European Space Agency
Every Cosmic Herald story on European Space Agency — missions, launches, discoveries, and the business of space, newest first.
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Astronomy
How Astronomers Measure Cosmic Distances: The Distance Ladder
No single method measures the universe. Astronomers climb a ladder — parallax, then pulsing Cepheid stars, then exploding white dwarfs, then redshift — each rung calibrating the next, and a crack near the top is now cosmology's biggest open problem.
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Astronomy
Euclid Doubles the Known Sample of the Universe's Most Ancient Quasars
ESA's Euclid telescope has found 31 new quasars from the cosmic dawn, including two record-breakers at redshifts 7.77 and 7.69, more than doubling the known sample from that era.
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Astronomy
Gaia Data Just Killed the 'Universal' Stellar Initial Mass Function
A Gaia-based survey of 110 Milky Way star clusters finds the stellar initial mass function's 'break mass' shifts with cluster age, undermining decades of assuming one universal recipe for how stars of different sizes form.
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Astronomy
Euclid Space Telescope Uncovers the Universe's Most Ancient Quasars
ESA's Euclid mission has spotted 31 quasars from the universe's first billion years, including two record-holders shining with a trillion Suns' worth of light just 670 million years after the Big Bang.
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Astronomy
Euclid Space Telescope Uncovers 31 Ancient Quasars, Two From the Universe's First 5 Percent
ESA's Euclid telescope has spotted 31 quasars from the early universe, including two dating to just 670 million years after the Big Bang, deepening a puzzle over how supermassive black holes grew so fast.
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Astronomy
X-ray Echoes of Dead Stars Nudge the Milky Way's Outer Arms Farther Out
Using dust-scattered X-ray light echoes from three gamma-ray bursts, astronomers re-measured two of the Milky Way's outer spiral arms and found them up to 10% farther from the galactic center than assumed.
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Astronomy
Hubble's 'Chandelier Cluster' Reveals Its Ancient Stars Formed in Two Separate Bursts
Hubble's June 2026 image of NGC 6723, the 'Chandelier Cluster,' shows its 10-billion-year-old stars formed in two closely spaced bursts — the second within 634 million years of the first — undercutting the old idea that globular clusters are single-age populations.
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Astronomy
Euclid's 60-Million-Star Portrait of the Galactic Bulge Lays Groundwork for Roman
Euclid's new visible-light mosaic of the Milky Way's crowded center packs 60 million stars across 22 Moons of sky — and quietly hands NASA's Roman telescope a two-year head start on its planet hunt.
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Astronomy
Asteroid 2026 JH2's Surprise Close Approach Exposes Detection Gaps in Planetary Defense
A 62-foot asteroid discovered just days before its closest approach demonstrates how near-Earth objects can slip past detection systems—and why autonomous surveys matter for planetary safety.
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Astronomy
Astronomers can't agree on how old the universe is. That's actually exciting.
Two different methods of measuring the expansion rate of the universe give two different answers — and the gap between them is too large to be a measurement error. Known as the Hubble tension, this disagreement might be pointing toward new physics that nobody has found yet.
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Astronomy
The Milky Way's skeleton is made of ghost stars — and Gaia is mapping every one
Gaia has revealed dozens of stellar streams threading through the galaxy — thin ribbons of stars from ancient satellite galaxies and globular clusters torn apart over billions of years. Astronomers are now reading them for evidence of dark matter and the Milky Way's violent past.
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Astronomy
Europe's 'dark universe detective' is building a 3D map of the invisible cosmos
Most of the universe is made of things we cannot see — dark matter and dark energy. ESA's Euclid telescope is surveying billions of galaxies across ten billion years of history to map that invisible scaffolding, with its first major cosmology data release due this October.
