April 4, 2026
Galaxies ghosting gravity
Astronomers Find a Third Galaxy Missing Its Dark Matter
Reddit splits: “Team Dark Matter” victory laps while “Team MOND” cries foul over ghost galaxies
TLDR: Astronomers report a third faint galaxy with little or no dark matter, backing a high-speed “Bullet Dwarf” crash idea. Comments split between dark matter fans celebrating, MOND loyalists pushing back, and curious onlookers asking if invisible “dark galaxies” could reveal themselves by bending background light.
Space gossip alert: astronomers say they’ve found a third ghostly galaxy, NGC 1052-DF9, that seems to be missing dark matter—the invisible stuff that usually helps hold galaxies together. The Yale-led team dropped a fresh preprint on arXiv, stacking DF9 onto the weird lineup with DF2 and DF4, and the comments lit up like a supernova.
Fans of dark matter are doing victory laps, pointing to DF2’s earlier measurements (later backed by Hubble) and cheering this new find as more proof that dark matter is a real thing you can separate from normal matter. MOND supporters—who think gravity changes its behavior at low accelerations—came in hot, re-litigating old distance debates and asking if this is really the nail in MOND’s coffin. The drama is delicious: it’s “Team Particle” vs “Team New Law,” with Sabine Hossenfelder’s explainer videos getting passed around like popcorn (link).
Meanwhile, the meme machine went brrr. The “Bullet Dwarf” collision theory got rebranded as cosmic Mario Kart—two baby galaxies smash, dark matter halos ghost through, and you’re left with airy, see-through star smudges. One user cracked that Zwicky should’ve named it “Gravimagic,” while another asked if there are totally invisible “dark galaxies” out there, detectable only if they lens background light. The vibe: equal parts science fight, dad jokes, and genuine awe at a universe that might be ghosting its own rules.
Key Points
- •A Yale-led team reports NGC 1052-DF9 as a third ultra-diffuse galaxy apparently lacking dark matter.
- •DF9 aligns with DF2 and DF4 in a linear “tail,” suggesting a shared origin from a single event.
- •DF2’s 2018 discovery showed low stellar velocities consistent with Newtonian gravity, challenging MOND expectations.
- •Hubble observations confirmed DF2’s distance after initial disputes, supporting the dark-matter-deficient interpretation.
- •The “Bullet Dwarf” collision scenario is proposed to explain separation of dark and normal matter, creating dark-matter-poor galaxies.