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Category: space – Page 177

Oops! Geoengineering Trick to Cool Brutal Heat Could Spike Temperature Elsewhere, Scientists Say

Researchers are warning that geoengineering efforts to help cool temperatures in California could trigger heatwaves in Europe, a “scary” implication given the sheer lack of regulation controlling such measures across the globe.

As The Guardian reports, scientists have suggested spraying aerosols into clouds over the ocean to cool down the surface below, a practice called “marine cloud brightening.” As the name suggests, the idea is to brighten clouds to make them reflect more of the Sun’s radiation back into space.

Last month, a team of University of Washington researchers attempted to do just that in the San Francisco Bay using a machine that sprays tiny sea-salt particles, amid criticism from environmentalists. The experiment was later shut down by city officials, citing health concerns.

Lockheed Martin and US Air Force Complete Flight Test of Intercontinental Ballistic Missile Reentry Vehicle

The Lockheed Martin and U.S. Air Force conducted a planned flight test of the unarmed, developmental Mk21A reentry vehicle in the Pacific Ocean on June 17. Mk21A is the U.S. Air Force’s integrated reentry vehicle and the critical front-end of the service’s future intercontinental ballistic missile (ICBM) weapon system. This flight test from Vandenberg Space Force Base in California, tested Lockheed Martin’s Mk21A design components and technologies for the vehicle. It also continues Lockheed Martin’s leadership and expertise in developing effective and reliable reentry vehicle technology.

This testing is done through Lockheed Martin’s Engineering and Manufacturing Development contract with the Air Force Nuclear Systems Center. Data collected during the event will further inform Mk21A design and future flight test activities. The company’s Mk21A program is on-schedule. Lockheed Martin is maturing its Mk21A design, which includes the arming and fuzing subsystem and support equipment, using advanced digital engineering tools, including advanced modeling and simulation. This allows for efficiency in schedule, reduced cost and risk, and increased confidence in system performance.

“This progress is built on a strong foundation—Lockheed Martin’s 65-plus years of demonstrated exceptional performance in reentry technologies and a pioneering digital engineering approach on this program from its beginning,” said Jay Watson, vice president of Strategic Reentry at Lockheed Martin. “We remain focused on delivering this capability for the warfighter as a trusted partner to the U.S. Air Force for ICBM reentry systems and modernization of the deterrent triad.”

Neutrino mixer

Why are neutrinos so light?

Did you know that every second more than 100 trillion tiny particles called neutrinos pass through your body without causing any harm? These mysterious particles are produced abundantly throughout the universe in events like nuclear reactions in the sun, radioactive decays in the Earth’s crust, and in high-energy collisions in space. In particular, these subatomic particles play a crucial role in the explosive deaths of stars known as supernovae, where they act as the driving force behind the explosion. Despite their abundance in the universe, they are incredibly difficult to detect directly in experiments since they pass right through any matter and only interact extremely rarely. At the LHC, their existence can only be inferred indirectly by summing up the energy of all other particles produced from the proton collisions and looking for missing energy that has been carried away by the neutrino, which escaped the experiment undetected.

Neutrinos are a type of fundamental particle known as a lepton and they are electrically neutral. They stand out among fundamental particles because of their peculiar characteristics. Not only do they interact exceptionally rarely, but they also possess a minuscule mass, approximately 500,000 times lighter than that of an electron. One possible explanation for the smallness of their mass is given by the “seesaw” mechanism. According to this theory, there exist additional new fundamental particles that are electrically neutral. The mechanism postulates that the masses of these new particles, known as “heavy neutral leptons” (HNLs), are mathematically linked to those of the normal neutrinos, like two sides of a seesaw. The theory also predicts that the HNLs will “mix” with their known cousins, neutrinos. This means that a neutrino, produced in an LHC collision, can change into an HNL, and the HNL can then decay back into known particles that the LHC experiments can detect!

The seesaw explanation for the neutrino mass is particularly attractive and various searches for HNLs have been performed at the LHC and by other experiments in the past (see an example where CMS muon detectors are exploited in such a search). The CMS Collaboration has recently published a new search that makes the assumption that the mixing between the HNLs and neutrinos is very small. In this special case, the HNL can be “long lived” and travel macroscopic distances away from the collision point before decaying. Experiments can then take advantage of the unusual signatures from these “displaced” particle decays when trying to find evidence for the existence of HNLs.

Impact of Space Flight on Human Health: A Focus on the Eye

Dr. Ana Diaz Artiles: “When we’re upright, a large part of our fluids are stored in our legs, but in microgravity we get a redistribution of fluids into the upper body.”

What physiological effects can extended periods of microgravity have on the human eye? This is what a recent study published in npj Microgravity hopes to address as a team of researchers investigated how the shifting of fluids under microgravity conditions could lead to eye vessel alterations. This study holds the potential to help space agencies, researchers, and the public better understand the short-and long-term physiological effects of microgravity, specifically with more humans traveling beyond Earth’s gravity on commercial spaceflights.

“When we experience microgravity conditions, we see changes in the cardiovascular system because gravity is not pulling down all these fluids as it typically does on Earth when we are in an upright position,” said Dr. Ana Diaz Artiles, who is an assistant professor in the Department of Aerospace Engineering at Texas A&M University and a co-author on the study. “When we’re upright, a large part of our fluids are stored in our legs, but in microgravity we get a redistribution of fluids into the upper body.”

For the study, the researchers analyzed how lower body negative pressure (LBNP), which involves the transferring of fluids from the upper body to the lower body, could potentially be used to counteract what’s known as Spaceflight Associated Neuro-ocular Syndrome (SANS), which, while still not well understood, often results in physiological changes in the eyes, also called ocular prefusion pressure (OPP). Using 24 participants, 12 male and 12 female, the researchers subjected the participants to treatments inside an LBNP chamber to ascertain the effects on counteracting OPP.

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