World Zoonoses Day: 'We have to act now to avoid even bigger catastrophes'

"The primary risks for future spillover of zoonotic diseases are deforestation of tropical environments and large-scale industrial farming of animals, specifically pigs and chickens at high density," says Emory disease ecologist Thomas Gillespie. (Getty Images)

By Carol Clark

On July 6 in 1885, Louis Pasteur successfully administered the first vaccine against rabies, one of the most feared diseases of that time. The bite of an infected animal transmits the rabies virus to humans, leading to an agonizing death without the vaccine.

World Zoonoses Day, held July 6 every year, marks this major breakthrough in the fight against zoonoses — diseases caused by germs that spread between animals and people. And yet, 135 years later, despite tremendous advances in science and medicine, the world is struggling to respond to the novel coronavirus — the latest devastating pathogen to spill over from animals.

“We are at a crisis point,” says Thomas Gillespie, associate professor in Emory University’s Department of Environmental Sciences and Rollins School of Public Health. “We have to act now. We cannot forsake this moment. If we don’t radically change our attitudes toward the natural world, things are going to get much, much worse. Pandemics will become increasingly common. What we are experiencing now will seem mild by comparison.”

Gillespie served as an expert reviewer for a report by the United Nations Environmental Program and partners, “Preventing future zoonotic disease outbreaks: Protecting the environment, animals and people in a post-COVID-19 world,” to be released July 6.

“The primary risks for future spillover of zoonotic diseases are deforestation of tropical environments and large-scale industrial farming of animals, specifically pigs and chickens at high density,” Gillespie says.

A disease ecologist, Gillespie studies how germs jump between wildlife, domesticated animals and people. Through this “One Health” approach, he aims to protect humans, ecosystems and biodiversity.

"We're all feeling the impact of the COVID-19 pandemic," Gillespie says. "That's created a sense of urgency that we haven't seen with past discussions of climate change and land-use change."

While vaccine development is important, pathogens can leap from animals to humans much faster than scientists can develop vaccines and treatments. “We also need complementary approaches that focus on the environment,” Gillespie notes. “It’s far cheaper to invest in the prevention of infectious disease outbreaks than to deal with the consequences of a pandemic.”

Gillespie is contributing his “One Health” expertise to an upcoming United Nations forum on the U.N. Sustainable Development Goals.

“The silos have broken down,” Gillespie says. “There is growing awareness that we don’t need a separate forum on climate change and another one for pandemics. Discussions about the environment and health should be integrated and not considered separately so that we can gain momentum. We really need to be sprinting right now. Climate change and the increase in pandemics are both signals that we have reached a tipping point.”

Genetic sequencing links the novel coronavirus that causes COVID-19 to horseshoe bats in China. The first detected outbreak sprang from a live animal market in Wuhan. Gillespie points out, however, that the coronavirus may have been circulating in remote, rural areas before it was detected in Wuhan, a city of 10 million where population density fueled rapid transmission.

He notes that no one has studied the ecological impacts of China’s Three Gorges Dam project. The world’s largest hydroelectric power station, it was built on the Yangtze River on what was previously a mix of secondary forest and agricultural land.

“Live animal markets are definitely dangerous places when it comes to spillover events,” Gillespie says, “but shutting all of them down won’t solve the bigger issue. The markets are just a small piece of a much bigger problem.”

Deforestation to make way for palm oil plantations, which changed the roosting habits of bats, was linked to a major Nipah virus outbreak in Malaysia. Evidence suggests that similar deforestation in West Africa for palm oil production may have played a role in outbreaks of Lassa fever and Ebola.

A meta-analysis by Gillespie and colleagues quantified how fragmentation of forests by agriculture facilitates the spread of pathogens from wildlife. Optimal rates of spillover occur once 40 percent of the forest cover disappears. “That opens a window where you’re going to see more germs jumping species,” Gillespie says. “And tropical environments are at primary risk for pathogen spillover due to simple mathematics — there is a much richer diversity of species living in the tropics than in other environments.”

In the developed world, and rapidly developing parts of the world, people are eating more animal protein and fried food than is recommended for human health. To meet the demand, corporations are clearing natural habitats for cattle ranches, for soybean fields to feed the cattle, and oil palm plantations for cooking oil.

Many species are endangered by these actions. Habitat loss, poaching and disease are the primary threats to the remaining great apes, Gillespie says. COVOID-19 poses a particularly dire situation for apes in danger of extinction, he adds, including bonobos, chimpanzees, gorillas and orangutans. Due to genetic similarities, they are highly susceptible to human respiratory diseases. Gillespie serves as an adviser on great apes to the International Union for Conservation of Nature (IUCN), and has worked to develop IUCN guidelines during the pandemic to limit human contact with the animals while also protecting them from poachers. Gillespie and colleagues created the “Non-human Primate COVID-19 Information Hub” to serve as a real-time resource on the issue.

Current policies fail to factor in the costs of wholesale extraction of resources and the destruction of natural habitats, Gillespie warns. Nature will persist, he adds, even as biodiversity diminishes.

“Nature will push forward, evolution will happen, without regard to human suffering,” Gillespie says. “Meanwhile, we’re ignoring how dependent we are on nature and how fragile we are in the grand scheme of things.”

Gillespie starts off his undergraduate Conservation Biology class with a quiz. Among the questions: How many people are there on the planet? Has the world reached its human carrying capacity?

The last item on the quiz asks students to list 10 species that occur in Atlanta. “None of the students ever writes Homo Sapiens,” Gillespie says. “Many people don’t think of themselves as part of nature anymore. They have this artificial sense that we’re apart from it.”

The pandemic is shifting perspectives. “We’re all feeling the impact of the COVID-19 pandemic,” Gillespie says. “That’s created a sense of urgency that we haven’t seen with past discussions on climate change and land-use change. People are recognizing the linkages between our financial and agricultural systems, the environment and our health. It’s critical right now to make the message as understandable as possible to as many people as possible.”

Follow Thomas Gillespie on Twitter: @BiodiversHealth.

Related:
Great apes and COVID-19: Experts raise the alarm for endangered species
Spillover: Why germs jump species from animals to people
Bat ecology in the era of pandemics

from eScienceCommons https://ift.tt/3eQFQUh

"The primary risks for future spillover of zoonotic diseases are deforestation of tropical environments and large-scale industrial farming of animals, specifically pigs and chickens at high density," says Emory disease ecologist Thomas Gillespie. (Getty Images)

By Carol Clark

On July 6 in 1885, Louis Pasteur successfully administered the first vaccine against rabies, one of the most feared diseases of that time. The bite of an infected animal transmits the rabies virus to humans, leading to an agonizing death without the vaccine.

World Zoonoses Day, held July 6 every year, marks this major breakthrough in the fight against zoonoses — diseases caused by germs that spread between animals and people. And yet, 135 years later, despite tremendous advances in science and medicine, the world is struggling to respond to the novel coronavirus — the latest devastating pathogen to spill over from animals.

“We are at a crisis point,” says Thomas Gillespie, associate professor in Emory University’s Department of Environmental Sciences and Rollins School of Public Health. “We have to act now. We cannot forsake this moment. If we don’t radically change our attitudes toward the natural world, things are going to get much, much worse. Pandemics will become increasingly common. What we are experiencing now will seem mild by comparison.”

Gillespie served as an expert reviewer for a report by the United Nations Environmental Program and partners, “Preventing future zoonotic disease outbreaks: Protecting the environment, animals and people in a post-COVID-19 world,” to be released July 6.

“The primary risks for future spillover of zoonotic diseases are deforestation of tropical environments and large-scale industrial farming of animals, specifically pigs and chickens at high density,” Gillespie says.

A disease ecologist, Gillespie studies how germs jump between wildlife, domesticated animals and people. Through this “One Health” approach, he aims to protect humans, ecosystems and biodiversity.

"We're all feeling the impact of the COVID-19 pandemic," Gillespie says. "That's created a sense of urgency that we haven't seen with past discussions of climate change and land-use change."

While vaccine development is important, pathogens can leap from animals to humans much faster than scientists can develop vaccines and treatments. “We also need complementary approaches that focus on the environment,” Gillespie notes. “It’s far cheaper to invest in the prevention of infectious disease outbreaks than to deal with the consequences of a pandemic.”

Gillespie is contributing his “One Health” expertise to an upcoming United Nations forum on the U.N. Sustainable Development Goals.

“The silos have broken down,” Gillespie says. “There is growing awareness that we don’t need a separate forum on climate change and another one for pandemics. Discussions about the environment and health should be integrated and not considered separately so that we can gain momentum. We really need to be sprinting right now. Climate change and the increase in pandemics are both signals that we have reached a tipping point.”

Genetic sequencing links the novel coronavirus that causes COVID-19 to horseshoe bats in China. The first detected outbreak sprang from a live animal market in Wuhan. Gillespie points out, however, that the coronavirus may have been circulating in remote, rural areas before it was detected in Wuhan, a city of 10 million where population density fueled rapid transmission.

He notes that no one has studied the ecological impacts of China’s Three Gorges Dam project. The world’s largest hydroelectric power station, it was built on the Yangtze River on what was previously a mix of secondary forest and agricultural land.

“Live animal markets are definitely dangerous places when it comes to spillover events,” Gillespie says, “but shutting all of them down won’t solve the bigger issue. The markets are just a small piece of a much bigger problem.”

Deforestation to make way for palm oil plantations, which changed the roosting habits of bats, was linked to a major Nipah virus outbreak in Malaysia. Evidence suggests that similar deforestation in West Africa for palm oil production may have played a role in outbreaks of Lassa fever and Ebola.

A meta-analysis by Gillespie and colleagues quantified how fragmentation of forests by agriculture facilitates the spread of pathogens from wildlife. Optimal rates of spillover occur once 40 percent of the forest cover disappears. “That opens a window where you’re going to see more germs jumping species,” Gillespie says. “And tropical environments are at primary risk for pathogen spillover due to simple mathematics — there is a much richer diversity of species living in the tropics than in other environments.”

In the developed world, and rapidly developing parts of the world, people are eating more animal protein and fried food than is recommended for human health. To meet the demand, corporations are clearing natural habitats for cattle ranches, for soybean fields to feed the cattle, and oil palm plantations for cooking oil.

Many species are endangered by these actions. Habitat loss, poaching and disease are the primary threats to the remaining great apes, Gillespie says. COVOID-19 poses a particularly dire situation for apes in danger of extinction, he adds, including bonobos, chimpanzees, gorillas and orangutans. Due to genetic similarities, they are highly susceptible to human respiratory diseases. Gillespie serves as an adviser on great apes to the International Union for Conservation of Nature (IUCN), and has worked to develop IUCN guidelines during the pandemic to limit human contact with the animals while also protecting them from poachers. Gillespie and colleagues created the “Non-human Primate COVID-19 Information Hub” to serve as a real-time resource on the issue.

Current policies fail to factor in the costs of wholesale extraction of resources and the destruction of natural habitats, Gillespie warns. Nature will persist, he adds, even as biodiversity diminishes.

“Nature will push forward, evolution will happen, without regard to human suffering,” Gillespie says. “Meanwhile, we’re ignoring how dependent we are on nature and how fragile we are in the grand scheme of things.”

Gillespie starts off his undergraduate Conservation Biology class with a quiz. Among the questions: How many people are there on the planet? Has the world reached its human carrying capacity?

The last item on the quiz asks students to list 10 species that occur in Atlanta. “None of the students ever writes Homo Sapiens,” Gillespie says. “Many people don’t think of themselves as part of nature anymore. They have this artificial sense that we’re apart from it.”

The pandemic is shifting perspectives. “We’re all feeling the impact of the COVID-19 pandemic,” Gillespie says. “That’s created a sense of urgency that we haven’t seen with past discussions on climate change and land-use change. People are recognizing the linkages between our financial and agricultural systems, the environment and our health. It’s critical right now to make the message as understandable as possible to as many people as possible.”

Follow Thomas Gillespie on Twitter: @BiodiversHealth.

Related:
Great apes and COVID-19: Experts raise the alarm for endangered species
Spillover: Why germs jump species from animals to people
Bat ecology in the era of pandemics

from eScienceCommons https://ift.tt/3eQFQUh

Moon and Antares in early July

These next few evenings – July 1 and 2, 2020 – let the moon introduce you to Antares. It’s a red star and the brightest star in the constellation Scorpius the Scorpion. Look first for the moon, and the nearby bright star will be Antares.

Any red-looking star that you can see with the unaided eye is either a red giant or red supergiant star. Antares is a red supergiant. This star, which is in the autumn of its years, is expected to explode as a supernova one of these days. No telling when that will be, however. It could happen tomorrow or a million years from now.

Although Antares lies way out there, at some 600 light-years distant, this star easily shines at 1st-magnitude brightness. In order to beam so brightly in our sky, this star must be extremely luminous, that is, intrinsically very brilliant as opposed to merely appearing bright because of a nearer distance.

Antares’ red color indicates a relatively cool surface temperature, and cool stars shine less brilliantly than hot stars of the same size. But Antares is just so big! Its sheer size makes this star more luminous than many stars with higher surface temperatures.

If Antares replaced the sun in our solar system, its circumference would extend beyond the orbit of the fourth planet, Mars. In this illustration, Antares is shown in contrast to another star, Arcturus, and our sun. Image via Wikimedia Commons.

Just how large is this incredible star? It’s not known with absolute certainty, but its radius is thought to be about three times the Earth’s distance from the sun (3 astronomical units). That’s about 3/5 the way from the sun to the orbit of Jupiter, the fifth planet outward from the sun. The radius of Antares is the equivalent of approximately 650 solar radii.

Presuming a radius of 650 solar radii and therefore a diameter of 650 solar diameters, that means the surface area of Antares exceeds that of our sun by some 122,500 times (Antares’ surface area = 650 x 650 = 122,500 solar). But Antares’ volume is actually a few hundred million times greater than the sun’s (Antares’ volume = 650 x 650 x 650 = 271,630,000 solar). And just to think that the sun has the volume of 1,300,000 Earths!

This artist’s concept shows the red supergiant star Antares in the constellation Scorpius. Image via ESO/ M. Kornmesser.

Bottom line: These next two evenings – July 1 and 2, 2020 – let the moon be your guide to Antares, a red supergiant star whose humongous size is truly difficult to fathom!

from EarthSky https://ift.tt/2BuAjEt

These next few evenings – July 1 and 2, 2020 – let the moon introduce you to Antares. It’s a red star and the brightest star in the constellation Scorpius the Scorpion. Look first for the moon, and the nearby bright star will be Antares.

Any red-looking star that you can see with the unaided eye is either a red giant or red supergiant star. Antares is a red supergiant. This star, which is in the autumn of its years, is expected to explode as a supernova one of these days. No telling when that will be, however. It could happen tomorrow or a million years from now.

Although Antares lies way out there, at some 600 light-years distant, this star easily shines at 1st-magnitude brightness. In order to beam so brightly in our sky, this star must be extremely luminous, that is, intrinsically very brilliant as opposed to merely appearing bright because of a nearer distance.

Antares’ red color indicates a relatively cool surface temperature, and cool stars shine less brilliantly than hot stars of the same size. But Antares is just so big! Its sheer size makes this star more luminous than many stars with higher surface temperatures.

If Antares replaced the sun in our solar system, its circumference would extend beyond the orbit of the fourth planet, Mars. In this illustration, Antares is shown in contrast to another star, Arcturus, and our sun. Image via Wikimedia Commons.

Just how large is this incredible star? It’s not known with absolute certainty, but its radius is thought to be about three times the Earth’s distance from the sun (3 astronomical units). That’s about 3/5 the way from the sun to the orbit of Jupiter, the fifth planet outward from the sun. The radius of Antares is the equivalent of approximately 650 solar radii.

Presuming a radius of 650 solar radii and therefore a diameter of 650 solar diameters, that means the surface area of Antares exceeds that of our sun by some 122,500 times (Antares’ surface area = 650 x 650 = 122,500 solar). But Antares’ volume is actually a few hundred million times greater than the sun’s (Antares’ volume = 650 x 650 x 650 = 271,630,000 solar). And just to think that the sun has the volume of 1,300,000 Earths!

This artist’s concept shows the red supergiant star Antares in the constellation Scorpius. Image via ESO/ M. Kornmesser.

Bottom line: These next two evenings – July 1 and 2, 2020 – let the moon be your guide to Antares, a red supergiant star whose humongous size is truly difficult to fathom!

from EarthSky https://ift.tt/2BuAjEt

How dust could make some exoplanets more habitable

Three computer simulations depicting how airborne dust can be distributed by winds on rocky exoplanets like Earth. Image via Denis Sergeev/ University of Exeter/ ScienceAlert.

What makes a planet habitable? Various factors can affect a planet’s ability to sustain life, such as temperature, amount of water, composition of both the planet and its atmosphere and the amount of radiation from the host star. Last month, researchers in the U.K. said they’ve found that a common component of atmospheres – dust – could increase the habitability of some exoplanets.

The peer-reviewed results were published in Nature Communications on June 9, 2020.

This is a significant finding, since it suggests that planets with a lot of dust in their atmospheres could have habitable conditions farther from their stars than previously thought. This would, in effect, expand the habitable zone, which is basically the region around a star where temperatures on a rocky could allow liquid water to exist.

Researchers from the University of Exeter, the Met Office and the University of East Anglia (UEA) were involved in the new study.

Effects of dust on the climate of planets. For a tidally locked planet (a) and non-tidally locked planet (b), panels a–d show the base state of the planets, e–h show the short- (stellar) and long-wave (infra-red) forcing (change in surface energy balance) introduced by dust and i–j show the resultant effect of the forcing on the surface temperature. Blue arrows show the motion of the planet around the star, and green arrows show the rotation of the planet relative to the star. Image via Boutle et al./ Nature Communications.

From the paper:

Identification of habitable planets beyond our solar system is a key goal of current and future space missions. Yet habitability depends not only on the stellar irradiance, but equally on constituent parts of the planetary atmosphere. Here we show, for the first time, that radiatively active mineral dust will have a significant impact on the habitability of Earth-like exoplanets.

In our own solar system, Mars typically comes to mind when we think of a dusty world, yet it remains a cold, dry planet on the surface due to its very thin atmosphere. But for some exoplanets, especially those that are tidally locked to their stars, it could be a different situation. Ian Boutle, from both the Met Office and University of Exeter and lead author of the study, said in a statement:

On Earth and Mars, dust storms have both cooling and warming effects on the surface, with the cooling effect typically winning out. But these ‘synchronised orbit’ planets are very different. Here, the dark sides of these planets are in perpetual night, and the warming effect wins out, whereas on the dayside, the cooling effect wins out. The effect is to moderate the temperature extremes, thus making the planet more habitable.

The dust factor is especially significant for planets orbiting red dwarf stars, the most common type of star in our galaxy. Many planets around those stars are likely to be tidally locked, orbiting with one side of the planet always facing the star, just as the moon always keeps one side facing Earth. Those planets would have one side always in daylight, and the other always in darkness. If there is a lot of dust, that could help cool down the hotter day side, and warm the colder night side.

Artist’s concept of a cloudy and rocky exoplanet orbiting a red dwarf star. Dust in the atmospheres of planets like this could moderate the temperature extremes if the planets are tidally locked, helping to make them more habitable. Image via L. Hustak/ J. Olmsted (STScI)/ NASA.

In an interesting scenario, dust could help hot planets retain their surface water, if they have any. A planet that is really hot, like Venus, could be cooled down by enough dust in the atmosphere. The amount of dust would then increase as water starts to be lost on the planet’s surface, which, ironically, in a process called negative climate feedback, would then slow down the loss of water. From the paper:

On tidally-locked planets, dust cools the day-side and warms the night-side, significantly widening the habitable zone. Independent of orbital configuration, we suggest that airborne dust can postpone planetary water loss at the inner edge of the habitable zone, through a feedback involving decreasing ocean coverage and increased dust loading.

The amount of energy a planet receives from its star is an important part of assessing habitability, but as Manoj Joshi from UEA noted, the composition of the atmosphere, including dust, is also very important:

Airborne dust is something that might keep planets habitable, but also obscures our ability to find signs of life on these planets. These effects need to be considered in future research.

The researchers performed a series of simulations of rocky Earth-sized planets and found that naturally occurring mineral dust can have a big impact on the habitability of such planets.

Mars is a very dusty place, and massive dust storms are common, but the dust doesn’t warm the planet much since the atmosphere is so thin. Image via SA/ Roscosmos/ CaSSIS/ CC BY-SA 3.0 IGO/ New Scientist.

Duncan Lyster, who ran an undergraduate experiment as part of the overall study (and now builds his own surfboards), also said:

It’s exciting to see the results of the practical research in my final year of study paying off. I was working on a fascinating exoplanet atmosphere simulation project, and was lucky enough to be part of a group who could take it on to the level of world-class research.

The researchers also point out that dust in a planet’s atmosphere must be taken into account when searching for possible biomarkers in that atmosphere. Those biomarkers could include gases such as oxygen, methane and ozone, and if there also was enough dust, the dust could obscure the detection of them, producing a false negative result. If potential biomarkers were missed in that way, the planet might be erroneously characterized as uninhabitable. Such biomarkers, which will be searched for with upcoming space telescopes like the James Webb Space Telescope (JWST) and others, will be a crucial aspect of the search for evidence of life beyond our solar system. Identifying them is already a challenge due to the extreme distances to these worlds, so knowing the amount of dust in a planetary atmosphere will be important as well. From the paper:

The inclusion of dust significantly obscures key biomarker gases (e.g. ozone, methane) in simulated transmission spectra, implying an important influence on the interpretation of observations. We demonstrate that future observational and theoretical studies of terrestrial exoplanets must consider the effect of dust.

Ian Boutle at the Met Office and University of Exeter, lead author of the new study. Image via Google Scholar.

Nathan Mayne from the University of Exeter, who assisted with the study, also noted how astrophysics in general will play a large role. He said:

Research such as this is only possible by crossing disciplines and combing the excellent understanding and techniques developed to study our own planet’s climate, with cutting edge astrophysics. To be able to involve undergraduate physics students in this, and other projects, also provides an excellent opportunity for those studying with us to directly develop the skills needed in such technical and collaborative projects. With game-changing facilities such as the JWST and E-ELT, becoming available in the near future, and set to provide a huge leap forward in the study of exoplanets, now is a great time to study physics!

The new assessment regarding exoplanetary dust will be very beneficial to scientists who will be looking for biomarkers and other evidence for habitable exoworlds, as well as studying how dust can affect a planet’s climate and environment overall.

Bottom line: Atmospheric dust could increase the habitability of some exoplanets.

Source: Mineral dust increases the habitability of terrestrial planets but confounds biomarker detection

Via University of Exeter

from EarthSky https://ift.tt/2NKeAuK

Three computer simulations depicting how airborne dust can be distributed by winds on rocky exoplanets like Earth. Image via Denis Sergeev/ University of Exeter/ ScienceAlert.

What makes a planet habitable? Various factors can affect a planet’s ability to sustain life, such as temperature, amount of water, composition of both the planet and its atmosphere and the amount of radiation from the host star. Last month, researchers in the U.K. said they’ve found that a common component of atmospheres – dust – could increase the habitability of some exoplanets.

The peer-reviewed results were published in Nature Communications on June 9, 2020.

This is a significant finding, since it suggests that planets with a lot of dust in their atmospheres could have habitable conditions farther from their stars than previously thought. This would, in effect, expand the habitable zone, which is basically the region around a star where temperatures on a rocky could allow liquid water to exist.

Researchers from the University of Exeter, the Met Office and the University of East Anglia (UEA) were involved in the new study.

Effects of dust on the climate of planets. For a tidally locked planet (a) and non-tidally locked planet (b), panels a–d show the base state of the planets, e–h show the short- (stellar) and long-wave (infra-red) forcing (change in surface energy balance) introduced by dust and i–j show the resultant effect of the forcing on the surface temperature. Blue arrows show the motion of the planet around the star, and green arrows show the rotation of the planet relative to the star. Image via Boutle et al./ Nature Communications.

From the paper:

Identification of habitable planets beyond our solar system is a key goal of current and future space missions. Yet habitability depends not only on the stellar irradiance, but equally on constituent parts of the planetary atmosphere. Here we show, for the first time, that radiatively active mineral dust will have a significant impact on the habitability of Earth-like exoplanets.

In our own solar system, Mars typically comes to mind when we think of a dusty world, yet it remains a cold, dry planet on the surface due to its very thin atmosphere. But for some exoplanets, especially those that are tidally locked to their stars, it could be a different situation. Ian Boutle, from both the Met Office and University of Exeter and lead author of the study, said in a statement:

On Earth and Mars, dust storms have both cooling and warming effects on the surface, with the cooling effect typically winning out. But these ‘synchronised orbit’ planets are very different. Here, the dark sides of these planets are in perpetual night, and the warming effect wins out, whereas on the dayside, the cooling effect wins out. The effect is to moderate the temperature extremes, thus making the planet more habitable.

The dust factor is especially significant for planets orbiting red dwarf stars, the most common type of star in our galaxy. Many planets around those stars are likely to be tidally locked, orbiting with one side of the planet always facing the star, just as the moon always keeps one side facing Earth. Those planets would have one side always in daylight, and the other always in darkness. If there is a lot of dust, that could help cool down the hotter day side, and warm the colder night side.

Artist’s concept of a cloudy and rocky exoplanet orbiting a red dwarf star. Dust in the atmospheres of planets like this could moderate the temperature extremes if the planets are tidally locked, helping to make them more habitable. Image via L. Hustak/ J. Olmsted (STScI)/ NASA.

In an interesting scenario, dust could help hot planets retain their surface water, if they have any. A planet that is really hot, like Venus, could be cooled down by enough dust in the atmosphere. The amount of dust would then increase as water starts to be lost on the planet’s surface, which, ironically, in a process called negative climate feedback, would then slow down the loss of water. From the paper:

On tidally-locked planets, dust cools the day-side and warms the night-side, significantly widening the habitable zone. Independent of orbital configuration, we suggest that airborne dust can postpone planetary water loss at the inner edge of the habitable zone, through a feedback involving decreasing ocean coverage and increased dust loading.

The amount of energy a planet receives from its star is an important part of assessing habitability, but as Manoj Joshi from UEA noted, the composition of the atmosphere, including dust, is also very important:

Airborne dust is something that might keep planets habitable, but also obscures our ability to find signs of life on these planets. These effects need to be considered in future research.

The researchers performed a series of simulations of rocky Earth-sized planets and found that naturally occurring mineral dust can have a big impact on the habitability of such planets.

Mars is a very dusty place, and massive dust storms are common, but the dust doesn’t warm the planet much since the atmosphere is so thin. Image via SA/ Roscosmos/ CaSSIS/ CC BY-SA 3.0 IGO/ New Scientist.

Duncan Lyster, who ran an undergraduate experiment as part of the overall study (and now builds his own surfboards), also said:

It’s exciting to see the results of the practical research in my final year of study paying off. I was working on a fascinating exoplanet atmosphere simulation project, and was lucky enough to be part of a group who could take it on to the level of world-class research.

The researchers also point out that dust in a planet’s atmosphere must be taken into account when searching for possible biomarkers in that atmosphere. Those biomarkers could include gases such as oxygen, methane and ozone, and if there also was enough dust, the dust could obscure the detection of them, producing a false negative result. If potential biomarkers were missed in that way, the planet might be erroneously characterized as uninhabitable. Such biomarkers, which will be searched for with upcoming space telescopes like the James Webb Space Telescope (JWST) and others, will be a crucial aspect of the search for evidence of life beyond our solar system. Identifying them is already a challenge due to the extreme distances to these worlds, so knowing the amount of dust in a planetary atmosphere will be important as well. From the paper:

The inclusion of dust significantly obscures key biomarker gases (e.g. ozone, methane) in simulated transmission spectra, implying an important influence on the interpretation of observations. We demonstrate that future observational and theoretical studies of terrestrial exoplanets must consider the effect of dust.

Ian Boutle at the Met Office and University of Exeter, lead author of the new study. Image via Google Scholar.

Nathan Mayne from the University of Exeter, who assisted with the study, also noted how astrophysics in general will play a large role. He said:

Research such as this is only possible by crossing disciplines and combing the excellent understanding and techniques developed to study our own planet’s climate, with cutting edge astrophysics. To be able to involve undergraduate physics students in this, and other projects, also provides an excellent opportunity for those studying with us to directly develop the skills needed in such technical and collaborative projects. With game-changing facilities such as the JWST and E-ELT, becoming available in the near future, and set to provide a huge leap forward in the study of exoplanets, now is a great time to study physics!

The new assessment regarding exoplanetary dust will be very beneficial to scientists who will be looking for biomarkers and other evidence for habitable exoworlds, as well as studying how dust can affect a planet’s climate and environment overall.

Bottom line: Atmospheric dust could increase the habitability of some exoplanets.

Source: Mineral dust increases the habitability of terrestrial planets but confounds biomarker detection

Via University of Exeter

from EarthSky https://ift.tt/2NKeAuK

COVID-19: “It could take months to build research up again”

There’s an atmosphere of excitement in Cambridge. After months of not being able to get into labs for anything other than COVID-19 research, universities are beginning to discuss how to reopen facilities.

It’s a conversation that Professor Richard Gilbertson, a children’s cancer researcher and director of the Cancer Research UK Cambridge Centre, is particularly pleased to be having.

Professor Richard Gilbertson.

“Lockdown has meant that lab research is essentially halted.” With universities and other institutions closing their facilities at the beginning of lockdown to all but COVID-19 research, scientists haven’t been able to get in the lab for a few months.

As many researchers in the centre work with cells to study cancer, Gilbertson says their work has quite literally been frozen in time.

“When you shutdown, you have to take the cells and freeze them to minus 80. And then they stay in suspended animation for the period of the lockdown.”

And while a lot of researchers have been able to analyse results and plan future experiments at home during lockdown, they’re itching to get back in the lab. Which is starting to become a reality. Universities are now looking at how to reopen facilities as lockdown rules relax, but it’s going to take scientists a while to get back up and running.

“A lot of experiments can take up to a year to build up again. So the shutdown is pretty devastating.”

Gilbertson says the cells researchers use to study cancer can take weeks or months to grow. “It’s a bit like a garden, you plant seeds and tend the garden and watch things grow in it, and only then are you ready to harvest.”

Scientists have to carefully grow their cellular garden, making sure they’re healthy before they begin their experiments. And while they still have the seeds for their research in the freezer, it will take a while before they’re ready.

“That’s why shutting down and then reopening is not an on off thing, it will take us a while to get back to previous productivity.”

This lag time is particularly problematic for early career researchers, who train in short bursts. “Your average PhD is somewhere between 3 and 4 years, so you can imagine why a year out of that can be absolutely devastating for someone’s training.”

Uncertain times

But it’s not just lab research that’s been affected, it’s everything. “Patients are always first and foremost in our minds,” says Gilbertson, which is why the impact of COVID-19 on clinical trials is particularly worrying.

“Most clinical trials stopped with COVID-19, we stopped enrolling patients onto clinical trials. And that was partly because the ‘machine’ that supports clinical trials was switched to COVID-19, and partly because of the capacity of hospitals. So that’s had a devastating effect for patients who would benefit from those trials.”

And while the immediate impact of COVID-19 on labs, clinical trials and cancer services is clear, it’s likely to be just the beginning.

“Another obvious area of impact is the economy,” says Gilbertson. We announced last week that because of the devasting impact of COVID-19 on our income, we could be forced to cut £150 million per year from our research funding.

“We live in a country that has fabulous cancer research, which is why I moved back here from the US. And yet most of that is funded by the generosity of the public. So periods like this can be devastating, because it can have a long-term knock on effect.”

And this uncertainty could have unseen consequences. “If you’re a new junior investigator, or a post doc, you’re getting to a point in your career where you need to decide if you’re going to stay in science,” says Gilbertson. “In a time of uncertainty, when you don’t know whether there will be grants available, that could sway people’s decisions, and they may go after a different career paths.”

This could mean some of the brightest scientists leave academic research, which would be a huge loss to cancer research.

“If you put all those things together, you can start to see how potentially devastating the pandemic has been for cancer research and cancer patients.”

Together we will still beat cancer

While there’s still a lot of uncertainty, Gilbertson is extremely excited to get the Centre back up and running, even if it’s not at full capacity at first. “With social distancing rules, we’re having to work back from how many people different departments can accommodate at any one time.”

Gilbertson and his colleagues now discussing which work to prioritise when the labs reopen. “We’re starting to think about who should be in the building and why they should be in the building. And that’s not a bad thing – COVID-19 has really made us think hard about prioritising the most important experiments.”

For Gilbertson, he’s particularly excited about two projects. “I’ve been going after a particular type of brain tumour – medulloblastoma – for 30 years, ever since I first saw a child die of it. We’re on the cusp of developing a kinder treatment that we hope would spare children getting radiotherapy, which would be absolutely fantastic. So we’re really chomping at the bit to get that going.”

The other project is a study that aims to understand more about how and why tumours spread to other parts of the body. “We think we’ve uncovered a mechanism that governs metastasis, which would be really exciting.”

But Gilbertson knows that getting these projects back up and running doesn’t just rely on getting scientists back in the lab. It also relies on the generosity of our supporters.

“I don’t think people hear it enough from researchers, but thank you so much for your support. The money you give helps to keep the lights on, keep our machines running, it means we can do those clinical trials, to find new treatments.

“If it wasn’t for that pound you were giving, none of that would happen, it would all go away. And with COVID-19, there’s a possibility that some of it could go away, so we need your support now more than ever.”

Katie 

COVID-19 has slowed us down, but we will never stop. 

> Donate today to help continue life-saving research.

from Cancer Research UK – Science blog https://ift.tt/2Akb9YP

There’s an atmosphere of excitement in Cambridge. After months of not being able to get into labs for anything other than COVID-19 research, universities are beginning to discuss how to reopen facilities.

It’s a conversation that Professor Richard Gilbertson, a children’s cancer researcher and director of the Cancer Research UK Cambridge Centre, is particularly pleased to be having.

Professor Richard Gilbertson.

“Lockdown has meant that lab research is essentially halted.” With universities and other institutions closing their facilities at the beginning of lockdown to all but COVID-19 research, scientists haven’t been able to get in the lab for a few months.

As many researchers in the centre work with cells to study cancer, Gilbertson says their work has quite literally been frozen in time.

“When you shutdown, you have to take the cells and freeze them to minus 80. And then they stay in suspended animation for the period of the lockdown.”

And while a lot of researchers have been able to analyse results and plan future experiments at home during lockdown, they’re itching to get back in the lab. Which is starting to become a reality. Universities are now looking at how to reopen facilities as lockdown rules relax, but it’s going to take scientists a while to get back up and running.

“A lot of experiments can take up to a year to build up again. So the shutdown is pretty devastating.”

Gilbertson says the cells researchers use to study cancer can take weeks or months to grow. “It’s a bit like a garden, you plant seeds and tend the garden and watch things grow in it, and only then are you ready to harvest.”

Scientists have to carefully grow their cellular garden, making sure they’re healthy before they begin their experiments. And while they still have the seeds for their research in the freezer, it will take a while before they’re ready.

“That’s why shutting down and then reopening is not an on off thing, it will take us a while to get back to previous productivity.”

This lag time is particularly problematic for early career researchers, who train in short bursts. “Your average PhD is somewhere between 3 and 4 years, so you can imagine why a year out of that can be absolutely devastating for someone’s training.”

Uncertain times

But it’s not just lab research that’s been affected, it’s everything. “Patients are always first and foremost in our minds,” says Gilbertson, which is why the impact of COVID-19 on clinical trials is particularly worrying.

“Most clinical trials stopped with COVID-19, we stopped enrolling patients onto clinical trials. And that was partly because the ‘machine’ that supports clinical trials was switched to COVID-19, and partly because of the capacity of hospitals. So that’s had a devastating effect for patients who would benefit from those trials.”

And while the immediate impact of COVID-19 on labs, clinical trials and cancer services is clear, it’s likely to be just the beginning.

“Another obvious area of impact is the economy,” says Gilbertson. We announced last week that because of the devasting impact of COVID-19 on our income, we could be forced to cut £150 million per year from our research funding.

“We live in a country that has fabulous cancer research, which is why I moved back here from the US. And yet most of that is funded by the generosity of the public. So periods like this can be devastating, because it can have a long-term knock on effect.”

And this uncertainty could have unseen consequences. “If you’re a new junior investigator, or a post doc, you’re getting to a point in your career where you need to decide if you’re going to stay in science,” says Gilbertson. “In a time of uncertainty, when you don’t know whether there will be grants available, that could sway people’s decisions, and they may go after a different career paths.”

This could mean some of the brightest scientists leave academic research, which would be a huge loss to cancer research.

“If you put all those things together, you can start to see how potentially devastating the pandemic has been for cancer research and cancer patients.”

Together we will still beat cancer

While there’s still a lot of uncertainty, Gilbertson is extremely excited to get the Centre back up and running, even if it’s not at full capacity at first. “With social distancing rules, we’re having to work back from how many people different departments can accommodate at any one time.”

Gilbertson and his colleagues now discussing which work to prioritise when the labs reopen. “We’re starting to think about who should be in the building and why they should be in the building. And that’s not a bad thing – COVID-19 has really made us think hard about prioritising the most important experiments.”

For Gilbertson, he’s particularly excited about two projects. “I’ve been going after a particular type of brain tumour – medulloblastoma – for 30 years, ever since I first saw a child die of it. We’re on the cusp of developing a kinder treatment that we hope would spare children getting radiotherapy, which would be absolutely fantastic. So we’re really chomping at the bit to get that going.”

The other project is a study that aims to understand more about how and why tumours spread to other parts of the body. “We think we’ve uncovered a mechanism that governs metastasis, which would be really exciting.”

But Gilbertson knows that getting these projects back up and running doesn’t just rely on getting scientists back in the lab. It also relies on the generosity of our supporters.

“I don’t think people hear it enough from researchers, but thank you so much for your support. The money you give helps to keep the lights on, keep our machines running, it means we can do those clinical trials, to find new treatments.

“If it wasn’t for that pound you were giving, none of that would happen, it would all go away. And with COVID-19, there’s a possibility that some of it could go away, so we need your support now more than ever.”

Katie 

COVID-19 has slowed us down, but we will never stop. 

> Donate today to help continue life-saving research.

from Cancer Research UK – Science blog https://ift.tt/2Akb9YP

Opportunity Costs And Why Fireworks Complaints Are Up This Year

Opportunity Costs And Why Fireworks Complaints Are Up This Year

The number of fireworks being lit off at night is out of control this year.

While people often light off fireworks close to the Fourth of July, this year fireworks have been lit in large numbers starting weeks earlier. New York City had a 4,000% increase in fireworks complaints in the first two weeks of June compared with last year. This prompted Mayor Bill de Blasio to vow a crackdown on illegal fireworks.

Complaints about fireworks are not confined to just New York City, but in cities across the country like San Francisco, Denver, Harrisburg, Albuquerque, Providence and many other places. This has led to a rise in conspiracy theories, including one that the nightly noise is an elaborate government plot to create confusion in neighborhoods.

I am an economist who has spoken and written about fireworks for years. After hearing a constant barrage nightly for weeks, I began wondering why so many people are lighting off fireworks this year.

It isn’t economics

There are two possible economic reasons behind an increase in fireworks usage: falling prices or increased supply. However, neither of these is the culprit behind the increase in fireworks usage this year.

The vast majority of the fireworks individuals shoot off in the U.S. are manufactured overseas, mainly in China. Each shipment of fireworks brought into the U.S. includes a detailed invoice that shows the quantity and price the importer paid.

Price data for the first four months of 2020 show importers paid an average of US$2.63 per kilogram for fireworks from China. A year earlier, importers paid an average of $2.60 per kilogram. This means prices rose slightly from 2019 to 2020, eliminating the falling price argument.

Increased supply is also not the reason. In a typical year there are two holidays with widespread firework usage; New Year’s Eve and the Fourth of July.

Deliveries in 2020 are an exception to this pattern. Because of the coronavirus, the U.S. imported very few fireworks in March. During the first four months of 2020 the U.S. imported 9 million kilograms of fireworks from China. While this seems like a large number, it is one-third less than a year earlier.

Fireworks are much more common around holidays like New Year’s Eve. Tayfun Coskun/Anadolu Agency via Getty Images

Nor is it legal reform

Another potential reason could be changes in laws.

Most major dense cities like New York, Chicago and San Francisco ban fireworks.

However, if neighboring jurisdictions have loosened their rules, then people can easily drive outside the city to purchase fireworks.

There has been a steady reduction in state prohibitions against individuals using fireworks. Today only one state, Massachusetts, completely prohibits individuals from owning and using any type of fireworks. All the rest allow them in some form.

However, the most recent two states to allow consumers to shoot off fireworks are New Jersey in 2017 and Delaware in 2018. Since most states relaxed prohibitions against fireworks more than two years ago, recent rule changes also cannot be behind the increase.

The most likely culprit

To find the real reason, it helps to consider that millions of Americans have been locked down in their homes and apartments for months. As an employee at a fireworks store in Stroudsburg, Pennsylvania, put it, “People are bored. They just want to blow stuff up.”

While this argument is understandable, I think the most likely reason is even simpler. And it has a lot to do with opportunity costs, something economists spend a lot of time thinking about.

Opportunity costs put a dollar value on what else a person could do with their time. For example, before the pandemic, I had many choices at night. I could work, go out with friends, watch television or see a movie in the theater.

By shutting down restaurants, theaters, bars and other venues, COVID-19 has dramatically reduced my choices.

The pandemic has also thrown millions out of work. Many people who would normally be working at night are not. This means the opportunity cost for using fireworks is exceptionally low compared with before, since there are so few opportunities to socialize, be entertained or work.

Beyond lower opportunity costs for fireworks users, there are many unemployed people who are now looking for opportunities to earn money. Buying fireworks in a rural area like northern Pennsylvania and selling them at higher prices in a city that bans their sale, such as New York City, can be easy and profitable.

So few arrests are made for fireworks that the FBI, which tracks problems like moonshining and polygamy on its detailed list of offenses, does not give it a category.

Idle hands

Fireworks are dangerous. While few people die each year from using them, the latest figures for 2019 show that fireworks hurt about 10,000 people per year in the U.S.

However, massive unemployment caused by COVID-19 is also dangerous.

There is an old quote that idle hands lead to mischief. In this case, idle people lead to large amounts of illegal firework usage.

My belief is that once the millions of unemployed people in the U.S. go back to work, the number of illegal fireworks shot off will rapidly decrease and will once again be limited to the times around New Year’s Eve and the Fourth of July.

Top image: Fireworks light up the sky over New York City in 2019. Gary Hershorn/Getty Images

By Jay L. Zagorsky, Senior Lecturer, Questrom School of Business, Boston University. This article is republished from The Conversation under a Creative Commons license. Read the original article.

sb admin Tue, 06/30/2020 - 12:17

Categories

Brain and Behavior

from ScienceBlogs - Where the world discusses science https://ift.tt/38gPcGz

Opportunity Costs And Why Fireworks Complaints Are Up This Year

The number of fireworks being lit off at night is out of control this year.

While people often light off fireworks close to the Fourth of July, this year fireworks have been lit in large numbers starting weeks earlier. New York City had a 4,000% increase in fireworks complaints in the first two weeks of June compared with last year. This prompted Mayor Bill de Blasio to vow a crackdown on illegal fireworks.

Complaints about fireworks are not confined to just New York City, but in cities across the country like San Francisco, Denver, Harrisburg, Albuquerque, Providence and many other places. This has led to a rise in conspiracy theories, including one that the nightly noise is an elaborate government plot to create confusion in neighborhoods.

I am an economist who has spoken and written about fireworks for years. After hearing a constant barrage nightly for weeks, I began wondering why so many people are lighting off fireworks this year.

It isn’t economics

There are two possible economic reasons behind an increase in fireworks usage: falling prices or increased supply. However, neither of these is the culprit behind the increase in fireworks usage this year.

The vast majority of the fireworks individuals shoot off in the U.S. are manufactured overseas, mainly in China. Each shipment of fireworks brought into the U.S. includes a detailed invoice that shows the quantity and price the importer paid.

Price data for the first four months of 2020 show importers paid an average of US$2.63 per kilogram for fireworks from China. A year earlier, importers paid an average of $2.60 per kilogram. This means prices rose slightly from 2019 to 2020, eliminating the falling price argument.

Increased supply is also not the reason. In a typical year there are two holidays with widespread firework usage; New Year’s Eve and the Fourth of July.

Deliveries in 2020 are an exception to this pattern. Because of the coronavirus, the U.S. imported very few fireworks in March. During the first four months of 2020 the U.S. imported 9 million kilograms of fireworks from China. While this seems like a large number, it is one-third less than a year earlier.

Fireworks are much more common around holidays like New Year’s Eve. Tayfun Coskun/Anadolu Agency via Getty Images

Nor is it legal reform

Another potential reason could be changes in laws.

Most major dense cities like New York, Chicago and San Francisco ban fireworks.

However, if neighboring jurisdictions have loosened their rules, then people can easily drive outside the city to purchase fireworks.

There has been a steady reduction in state prohibitions against individuals using fireworks. Today only one state, Massachusetts, completely prohibits individuals from owning and using any type of fireworks. All the rest allow them in some form.

However, the most recent two states to allow consumers to shoot off fireworks are New Jersey in 2017 and Delaware in 2018. Since most states relaxed prohibitions against fireworks more than two years ago, recent rule changes also cannot be behind the increase.

The most likely culprit

To find the real reason, it helps to consider that millions of Americans have been locked down in their homes and apartments for months. As an employee at a fireworks store in Stroudsburg, Pennsylvania, put it, “People are bored. They just want to blow stuff up.”

While this argument is understandable, I think the most likely reason is even simpler. And it has a lot to do with opportunity costs, something economists spend a lot of time thinking about.

Opportunity costs put a dollar value on what else a person could do with their time. For example, before the pandemic, I had many choices at night. I could work, go out with friends, watch television or see a movie in the theater.

By shutting down restaurants, theaters, bars and other venues, COVID-19 has dramatically reduced my choices.

The pandemic has also thrown millions out of work. Many people who would normally be working at night are not. This means the opportunity cost for using fireworks is exceptionally low compared with before, since there are so few opportunities to socialize, be entertained or work.

Beyond lower opportunity costs for fireworks users, there are many unemployed people who are now looking for opportunities to earn money. Buying fireworks in a rural area like northern Pennsylvania and selling them at higher prices in a city that bans their sale, such as New York City, can be easy and profitable.

So few arrests are made for fireworks that the FBI, which tracks problems like moonshining and polygamy on its detailed list of offenses, does not give it a category.

Idle hands

Fireworks are dangerous. While few people die each year from using them, the latest figures for 2019 show that fireworks hurt about 10,000 people per year in the U.S.

However, massive unemployment caused by COVID-19 is also dangerous.

There is an old quote that idle hands lead to mischief. In this case, idle people lead to large amounts of illegal firework usage.

My belief is that once the millions of unemployed people in the U.S. go back to work, the number of illegal fireworks shot off will rapidly decrease and will once again be limited to the times around New Year’s Eve and the Fourth of July.

Top image: Fireworks light up the sky over New York City in 2019. Gary Hershorn/Getty Images

By Jay L. Zagorsky, Senior Lecturer, Questrom School of Business, Boston University. This article is republished from The Conversation under a Creative Commons license. Read the original article.

sb admin Tue, 06/30/2020 - 12:17

Categories

Brain and Behavior

from ScienceBlogs - Where the world discusses science https://ift.tt/38gPcGz

When the sky exploded: Remembering Tunguska

Photo from the Soviet Academy of Science 1927 expedition, led by Leonid Kulik, showing trees knocked over by the Tunguska blast in 1908. Image via Wikipedia.

June 30 is Asteroid Day 2020

On the morning of June 30, 1908, the largest asteroid impact in recorded history occurred in a remote part of Siberia, Russia. The explosion happened over the sparsely populated Eastern Siberian taiga, above Siberia’s Podkamennaya Tunguska River in what is now Krasnoyarsk Krai. The blast flattened an estimated 80 million trees over an area of 830 square miles (2,150 square km) of forest. We now celebrate Asteroid Day each year on the anniversary of what is now known as the Tunguska event.

Witnesses reported seeing a fireball – a bluish light, nearly as bright as the sun – moving across the sky, followed by a flash and a sound similar to artillery fire. Along with the sound was a powerful shockwave that broke windows hundreds of miles away and knocked people off their feet. The explosion in the sky was like nothing ever seen before.

Even though there was no crater found, it is still categorized as an impact event, and is believed to have been caused by an incoming asteroid (or comet), which never actually struck Earth but instead exploded in the atmosphere, causing what is known as an air burst, three to six miles (five to ten km) above Earth’s surface. Even though the asteroid didn’t hit the Earth per se, the atmospheric explosion was still enough to cause massive damage to the forest in the region. Recent research shows that the object was most likely a stony asteroid the size of a five-story building that broke apart about 15 miles (24 km) above the ground. It is estimated the asteroid entered Earth’s atmosphere traveling at a speed of about 33,500 miles (54,000 km) per hour.

Another view of fallen trees at Tunguska in Siberia, in 1929. It wasn’t until 1927 that Russian scientists – led by Leonid Kulik – were finally able to get to the scene. Photo via the Soviet Academy of Science/ NASA Science.

The explosion released enough energy to kill reindeer and flatten trees for many miles around the blast site. At the time, it was difficult to reach this remote part of Siberia. It wasn’t until 1927 that Leonid Kulik led the first Soviet research expedition to investigate the Tunguska event. He made a initial trip to the region, interviewed local witnesses and explored the region where the trees had been felled. He became convinced that they were all turned with their roots to the center. He did not find any meteorite fragments, and he did not find a meteorite crater.

So what happened? Over the years, scientists and others concocted fabulous explanations for the Tunguska explosion. Some were pretty wild, such as the encounter of Earth with a stricken alien spacecraft, or a mini-black-hole, or a particle of antimatter.

But the truth is rather more ordinary. It is now thought that, in all likelihood, a small icy comet or stony asteroid collided with Earth’s atmosphere. If it were an asteroid, it might have been about a third as big as a football field – moving at about 10 miles (15 km) per second.

Photo of an air burst, in this case from a U.S. Navy submarine-launched Tomahawk cruise missile. A similar kind of air burst from an incoming asteroid or comet is thought to have flattened the trees in Siberia in 1908. Image via Wikimedia Commons.

In 2019, new research – inspired by a workshop held at NASA’s Ames Research Center in Silicon Valley and sponsored by the NASA Planetary Defense Coordination Office – was published about the Tunguska event, in a series of papers in a special issue of the journal Icarus. The theme of the workshop was reexamining the astronomical cold case of the 1908 Tunguska impact event.

Some vital clues as to what happened during the Tunguska event appeared on February 15, 2013, when a smaller but still impressive meteor burst in the atmosphere near Chelyabinsk, Russia. As NASA explained:

New evidence to help solve the mystery of Tunguska had arrived. This highly documented fireball created an opportunity for researchers to apply modern computer modeling techniques to explain what was seen, heard and felt.

The models were used with video observations of the fireball and maps of the damage on the ground to reconstruct the original size, motion and speed of the Chelyabinsk object. The resulting interpretation is that Chelyabinsk was most likely a stony asteroid the size of a five-story building that broke apart 15 miles above the ground. This generated a shock wave equivalent to a 550-kiloton explosion. The explosion’s shockwave blew out roughly a million windows and injured more than a thousand people. Fortunately, the force of the explosion was not enough to knock down trees or structures.

Per current understanding of the asteroid population, an object like the Chelyabinsk meteor can impact the Earth every 10 to 100 years on average.

Map showing the approximate location of the Tunguska event of 1908 in Siberia, Russia. Image via Wikipedia.

Approximate size comparison of the asteroids/meteorites that exploded over Tunguska and Chelyabinsk, in relation to the Empire State Building and the Eiffel Tower. Image via Wikipedia.

Read more about NASA’s research on the Tunguska event

Due to the Tunguska event, and other, smaller impacts, astronomers have come to take the possibility of catastrophic comet and asteroid impacts more seriously in recent decades. They now have regular observing programs to watch for Near-Earth Objects, as they’re called. There are regular meetings to discuss what might happen if we did find a large object on a collision course with Earth. And space scientists are planning missions to an asteroid, including ESA’s Hera mission, due to launch to the Didymos pair of near-Earth asteroids in 2024, and NASA’s DART mission, also traveling to Didymos, which will launch sometime in late 2021.

Lorien Wheeler, a researcher at NASA Ames Research Center, working on NASA’s Asteroid Threat Assessment Project, said:

Because there are so few observed cases, a lot of uncertainty remains about how large asteroids break up in the atmosphere and how much damage they could cause on the ground. However, recent advancements in computational models, along with analyses of the Chelyabinsk and other meteor events, are helping to improve our understanding of these factors so that we can better evaluate potential asteroid threats in the future.

Smoke trail from the Chelyabinsk meteor, February 15, 2013. Image via Alex Alishevskikh, who caught it about a minute after the blast.

Astronomer David Morrison, also at NASA Ames Research Center, commented:

Tunguska is the largest cosmic impact witnessed by modern humans. It also is characteristic of the sort of impact we are likely to have to protect against in the future.

On February 15, 2013, a similar although smaller airburst occurred over the city of Chelyabinsk, Russia. In this case, the airburst was likely caused by a stony asteroid or meteorite the size of a five-story building that broke apart 15 miles (24 km) above the ground. The shockwave from the blast, equivalent to a 550 kiloton explosion, blew out roughly a million windows and injured more than a thousand people in six cities across Russia.

Bottom line: On June 30, 1908, an object from space, thought to be an asteroid, exploded above Siberia, Russia, in what has become known as the Tunguska event. The explosion flattened thousands of trees, killed reindeer and blew out windows hundreds of miles away.

Source: Icarus special papers on Tunguska

Via NASA

Via NASA Science

Via Wikipedia

from EarthSky https://ift.tt/2KOzXMd

Photo from the Soviet Academy of Science 1927 expedition, led by Leonid Kulik, showing trees knocked over by the Tunguska blast in 1908. Image via Wikipedia.

June 30 is Asteroid Day 2020

On the morning of June 30, 1908, the largest asteroid impact in recorded history occurred in a remote part of Siberia, Russia. The explosion happened over the sparsely populated Eastern Siberian taiga, above Siberia’s Podkamennaya Tunguska River in what is now Krasnoyarsk Krai. The blast flattened an estimated 80 million trees over an area of 830 square miles (2,150 square km) of forest. We now celebrate Asteroid Day each year on the anniversary of what is now known as the Tunguska event.

Witnesses reported seeing a fireball – a bluish light, nearly as bright as the sun – moving across the sky, followed by a flash and a sound similar to artillery fire. Along with the sound was a powerful shockwave that broke windows hundreds of miles away and knocked people off their feet. The explosion in the sky was like nothing ever seen before.

Even though there was no crater found, it is still categorized as an impact event, and is believed to have been caused by an incoming asteroid (or comet), which never actually struck Earth but instead exploded in the atmosphere, causing what is known as an air burst, three to six miles (five to ten km) above Earth’s surface. Even though the asteroid didn’t hit the Earth per se, the atmospheric explosion was still enough to cause massive damage to the forest in the region. Recent research shows that the object was most likely a stony asteroid the size of a five-story building that broke apart about 15 miles (24 km) above the ground. It is estimated the asteroid entered Earth’s atmosphere traveling at a speed of about 33,500 miles (54,000 km) per hour.

Another view of fallen trees at Tunguska in Siberia, in 1929. It wasn’t until 1927 that Russian scientists – led by Leonid Kulik – were finally able to get to the scene. Photo via the Soviet Academy of Science/ NASA Science.

The explosion released enough energy to kill reindeer and flatten trees for many miles around the blast site. At the time, it was difficult to reach this remote part of Siberia. It wasn’t until 1927 that Leonid Kulik led the first Soviet research expedition to investigate the Tunguska event. He made a initial trip to the region, interviewed local witnesses and explored the region where the trees had been felled. He became convinced that they were all turned with their roots to the center. He did not find any meteorite fragments, and he did not find a meteorite crater.

So what happened? Over the years, scientists and others concocted fabulous explanations for the Tunguska explosion. Some were pretty wild, such as the encounter of Earth with a stricken alien spacecraft, or a mini-black-hole, or a particle of antimatter.

But the truth is rather more ordinary. It is now thought that, in all likelihood, a small icy comet or stony asteroid collided with Earth’s atmosphere. If it were an asteroid, it might have been about a third as big as a football field – moving at about 10 miles (15 km) per second.

Photo of an air burst, in this case from a U.S. Navy submarine-launched Tomahawk cruise missile. A similar kind of air burst from an incoming asteroid or comet is thought to have flattened the trees in Siberia in 1908. Image via Wikimedia Commons.

In 2019, new research – inspired by a workshop held at NASA’s Ames Research Center in Silicon Valley and sponsored by the NASA Planetary Defense Coordination Office – was published about the Tunguska event, in a series of papers in a special issue of the journal Icarus. The theme of the workshop was reexamining the astronomical cold case of the 1908 Tunguska impact event.

Some vital clues as to what happened during the Tunguska event appeared on February 15, 2013, when a smaller but still impressive meteor burst in the atmosphere near Chelyabinsk, Russia. As NASA explained:

New evidence to help solve the mystery of Tunguska had arrived. This highly documented fireball created an opportunity for researchers to apply modern computer modeling techniques to explain what was seen, heard and felt.

The models were used with video observations of the fireball and maps of the damage on the ground to reconstruct the original size, motion and speed of the Chelyabinsk object. The resulting interpretation is that Chelyabinsk was most likely a stony asteroid the size of a five-story building that broke apart 15 miles above the ground. This generated a shock wave equivalent to a 550-kiloton explosion. The explosion’s shockwave blew out roughly a million windows and injured more than a thousand people. Fortunately, the force of the explosion was not enough to knock down trees or structures.

Per current understanding of the asteroid population, an object like the Chelyabinsk meteor can impact the Earth every 10 to 100 years on average.

Map showing the approximate location of the Tunguska event of 1908 in Siberia, Russia. Image via Wikipedia.

Approximate size comparison of the asteroids/meteorites that exploded over Tunguska and Chelyabinsk, in relation to the Empire State Building and the Eiffel Tower. Image via Wikipedia.

Read more about NASA’s research on the Tunguska event

Due to the Tunguska event, and other, smaller impacts, astronomers have come to take the possibility of catastrophic comet and asteroid impacts more seriously in recent decades. They now have regular observing programs to watch for Near-Earth Objects, as they’re called. There are regular meetings to discuss what might happen if we did find a large object on a collision course with Earth. And space scientists are planning missions to an asteroid, including ESA’s Hera mission, due to launch to the Didymos pair of near-Earth asteroids in 2024, and NASA’s DART mission, also traveling to Didymos, which will launch sometime in late 2021.

Lorien Wheeler, a researcher at NASA Ames Research Center, working on NASA’s Asteroid Threat Assessment Project, said:

Because there are so few observed cases, a lot of uncertainty remains about how large asteroids break up in the atmosphere and how much damage they could cause on the ground. However, recent advancements in computational models, along with analyses of the Chelyabinsk and other meteor events, are helping to improve our understanding of these factors so that we can better evaluate potential asteroid threats in the future.

Smoke trail from the Chelyabinsk meteor, February 15, 2013. Image via Alex Alishevskikh, who caught it about a minute after the blast.

Astronomer David Morrison, also at NASA Ames Research Center, commented:

Tunguska is the largest cosmic impact witnessed by modern humans. It also is characteristic of the sort of impact we are likely to have to protect against in the future.

On February 15, 2013, a similar although smaller airburst occurred over the city of Chelyabinsk, Russia. In this case, the airburst was likely caused by a stony asteroid or meteorite the size of a five-story building that broke apart 15 miles (24 km) above the ground. The shockwave from the blast, equivalent to a 550 kiloton explosion, blew out roughly a million windows and injured more than a thousand people in six cities across Russia.

Bottom line: On June 30, 1908, an object from space, thought to be an asteroid, exploded above Siberia, Russia, in what has become known as the Tunguska event. The explosion flattened thousands of trees, killed reindeer and blew out windows hundreds of miles away.

Source: Icarus special papers on Tunguska

Via NASA

Via NASA Science

Via Wikipedia

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Dust-laden sunsets over Florida and Texas

View at EarthSky Community Photos. | A sunset shrouded in African dust, captured by John Merriam in Florida on June 28, 2020. Notice the layers of dust, and the bird! Thank you, John!

John Merriam of St. Augustine, Florida, caught the very dusty sunset above on June 28, 2020. He wrote:

The dust has been so thick that most evenings, if it wasn’t storming, you couldn’t see the sun at all. Worked out pretty well this time, and I had no idea the bird was there until I got home and saw the full size image. Taken on the shores of the St Johns River in NW St Johns County, Florida.

This very dusty sunset isn’t just a local phenomenon. It’s due to an unusually large plume of dust from northern Africa’s Saharan Desert, which wafted across the Atlantic beginning just after mid-June. The African plume has brought extremely dusty skies to parts of the U.S. south, and into Texas. The Washington Post’s Capital Weather Gang wrote on June 25, 2020:

An unusually thick, nearly 5,000-mile-long plume of dust that was whisked off the Sahara Desert by storm-related winds June 14 is moving ashore along the coast of the Gulf of Mexico from Texas to the Florida Panhandle. It is predicted to cause a deterioration in air quality and turn the sky a milky white, and its impacts won’t be limited to the coast …

Although plumes of Sahara Desert dust are routinely ejected from Africa’s west coast during June, the ongoing event is extraordinarily rare, scientists said. This event stands out in terms of the dust layer’s thickness, its low altitude and geographic reach, causing a dramatic deterioration in air quality in Puerto Rico, Barbados, Guadeloupe and numerous other locations where records are maintained.

Read more from the Washington Post: Saharan dust plume, the largest in decades, spills over Gulf Coast

Read more from EarthSky: Saharan-fed sunsets in the U.S.

EarthSky’s Deborah Byrd reports that skies have been exceedingly dusty over Austin, Texas, too, despite recent rains. She caught this view of the eastern sky at sunset on June 28, 2020. The view is to the east. You can see the dust especially looking toward the horizon. “That tall building on the far right of the photo is in downtown Austin,” Deborah said. “Normally, I can see it clearly from my back deck, but, in recent days, the view of that building and all of downtown has been constantly shrouded in dust.” Photo by Deborah Byrd.

On June 16, 2020, NOAA’s GOES-East satellite captured this GeoColor imagery of an expansive plume of dust from the Sahara Desert traveling westward across the Atlantic Ocean. NOAA said on June 18 that the dust was expected to reach the Caribbean and parts of the U.S. … and so it has. Read more about this image.

Bottom line: From Florida to Texas, the U.S. south has had very dusty skies in late June 2020. The dust is due to an unusually large dust plume that left northern Africa’s Saharan Desert in mid-June.

from EarthSky https://ift.tt/2AgFYgZ

View at EarthSky Community Photos. | A sunset shrouded in African dust, captured by John Merriam in Florida on June 28, 2020. Notice the layers of dust, and the bird! Thank you, John!

John Merriam of St. Augustine, Florida, caught the very dusty sunset above on June 28, 2020. He wrote:

The dust has been so thick that most evenings, if it wasn’t storming, you couldn’t see the sun at all. Worked out pretty well this time, and I had no idea the bird was there until I got home and saw the full size image. Taken on the shores of the St Johns River in NW St Johns County, Florida.

This very dusty sunset isn’t just a local phenomenon. It’s due to an unusually large plume of dust from northern Africa’s Saharan Desert, which wafted across the Atlantic beginning just after mid-June. The African plume has brought extremely dusty skies to parts of the U.S. south, and into Texas. The Washington Post’s Capital Weather Gang wrote on June 25, 2020:

An unusually thick, nearly 5,000-mile-long plume of dust that was whisked off the Sahara Desert by storm-related winds June 14 is moving ashore along the coast of the Gulf of Mexico from Texas to the Florida Panhandle. It is predicted to cause a deterioration in air quality and turn the sky a milky white, and its impacts won’t be limited to the coast …

Although plumes of Sahara Desert dust are routinely ejected from Africa’s west coast during June, the ongoing event is extraordinarily rare, scientists said. This event stands out in terms of the dust layer’s thickness, its low altitude and geographic reach, causing a dramatic deterioration in air quality in Puerto Rico, Barbados, Guadeloupe and numerous other locations where records are maintained.

Read more from the Washington Post: Saharan dust plume, the largest in decades, spills over Gulf Coast

Read more from EarthSky: Saharan-fed sunsets in the U.S.

EarthSky’s Deborah Byrd reports that skies have been exceedingly dusty over Austin, Texas, too, despite recent rains. She caught this view of the eastern sky at sunset on June 28, 2020. The view is to the east. You can see the dust especially looking toward the horizon. “That tall building on the far right of the photo is in downtown Austin,” Deborah said. “Normally, I can see it clearly from my back deck, but, in recent days, the view of that building and all of downtown has been constantly shrouded in dust.” Photo by Deborah Byrd.

On June 16, 2020, NOAA’s GOES-East satellite captured this GeoColor imagery of an expansive plume of dust from the Sahara Desert traveling westward across the Atlantic Ocean. NOAA said on June 18 that the dust was expected to reach the Caribbean and parts of the U.S. … and so it has. Read more about this image.

Bottom line: From Florida to Texas, the U.S. south has had very dusty skies in late June 2020. The dust is due to an unusually large dust plume that left northern Africa’s Saharan Desert in mid-June.

from EarthSky https://ift.tt/2AgFYgZ