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What if a galaxy could exist without the brilliant stars that normally make galaxies visible? Cloud-9 may offer astronomers one of the most intriguing examples yet. Located near the spiral galaxy M94, this mysterious hydrogen-rich object appears to contain enormous amounts of gas while producing almost no detectable starlight.

Astrophysicists have completed ASTRID, the largest cosmological hydrodynamic simulation ever run, tracing the universe from the cosmic dawn ($z=99$) down to the present day ($z=0$). By resolving 166 billion particles across 815 million light-years, ASTRID unveils how supermassive black holes co-evolve with galaxies and sculpt the cosmic web.

Scientists have uncovered the first robust evidence of a black hole and neutron star crashing together while orbiting in an oval path, challenging long-standing assumptions about cosmic pair formation. Most neutron star-black hole pairs are expected to adopt circular orbits long before merging, their orbits slowly rounded out by the constant emission of gravitational waves over millions of years.

Far from the warmth of any star, moons orbiting rogue gas giants might harbor oceans of liquid water—and potentially complex life—for billions of years. Liquid water is considered essential for life. Surprisingly, however, stable conditions that are conducive to life could exist far from any sun.

Look up on a clear night and you'll see the streaks of our modern satellite networks. What you don't see is the growing fallout for the atmosphere that keeps us alive. A wave of satellite launches and reentries is changing the chemistry and physics of the middle and upper atmosphere. Studies warn of ozone depletion, stratospheric heating, and new metal aerosols from burning spacecraft.