More Space Debris Trouble, A Very Big Ship, & The Microbe of the Year

This week’s science bits from SWTG

Satellite Debris Could Interfere with Earth’s Magnetic Field

Space debris illustration. Image: ESA

We have heard that space debris is accumulating and posing a risk to satellites up there, but it turns out the problem may be worse than we thought. According to a new preprint that just appeared on the arXiv, the debris might pose a risk to Earth’s magnetic field even if satellites burn up upon reentry because, well, just because they burn up doesn’t mean the stuff they’re made of disappears.

The author, Dr. Sierra Solter-Hunt, estimates that the metals contained in the debris will eventually form a layer able to conduct electricity, which would create its own magnetic field and meddle with the already existing one. She calls for continuous monitoring and analysis of the artificial charged dust. 

The problem is still somewhat in the future, but by some estimates, in the next twenty years we’ll have half a million satellites or more orbiting our planet, and yes, it would make sense to think about the consequences before shooting more stuff up there. 

The preprint is here, and you can find an ESA video about the increasing mass of space debris here.

China Unveils Plan for Containerships Powered by Thorium-Fueled Nuclear Molten Salt Reactors 

The projected design for the new container ship. Image: CSSC Public Release. 

In December, at the Marintec China Expo in Shanghai, China’s State Shipbuilding Corporation (CSSC) unveiled plans for the world’s largest-ever containership, the KUN-24AP, which will be powered by a Thorium Molten Salt Reactor.

“The ultra-large nuclear container ship is designed to truly achieve ‘zero emissions’ during the ship’s operating cycle”, the CSSC revealed in a post on Weibo quoted in the South China Morning Post. The Weibo post continued: “This ship type has high safety. The reactor operates at high temperature and low pressure, can avoid core melting in principle, and has anti-proliferation and inherent safety features.” 

The new containership will refuel continuously without reactor shutdown and boast a high burn-up (a low waste-to-fuel ratio). The Norwegian Classification Society DNV has approved the preliminary design. Press release here, another here, and a primer on thorium reactors here.

Microbe of the Year!

Bacillus subtilis forms biofilms with diverse structures. Image: Adrian Daerr, WikiCommons

It’s official: The microbe of the year 2023 is Bacillus subtilis. We had heard of 2023, but in all honesty, we were not fully aware that microbes win awards, so we had a look. 

Bacillus subtilis, aka the hay or grass bacillus, was chosen by the Association for General and Applied MIcrobiology for its many uses in manufacturing and production. The bacillus is commonly found in soil, the gastrointestinal tract of animals, and in the dried rice straw used in Asian cuisine to ferment soybeans for tofu. 

Subtilis grows quickly, often forming complex biofilm structures that adapt to and interact with their environment. The bacillus is used in bioindustries to efficiently convert organic substrates to products such as vitamin B2 or vitamin B5, various thickeners and antifreeze agents, and enzymes such as amylase, protease, and lipase, which are used in laundry detergents, for example. The spores of subtilis are even used in the construction industry, where they heal cracks in concrete.

You find a press release about the microbe of the year here, a paper about its ability to form biofilms here, and a paper about its use in construction here.