Space missions and ground-based experiments that probe the cosmic microwave background and the early universe’s evolution.
The BICEP/Keck experiment is a series of South Pole telescopes searching for the faint polarization pattern in the cosmic microwave background that would signal primordial gravitational waves from cosmic inflation. While no direct detection has been made as of 2025, the experiment has set the tightest constraints yet on inflation models.
NASA’s Wilkinson Microwave Anisotropy Probe (WMAP) mapped the cosmic microwave background with unprecedented precision, transforming our understanding of the universe’s age, composition, and evolution. Its nine-year dataset confirmed the standard Lambda-CDM model and provided a detailed timeline from the first moments to the present day.
Ground-based cosmic microwave background (CMB) experiments such as the Atacama Cosmology Telescope (ACT) and the Simons Observatory measure the oldest light in the universe with extraordinary precision. This article explains how they work, what they reveal about cosmic history, and how they complement space missions like Planck.
The COBE satellite measured the cosmic microwave background (CMB) with unprecedented precision, confirming its perfect blackbody spectrum and detecting the tiny anisotropies that seeded galaxies. Its findings solidified the Big Bang model and opened the era of precision cosmology.
CMB-S4 was a planned next-generation ground-based observatory designed to map the cosmic microwave background with over 500,000 superconducting detectors. Although cancelled in July 2025, its science goals — testing inflation, measuring neutrino masses, and probing new light relics — remain central to modern cosmology.
The cosmic microwave background (CMB) is the oldest light in the universe, but it is contaminated by emissions from our galaxy and distant sources. This article explains the techniques astronomers use to separate the CMB signal from these foregrounds, and how these efforts reveal the universe’s earliest moments and subsequent evolution.
Baryon acoustic oscillations (BAOs) are a fossil imprint of sound waves in the early universe, appearing as a subtle clustering pattern in galaxy distributions. Galaxy surveys detect this pattern by measuring the correlation function or power spectrum, revealing a characteristic scale that serves as a standard ruler for cosmic expansion. This guide explains the detection method, its cosmic significance, and the full timeline of cosmic evolution from the Planck epoch to today.
Particle accelerators like the LHC and RHIC smash heavy ions at near-light speed to recreate the quark-gluon plasma that filled the universe microseconds after the Big Bang. These experiments let physicists probe the fundamental conditions of the cosmos, from the Planck epoch to the formation of the first atoms.
The first stars, known as Population III, ended the cosmic dark ages and seeded the universe with heavy elements. Observing them directly is one of astronomy’s greatest challenges because they are extremely distant, faint, short-lived, and their light is redshifted far into the infrared. This guide explains the obstacles, the cosmic epochs that set the stage, and how missions like JWST are pushing the observational frontier.
CMB-S4 was a proposed next-generation ground-based observatory designed to study the cosmic microwave background and probe the universe’s earliest moments. Although canceled in 2025, its scientific goals and technical innovations continue to shape cosmology. This article explains the experiment, the cosmic epochs it would have explored, and why the CMB remains a cornerstone of modern astrophysics.
