In order to get sunlight at night, they installed a large mirror on the satellite...｜Environmental Trumpet

Hello everyone, this is the 17th issue of the Environmental Trumpet column. In this issue, we have collected the following environmental research and news worth reading:

1) “Artificial sunlight”: You can also bask in the sun at night

2) Wear the “air conditioner” on your body

3) Purple bacteria, an environmentally friendly plastic processing plant

4) Air pollution exacerbates thunderstorms

5) The weather is too hot, so the trees cut off their own arms?

“ Artificial Sunlight” : You can also bask in the sun at night

Recently, the startup Reflect Orbital has been hotly discussed because of a magical video. In the video, as long as you locate the place you want to illuminate on your phone and click "Apply for Sunlight", the night will turn into day .

Wherever you want to highlight｜@colecallina/X

The inspiration for "artificial sunshine" comes from a popular science video, which mentions that the average amount of sunlight received per unit area by German solar panels is only one-third of that in the Sahara region, which is far from meeting Germany's power generation needs.

So, the company's founder Ben Nowack imagined whether it would be possible to build a large optical network like the national power grid. He initially wanted to set up large mirrors on the ground to reflect light into laser beam vacuum tubes . These vacuum tubes were spread all over the place like wires, and then transported sunlight to various places for people to use at any time.

However, this method has a high economic cost. Novak turned to another idea: directly install huge reflectors on artificial satellites to use satellites to reflect and transmit sunlight . To this end, Novak designed a collimator that can focus the divergent light into a beam and can be made into a large-area device.

Ben Nowack designed a collimator with a large number of parabolic grooves | Ben Nowack

In March this year, Novak completed preliminary testing of the "artificial sunlight" device on a hot air balloon , and the reflected light was successfully received by the solar panels on the ground. The next step is to install the device on a real satellite to verify the effectiveness of the design.

Reflect Orbital has also opened reservations for its "artificial sunlight" service, which can illuminate for four minutes at a time and has a range of 5 kilometers in diameter. It is expected to be delivered starting in the fourth quarter of 2025.

However, "artificial sunlight" has also raised concerns - nighttime sunlight may have a negative impact on organisms around the illuminated areas .

Wear the "air conditioner" on your body

Shou Dahua and his team at the Hong Kong Polytechnic University have developed the first adaptive high-temperature clothing and published their research results in Advanced Materials. In a hot environment, this clothing can automatically adapt to temperature changes and make people feel comfortable.

The design of the thermal protective suit was inspired by an animal in nature, the pigeon. The pigeon has an adaptive mechanism for temperature changes. When the temperature drops, the pigeon will fluff up its feathers to increase the air layer, thereby increasing the thermal resistance . When the thermal resistance increases, the transfer of heat will be hindered, and the pigeon will not easily get cold due to the drop in temperature.

Pigeon: I can do more than just coo｜Pixabay (left), 2024 Research and Innovation Office, The Hong Kong Polytechnic University (right)

The same principle, increasing thermal resistance and reducing heat exchange can not only keep you "warm in winter" but also "cool in summer". Taking advantage of this, the research team designed a unique fabric consisting of three layers: the outermost flame retardant layer, the breathable waterproof and moisture-proof layer, and the thermal lining layer. A non-toxic, non-flammable, low-boiling liquid is also added to the lining layer. When the outside temperature rises, the liquid turns into gas, causing the lining layer to expand. The process of liquid turning into gas not only absorbs a certain amount of heat, but also increases the thermal resistance of the lining layer after expansion, thereby achieving a heat-insulating effect. Under extreme conditions, thermal protective clothing can make the inner surface temperature at least 10°C lower than traditional heat-resistant clothing .

The research team tested the performance of the protective suit. Although a small amount of liquid was added to the new design, the test found that the liquid was completely encapsulated and would not leak, and the liquid could be repeatedly converted into gas, allowing the protective suit to be used for a long time.

Purple bacteria, a factory for processing environmentally friendly plastics

Purple bacteria are a relatively special type of microorganisms. They can carry out photosynthesis like plants, but they do not contain chlorophyll in their bodies. Instead, they fix carbon dioxide through other pigments .

Recently, two research teams from the University of Washington discovered that purple bacteria are a dark horse in the production of bio-based plastics , thanks to their carbon fixation ability.

Most purple bacteria contain purple-red pigments | Joe Angeles

Under the premise of ensuring stable light, one of the research teams designed a variety of experimental methods to cultivate purple bacteria. The results showed that two purple bacteria of the genus Rhodomicrobium can produce polyhydroxyalkanoates (PHA) under phototrophic conditions, which can become raw materials for bio-based plastics after purification . The experiment also found that under a small amount of electrical stimulation and nitrogen supply, the two purple bacteria produced more PHA.

Another research team took a completely different experimental approach: genetic engineering. The researchers used a strain of Rhodopseudomonas palustris TIE-1 as a receptor and inserted the gene for RuBisCO, an enzyme related to photosynthesis, into the bacteria. The results showed that the activity of TIE-1 bacteria changed significantly. According to previous literature, TIE-1 bacteria do not produce polymers to store carbon sources. However, after gene editing , the research team extracted a large amount of PHA from the bacteria and successfully transformed the bacteria into a raw material production plant for bio-based plastics.

Such "microbial processing plants" can not only absorb carbon dioxide from the atmosphere through photosynthesis, but also produce fully biodegradable plastic raw materials, bringing hope for the green transformation of plastic production.

Air pollution can exacerbate thunderstorms

Why are thunderstorms taking longer to come to work? A study published in Atmospheric Research found that air pollution is exacerbating summer thunderstorms .

Air pollution emits a large amount of particulate pollutants, which rise into clouds with updrafts. However, due to the sedimentation of the particles themselves, convection in the atmosphere will further separate the particles and achieve charge separation, which will lead to more lightning.

In an unstable atmospheric environment, increased pollution may intensify the occurrence of lightning｜Pixabay

The study mainly analyzed thunderstorm data in the Washington, D.C. and Kansas City areas of the United States, including hundreds of thousands of thunderstorm events. By analyzing the occurrence time and meteorological conditions of thunderstorm events, the researchers not only summarized the laws of thunderstorm occurrence, but also explored the relationship between thunderstorm occurrence and atmospheric particulate matter.

The results showed that both regions were more prone to thunderstorms in the afternoon and evening, and Thursday was often the peak time for thunderstorms. The study speculated that the peak period may be related to changes in local air quality.

In addition, as a major factor that promotes the occurrence of thunderstorms, the concentration of atmospheric particulate matter has a greater impact on the severity of thunderstorms than the size of the particles. When the concentration of particulate matter is low, the atmospheric environment is not very stable, and increased pollution can easily aggravate the occurrence of thunderstorms ; when the concentration of particulate matter is too high, exceeding a certain threshold, the atmospheric stability may increase, and the number of thunderstorms may be suppressed.

The weather is too hot, and the trees cut off their own arms?

Have you ever noticed that in the summer, some seemingly healthy trees suddenly lose branches. These branches are not broken by typhoons, but by the trees themselves.

The phenomenon of branch breakage remains a mystery, and the scientific community has different explanations for it.

Because branch breakage mostly occurs in the summer , some scholars believe that this may be related to high temperatures . In the spring, the continuous rain, humid air and suitable temperature nourish the trees and allow them to thrive; but in the summer, the temperature soars and the hot weather accelerates the evaporation of water from the trees. In order to ensure that they have sufficient water, the trees may "prune" some branches by themselves to reduce water loss.

Extreme heat may be the last straw for the branches' survival｜Pixabay

Another explanation is that in winter, trees suffer from low temperatures , becoming weak and unhealthy inside. When new branches sprout and grow the next year, the pressure of the new growth overwhelms the trees and they have no choice but to break off their branches.

Historically, tree branch falls have been recorded in hot climates such as Australia, South Africa and the southwestern United States, but since the 1970s they have expanded to areas such as the northern United States and the United Kingdom.

In 2023, researchers conducted a study on the sudden falling of tree branches in four cities in Portugal. They believed that the falling of branches is not only related to the growth state of the branches, but also to environmental conditions. Climate change may be one of the main reasons for aggravating this phenomenon .

Overall, the trees themselves may have health problems, and the extreme heat has only added fuel to the fire . People standing under the trees, in addition to being careful of being struck by lightning, also need to watch out for branches falling off...

Author: Xiao Xiaoze

Edited by: Yellowtail Pollock