Readers discuss dark energy, Ötzi’s tattoos and sneaky plant invasions

Secrets of space New data hint that dark energy’s density, commonly thought to remain constant, might vary over time, Emily Conover reported in “3-D map hints at dark energy’s secrets” (SN: 5/4/24 & 5/18/24, p. 6). In the standard picture of the cosmos, the amount of dark energy is increasing as the universe expands. Reader […]Science News