-
Posts
-
By +Edouard · Posted
This is why science is the only path to truth. It isn't rigid in its beliefs, rather it changes its views based on scientific discoveries. -
By hellowalkman · Posted
A 13 billion year old secret about our Universe's origin was revealed by Sayan Sen Image by Pascal Küffer via Pexels Researchers at the Max-Planck-Institut für Kernphysik (MPIK) in Heidelberg had recreated a key chemical reaction from the early universe, producing results that could change scientists' understanding of how the first stars formed. The study focused on the helium hydride ion (HeH⁺), which is widely regarded as the first molecule to form in the universe. Scientists believe HeH⁺ appeared around 380,000 years after the Big Bang, when the universe had cooled enough for electrons and atomic nuclei to combine into neutral atoms in a period known as recombination. This marked the beginning of chemistry in the cosmos. Immediately after the Big Bang about 13.8 billion years ago, the universe was extremely hot and dense. As it expanded and cooled, hydrogen and helium became the dominant elements. Once neutral helium atoms formed, they could react with ionised hydrogen nuclei, or protons, to create helium hydride ions. Although simple in structure, HeH⁺ played an important role in the young universe. It was the first step in a chain of reactions that eventually produced molecular hydrogen (H₂), a molecule made up of two hydrogen atoms and now the most abundant molecule in the universe. Molecular hydrogen later became a key ingredient in the formation of the first stars. At the time, the universe had entered a phase often called the cosmological "dark age." Matter had become transparent to light following recombination, but there were still no stars or galaxies producing visible light. Several hundred million years would pass before the first stars appeared. For those first stars to form, large clouds of gas had to collapse under their own gravity. To do that, the gas needed to cool by releasing energy. While hydrogen atoms can help with this process at high temperatures, they become less effective below about 10,000 degrees Celsius. Molecules can continue the cooling process by releasing energy through rotational and vibrational motions. Scientists have long considered HeH⁺ a potentially important coolant because of its comparatively large dipole moment, a property that describes how electric charge is distributed within a molecule and allows it to release energy efficiently. The amount of helium hydride present in the early universe may therefore have influenced how easily the first stars could form. At the same time, HeH⁺ was constantly being destroyed. Under primordial conditions, its main destruction mechanisms were recombination with free electrons and chemical reactions with hydrogen atoms. These reactions ultimately helped produce molecular hydrogen, linking the formation and destruction of HeH⁺ to the chemistry that shaped the early universe. For many years, theoretical studies suggested that reactions between HeH⁺ and hydrogen atoms would become much slower at low temperatures. Scientists believed there was an energy barrier along the reaction pathway that reduced the chances of the reaction taking place in the cold conditions of the early universe. The new study suggests otherwise. To investigate the process, researchers recreated a closely related reaction using deuterium, a naturally occurring isotope of hydrogen that contains one proton and one neutron in its nucleus. When HeH⁺ collides with deuterium, it forms an HD⁺ ion and a neutral helium atom. This allows scientists to study the reaction in a controlled way while closely mimicking the behaviour of the original reaction involving hydrogen. The experiments were carried out at the Cryogenic Storage Ring (CSR) at MPIK, a specialised facility designed to recreate conditions similar to those found in space. Researchers stored HeH⁺ ions in the 35-metre storage ring for up to 60 seconds at temperatures just a few kelvins above absolute zero and merged them with a beam of neutral deuterium atoms. By adjusting the speeds of the two particle beams, the team measured how the reaction rate changed with collision energy, which is directly related to temperature. The researchers found that the reaction rate remains almost constant as temperatures decrease. In other words, the reaction does not slow down at low temperatures as earlier models predicted. “Previous theories predicted a significant decrease in the reaction probability at low temperatures, but we were unable to verify this in either the experiment or new theoretical calculations by our colleagues,” explained Dr Holger Kreckel of MPIK. “The reactions of HeH⁺ with neutral hydrogen and deuterium therefore appear to have been far more important for chemistry in the early universe than previously assumed,” he continued. According to the researchers, the reaction appears to be barrierless, meaning there is no energy obstacle preventing it from taking place efficiently even at very low temperatures. The findings support recent theoretical work led by physicist Yohann Scribano, whose group identified an error in a widely used potential energy surface, a mathematical model used to describe how the energy of a system changes during a chemical reaction. The error appears to have caused previous studies to significantly underestimate reaction rates under primordial conditions. The new calculations closely match the experimental results. Together, they suggest that helium chemistry in the early universe may need to be re-evaluated. Because molecules such as HeH⁺ and molecular hydrogen played an important role in cooling primordial gas clouds, the findings could help scientists build more accurate models of how the first stars formed. By showing that helium hydride was likely destroyed more efficiently than previously thought, the study offers new insight into the chemical processes that shaped the universe during its earliest stages and helped set the conditions for the emergence of the first stars. Source: Max-Planck Institute, EDP Sciences This article was generated with some help from AI and reviewed by an editor. Under Section 107 of the Copyright Act 1976, this material is used for the purpose of news reporting. Fair use is a use permitted by copyright statute that might otherwise be infringing. -
.thumb.png.b7089ebbdf00d96b3b92dddbd04bac02.png)
By PsYcHoKiLLa · Posted
"What an interesting smell you've discovered" -
By thartist · Posted
It could EASILY be 70 for the base game BUT + lots of FOMO to make it up to 100-120, like a few days Early Access, online money, pre-order bonus cars, weapons, missions, clothing, avatars or profile stuff, etc... And still WAY TOO MANY people would buy those and make Rockstar insane money. -
By Nick H. · Posted
Just to understand: your solution to getting rid of an online password manager is...another online password manager?
-
-
Recent Achievements
-
JuvenileDelinquent earned a badge
Dedicated
-
DrWankel earned a badge
First Post
-
DrWankel earned a badge
Reacting Well
-
Supreme Spray LV earned a badge
Week One Done
-
Genuinetonerink- Dubai earned a badge
Week One Done
-
-
Popular Contributors
-
Tell a friend
.thumb.png.b7089ebbdf00d96b3b92dddbd04bac02.png)
Question
Si Veteran
Please use this thread as a reference for this topic, as time goes on and availabilty changes, the poll will be updated.
Link to comment
https://www.neowin.net/forum/topic/323306-your-favourite-antivirus/Share on other sites
791 answers to this question
Recommended Posts