Archive for the ‘cosmology’ category: Page 5

Aug 29, 2023

Pulsars Detected the Background Gravitational Hum of the Universe. Now Can They Detect Single Mergers?

Posted by in categories: cosmology, physics

After over a decade of observations of pulsars, astronomers could finally tease out the gravitational wave background of the Universe, the combined signal from merging supermassive black holes. But it was just the general presence of mergers, not specific events. A new paper proposes that the same pulsars could next be used to detect the gravitational waves from individual merging supermassive black holes. The more nearby pulsars astronomers can find, the more accurate their measurements will become.

Aug 28, 2023

Black hole total recoil

Posted by in category: cosmology

A black hole created by the collision of two parent bodies can rebound at a speed of more than 28,000 kilometres per second.

Aug 28, 2023

Scientists spot edge of supermassive black hole accidentally

Posted by in category: cosmology

Supermassive black holes sit at the center of many galaxies and are often surrounded by accretion disks that they feed on. Scientists observed a previously unexplored region near one – by accident.

Aug 26, 2023

Researchers define the ‘speed limit’ of black holes, suggesting new laws of physics

Posted by in categories: cosmology, physics

When supermassive black holes barrel toward collision, they can reach speeds of up to 1/10th the speed of light, new research suggests.

Aug 25, 2023

Did A Black Hole Give Birth To Our Universe?

Posted by in category: cosmology

And do our black holes give birth to baby Universes?

Aug 24, 2023

Physicists Detect Mysterious X Particles in ‘Primordial Soup’ For The First Time

Posted by in categories: cosmology, particle physics

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’.

Aug 24, 2023

Low-background Neutron Detector for Precise Measurement of Reaction Cross-Section

Posted by in categories: cosmology, nuclear energy, particle physics

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.

Aug 24, 2023

Black holes can speed through the universe at 17,500 miles per second, scientists say — and the discovery could reveal new laws of physics

Posted by in categories: cosmology, physics

The discovery could change how we understand “the smallest to the largest objects in the universe,” a co-author of the study said.

Aug 24, 2023

Black Hole May Have Formed by Direct Collapse

Posted by in category: cosmology

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.

Aug 23, 2023

Before the Big Bang 11: Did the Universe Create itself? The PTC model

Posted by in categories: cosmology, evolution, quantum physics, time travel

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 and Penrose’s Conformal Cyclic Cosmology 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.

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