out to be lower than the previous 'gold standard' and even further from the Planck satellite data. This sharpens the 'Hubble tension' and suggests our knowledg
arXiv:2509.09665 · 2025-09-11

Dark Energy: Constancy Questioned

Recent observations of supernovae, galaxy distribution, and the Big Bang afterglow show that dark energy density is not constant. This challenges the standard cosmological model and promises a revision of the Universe's evolution.
arXiv:2509.17124 · 2025-09-21

Supernovae Point to a Changing Dark Energy

It was previously thought that Type Ia supernovae were reliable 'standard candles' for measuring distances, their brightness independent of age. New research shows: old stars produce dimmer explosions. This distorts the cosmic ruler. Correcting for age removes the discrepancy, and the data leans tow
arXiv:2510.13121 · 2025-10-15

Dark Energy Is Not Constant: A New Look at the Universe's Acceleration

Analysis of galaxy maps, quasar light, and supernovae shows that the simple model of constant dark energy is losing to a version with a smoothly changing force. This needs verification, but it's intriguing.
arXiv:2510.21976 · 2025-10-24

Black Holes Instead of Dark Energy

Researchers simulated how primordial black holes with a repulsive core accelerate the expansion of the universe. Ultra-light ones triggered inflation, while black holes with the mass of an asteroid and the size of a proton mimic early dark energy, resolving the famous discrepancy in the measurement
arXiv:2511.18080 · 2025-11-22

Dark Energy: Phantom or Illusion?

Observations show that dark energy in the early Universe behaved unusually, as if gaining strength. The KMIX model explains this as a visual trick, eliminating the 'Big Rip' scenario. A fast machine learning method helped compare the theory with data — and the result is encouraging.
arXiv:2511.23463 · 2025-11-28

Universe's expansion rate refined using supernova 'twins'

By comparing supernova 'twins', astronomers eliminated the effect of cosmic dust and arrived at a more precise expansion rate. It turned out higher than what observations of the early universe suggest. The 'Hubble tension'—as this discrepancy is called—has been confirmed, meaning our picture of the
arXiv:2512.02391 · 2025-12-02

The Twinkling of Quasars and the Variable Dark Energy

Astronomers noticed that the light of quasars flickers like a candle flame. By analyzing the flickering pattern, they can determine the quasar's true brightness and calculate its distance. This allowed them to peer into the Universe's past and see that dark energy may not have been constant over tim
arXiv:2512.07931 · 2025-12-08

Why Has Cosmology Cracked?

Different ways to measure the expansion rate, the properties of dark matter and energy, yield contradictions. Before changing physics, scientists are checking if their instruments are off. But increasingly it seems: the yeast is alive, and the recipe of the cosmos is not eternal.
arXiv:2601.01525v1 · 2026-01-04

Dark Energy as a Falling Pencil

New research explains dark energy as a loss of spatial equilibrium. A tiny dilaton field, born from that event, drives the repulsive push. It resolves the conflict in expansion rate measurements and hints at the cosmos's future trajectory.
arXiv:2601.01938v1 · 2026-01-05

Dark Dance: How Energy and Matter Swap Roles

Eight models of interaction between dark energy and dark matter fit observations better than the standard theory. Surprisingly, in the past, dark energy density could have been negative—like an energy debt in the dance. The finding refines the history of the expansion of the universe.
arXiv:2601.03122v1 · 2026-01-06

Dark Energy Controls the Weight of Dark Matter

Scientists have proposed that dark energy affects the mass of dark matter particles. This energy exchange accurately reproduces the observed expansion of the Universe and alters the growth of galaxy clusters by 10% — a difference that new telescopes will test. If the connection is confirmed, our und
arXiv:2601.05235v1 · 2026-01-08

Galaxy Rotation in Voids Tests Inflation

In giant cosmic voids, galaxies spin like a single ensemble. Their dance creates a barely noticeable difference in glow from different sides. It turns out that this effect is the most accurate indicator of how uniformly matter was foamed up at the moment of inflation. It is enough to measure it to f
arXiv:2601.06589v1 · 2026-01-10

Dark Energy: A Recipe with a Pinch of Salt

Analysis of DESI data showed that adding a tiny negative fraction to dark energy improves agreement with observations, making it almost perfectly constant. Like a pinch of salt in dough, this addition brings harmony to the universe's expansion.
arXiv:2601.06656v1 · 2026-01-10

The Universe Whispers: [tag:dark_energy]dark energy[/tag] is not alone

Scientists have long debated: is dark energy constant or does it change? Fresh measurements point to a third path — it is conversing with dark matter. This turns a lone cosmic force into a duet of invisible interlocutors.
arXiv:2601.07361v1 · 2026-01-12

Dark Energy as a Spring: A Model with No Tuning

Astronomers tested a model where dark energy is not a constant force, but a spring gradually losing its tension. The most surprising part: that same spring also explains dark matter, and all properties are set by fundamental theory without a single free parameter. Data from the DESI, Planck, and sup
arXiv:2601.08943v1 · 2026-01-13

Dark Dancers: When Dark Matter and Dark Energy Dance Together

The universe is expanding, but two measurement methods give different speeds—this puzzle was called the Hubble tension. Scientists have proposed a model in which dark matter and dark energy are not strangers but interact, like dance partners. This simple assumption smooths out the contradiction. Tes
arXiv:2601.19662 · 2026-01-27

Dark Energy Didn’t Kick In Right Away

The 'late-waking' dark energy model: the mysterious force lay dormant for the first few billion years, then suddenly kicked in later. Telescope data allow for such a scenario, and in some combinations, it’s even more likely than the standard one. Yet the biggest puzzle—the discrepancy in measuring t
arXiv:2603.13137 · 2026-03-13

Two Flavors of Early Dark Energy Ease Cosmic Tension

Adding a second type of early dark energy helps resolve a stubborn mismatch: the universe's expansion rate measured today versus the rate inferred from the Big Bang's afterglow. The two-ingredient model narrows the gap and fits the afterglow's fine details, hinting that the early universe was more i
arXiv:2604.13535 · 2026-04-15

The Conductor with a False Note: Why Quintessence Couldn't Save Inflation

The quintessential inflation model based on α-attractors describes inflation and modern dark energy as different roles of a single scalar field. Its key prediction is a kination stage, which amplifies high-frequency gravitational waves and leaves an imprint on the cosmic microwave background and pri
arXiv:2605.00735v1 · 2026-05-01

Ocean of Currents: Why the Universe's Acceleration Varies with Direction

What if the cosmic ocean expands unevenly? Using 1701 supernovae from Pantheon+, astrophysicists checked this and found a disturbing ripple — a dipole anisotropy in q0. But once they accounted for galaxies' peculiar velocities, the illusion almost dissolved. It's an artifact of our own drift, not ex
arXiv:2605.03004v1 · 2026-05-04

Waffle Structure of the Vacuum: From String Fluxes to Dark Energy

Researchers modified the classic Bousso–Polchinski model, representing vacuum energy as the difference of contributions in flux space. As a result, small values of the cosmological constant form not spheres, but the thinnest 'waffles' — hyperdisks. Analysis of a database of 532 million Calabi–Yau ma
arXiv:2605.05357v1 · 2026-05-06

Dark Energy Isn't Constant?

For a long time, dark energy was thought to be an unchanging force accelerating cosmic expansion. But the DESI instrument, by studying galaxy distributions, found that its influence has weakened by about 10% over billions of years. This undermines the foundations of the standard picture and paves th
arXiv:2605.10476 · 2026-05-11

Orbital Web: Why the Big Rip Will Wait at Least 30 Years

Cosmology allows for a terrifying scenario of phantom dark energy, where the universe's expansion accelerates so violently that it tears apart galaxies, stars, and atoms. Deep-space detectors can't spot a sudden shift to this state: light from distant supernovae has traveled billions of years. So Ro
arXiv:2605.13705v1 · 2026-05-13

Inflation and Dark Energy: One Cosmic Spring?

Calculations suggest: the same quantum field, if it is particularly sensitive to the curvature of space, could act both as the engine of inflation and as dark energy. To do this, the field must be nearly ten times heavier than the Planck mass — roughly like a speck of dust. This coincidence hints th
arXiv:2605.14729v1 · 2026-05-14

Cosmic Booster Solves the Hubble Riddle

The Universe is expanding, but measurements of the rate from early times and today disagree — this puzzle is called the Hubble tension. A new model introduces an invisible chameleon field that recently began nudging expansion further and adds invisible mass that holds galaxies together. Near Earth,
arXiv:2605.14977 · 2026-05-14

The Devourer Universe: Dark Energy from World Mergers

In a new cosmological model, the source of accelerated expansion is not a mysterious cosmological constant but the process of absorbing other universes. The merger intensity is set by a single constant g, calibrated by the local value of the Hubble constant. The computed evolution of the dark energy
arXiv:2605.15045v1 · 2026-05-14

Dark Energy Twice Went Unstable

Dark energy, which makes the Universe expand ever faster, twice briefly crossed stable boundaries — DESI observations revealed this. The model explains such behavior by interaction with dark matter particles: their coupling creates an illusion of violation, but the system remains stable. The theory
arXiv:2605.20060 · 2026-05-19

Black Hole Shrinks in an Expanding Universe

Scientists have for the first time combined a rotating black hole and the expansion of the Universe in a mathematical model. It turns out that in the inflating cosmos, its point of no return and the twisted region of space gradually shrink — even though the hole's mass remains unchanged. And mysteri
arXiv:2605.22895 · 2026-05-21

Is Dark Energy Changing? A Fresh Look

A new method allowed a direct measurement of dark energy's strength and found: it's weaker than expected, meaning it might change over time.
arXiv:2605.27230 · 2026-05-26

The Universe Doesn't Remember Its Youth: The Echo of Quantum Gravity Can't Be Caught

Cosmologists searched for the imprint of the tumultuous birth of the universe in galaxy distance data and the afterglow of the Big Bang. But all measurements fit perfectly into the standard model, with no 'memory'. If a trace exists, it's too faint for current instruments.
arXiv:2606.00227 · 2026-05-29

Light Leaks into Darkness: How Photons Become Dark Matter

Two key methods for measuring the expansion rate of the Universe — the cosmic microwave background and supernovae — yield values differing by 5 sigma. A hybrid model adds to the cosmological redshift a contribution from quantum conversion of photons into hidden mass. Analysis of the Pantheon+SH0ES c
arXiv:2606.02097v1 · 2026-06-01

The Cosmic Metronome Falls Out of Rhythm: Dark Energy Rewrites Hubble's Symphony

The DESI instrument, mapping millions of galaxies, has picked up signs of dark energy evolution. This discovery rewrites the rules for measuring the Universe's expansion rate: the local Hubble constant might drop by several km/s/Mpc. The drama of the Hubble tension — the discrepancy between the earl
arXiv:2606.05358v1 · 2026-06-03

The Dusty Truth: Why Supernovae Finally Spoke with One Voice

An international team led by Marco Giunto analyzed nearly a thousand Type Ia supernovae from the ZTF survey and showed that the differences in their color and brightness are almost entirely caused by dust in their host galaxies, not by the physics of the explosions themselves. This settles a long-st
arXiv:2606.06593v1 · 2026-06-04

Dark Matter's Invisible Sparks: Tiny Black Holes as Stellar Detonators

What if dark matter isn’t just passive, but can actually ignite stars? New research simulates white dwarf explosions triggered by the passage of a primordial black hole—a candidate for dark matter. Hydrodynamic simulations and nucleosynthesis calculations of 495 isotopes show that such Type Ia super
arXiv:2606.07505v2 · 2026-06-05

Quantum Trick Accelerates the Universe Without Dark Energy

The universe is expanding at an accelerating rate. Usually this is blamed on dark energy. But a new explanation is post-selection, a quantum trick where the future selects scenarios that suit it. This removes the mystery and explains why the acceleration started just now.
arXiv:2606.12297 · 2026-06-10

Early dark energy reconciles the different ‘thermometers’ of the Universe

Astronomers added a short-lived dark energy to the standard model, which appeared right after the Big Bang. This idea reconciled two methods of measuring cosmic expansion that previously gave different speeds—like two different thermometers. This approach strengthens the model without a major overha
arXiv:2606.19090 · 2026-06-17

Cosmic Tuning Fork: KLT-Net Neural Network Rewrites the Distance Ladder

Using 1701 Type Ia supernovae, the KLT-Net neural network reconstructs distance modulus for the first time without relying on cosmological models. The harmony of three architectures—KAN, LSTM, and Transformer—captures both local nuances and the global rhythm of expansion. The result: Hubble constant
arXiv:2607.06959 · 2026-07-08

Anchor in the Shallows: Why DESI Data Misses the Universe's Acceleration

Is the Universe accelerating its expansion—or not? The latest DESI survey, combined with Planck cosmic microwave background data, yields no clear answer for the current epoch, unlike older SDSS data. Researchers have shown that the root of the discrepancy is DESI's lack of measurements at low redshi
arXiv:2607.07348 · 2026-07-08

Dark Energy's Seesaw: A New Explanation for a Strange Signal

The mysterious force accelerating the universe turns out to be fickle. In a new model, dark energy is like steam that partially condenses into 'droplets' when cooled. Massive galaxy clusters act as refrigerators, their gravity creating pressure differences. This solves recent anomalies in supernova
arXiv:2607.08120 · 2026-07-09