Simons Observatory’s 6-meter Large Aperture Telescope in Chile’s Atacama Desert was set to begin surveying the sky in October 2026, Science reported on Oct. 14. Its target is the cosmic microwave background, light emitted about 380,000 years after the Big Bang. The observatory’s three smaller telescopes have a different task: looking for a possible imprint of cosmic inflation, a hypothesized burst of expansion in the universe’s earliest moments.
Two of the 0.5-meter small-aperture telescopes began observations almost two years before Science’s report; the third joined more recently. They study broad patterns in the light’s polarization that might contain swirls left by gravitational waves from inflation. Observatory spokesperson Jo Dunkley estimated researchers might see the swirls after about five years, though Science notes that some models suggest it could take longer.
The large telescope, meanwhile, is designed to make fine-scale maps of a large portion of the microwave background. Researchers hope to compare those early-universe patterns with the later distribution of matter to help constrain neutrino mass. Hot gas between galaxies also scatters microwave-background light, leaving distortions that can identify galaxy clusters. An earlier telescope at the site found thousands this way; Simons could detect as many as 40,000, . Observatory co-director Mark Devlin pointed to clusters in the early universe as a way to investigate how such large structures formed so soon.
