The Dark Energy Spectroscopic Instrument (DESI) has finished its originally planned five-year survey, producing the most detailed three-dimensional map of the universe to date. Completed ahead of schedule on April 14–16, 2026 at Kitt Peak National Observatory in Arizona, DESI has recorded spectra for more than 47 million galaxies and quasars and over 20 million stars using 5,000 fiber-optic positioners on the Nicholas U. Mayall 4‑meter telescope. Managed by Lawrence Berkeley National Laboratory, the international collaboration of roughly 900 researchers exceeded initial targets of 34 million objects and will continue observations and possible upgrades into the late 2020s. The dataset—covering tens of thousands of square degrees and spanning billions of years of cosmic history—provides precise redshifts essential for baryon acoustic oscillation and other probes of cosmic expansion. Early DESI results from year-one data hinted that dark energy may be evolving rather than constant; the full five-year survey will allow that signal to be tested. Processing and validation of the full dataset are underway, with first papers based on the complete survey expected in 2027 and further public releases to follow.

Blue Origin’s New Glenn rocket completed its third flight on April 19, 2026, marking the company’s first reuse of an orbital-class first stage. The booster, nicknamed “Never Tell Me The Odds,” successfully landed on the company droneship Jacklyn after liftoff from Cape Canaveral, Florida, at about 7:25 a.m. EDT. The mission carried AST SpaceMobile’s BlueBird 7 — a 2,400-square-foot direct-to-cellphone communications satellite — but the rocket’s upper stage placed the payload into an off‑nominal, lower-than-planned orbit. AST SpaceMobile confirmed the satellite powered on but said its on‑board thrusters could not raise it to an operational altitude and that the craft will be de‑orbited; the company expects the loss to be covered by insurance and said replacement satellites are in production. Blue Origin acknowledged the off‑nominal insertion and said it is assessing the anomaly. The mixed outcome — a milestone for booster reuse paired with a mission‑critical upper stage failure — will prompt investigations and could influence customer confidence and launch manifest planning for both Blue Origin and its commercial partners.

The annual Lyrid meteor shower will peak in moonless skies overnight April 21–22, 2026, offering skywatchers a good opportunity to see fast, bright meteors and occasional fireballs. The Lyrids run April 14–30 and typically produce about 10–20 meteors per hour under ideal, dark-sky conditions; some outlets cite peak rates of 15–20 per hour. The shower’s radiant lies in the constellation Lyra near the bright star Vega. This year’s favourable timing — with a new moon on April 17 leaving dark pre-dawn hours for the peak — should improve visibility, especially across Northern Hemisphere latitudes. The Lyrids originate from debris shed by Comet C/1861 G1 (Thatcher), a long‑period comet with an ~415‑year orbit. Historical outbursts have occasionally produced much higher rates, but such spikes are rare and unpredictable. Recommended viewing advice includes finding a dark, unobstructed site, allowing 20–30 minutes for night‑vision adaptation, facing away from city lights, and scanning wide areas of sky rather than staring at the radiant.

A new wave-physics model developed by researchers at MIT predicts that gentle breezes on Saturn’s moon Titan could generate waves up to about 3 metres (10 feet) high on its hydrocarbon lakes. The model, dubbed PlanetWaves, extends traditional wind-wave theory by incorporating atmospheric pressure and the liquids’ properties—density, viscosity and surface tension—then was validated against 20 years of Lake Superior buoy data. Low gravity (about 14% of Earth’s) and the light nature of methane-ethane mixtures mean modest winds can build large, slow-moving swells over long fetches. The result helps reconcile Cassini’s largely smooth radar returns with geomorphic evidence for shoreline erosion and transient radar-bright patches observed in some flybys. Lead authors including Una Schneck and collaborators Andrew Ashton and Taylor Perron note the findings matter for interpreting Titan’s coastal features and for engineering any future lake-going or floatation probes; they also have implications for modeling waves on other worlds and some exoplanet scenarios.

Using 18 years of very long baseline interferometry (VLBI) radio observations, an international team has for the first time derived a real-time measurement of the kinetic power and speed of jets from the stellar-mass black hole Cygnus X-1. The system — a ~21-solar-mass black hole orbiting a ~40-solar-mass O-type star, HDE 226868 — shows jets bent repeatedly by the companion’s fierce stellar wind. By modelling the wind’s ram pressure and matching the observed jet deflection, researchers infer an instantaneous kinetic power of roughly 2×10^37 ergs per second (often translated as the equivalent output of ~10,000 Suns) and a jet speed near half the speed of light. The study finds the jets carry about 10% of the accretion energy. Results are reported in Nature Astronomy and rely on data from the European VLBI Network and collaborators including the International Centre for Radio Astronomy Research.

Blue Origin’s New Glenn rocket launched from Cape Canaveral on April 19, 2026, achieving the company’s first reuse of a New Glenn first stage but failing to place its customer payload into the intended orbit. Liftoff occurred at about 7:25 a.m. EDT; the booster — nicknamed “Never Tell Me The Odds” — successfully returned to and landed on the droneship Jacklyn. AST SpaceMobile’s BlueBird 7 satellite separated and powered on, but Blue Origin and AST said the upper stage placed it into a lower-than-planned, off-nominal orbit. AST SpaceMobile said the altitude is too low for the satellite’s on‑board thrusters to correct and the craft will be de‑orbited; the firm expects the financial loss to be covered by insurance. BlueBird 7 is one of AST’s large “Block 2” direct-to-cellphone relay satellites, featuring a roughly 2,400 sq ft phased-array antenna and intended to expand the company’s space‑based cellular broadband constellation. Both companies have opened investigations; Blue Origin is assessing the second‑stage performance and the implications for future New Glenn missions, including planned launches tied to NASA and Blue Origin’s lunar lander program.