Accelerating Universe Expansion (Dark Energy)
1998The discovery that the expansion of the universe is accelerating rather than decelerating under gravity alone, implying a mysterious repulsive component ("dark energy") makes up roughly 68% of the universe's total energy density. Established independently by two competing teams measuring the brightness/redshift relation of distant Type Ia supernovae: the Supernova Cosmology Project (Saul Perlmutter, work begun 1988) and the High-Z Supernova Search Team (Brian Schmidt, work begun 1994, joined by Adam Riess). Riess et al. submitted first (Astronomical Journal, March 13 1998, published Sept 1998); Perlmutter et al. followed (Astrophysical Journal, 1999). Jointly named Science magazine's 1998 "Breakthrough of the Year." Perlmutter, Schmidt, and Riess shared the 2011 Nobel Prize in Physics "for the discovery of the accelerating expansion of the universe through observations of distant supernovae." Independently significant on its own terms as one of the most consequential empirical results in modern cosmology, admitted here on that basis -- not merely as a target for any one enablement edge (docs/APPLIED_BASIC_ENABLEMENT_ADMISSION.md Sec 2 criterion 2).
Originators
- Supernova Cosmology Project
- High-Z Supernova Search Team
Landmark Paper
Checked 2026-09-19 — interim signal only, see docs/BASIC_ROADMAP.md Phase 10
Enabled By
- Charge-Coupled Device (CCD) (1969)Scientific Instrumentationbasis: empirical
Passes all four criteria of docs/APPLIED_BASIC_ENABLEMENT_ADMISSION.md Sec 2: (1) temporal ordering -- CCD 1969 precedes the 1998 discovery; (2) both nodes independently admitted on their own merits, not created to manufacture this edge; (3) named causal claim -- the Nobel Committee's own 2011 press release states "new digital imaging sensors (CCD, Nobel Prize in Physics in 2009)... opened possibilities for this groundbreaking research," a Nobel-committee-authored claim linking one Nobel-recognized technology directly to another; (4) counterfactual necessity -- corroborated independently of the Nobel text: NOIRLab's own CCD history documents that "the advent of CCD cameras enabled simultaneous photometric measurement across the entire focal plane and opened up... the massive surveys of type Ia supernovae that resulted in the discovery of cosmic acceleration," and the prior photographic-plate era lacked the quantum efficiency and linearity needed for the sub-percent photometric precision this measurement required at these distances. Third real Applied->Basic edge on this graph, and the first admitted via the formal test rather than ad hoc research.
Connections
No verified edges into the applied tree or elsewhere in Basic yet — never rendered as fabricated, just absent.