A doubling of the amount of CO₂ in the atmosphere could cause an increase in the average temperature on Earth from 7 to a maximum of 14 degrees. This is shown in the analysis of sediments from the Pacific Ocean off the coast of California, by researchers at NIOZ and the Universities of Utrecht and Bristol. Their results were published in Nature Communications.

“The temperature rise we found is much larger than the 2.3 to 4.5 degrees that the UN climate panel, IPCC, has been estimating so far,” said the first author, Caitlyn Witkowski.

The researchers used a 45-year-old drill core extracted from the bottom of the Pacific Ocean. “I realized that this core is very attractive for researchers, because the ocean floor at that spot has had oxygen-free conditions for many millions of years,” said Professor Jaap Sinninghe Damsté, senior scientist at NIOZ and professor of organic geochemistry at Utrecht University.

“As a result, organic matter is not broken down as quickly by microbes and more carbon is preserved,” Damsté said. He was also the supervisor of Witkowski, whose doctorate thesis included this research.

“CO₂ over the past 15 million years has never before been examined from a single location,” Witkowski said. The upper thousand meters of the drill core correspond to the past 18 million years. From this record, the researchers were able to extract an indication of the past seawater temperature and an indication of ancient atmospheric CO₂ levels, using a new approach.

Derived temperature

The researchers derived the temperature using a method developed 20 years ago at NIOZ, called the TEX₈₆ method. “That method uses specific substances that are present in the membrane of archaea, a distinct class of microorganisms,” Damsté explains.

“Those archaea optimize the chemical composition of their membrane depending on the temperature of the water in the upper 200 meters of the ocean. Substances from that membrane can be found as molecular fossils in the ocean sediments, and analyzed to this day.”

CO₂ from chlorophyll and cholesterol

The researchers developed a new approach to derive past atmospheric CO₂ content by using the chemical composition of two specific substances commonly found in algae: chlorophyll and cholesterol. This is the first study to use cholesterol for quantitative CO₂ and the first study to use chlorophyll for this time period. To create these substances, algae must absorb CO₂ from the water and fix it via photosynthesis.

Damsté said, “A very small fraction of the carbon on Earth occurs in a ‘heavy form,’ ¹³C instead of the usual ¹²C. Algae have a clear preference for ¹²C. However, the lower the CO₂ concentration in the water, the more algae will also use the rare ¹³C. Thus, the ¹³C content of these two substances is a measure of the CO₂ content of the ocean water. And that in turn, according to solubility laws, correlates with the CO₂ content of the atmosphere.”

Using this new method, it appears that the CO₂ concentration dropped from about 650 parts per million, 15 million years back, to 280 just before the industrial revolution.

Stronger relationship

When the researchers plot the derived temperature and atmospheric CO₂ levels of the past 15 million years against each other, they find a strong relationship.

The average temperature 15 million years back was over 18 degrees: 4 degrees warmer than today and about the level that the UN climate panel, IPCC, predicts for the year 2100 in the most extreme scenario.

“So, this research gives us a glimpse of what the future could hold if we take too few measures to reduce CO₂ emissions and also implement few technological innovations to offset emissions,” Damsté said.

“The clear warning from this research is CO₂ concentration is likely to have a stronger impact on temperature than we are currently taking into account.”

The space environment is harsh and full of extreme radiation. Scientists designing spacecraft and satellites need materials that can withstand these conditions.

In a paper published in January 2024 in Nature Communications, my team of materials researchers demonstrated that a next-generation semiconductor material called metal-halide perovskite can actually recover and heal itself from radiation damage.

Metal-halide perovskites are a class of materials discovered in 1839 that are found abundantly in Earth’s crust. They absorb sunlight and efficiently convert it into electricity, making them a potentially good fit for space-based solar panels that can power satellites or future space habitats.

Researchers make perovskites in the form of inks, then coat the inks onto glass plates or plastic, creating thin, filmlike devices that are lightweight and flexible.

Surprisingly, these thin-film solar cells perform as well as conventional silicon solar cells in laboratory demonstrations, even though they are almost 100 times thinner than traditional solar cells.

But these films can degrade if they’re exposed to moisture or oxygen. Researchers and industry are currently working on addressing these stability concerns for terrestrial deployment.

To test how they might hold up in space, my team developed a radiation experiment. We exposed perovskite solar cells to protons at both low and high energies and found a unique, new property.

The high-energy protons healed the damage caused by the low-energy protons, allowing the device to recover and continue doing its job. The conventional semiconductors used for space electronics do not show this healing.

My team was surprised by this finding. How can a material that degrades when exposed to oxygen and moisture not only resist the harsh radiation of space but also self-heal in an environment that destroys conventional silicon semiconductors?

In our paper, we started to unravel this mystery.

Why it matters

Scientists predict that in the next 10 years, satellite launches into near-Earth orbit will increase exponentially, and space agencies such as NASA aim to establish bases on the moon.

Materials that can tolerate extreme radiation and self-heal would change the game.

Researchers estimate that deploying just a few pounds of perovskite materials into space could generate up to 10,000,000 watts of power. It currently costs about US$4,000 per kilogram ($1,818 per pound) to launch materials into space, so efficient materials are important.

What still isn’t known

Our findings shed light on a remarkable aspect of perovskites—their tolerance to damage and defects. Perovskite crystals are a type of soft material, which means that their atoms can move into different states that scientists call vibrational modes.

Atoms in perovskites are normally arranged in a lattice formation. But radiation can knock the atoms out of position, damaging the material. The vibrations might help reposition the atoms back into place, but we’re still not sure exactly how this process works.

What’s next?

Our findings suggest that soft materials might be uniquely helpful in extreme environments, including space.

But radiation isn’t the only stress that materials have to weather in space. Scientists don’t yet know how perovskites will fare when exposed to vacuum conditions and extreme temperature variations, along with radiation, all at once. Temperature could play a role in the healing behavior my team saw, but we’ll need to conduct more research to determine how.

These results tell us that soft materials could help scientists develop technology that works well in extreme environments. Future research could dive deeper into how the vibrations in these materials relate to any self-healing properties.

This article is republished from The Conversation under a Creative Commons license. Read the original article.

A French-Chinese satellite blasted off Saturday on a hunt for the mightiest explosions in the universe, in a notable example of cooperation between a Western power and the Asian giant.

Developed by engineers from both countries, the Space Variable Objects Monitor (SVOM) is carrying four instruments—two French, two Chinese—that will seek out gamma-ray bursts, the light from which has traveled billions of light years to reach Earth.

The 930-kilogram (2,050-pound) satellite “successfully” took off around 3:00 pm (0700 GMT) aboard a Chinese Long March 2-C rocket from a space base in Xichang, in southwestern Sichuan province, China’s National Space Administration said.

Gamma-ray bursts generally occur after the explosion of huge stars—those more than 20 times as big as the sun—or the fusion of compact stars.

The extremely bright cosmic beams can give off a blast of energy equivalent to more than a billion billion suns.

Observing them is like “looking back in time, as the light from these objects takes a long time to reach us”, Ore Gottlieb, an astrophysicist at the Flatiron Institute’s Center for Astrophysics in New York, told AFP.

‘Several mysteries’

The rays carry traces of the gas clouds and galaxies they pass through on their journey through space—valuable data for better understanding the history and evolution of the universe.

“SVOM has the potential to unravel several mysteries in the field of (gamma-ray bursts), including detecting the most distant GRBs in the universe, which correspond to the earliest GRBs,” Gottlieb said.

The most distant bursts identified to date were produced just 630 million years after the Big Bang—when the universe was in its infancy.

“We are… interested in gamma-ray bursts for their own sake because they are very extreme cosmic explosions which allow us to better understand the death of certain stars,” said Frederic Daigne, an astrophysicist at the Paris Institute of Astrophysics.

“All of this data makes it possible to test the laws of physics with phenomena that are impossible to reproduce in the laboratory on Earth.”

Once analyzed, the data could help to improve understanding of the composition of space, and the dynamics of gas clouds or other galaxies.

The project stems from a partnership between the French and Chinese space agencies as well as other scientific and technical groups from both nations.

“It’s a great success. We’ve managed to work well with our Chinese colleagues,” Philippe Baptiste, CEO of France’s CNES space agency, told AFP after the launch.

Space cooperation at this level between the West and China is fairly uncommon, especially since the United States banned all collaboration between NASA and Beijing in 2011.

Race against time

“US concerns on technology transfer have inhibited US allies from collaborating with the Chinese very much, but it does happen occasionally,” said Jonathan McDowell, an astronomer at the Harvard-Smithsonian Center for Astrophysics in the United States.

In 2018, China and France jointly launched CFOSAT, an oceanographic satellite mainly used in marine meteorology.

Several European countries have also taken part in China’s Chang’e lunar exploration program.

So while SVOM is “by no means unique”, it remains “significant” in the context of space collaboration between China and the West, said McDowell.

Once in orbit 625 kilometers (388 miles) above the Earth, the satellite will send its data back to observatories.

The main challenge is that gamma-ray bursts are extremely brief, leaving scientists in a race against time to gather information.

Once it detects a burst, SVOM will send an alert to a team on duty around the clock.

Within five minutes, they will have to rev up a network of telescopes on the ground that will align precisely with the axis of the burst’s source to make more detailed observations.

© 2024 AFP