Planck Space Observatory (2009–2013)

ESA's Planck Space Observatory mapped the cosmic microwave background radiation with unprecedented precision, refining the universe's age to 13.8 billion years and measuring the Hubble constant to 67.4 km/s/Mpc. Its data reveals temperature fluctuations as small as one part in 100,000, seeding all cosmic structure. This accuracy surpasses #8 COBE's resolution by over 100-fold, solidifying Planck's role as the definitive benchmark in modern cosmology.