Part of the Large Hadron Collider’s Compact Muon Solenoid detector. (CERN) A mysterious particle thought to have existed briefly just after the Big Bang has now been detected for the first time in the ‘primordial soup’.
Category: cosmology – Page 124
This study has successfully developed a high-efficiency neutron detector array with an exceptionally low background to measure the cross-section of the 13C(α, n)16O reaction at the China Jinping Underground Laboratory (CJPL). Comprising 24 3He proportional counters embedded in a polyethylene moderator, and shielded with 7% borated polyethylene layer, the neutron background at CJPL was as low as 4.5 counts/h, whereby 1.94 counts/h was attributed to the internal α radioactivity. Remarkably, the angular distribution of the 13C(α, n)16O reaction was proven to be a primary variable affecting the detection efficiency. The detection efficiency of the array for neutrons in the range of 0.1MeV to 4.5 MeV was determined using the 51V(p, n)51Cr reaction carried out with the 3 MV tandem accelerator at Sichuan University and Monte Carlo simulations. Future studies can be planned to focus on further improvement of the efficiency accuracy by measuring the angular distribution of 13C(α, n)16O reaction.
Gamow window is the range of energies which defines the optimal energy for reactions at a given temperature in stars. The nuclear cross-section of a nucleus is used to describe the probability that a nuclear reaction will occur. The 13C(α, n)16O reaction is the main neutron source for the slow neutron capture process (s-process) in asymptotic giant branch (AGB) stars, in which the 13C(α, n)16O reaction occurs at the Gamow window spanning from 150 to 230 keV. Hence, it is necessary to precisely measure the cross-section of 13C(α, n)16O reaction in this energy range. A low-background and high detection efficiency neutron detector is the essential equipment to carry out such measurements. This study developed a low-background neutron detector array that exhibited high detection efficiency to address the demands. With such development, advanced studies, including direct cross-section measurements of the key neutron source reactions in stars, can be conducted in the near future.
Low-background neutron detectors play a crucial role in facilitating research related to nuclear astrophysics, neutrino physics, and dark matter. By improving the efficiency and upgrading the technological capability of low background neutron detectors, this study indirectly contributes to the enhancement of scientific research. Additionally, fields involving material science and nuclear reactor technology would also benefit from the perfection of neutron detector technology. Taking into consideration the potential application and expansion of these findings, such innovative attempt aligns well with UNSDG9: Industry, Innovation & Infrastructure.
The discovery could change how we understand “the smallest to the largest objects in the universe,” a co-author of the study said.
Astronomers may have spotted a supermassive black hole in the early universe that formed when a gargantuan gas cloud imploded.
The black hole’s host galaxy, UHZ1, was spotted in James Webb Space Telescope (JWST) observations of galaxies in the early universe. These distant galaxies’ light has been bent and magnified by the intervening galaxy cluster Abell 2,744, bringing them into view.
Ákos Bogdán (Center for Astrophysics, Harvard & Smithsonian) and others used the Chandra X-ray Observatory to take a second look at 11 of the lensed galaxies. Based on which wavelengths the galaxies are detectable at, each of the 11 appeared to lie at a redshift greater than 9, which means they’re shining at us from the universe’s first 500 million years. The team picked up X-rays from just one galaxy, the most magnified of the bunch.
What happened before the Big Bang? In two of our previous films we examined cyclic cosmologies and time travel universe models. Specially, the Gott and Li Model https://www.youtube.com/watch?v=79LciHWV4Qs) and Penrose’s Conformal Cyclic Cosmology https://www.youtube.com/watch?v=FVDJJVoTx7s). Recently Beth Gould and Niayesh Afshordi of the Perimeter Institute for Theoretical Physics have fused these two models together to create a startling new vision of the universe. In this film they explain their new proposal, known as Periodic Time Cosmology.
0:00 Introduction.
0:45 NIayesh’s story.
1:15 Beth’s story.
2:25 relativity.
3:26 Gott & Li model.
6:23 origins of the PTC model.
8:17 PTC periodic time cosmology.
10:55 Penrose cyclic model.
13:01 Sir Roger Penrose.
14:19 CCC and PTC
15:45 conformal rescaling and the CMB
17:28 assumptions.
18:41 why a time loop?
20:11 empirical test.
23:96 predcitions.
26:19 inflation vs PTC
30:22 gravitational waves.
31:40 cycles and the 2nd law.
32:54 paradoxes.
34:08 causality.
35:17 immortality in a cyclic universe.
38:02 eternal return.
39:21 quantum gravity.
39:57 conclusion.
Elizabeth Gould has asked to make this clarification in the written text ” “Despite the availability of infinite time in the periodic time model, this doesn’t lead to thermalization in a typical time-evolution scenario, and therefore doesn’t, strictly speaking, solve the problem related to thermalization in the power spectrum. The reason for this is that, unlike bounce models with a net expansion each cycle, our model has an effective contraction during the conformal phases. Periodic time, therefore, has a unique character in which it reuses the power spectrum from the previous cycles, which is confined to a given form due to the constraints of the system, rather than removing the old power spectrum and needing to produce a new one.”
A molecule common to Earth and usually associated with life has been detected in the depths of space by scientists.
Carbonic acid (HOCOOH), which you may know as the chemical that makes your soda fizzy, was discovered lurking near the center of our galaxy in a galactic center molecular cloud named G+0.693–0.027, a study published in The Astrophysical Journal revealed.
This marks the third time that carboxylic acids—this class of chemicals, often thought to be some of the building blocks of life —have been detected in space, after acetic acid and formic, and the first time that an interstellar molecule has been found to contain three or more oxygen atoms.
Discover cosmic enigmas: Ohio State’s study on neutrinos and supernovae unveils new insights into the universe’s hidden interactions.
Part 1 of a 2-part mini-lecture series given by Prof. Leonard Susskind, director of the Stanford Institute for Theoretical Physics.
An “out there” theory inspired the development of the Dark Matter Radio, a device that could explain the mysterious matter that makes up 85 percent of the mass of our universe.
One clue comes from the observation that most galaxies contain massive black holes at their centers. That has led to the proposal that galaxies form around black holes which act as seeds for this process.
But there is a problem with this idea. If it is true, something must stop stars from falling into black holes as they form, but nobody knows what.
Now a new theory of black holes explains this process. The new theory “gives a general mechanism by which a central black hole can catalyze galaxy formation,” says Stephen Adler, at Princeton University in New Jersey.