Planck (spacecraft) in the context of "Cosmic microwave background"

The cosmic microwave background (CMB, CMBR), or relic radiation, is microwave radiation that fills all space in the observable universe. With a standard optical telescope, the background space between stars and galaxies is almost completely dark. However, a sufficiently sensitive radio telescope detects a faint background glow that is almost uniform and is not associated with any star, galaxy, or other object. This glow is strongest in the microwave region of the electromagnetic spectrum. Its energy density exceeds that of all the photons emitted by all the stars in the history of the universe. The accidental discovery of the CMB in 1964 by American radio astronomers Arno Allan Penzias and Robert Woodrow Wilson was the culmination of work initiated in the 1940s.

The CMB is landmark evidence of the Big Bang theory for the origin of the universe. In the Big Bang cosmological models, during the earliest periods, the universe was filled with an opaque fog of dense, hot plasma of sub-atomic particles. As the universe expanded, this plasma cooled to the point where protons and electrons combined to form neutral atoms of mostly hydrogen. Unlike the plasma, these atoms could not scatter thermal radiation by Thomson scattering, and so the universe became transparent. Known as the recombination epoch, this decoupling event released photons to travel freely through space. However, the photons have grown less energetic due to the cosmological redshift associated with the expansion of the universe. The surface of last scattering refers to a shell at the right distance in space so photons are now received that were originally emitted at the time of decoupling.

In physical cosmology, the shape of the universe refers to both its local and global geometry. Local geometry is defined primarily by its curvature, while the global geometry is characterised by its topology (which itself is constrained by curvature). General relativity explains how spatial curvature (local geometry) is constrained by gravity. The global topology of the universe cannot be deduced from measurements of curvature inferred from observations within the family of homogeneous general relativistic models alone, due to the existence of locally indistinguishable spaces with varying global topological characteristics. For example; a multiply connected space like a 3 torus has everywhere zero curvature but is finite in extent, whereas a flat simply connected space is infinite in extent (such as Euclidean space).

Current observational evidence (WMAP, BOOMERanG, and Planck for example) imply that the observable universe is spatially flat to within a 0.4% margin of error of the curvature density parameter with an unknown global topology. It is currently unknown whether the universe is simply connected like euclidean space or multiply connected like a torus.

The Wilkinson Microwave Anisotropy Probe (WMAP), originally known as the Microwave Anisotropy Probe (MAP and Explorer 80), was a NASA spacecraft operating from 2001 to 2010 which measured temperature differences across the sky in the cosmic microwave background (CMB) – the radiant heat remaining from the Big Bang. Headed by Professor Charles L. Bennett of Johns Hopkins University, the mission was developed in a joint partnership between the NASA Goddard Space Flight Center and Princeton University. The WMAP spacecraft was launched on 30 June 2001 from Florida. The WMAP mission succeeded the COBE space mission and was the second medium-class (MIDEX) spacecraft in the NASA Explorer program. In 2003, MAP was renamed WMAP in honor of cosmologist David Todd Wilkinson (1935–2002), who had been a member of the mission's science team. After nine years of operations, WMAP was switched off in 2010, following the launch of the more advanced Planck spacecraft by European Space Agency (ESA) in 2009.

WMAP's measurements played a key role in establishing the current Standard Model of Cosmology: the Lambda-CDM model. The WMAP data are very well fit by a universe that is dominated by dark energy in the form of a cosmological constant. Other cosmological data are also consistent, and together tightly constrain the Model. In the Lambda-CDM model of the universe, the age of the universe is 13.772±0.059 billion years. The WMAP mission's determination of the age of the universe is to better than 1% precision. The current expansion rate of the universe is (see Hubble constant) 69.32±0.80 km·s·Mpc. The content of the universe currently consists of 4.628%±0.093% ordinary baryonic matter; 24.02%+0.88%
−0.87% cold dark matter (CDM) that neither emits nor absorbs light; and 71.35%+0.95%
−0.96% of dark energy in the form of a cosmological constant that accelerates the expansion of the universe. Less than 1% of the current content of the universe is in neutrinos, but WMAP's measurements have found, for the first time in 2008, that the data prefer the existence of a cosmic neutrino background with an effective number of neutrino species of 3.26±0.35. The contents point to a Euclidean flat geometry, with curvature (${\displaystyle \Omega _{k}}$) of −0.0027+0.0039
−0.0038. The WMAP measurements also support the cosmic inflation paradigm in several ways, including the flatness measurement.

The Geneva Observatory (French: Observatoire de Genève, German: Observatorium von Genf) is an astronomical observatory at Sauverny (CH) in the municipality of Versoix, Canton of Geneva, in Switzerland. It shares its buildings with the astronomy department of the École Polytechnique Fédérale de Lausanne. It has been active in discovering exoplanets, in stellar photometry, modelling stellar evolution, and has been involved in the European Space Agency's Hipparcos, INTEGRAL, Gaia, and Planck missions.

In 1995, the first exoplanet found orbiting a main-sequence star, 51 Pegasi b, was discovered by two scientists of the observatory, Michel Mayor and Didier Queloz, using the radial velocity method with the 1.9-metre telescope at Haute-Provence Observatory in France. Mayor and Queloz were awarded (half of) the Nobel Prize in Physics 2019 for this discovery.

SMACS J0723.3–7327, commonly referred to as SMACS 0723, is a galaxy cluster about 4 billion light years from Earth, within the southern constellation of Volans (RA/Dec = 110.8375, −73.4391667). It is a patch of sky visible from the Southern Hemisphere on Earth and often observed by the Hubble Space Telescope and other telescopes in search of the deep past. It was the target of the first full-color image to be unveiled by the James Webb Space Telescope (JWST), imaged using NIRCam, with spectra included, showing objects lensed by the cluster with redshifts implying they are 13.1 billion years old. The cluster has been previously observed by the Hubble Space Telescope (HST) as part of the Southern MAssive Cluster Survey (SMACS), as well as Planck and Chandra.

In 2022, in the field gravitationally lensed by SMAC 0723, some of the then most ancient massive star clusters were discovered in a lensed galaxy called the "Sparkler Galaxy".