The force pushing galaxies apart might be getting weaker
Cosmic Acceleration: Dark Energy and the Evolution of the Universe from Baryon Acoustic Oscillations in the 21st Century
Dark energy, which causes galaxies to speed away from each other, has weakened over billions of years according to fresh data. Until last year, all findings were consistent with dark energy being a ‘cosmological constant’, meaning that the Universe should continue to expand at an increasingly fast rate. Cosmic expansion is now less rapid than it was 4.5 billion years ago due to the lower amount of dark energy in the space.
Catherine Heymans, the astronomer at the University of Edinburgh, UK, and the Astronomer Royal for Scotland, is now paying attention.
The Kitt Peak National Observatory is home to the DESI telescope. It uses 5,000 robotic arms to point the optical fibres in the field of view. The degree to which the light waves stretched by expansion of space on their way to Earth affects how much redshifted the object is. Researchers can estimate an object’s distance using their redshift to create a map of the Universe’s expansion history.
In that map, researchers then look at the density of galaxies to identify variations that are left over from sound waves called baryon acoustic oscillations (BAOs), which existed before stars began to form. The universe’s largest known features include the variations that started out at 150 kiloparsecs in the primordial Universe and have now grown to more than 150 megaparsecs.
A human hair lamp made to look like a woman or a man from Lake Mungo, New Zealand, in June 1960–December 2000
Over the past five years, around 9,000 satellites were launched into Earth’s atmosphere, increasing the number from just over 2,000 to 11,000. Many of those people are members of the Starlink system run by Musk’s company, to name a few. The spacecraft play a crucial role in connecting people around the world, but their soaring numbers are giving astronomers a headache by creating streaks in images and interfering with observations. The focus now is damage control. Astronomers are working with satellite companies to build a system that will enable them to map the universe and make sense of it.
A case in Australia regarding the fate of human remains taken from Lake Mungo in the 1960s and 1970s is nearing a conclusion. The remains of a woman and a man are both believed to be from the world’s oldest-known cremation. The bones are remains of Aboriginal Australian people and — along with many more from the same area — have come to represent both the history of First Nations people and how science has sometimes disrespected their rights, by treating their ancestors as scientific material without permission. In 2022, the process began to rebury the remains — but there is disagreement, both among scientists and members of Aboriginal Australian communities, about whether that was the right decision.
Physicists have created a new form of light. The image above was shown on a monochromatic display with pixels less than 100 micrometres across, about the width of a human hair. The team made an even tinier lamp if that was small enough. Even with the most powerful optical microscopes, the small width of the display’s pixels was too small to be resolved. 3 min read.
Source: Daily briefing: The mysterious force pushing galaxies apart might be getting weaker
How quickly can AI learn to master long tasks? An experimental study of a quantum communication record breaking the Great Wall and Stellenbosch campus
Artificial intelligence systems could catch up to human computer programmers on long tasks in 4 years, since they have yet to catch up. Since 2019, the ‘task-completion time horizon’ — a metric devised to track how long programmers take to complete tasks that AI can complete with a 50% success rate — has doubled roughly every seven months. It is thought that tasks that take humans a month will be mastered by 2029, or sooner. According to the professor, uncertainties about how artificial intelligence will be used aren’t always useful.
A study in mice showed that immune cells in the skin create bandages to keep harmfulbacteria from spreading during an injury. Researchers found that white blood cells called neutrophils form a ring of protein-rich ‘goo’ around areas where the skin has been breached to trap pathogens. Neutrophils are known to kill pathogens by eating them or releasing toxins. The second wave of neutrophils is used to form the sticky barrier after the initial attack.
Researchers have broken the record for quantum communication by sending an encryption key nearly 13,000 kilometres from China to South Africa via a ‘microsatellite’. There were laser light beams from a rooftop in Beijing to another at the university. The pulses formed a quantum key used to encrypt two images — one of China’s Great Wall and one showing part of Stellenbosch’s campus. Sending messages through space between any two locations on Earth is a step closer with the quantum key distribution feat.