from carbon dioxide.
Science fiction stories are chock full of terraforming schemes and oxygen generators for a very good reason—we humans need molecular oxygen (O2) to breathe, and space is essentially devoid of it. Even on other planets with thick atmospheres, O2 is hard to come by.
So, when we explore space, we need to bring our own oxygen supply. That is not ideal because a lot of energy is needed to hoist things into space atop a rocket, and once the supply runs out, it is gone.
One place molecular oxygen does appear outside of Earth is in the wisps of gas streaming off comets. The source of that oxygen remained a mystery until two years ago when Konstantinos P. Giapis, a professor of chemical engineering at Caltech, and his postdoctoral fellow Yunxi Yao, proposed the existence of a new chemical process that could account for its production. Giapis, along with Tom Miller, professor of chemistry, have now demonstrated a new reaction for generating oxygen that Giapis says could help humans explore the universe and perhaps even fight climate change at home. More fundamentally though, he says the reaction represents a new kind of chemistry discovered by studying comets.
Most chemical reactions require energy, which is typically provided as heat. Giapis's research shows that some unusual reactions can occur by providing kinetic energy. When water molecules are shot like extremely tiny bullets onto surfaces containing oxygen, such as sand or rust, the water molecule can rip off that oxygen to produce molecular oxygen. This reaction occurs on comets when water molecules vaporize from the surface and are then accelerated by the solar wind until they crash back into the comet at high speed.
Comets, however, also emit carbon dioxide (CO2). Giapis and Yao wanted to test if CO2 could also produce molecular oxygen in collisions with the comet surface. When they found O2 in the stream of gases coming off the comet, they wanted to confirm that the reaction was similar to water's reaction. They designed an experiment to crash CO2 onto the inert surface of gold foil, which cannot be oxidized and should not produce molecular oxygen. Nonetheless, O2 continued to be emitted from the gold surface. This meant that both atoms of oxygen come from the same CO2 molecule, effectively splitting it in an extraordinary manner.
"At the time we thought it would be impossible to combine the two oxygen atoms of a CO2 molecule together because CO2 is a linear molecule, and you would have to bend the molecule severely for it to work," Giapis says. "You're doing something really drastic to the molecule."
The apparatus Giapis designed to perform the reaction works like a particle accelerator, turning the CO2 molecules into ions by giving them a charge and then accelerating them using an electric field, albeit at much lower energies than are found in a particle accelerator. However, he adds that such a device is not necessary for the reaction to occur.
"You could throw a stone with enough velocity at some CO2 and achieve the same thing," he says. "It would need to be traveling about as fast as a comet or asteroid travels through space."
That could explain the presence of small amounts of oxygen that have been observed high in the Martian atmosphere. There has been speculation that the oxygen is being generated by ultraviolet light from the sun striking CO2, but Giapis believes the oxygen is also generated by high-speed dust particles colliding with CO2 molecules.
He hopes that a variation of his reactor could be used to do the same thing at more useful scales—perhaps one day serving as a source of breathable air for astronauts on Mars or being used to combat climate change by pulling CO2, a greenhouse gas, out of Earth's atmosphere and turning it into oxygen. He acknowledges, however, that both of those applications are a long way off because the current version of the reactor has a low yield, creating only one to two oxygen molecules for every 100 CO2 molecules shot through the accelerator.
Wednesday, May 29, 2019
Wednesday, May 08, 2019
Nature is essential
You may go your entire life without seeing an endangered species, yet the globe's biodiversity crisis threatens all of humanity in numerous unseen or unrecognized ways, scientists say.
A massive United Nations report this week warned that nature is in trouble, estimated 1 million species are threatened with extinction if nothing is done and said the worldwide deterioration of nature is everybody's problem.
"Nature is essential for human existence and good quality of life," the report said.
Food, energy, medicine, water, protection from storms and floods and slowing climate change are some of the 18 ways nature helps keep people alive, the report said. And it concluded 14 of those are on long-term declining trends.
"You destroy nature and it's going to bite you back," Duke University ecology Stuart Pimm said, pointing to how difficult it has been for China to recover from decades of forest loss.
The Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) report points to more than 2,500 wars and other conflicts over fossil fuels, water, food and land to show how important nature is.
"Protecting biodiversity means protecting mankind because we human beings depend fundamentally on the diversity of the living," UNESCO Director-General Audrey Azoulay said in announcing the report in Paris.
Here are four ways humanity depends on nature, according to the report and scientists:
FOOD
Nearly all food comes directly from nature, said report co-author Kai Chan, an environmental scientist at the University of British Columbia. Even though overall the world is growing more food, pressure on crops from pollution, habitat changes and other forces has made prices soar and even caused food riots in Latin America, he said.
Pollinators across the globe, not just bees, are in decline. Three quarters of the world's food crops, including fruits, vegetables, coffee and cocoa, require pollination. The report said pollinator loss could cost the world $285 billion to $577 billion a year.
MEDICINE and HEALTH
About 70% of the drugs used to fight cancer "are natural or are synthetic products inspired by nature," the report said. About 4 billion people rely primarily on natural medicines.
George Mason University ecologist Thomas Lovejoy points to a single heat-thriving microbe that comes out of Yellowstone National Park's hot springs. Pieces of its genetic code are the key to a scientific technique called polymerase chain reaction (PCR) that is used for medical, genetic and forensic tests and much of modern biotechnology.
"Nature underpins all dimensions of human health," the report said.
FIGHTING CLIMATE CHANGE
The world's forests and oceans suck nearly 6.2 billion tons (5.6 billion metric tons) of heat-trapping carbon dioxide out of the air each year, the report said. That's about 60% of what humans produce through burning fossil fuels.
Earth would be warming more and faster without forests and oceans, scientists said.
Climate change and biodiversity loss are equally huge environmental problems that make each other worse, report chairman Robert Watson said.
STORM PROTECTION
People can build expensive time-consuming sea walls to fight the rise of oceans from climate change or the same protection can be offered by coastal mangroves, the report said.
But mangroves are in trouble, Watson said.
"They often act as a nursery for fisheries basically," Watson said. "And they clearly help to protect land from severe weather events and storm surges from the sea."
The problem, he said, is that many mangrove systems have been converted to shrimp farms, leaving the land vulnerable to storm surges and devoid of biodiversity.
LIVING PLANET
People may think of biodiversity or endangered species as something detached from their daily lives. But those people don't understand that Earth functions as a "living planet" with many parts dependent on each other, George Mason's Lovejoy said.
"We're here in Paris. Can you experience Paris without nature?" asked report co-chairman Eduardo Brondizio of Indiana University. "Every place we turn here we see biodiversity exposed to us in the streets. When we open the tap here, we drink excellent water. When we look at the parks, when we look at the atmosphere here in the city, it's all about nature."
-- by Seth Borenstein, Associated Press
A massive United Nations report this week warned that nature is in trouble, estimated 1 million species are threatened with extinction if nothing is done and said the worldwide deterioration of nature is everybody's problem.
"Nature is essential for human existence and good quality of life," the report said.
Food, energy, medicine, water, protection from storms and floods and slowing climate change are some of the 18 ways nature helps keep people alive, the report said. And it concluded 14 of those are on long-term declining trends.
"You destroy nature and it's going to bite you back," Duke University ecology Stuart Pimm said, pointing to how difficult it has been for China to recover from decades of forest loss.
The Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) report points to more than 2,500 wars and other conflicts over fossil fuels, water, food and land to show how important nature is.
"Protecting biodiversity means protecting mankind because we human beings depend fundamentally on the diversity of the living," UNESCO Director-General Audrey Azoulay said in announcing the report in Paris.
Here are four ways humanity depends on nature, according to the report and scientists:
FOOD
Nearly all food comes directly from nature, said report co-author Kai Chan, an environmental scientist at the University of British Columbia. Even though overall the world is growing more food, pressure on crops from pollution, habitat changes and other forces has made prices soar and even caused food riots in Latin America, he said.
Pollinators across the globe, not just bees, are in decline. Three quarters of the world's food crops, including fruits, vegetables, coffee and cocoa, require pollination. The report said pollinator loss could cost the world $285 billion to $577 billion a year.
MEDICINE and HEALTH
About 70% of the drugs used to fight cancer "are natural or are synthetic products inspired by nature," the report said. About 4 billion people rely primarily on natural medicines.
George Mason University ecologist Thomas Lovejoy points to a single heat-thriving microbe that comes out of Yellowstone National Park's hot springs. Pieces of its genetic code are the key to a scientific technique called polymerase chain reaction (PCR) that is used for medical, genetic and forensic tests and much of modern biotechnology.
"Nature underpins all dimensions of human health," the report said.
FIGHTING CLIMATE CHANGE
The world's forests and oceans suck nearly 6.2 billion tons (5.6 billion metric tons) of heat-trapping carbon dioxide out of the air each year, the report said. That's about 60% of what humans produce through burning fossil fuels.
Earth would be warming more and faster without forests and oceans, scientists said.
Climate change and biodiversity loss are equally huge environmental problems that make each other worse, report chairman Robert Watson said.
STORM PROTECTION
People can build expensive time-consuming sea walls to fight the rise of oceans from climate change or the same protection can be offered by coastal mangroves, the report said.
But mangroves are in trouble, Watson said.
"They often act as a nursery for fisheries basically," Watson said. "And they clearly help to protect land from severe weather events and storm surges from the sea."
The problem, he said, is that many mangrove systems have been converted to shrimp farms, leaving the land vulnerable to storm surges and devoid of biodiversity.
LIVING PLANET
People may think of biodiversity or endangered species as something detached from their daily lives. But those people don't understand that Earth functions as a "living planet" with many parts dependent on each other, George Mason's Lovejoy said.
"We're here in Paris. Can you experience Paris without nature?" asked report co-chairman Eduardo Brondizio of Indiana University. "Every place we turn here we see biodiversity exposed to us in the streets. When we open the tap here, we drink excellent water. When we look at the parks, when we look at the atmosphere here in the city, it's all about nature."
-- by Seth Borenstein, Associated Press
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