200 most important Astronomy topics - Sykalo Eugen 2023

The Cosmic Microwave Background S4 Experiment

The universe is a vast expanse of space, time, and matter that has fascinated astronomers, cosmologists, and physicists for centuries. One of the most important discoveries in modern cosmology is the cosmic microwave background (CMB), which is the afterglow of the Big Bang. The CMB provides us with a window into the early universe, allowing us to probe its properties and evolution. The CMB is a faint signal that pervades the entire sky, and it has been measured with increasing precision over the past few decades. In this article, we will discuss the latest results from the Cosmic Microwave Background S4 Experiment, which is one of the most ambitious CMB experiments to date.

What is the Cosmic Microwave Background?

The cosmic microwave background is a relic radiation that was emitted when the universe was only 380,000 years old. At that time, the universe was still hot and dense, and it was filled with a plasma of protons, electrons, and photons. As the universe cooled down, the protons and electrons combined to form neutral hydrogen atoms, which made the universe transparent to radiation. The photons that were emitted at that time have been traveling through space ever since, and they have cooled down as the universe expanded. Today, these photons have a temperature of about 2.7 Kelvin, which corresponds to a wavelength of about 1.06 cm.

The CMB is a blackbody radiation, which means that it has a spectrum that is determined solely by its temperature. The CMB spectrum has been measured with high precision, and it is found to be almost exactly a blackbody spectrum with a temperature of 2.7255 ± 0.0006 K. This temperature is extremely uniform across the sky, with variations of only a few parts in 100,000. These variations are the key to understanding the properties of the early universe, and they have been studied extensively over the past few decades.

What is the Cosmic Microwave Background S4 Experiment?

The Cosmic Microwave Background S4 Experiment is a collaboration of more than 200 scientists from 45 institutions around the world. The experiment aims to measure the polarization of the CMB with unprecedented accuracy, in order to study the early universe and its evolution. Polarization is a property of light that describes the orientation of its electric field. In the case of the CMB, polarization is caused by the scattering of the CMB photons off free electrons in the early universe. The polarization of the CMB contains valuable information about the properties of the early universe, such as the nature of dark matter and the energy scale of inflation.

The S4 experiment consists of three telescopes located at different sites in Chile and the South Pole. The telescopes observe the sky at frequencies between 30 GHz and 270 GHz, which correspond to wavelengths between 1.1 cm and 1.1 mm. The telescopes are equipped with highly sensitive detectors called bolometers, which are cooled to extremely low temperatures in order to minimize noise. The data from the telescopes is combined to produce high-resolution maps of the polarization of the CMB over a large fraction of the sky.

What are the latest results from the Cosmic Microwave Background S4 Experiment?

The S4 experiment is still ongoing, and the first results are expected to be released in the next few years. However, the experiment has already produced some impressive preliminary data. In 2019, the S4 collaboration released a paper describing the design and goals of the experiment. The paper estimated that the experiment would be able to measure the polarization of the CMB with an accuracy of 0.3 μK-arcmin, which is more than ten times better than the current best measurement.

The S4 experiment is expected to provide valuable information about the early universe, including the properties of dark matter and the energy scale of inflation. It may also shed light on other important cosmological questions, such as the nature of dark energy and the geometry of the universe. The S4 experiment is one of the most ambitious CMB experiments to date, and it is expected to produce groundbreaking results in the coming years.