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Photo of a CMB-S4 detector wafer being prepared for testing inside a cryostat at Lawrence Berkeley National Laboratory.Credit: Thor Swift/Lawrence Berkeley National Laboratory
Astronomers are currently pushing the frontiers of astronomy. At this very moment, observatories like the James Webb Space Telescope (JWST) are visualizing the universe’s oldest stars and galaxies, which formed during a period known as the “Dark Ages of the Universe.” This period was previously inaccessible to telescopes because the universe was permeated by clouds of neutral hydrogen.
As a result, the only visible light today is seen either as relic radiation from the Big Bang, the Cosmic Microwave Background (CMB), or as a 21 cm spectral line produced by the reionization of hydrogen (also known as the hydrogen line). You can
As the veil of the Dark Ages slowly lifts, scientists are considering the next frontier in astronomy and cosmology by observing the “primordial gravitational waves” created by the Big Bang. In recent news, it was announced that the National Science Foundation (NSF) has awarded her $3.7 million to the University of Chicago. This is the first part of a grant that could reach up to $21.4 million. The purpose of this grant is to fund the development of the next generation of telescopes that will map the CMB and the gravitational waves produced shortly after the Big Bang.
Gravitational waves (GWs), originally predicted by Einstein’s theory of general relativity, are ripples in space-time caused by the merger of massive objects like black holes and neutron stars. Scientists also theorize that there may be GWs that formed during the Big Bang and can still be seen as background oscillations today. In collaboration with Lawrence Berkeley National Laboratory (LBNL), researchers on the University of Chicago CMB-S4 project are building telescopes and infrastructure in Antarctica and Chile to search for these waves.
The collaboration currently includes 450 scientists from more than 100 institutions in 20 countries. The entire project is proposed to be jointly funded by NSG and the U.S. Department of Energy (DoE), with the NSF portion to be led by the University of Chicago and the DoE portion to be led by Lawrence Berkeley National Laboratory. . The project will cost around $800 million in total and is expected to be operational by the early 2030s. In addition to exploring the primordial GW, these telescopes can also map the CMB in incredible detail and reveal how the universe has changed over time.
These telescopes could also help explore the elusive “dark universe” and test current cosmological models. John Carlstrom is the Subramanyan Chandrasekhar Distinguished Professor of Astronomy, Astrophysics, and Physics at the University of Chicago and project scientist for CMB-S4. “With these telescopes, we will not only test theories about how the entire universe came to be, but we will also explore physics on the most extreme scales in ways that particle physics experiments on Earth will never be able to do. “We will investigate the science,” he said in the paper. University of Chicago News Statement.
Scientists have been mapping the universe for decades because the CMB contains information about the birth of the universe. These include space telescopes such as the Soviet Union’s RELIKT-1, NASA’s Cosmic Background Explorer (COBE), Wilkinson Microwave Anisotropy Probe (WMAP), and ESA’s Planck satellite. These missions made detailed measurements of tiny temperature anisotropies (variations) within the CMB, providing hints about how the universe began. But what is needed are telescopes sensitive enough to answer deeper cosmological questions, such as whether the universe began with explosive inflation.
To achieve this objective, CMB-S4 will build highly complex instruments to map the first light of the universe from the spacecraft and the ground. The array includes two new telescopes on Chile’s Atacama Plateau and nine small telescopes at NSF’s South Pole Station (SPS). The project also relies on the South Pole Telescope, which has been operating at SPS since 2007. The Chilean telescope will carry out a wide survey of the sky to capture more detailed images of the CMB, with each site playing a key role. . Telescopes at NSF’s Antarctic base, on the other hand, provide deep and continuous observations of smaller parts of the sky.
Observations from Chile will improve our understanding of the evolution and distribution of matter and help us search for relic particles of light that may have existed in the early universe. Telescopes in the South Pole, on the other hand, will provide a unique view of the universe as they will be able to continuously observe a portion of the sky in Antarctica, where the rest of the Earth rotates. Their joint efforts will allow astronomers to look for ripples in spacetime that can only emerge from spaces smaller than subatomic particles that suddenly expand into much larger volumes.
Jim Strait, a physicist at Lawrence Berkeley National Laboratory, said:CMB-S4 Project Director), which is an ambitious but worthy goal. “In many ways, the inflation theory looks good, but most of the empirical evidence is somewhat circumstantial,” he said. “The discovery of primordial gravitational waves will be what some call the ‘smoking gun’ for inflation.”
These ripples interact with the CMB and leave clear (but very faint) traces, so large-scale, continuous mapping of the CMB should provide an indication of its presence. CMB-S4 should also provide clues about the nature of dark matter and dark energy. The former is theorized to account for the majority of the universe’s mass (about 69%), while the latter is responsible for the accelerating rate of expansion. Additionally, mapping primordial gravitational waves can also help scientists discover the relationship between gravity and quantum mechanics.
Since microwave detectors are already very sensitive, measurements are dominated by background noise and local interference. Therefore, the plan is to equip the integrated CMB-S4 experiment with approximately 500,000 superconducting detectors, more than all previous experiments combined, to provide accurate measurements of signal levels and reduce noise. In order to do so, the number of measurements will be significantly increased. A new grant from NSF will help fund the design of the new telescope and site infrastructure, which will be the most complex ever built.
