A chameleon can alter the color of its skin so it either blends into the background to hide or stands out to defend its territory and attract a mate. The chameleon makes this trick look easy, using photonic crystals in its skin. Scientists, however, have struggled to make a photonic crystal “smart skin” that changes color in response to the environment, without also changing in size.
The journal ACS Nano published research led by chemists at Emory University that found a solution to the problem. They developed a flexible smart skin that reacts to heat and sunlight while maintaining a near constant volume.
“Watching a chameleon change colors gave me the idea for the breakthrough,” says first author Yixiao Dong, a PhD candidate in Emory’s Department of Chemistry. “We’ve developed a new concept for a color-changing smart skin, based on observations of how nature does it.”
A chameleon can alter the color of its skin so it either blends into the background to hide or stands out to defend its territory and attract a mate. The chameleon makes this trick look easy, using photonic crystals in its skin. Scientists, however, have struggled to make a photonic crystal “smart skin” that changes color in response to the environment, without also changing in size.
The journal ACS Nano published research led by chemists at Emory University that found a solution to the problem. They developed a flexible smart skin that reacts to heat and sunlight while maintaining a near constant volume.
“Watching a chameleon change colors gave me the idea for the breakthrough,” says first author Yixiao Dong, a PhD candidate in Emory’s Department of Chemistry. “We’ve developed a new concept for a color-changing smart skin, based on observations of how nature does it.”
Here in the Northern Hemisphere, we call the full moon closest to the autumn equinox the Harvest Moon. Depending on your time zone, 2019’s autumn equinox for the Northern Hemisphere comes on September 22 or 23. And the September full moon comes on the night of Friday, September 13, for the most of North America, and on September 14 for much of the rest of the world. Thus, for the Northern Hemisphere, this upcoming full moon – the full moon closest to our autumn equinox – is our Harvest Moon.
For the Southern Hemisphere, the Harvest Moon always comes in March or early April.
Harvest Moon is just a name. In some ways, it’s like any other full moon name. But these autumn full moons do have special characteristics, related to the time of moonrise. Nature is particularly cooperative in giving us full-looking moons near the horizon after sunset, for several evenings in a row, around the time of the Harvest Moon.
Harvest Moon sunset and moonrise – September 19, 2013 – as seen by EarthSky Facebook friend Andy Somers in Noumea, New Caledonia. One of the characteristics of the Harvest Moon is that it rises around the time of sunset for several evenings in a row.
What is a Harvest Moon? On average, the moon rises about 50 minutes later each day. But when a full moon happens close to an autumn equinox, the moon rises closer to the time of sunset. For mid-temperate latitudes, it rises only about 25 to 30 minutes later daily for several days before and after the full Harvest moon.
For very high northern latitudes, there’s even less time between successive moonrises.
The difference between 50 minutes and 30 minutes might not seem like much. But it means that, in the nights after a full Harvest Moon, you’ll see the moon ascending in the east relatively soon after sunset. The moon will rise during or near twilight on these nights, making it seem as if there are several full moons – for a few nights in a row – around the time of the Harvest Moon.
Why does this happen? Check out the illustrations below:
In autumn, the ecliptic – marking the moon’s approximate path across our sky – makes a narrow angle with the evening horizon. Image via classicalastronomy.com.
The narrow angle of the ecliptic means the moon rises noticeably farther north on the horizon from one night to the next. So there is no long period of darkness between sunset and moonrise. Image via classicalastronomy.com.
Is the Harvest Moon bigger, or brighter or more colorful? Not necessarily.
Because the moon’s orbit around Earth isn’t a perfect circle, the Harvest Moon’s distance from Earth – and apparent size in our sky – is a bit different from year to year. In 2019, the Harvest Moon is actually a micro-moon or mini-moon: the most distant and smallest full moon of the year. But four years ago – September 28, 2015 – the Harvest Moon was the year’s closest and biggest supermoon.
Still, in any year, you might think the Harvest Moon looks bigger or brighter or more orange. That’s because the Harvest Moon has such a powerful mystique. Many people look for it shortly after sunset around the time of full moon. After sunset around the time of any full moon, the moon will always be near the horizon. It’ll just have risen. It’s the location of the moon near the horizon that causes the Harvest Moon – or any full moon – to look big and orange in color.
The orange color of a moon near the horizon is a true physical effect. It stems from the fact that – when you look toward the horizon – you’re looking through a greater thickness of Earth’s atmosphere than when you gaze up and overhead.
The bigger-than-usual size of a moon seen near the horizon is something else entirely. It’s a trick that your eyes are playing – an illusion – called the Moon Illusion. You can find many lengthy explanations of the Moon Illusion by doing an online search for those words.
Jarred Donkersley caught this photo of 2016’s Harvest Moon at the Vincent Thomas Bridge in San Pedro, California.
When is the Harvest Moon in 2019? The exact time of this September’s full moon is September 14 at 04:33 Universal Time. At U.S. time zones, that translates to September 14, at 12:33 a.m. EDT – yet on Friday, September 13, at 11:33 a.m. CDT, 10:33 a.m. MDT, 9:33 a.m. PDT, 8:33 a.m. AKDT (Alaska Daylight Time), and 6:33 a.m. HST (Hawaiian Standard Time).
So watch for the Harvest Moon on September 13 or 14 … or any of the nights around then.
By the way, more often than not, the September full moon is the Northern Hemisphere’s Harvest Moon. But if the full moon occurs in early October – as it did in 2017 and will again in 2020 – the October full moon is that year’s Harvest Moon.
Ed and Bettina Berg in Las Vegas, Nevada, contributed this image of the 2016 Harvest Moon.
How did the Harvest Moon get its name? The shorter-than-usual lag time between moonrises around the full Harvest Moon means no long period of darkness between sunset and moonrise for days in succession.
In the days before tractor lights, the lamp of the Harvest Moon helped farmers to gather their crops, despite the diminishing daylight hours. As the sun’s light faded in the west, the moon would soon rise in the east to illuminate the fields throughout the night.
Who named the Harvest Moon? That name probably sprang to the lips of farmers throughout the Northern Hemisphere, on autumn evenings, as the Harvest Moon aided in bringing in the crops.
The name was popularized in the early 20th century by the song below.
Shine On Harvest Moon
By Nora Bayes and Jack Norworth (1903)
Shine on, shine on harvest moon
Up in the sky,
I ain’t had no lovin’
Since January, February, June or July
Snow time ain’t no time to stay
Outdoors and spoon,
So shine on, shine on harvest moon,
For me and my gal.
And don’t miss this more recent version of the song by Leon Redbone.
Bottom line: According to skylore, the closest full moon to the autumn equinox is the Harvest Moon. In 2019, the autumnal equinox for the Northern Hemisphere comes on September 22 or 23, depending on time zone. So this hemisphere’s Harvest Moon is the full moon on the night of September 13 or 14, 2019.
Here in the Northern Hemisphere, we call the full moon closest to the autumn equinox the Harvest Moon. Depending on your time zone, 2019’s autumn equinox for the Northern Hemisphere comes on September 22 or 23. And the September full moon comes on the night of Friday, September 13, for the most of North America, and on September 14 for much of the rest of the world. Thus, for the Northern Hemisphere, this upcoming full moon – the full moon closest to our autumn equinox – is our Harvest Moon.
For the Southern Hemisphere, the Harvest Moon always comes in March or early April.
Harvest Moon is just a name. In some ways, it’s like any other full moon name. But these autumn full moons do have special characteristics, related to the time of moonrise. Nature is particularly cooperative in giving us full-looking moons near the horizon after sunset, for several evenings in a row, around the time of the Harvest Moon.
Harvest Moon sunset and moonrise – September 19, 2013 – as seen by EarthSky Facebook friend Andy Somers in Noumea, New Caledonia. One of the characteristics of the Harvest Moon is that it rises around the time of sunset for several evenings in a row.
What is a Harvest Moon? On average, the moon rises about 50 minutes later each day. But when a full moon happens close to an autumn equinox, the moon rises closer to the time of sunset. For mid-temperate latitudes, it rises only about 25 to 30 minutes later daily for several days before and after the full Harvest moon.
For very high northern latitudes, there’s even less time between successive moonrises.
The difference between 50 minutes and 30 minutes might not seem like much. But it means that, in the nights after a full Harvest Moon, you’ll see the moon ascending in the east relatively soon after sunset. The moon will rise during or near twilight on these nights, making it seem as if there are several full moons – for a few nights in a row – around the time of the Harvest Moon.
Why does this happen? Check out the illustrations below:
In autumn, the ecliptic – marking the moon’s approximate path across our sky – makes a narrow angle with the evening horizon. Image via classicalastronomy.com.
The narrow angle of the ecliptic means the moon rises noticeably farther north on the horizon from one night to the next. So there is no long period of darkness between sunset and moonrise. Image via classicalastronomy.com.
Is the Harvest Moon bigger, or brighter or more colorful? Not necessarily.
Because the moon’s orbit around Earth isn’t a perfect circle, the Harvest Moon’s distance from Earth – and apparent size in our sky – is a bit different from year to year. In 2019, the Harvest Moon is actually a micro-moon or mini-moon: the most distant and smallest full moon of the year. But four years ago – September 28, 2015 – the Harvest Moon was the year’s closest and biggest supermoon.
Still, in any year, you might think the Harvest Moon looks bigger or brighter or more orange. That’s because the Harvest Moon has such a powerful mystique. Many people look for it shortly after sunset around the time of full moon. After sunset around the time of any full moon, the moon will always be near the horizon. It’ll just have risen. It’s the location of the moon near the horizon that causes the Harvest Moon – or any full moon – to look big and orange in color.
The orange color of a moon near the horizon is a true physical effect. It stems from the fact that – when you look toward the horizon – you’re looking through a greater thickness of Earth’s atmosphere than when you gaze up and overhead.
The bigger-than-usual size of a moon seen near the horizon is something else entirely. It’s a trick that your eyes are playing – an illusion – called the Moon Illusion. You can find many lengthy explanations of the Moon Illusion by doing an online search for those words.
Jarred Donkersley caught this photo of 2016’s Harvest Moon at the Vincent Thomas Bridge in San Pedro, California.
When is the Harvest Moon in 2019? The exact time of this September’s full moon is September 14 at 04:33 Universal Time. At U.S. time zones, that translates to September 14, at 12:33 a.m. EDT – yet on Friday, September 13, at 11:33 a.m. CDT, 10:33 a.m. MDT, 9:33 a.m. PDT, 8:33 a.m. AKDT (Alaska Daylight Time), and 6:33 a.m. HST (Hawaiian Standard Time).
So watch for the Harvest Moon on September 13 or 14 … or any of the nights around then.
By the way, more often than not, the September full moon is the Northern Hemisphere’s Harvest Moon. But if the full moon occurs in early October – as it did in 2017 and will again in 2020 – the October full moon is that year’s Harvest Moon.
Ed and Bettina Berg in Las Vegas, Nevada, contributed this image of the 2016 Harvest Moon.
How did the Harvest Moon get its name? The shorter-than-usual lag time between moonrises around the full Harvest Moon means no long period of darkness between sunset and moonrise for days in succession.
In the days before tractor lights, the lamp of the Harvest Moon helped farmers to gather their crops, despite the diminishing daylight hours. As the sun’s light faded in the west, the moon would soon rise in the east to illuminate the fields throughout the night.
Who named the Harvest Moon? That name probably sprang to the lips of farmers throughout the Northern Hemisphere, on autumn evenings, as the Harvest Moon aided in bringing in the crops.
The name was popularized in the early 20th century by the song below.
Shine On Harvest Moon
By Nora Bayes and Jack Norworth (1903)
Shine on, shine on harvest moon
Up in the sky,
I ain’t had no lovin’
Since January, February, June or July
Snow time ain’t no time to stay
Outdoors and spoon,
So shine on, shine on harvest moon,
For me and my gal.
And don’t miss this more recent version of the song by Leon Redbone.
Bottom line: According to skylore, the closest full moon to the autumn equinox is the Harvest Moon. In 2019, the autumnal equinox for the Northern Hemisphere comes on September 22 or 23, depending on time zone. So this hemisphere’s Harvest Moon is the full moon on the night of September 13 or 14, 2019.
Artist’s concept of a lake at the north pole of Saturn’s large moon Titan. This image illustrates the raised rims and rampart-like features seen by NASA’s Cassini spacecraft around some Titan lakes. Scientists think these features might indicate underground explosions, which carved out the lake beds long ago. Image via NASA/JPL-Caltech.
During its 13 years of scrutinizing Saturn and its moons, the Cassini spacecraft executed dozens of close flybys of the system’s largest moon, Titan. It found that Titan has a cycle much like our water cycle, with a kind of “rain,” although Titan’s rain consists of liquid methane and other organic compounds, not water. Cassini also revealed that Titan’s methane rain has filled basins on its surface, so that this frigid moon is the only world in our solar system, besides Earth, known to have stable surface lakes and seas (albeit not made of water). This week, using radar data from Cassini, scientists published a new scenario to explain why some methane-filled lakes on Titan are surrounded by steep rims that reach hundreds of feet high. The models suggests that explosions of warming nitrogen created the lake basins in the moon’s crust.
The new work was published September 9, 2019, in the peer-reviewed journal Nature Geoscience.
The study suggests that some of Titan’s smaller lakes – just tens of miles across – might have formed when pockets of liquid nitrogen in Titan’s crust warmed, turning into explosive gas that blew out craters, which then filled with liquid methane. Giuseppe Mitri of Italy’s G. d’Annunzio University and Jonathan Lunine of Cornell University in Ithaca, New York, co-authored the new study. They said their theory explains why some of the smaller lakes near Titan’s north pole, like Winnipeg Lacus, appear in radar imaging to have such very steep rims. The rims, their statement said:
Infrared view of seas and lakes in Titan’s northern hemisphere, taken by Cassini in 2014. Sunlight can be seen glinting off the southern part of Titan’s largest sea, Kraken Mare. Image via NASA/JPL-Caltech/University of Arizona/University of Idaho.
The rampart-like rims around some small Titan lakes are hard to explain with other models. Most alternate models of lake formation on Titan show liquid methane dissolving the moon’s bedrock of ice and solid organic compounds, carving reservoirs that fill with the liquid. On Earth, bodies of water that formed similarly, by dissolving surrounding limestone, are known as karst lakes. On Titan, this karstic model might explain some of Titan’s lakes – those with sharp boundaries – but, Mitri and Lunine believe, it does not explain all of them. Mitri commented in a statement:
… We were not finding any explanation that fit with a karstic lake basin. In reality, the morphology was more consistent with an explosion crater, where the rim is formed by the ejected material from the crater interior. It’s totally a different process.
Their statement further explained:
Over the last half-billion or billion years on Titan, methane in its atmosphere has acted as a greenhouse gas, keeping the moon relatively warm – although still cold by Earth standards. Scientists have long believed that the moon has gone through epochs of cooling and warming, as methane is depleted by solar-driven chemistry and then resupplied.
In the colder periods, nitrogen dominated the atmosphere, raining down and cycling through the icy crust to collect in pools just below the surface …
And so, said Jonathan Lunine:
These lakes with steep edges, ramparts and raised rims would be a signpost of periods in Titan’s history when there was liquid nitrogen on the surface and in the crust.
He added that even localized warming would have been enough to turn the liquid nitrogen into vapor, cause it to expand quickly and blow out a crater.
So, it seems, studies based on Cassini spacecraft data keep coming, even though Cassini itself burned up in Saturn’s atmosphere, ending its 13-year orbit around the planet, in 2017. And, scientists say, they don’t expect the mining of Cassini data to end anytime soon. Cassini Project Scientist Linda Spilker of JPL commented:
This is a completely different explanation for the steep rims around those small lakes, which has been a tremendous puzzle. As scientists continue to mine the treasure trove of Cassini data, we’ll keep putting more and more pieces of the puzzle together. Over the next decades, we will come to understand the Saturn system better and better.
Bottom line: A new study suggests the high rampart-like rims around some of the smaller lakes on Titan might have been caused by explosions of warming nitrogen.
Artist’s concept of a lake at the north pole of Saturn’s large moon Titan. This image illustrates the raised rims and rampart-like features seen by NASA’s Cassini spacecraft around some Titan lakes. Scientists think these features might indicate underground explosions, which carved out the lake beds long ago. Image via NASA/JPL-Caltech.
During its 13 years of scrutinizing Saturn and its moons, the Cassini spacecraft executed dozens of close flybys of the system’s largest moon, Titan. It found that Titan has a cycle much like our water cycle, with a kind of “rain,” although Titan’s rain consists of liquid methane and other organic compounds, not water. Cassini also revealed that Titan’s methane rain has filled basins on its surface, so that this frigid moon is the only world in our solar system, besides Earth, known to have stable surface lakes and seas (albeit not made of water). This week, using radar data from Cassini, scientists published a new scenario to explain why some methane-filled lakes on Titan are surrounded by steep rims that reach hundreds of feet high. The models suggests that explosions of warming nitrogen created the lake basins in the moon’s crust.
The new work was published September 9, 2019, in the peer-reviewed journal Nature Geoscience.
The study suggests that some of Titan’s smaller lakes – just tens of miles across – might have formed when pockets of liquid nitrogen in Titan’s crust warmed, turning into explosive gas that blew out craters, which then filled with liquid methane. Giuseppe Mitri of Italy’s G. d’Annunzio University and Jonathan Lunine of Cornell University in Ithaca, New York, co-authored the new study. They said their theory explains why some of the smaller lakes near Titan’s north pole, like Winnipeg Lacus, appear in radar imaging to have such very steep rims. The rims, their statement said:
Infrared view of seas and lakes in Titan’s northern hemisphere, taken by Cassini in 2014. Sunlight can be seen glinting off the southern part of Titan’s largest sea, Kraken Mare. Image via NASA/JPL-Caltech/University of Arizona/University of Idaho.
The rampart-like rims around some small Titan lakes are hard to explain with other models. Most alternate models of lake formation on Titan show liquid methane dissolving the moon’s bedrock of ice and solid organic compounds, carving reservoirs that fill with the liquid. On Earth, bodies of water that formed similarly, by dissolving surrounding limestone, are known as karst lakes. On Titan, this karstic model might explain some of Titan’s lakes – those with sharp boundaries – but, Mitri and Lunine believe, it does not explain all of them. Mitri commented in a statement:
… We were not finding any explanation that fit with a karstic lake basin. In reality, the morphology was more consistent with an explosion crater, where the rim is formed by the ejected material from the crater interior. It’s totally a different process.
Their statement further explained:
Over the last half-billion or billion years on Titan, methane in its atmosphere has acted as a greenhouse gas, keeping the moon relatively warm – although still cold by Earth standards. Scientists have long believed that the moon has gone through epochs of cooling and warming, as methane is depleted by solar-driven chemistry and then resupplied.
In the colder periods, nitrogen dominated the atmosphere, raining down and cycling through the icy crust to collect in pools just below the surface …
And so, said Jonathan Lunine:
These lakes with steep edges, ramparts and raised rims would be a signpost of periods in Titan’s history when there was liquid nitrogen on the surface and in the crust.
He added that even localized warming would have been enough to turn the liquid nitrogen into vapor, cause it to expand quickly and blow out a crater.
So, it seems, studies based on Cassini spacecraft data keep coming, even though Cassini itself burned up in Saturn’s atmosphere, ending its 13-year orbit around the planet, in 2017. And, scientists say, they don’t expect the mining of Cassini data to end anytime soon. Cassini Project Scientist Linda Spilker of JPL commented:
This is a completely different explanation for the steep rims around those small lakes, which has been a tremendous puzzle. As scientists continue to mine the treasure trove of Cassini data, we’ll keep putting more and more pieces of the puzzle together. Over the next decades, we will come to understand the Saturn system better and better.
Bottom line: A new study suggests the high rampart-like rims around some of the smaller lakes on Titan might have been caused by explosions of warming nitrogen.
The green flash image at the top of this post was taken by Jim Grant, an EarthSky friend on Facebook. He captured it off the coast of Ocean Beach, California, and identified it a mock mirage green flash.
It’s not hard to see a green flash with the eye alone, when sky conditions are right, and when you’re looking toward a very clear and very distant horizon. That’s why those who live near an ocean tend to report green flashes most often. A sea horizon is the best place to see them.
The video below, posted to EarthSky by Vladek in 2016, is an excellent example of the experience of seeing a green flash:
Most people see green flashes just at sunset, at the last moment before the sun disappears below the horizon. Be careful and don’t look too soon. If you do look too soon, the light of the sunset will dazzle (or damage) your eyes, and you’ll miss your green flash chance that day.
But if you wait – looking away until just the thinnest rim of the sun appears above the horizon – that day’s green flash could be yours.
Of course, the green flash can be seen before sunrise, too, although it’s harder at that time of day to know precisely when to look.
Mock mirage and green flash seen from San Francisco in 2006. Image via Brocken Inaglory/Wikimedia Commons.
There are many different types of green flash. Some describe a streak or ray of the color green … like a green flame shooting up from the sunrise or sunset horizon.
The most common green flash, though – the one most people describe – is a flash of the color green seen when the sun is nearly entirely below the horizon.
Again … you need a distant horizon to see any of these phenomena, and you need a distinct edge to the horizon. That’s why these green flashes, streaks, and rays are most often seen over the ocean. But you can see them over land, too, if your horizon is far enough away.
Pollution or haze on the horizon will hide this instantaneous flash of the color green.
Jim Grant photographed this green flash on April 27, 2012, off the coast of San Diego.
And, of course, Les Cowley at the great website Atmospheric Optics devotes many pages to the green flash phenomenon. Notice the menu bar at the left side of the page; it’ll let you explore many different types of green flashes.
Green flash atop sun pyramid via astrophotographer Colin Legg in Australia.
Bottom line: The green flash is legendary, and some people have told us they thought it was a myth, like a unicorn or a pot of gold at the end of a rainbow. But green flashes are very real. You need a distant and exceedingly clear horizon to see them at the last moment before the sun disappears below the horizon at sunset.
The green flash image at the top of this post was taken by Jim Grant, an EarthSky friend on Facebook. He captured it off the coast of Ocean Beach, California, and identified it a mock mirage green flash.
It’s not hard to see a green flash with the eye alone, when sky conditions are right, and when you’re looking toward a very clear and very distant horizon. That’s why those who live near an ocean tend to report green flashes most often. A sea horizon is the best place to see them.
The video below, posted to EarthSky by Vladek in 2016, is an excellent example of the experience of seeing a green flash:
Most people see green flashes just at sunset, at the last moment before the sun disappears below the horizon. Be careful and don’t look too soon. If you do look too soon, the light of the sunset will dazzle (or damage) your eyes, and you’ll miss your green flash chance that day.
But if you wait – looking away until just the thinnest rim of the sun appears above the horizon – that day’s green flash could be yours.
Of course, the green flash can be seen before sunrise, too, although it’s harder at that time of day to know precisely when to look.
Mock mirage and green flash seen from San Francisco in 2006. Image via Brocken Inaglory/Wikimedia Commons.
There are many different types of green flash. Some describe a streak or ray of the color green … like a green flame shooting up from the sunrise or sunset horizon.
The most common green flash, though – the one most people describe – is a flash of the color green seen when the sun is nearly entirely below the horizon.
Again … you need a distant horizon to see any of these phenomena, and you need a distinct edge to the horizon. That’s why these green flashes, streaks, and rays are most often seen over the ocean. But you can see them over land, too, if your horizon is far enough away.
Pollution or haze on the horizon will hide this instantaneous flash of the color green.
Jim Grant photographed this green flash on April 27, 2012, off the coast of San Diego.
And, of course, Les Cowley at the great website Atmospheric Optics devotes many pages to the green flash phenomenon. Notice the menu bar at the left side of the page; it’ll let you explore many different types of green flashes.
Green flash atop sun pyramid via astrophotographer Colin Legg in Australia.
Bottom line: The green flash is legendary, and some people have told us they thought it was a myth, like a unicorn or a pot of gold at the end of a rainbow. But green flashes are very real. You need a distant and exceedingly clear horizon to see them at the last moment before the sun disappears below the horizon at sunset.
87 items this week, with 23 available as open access.
What are we doing on Mars?
We're from Earth, yet Included in this week's trawl of research articles are Streeter et al with Surface warming during the 2018/Mars Year 34 Global Dust Storm. Why are we visiting Mars today? Because the same storm that silenced the doughty Opportunity rover after over 14 years of operation yields an interesting research result on the dust-up's temporary effect on the Martian climate:
The impact of Mars’ 2018 Global Dust Storm (GDS) on surface and near‐surface air temperatures was investigated using an assimilation of Mars Climate Sounder (MCS) observations. Rather than simply resulting in cooling everywhere from solar absorption (average surface radiative flux fell 26 Wm‐2), the globally‐averaged result was a 0.9 K surface warming. These diurnally‐averaged surface temperature changes had a novel, highly non‐uniform spatial structure, with up to 16 K cooling/19 K warming. Net warming occurred in low thermal inertia (TI) regions, where rapid night‐time radiative cooling was compensated by increased longwave emission and scattering. This caused strong nightside warming, outweighing dayside cooling. The reduced surface‐air temperature gradient closely coupled surface and air temperatures, even causing local dayside air warming.
Note the similar causal mechanism and ultimate effect of increased surface temperatures to what a little additional CO2 in Earth's atmosphere produces. Despite a drastic reduction of surface energy delivery to Mars, night time temperatures rose and this effect was even true to some extent in day time.
Leaving aside dust not being gaseous, the principle and concerning difference between the two is that dust rapidly drops out of the atmosphere whether on Mars or at home, while the additional CO2 we've liberated into our local thin skin of gas will require several hundred years to find a permanent new home away from where it causes deleterious effects on our climate.
The global warming potential (GWP) is widely used in policy analysis, national greenhouse gas (GHG) accounting, and technology life cycle assessment (LCA) to compare the impact of non-CO2 GHG emissions to the impact of CO2 emissions. While the GWP is simple and versatile, different views about the appropriate choice of time horizon—and the factors that affect that choice—can impede decision-making. If the GWP is viewed as an approximation to a climate metric that more directly measures economic impact—the global damage potential (GDP)—then the time horizon may be viewed as a proxy for the discount rate. However, the validity of this equivalence rests on the theoretical basis used to equate the two metrics. In this paper, we develop a new theoretical basis for relating the GWP time horizon and the economic discount rate that avoids the most restrictive assumptions of prior studies, such as an assumed linear relationship between economic damages and temperature. We validate this approach with an extensive set of numerical experiments using an up-to-date climate emulator that represents state-dependent climate-carbon cycle feedbacks. The numerical results largely confirm the theoretical finding that, under certain reasonable assumptions, time horizons in the GWP of 100 years and 20 years are most consistent with discount rates of approximately 3% and 7% (or greater), respectively.
Introduction of the "discount rate" into thinking about climate change mitigation and adaptation costs and expenditures confuses simple and ignorant minds (such as the author of this blog entry). Application of a scrupulously calculated discount rate to the question of spending related to climate change is promised to yield a brighter future.To this layperson establishing this magic number appears to be a form of paralytic perfectionism and as well seems dependent on unreliable information about a future beyond our ken.
As a person who spends time on boats and yet fully intends to never fall overboard, I can spend a lot or a little on a "PFD" (personal flotation device) despite knowing full well that any such expenditure large or small will be much more productively employed in a true investment even at a very poor interest rate, per the advice of economic experts. The wisdom and promised benefits of not buying a PFD hold true until the exact moment when I pitch overboard into cold water and shortly am depending on the PFD for continued survival, at which point more riches in the future become crisply abstract. Surely if I'm dead I won't be able to grow my personal economy; staying alive appears to be a prime requirement for my successful economic outcome. Thus I choose to waste money now on a quality PFD despite it not being a rational choice in the formal economic sense.
Assuming we'll stay high and dry may drive the decision to not buy a PFD and instead invest elsewhere. Similarly, overweening fascination with and pursuit of establishing theoretically defensible discount rates in connection with climate change appears to hinge on a relatively static scenario of a functioning economy resembling to some degree what we've come to expect from the past: a machine producing more or less steady and uninterrupted growth. It seems arguable that assumptions required to model such an economy and produce an academically worthy and admirable result are not necessarily valid given the broadly agreed dire projections we face of global warming and its various knock-on disruptions; we're entering an era with challenges on a scale and breadth we've not yet encountered and so old rules may not apply.
What am I missing?
Ideally an actual economist would explain this in terms an ordinary layperson might understand. Coming up for air and offering some conclusions with clear directions based on the assumption we will be falling overboard and indeed have already lost our grip and footing— are clumsily plunging over the lifelines into a life-threatening circumstance— would be very helpful. Is there an argument for obtaining a PFD, the notionally irrational choice to spend money to buy some better luck, a wager to help assure a future?
Please let us know if you're aware of an article you think may be of interest for Skeptical Science research news, or if we've missed something that may be important. Send your input to Skeptical Science via our contact form.
The previous edition of Skeptical Science new research may be found here.
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87 items this week, with 23 available as open access.
What are we doing on Mars?
We're from Earth, yet Included in this week's trawl of research articles are Streeter et al with Surface warming during the 2018/Mars Year 34 Global Dust Storm. Why are we visiting Mars today? Because the same storm that silenced the doughty Opportunity rover after over 14 years of operation yields an interesting research result on the dust-up's temporary effect on the Martian climate:
The impact of Mars’ 2018 Global Dust Storm (GDS) on surface and near‐surface air temperatures was investigated using an assimilation of Mars Climate Sounder (MCS) observations. Rather than simply resulting in cooling everywhere from solar absorption (average surface radiative flux fell 26 Wm‐2), the globally‐averaged result was a 0.9 K surface warming. These diurnally‐averaged surface temperature changes had a novel, highly non‐uniform spatial structure, with up to 16 K cooling/19 K warming. Net warming occurred in low thermal inertia (TI) regions, where rapid night‐time radiative cooling was compensated by increased longwave emission and scattering. This caused strong nightside warming, outweighing dayside cooling. The reduced surface‐air temperature gradient closely coupled surface and air temperatures, even causing local dayside air warming.
Note the similar causal mechanism and ultimate effect of increased surface temperatures to what a little additional CO2 in Earth's atmosphere produces. Despite a drastic reduction of surface energy delivery to Mars, night time temperatures rose and this effect was even true to some extent in day time.
Leaving aside dust not being gaseous, the principle and concerning difference between the two is that dust rapidly drops out of the atmosphere whether on Mars or at home, while the additional CO2 we've liberated into our local thin skin of gas will require several hundred years to find a permanent new home away from where it causes deleterious effects on our climate.
The global warming potential (GWP) is widely used in policy analysis, national greenhouse gas (GHG) accounting, and technology life cycle assessment (LCA) to compare the impact of non-CO2 GHG emissions to the impact of CO2 emissions. While the GWP is simple and versatile, different views about the appropriate choice of time horizon—and the factors that affect that choice—can impede decision-making. If the GWP is viewed as an approximation to a climate metric that more directly measures economic impact—the global damage potential (GDP)—then the time horizon may be viewed as a proxy for the discount rate. However, the validity of this equivalence rests on the theoretical basis used to equate the two metrics. In this paper, we develop a new theoretical basis for relating the GWP time horizon and the economic discount rate that avoids the most restrictive assumptions of prior studies, such as an assumed linear relationship between economic damages and temperature. We validate this approach with an extensive set of numerical experiments using an up-to-date climate emulator that represents state-dependent climate-carbon cycle feedbacks. The numerical results largely confirm the theoretical finding that, under certain reasonable assumptions, time horizons in the GWP of 100 years and 20 years are most consistent with discount rates of approximately 3% and 7% (or greater), respectively.
Introduction of the "discount rate" into thinking about climate change mitigation and adaptation costs and expenditures confuses simple and ignorant minds (such as the author of this blog entry). Application of a scrupulously calculated discount rate to the question of spending related to climate change is promised to yield a brighter future.To this layperson establishing this magic number appears to be a form of paralytic perfectionism and as well seems dependent on unreliable information about a future beyond our ken.
As a person who spends time on boats and yet fully intends to never fall overboard, I can spend a lot or a little on a "PFD" (personal flotation device) despite knowing full well that any such expenditure large or small will be much more productively employed in a true investment even at a very poor interest rate, per the advice of economic experts. The wisdom and promised benefits of not buying a PFD hold true until the exact moment when I pitch overboard into cold water and shortly am depending on the PFD for continued survival, at which point more riches in the future become crisply abstract. Surely if I'm dead I won't be able to grow my personal economy; staying alive appears to be a prime requirement for my successful economic outcome. Thus I choose to waste money now on a quality PFD despite it not being a rational choice in the formal economic sense.
Assuming we'll stay high and dry may drive the decision to not buy a PFD and instead invest elsewhere. Similarly, overweening fascination with and pursuit of establishing theoretically defensible discount rates in connection with climate change appears to hinge on a relatively static scenario of a functioning economy resembling to some degree what we've come to expect from the past: a machine producing more or less steady and uninterrupted growth. It seems arguable that assumptions required to model such an economy and produce an academically worthy and admirable result are not necessarily valid given the broadly agreed dire projections we face of global warming and its various knock-on disruptions; we're entering an era with challenges on a scale and breadth we've not yet encountered and so old rules may not apply.
What am I missing?
Ideally an actual economist would explain this in terms an ordinary layperson might understand. Coming up for air and offering some conclusions with clear directions based on the assumption we will be falling overboard and indeed have already lost our grip and footing— are clumsily plunging over the lifelines into a life-threatening circumstance— would be very helpful. Is there an argument for obtaining a PFD, the notionally irrational choice to spend money to buy some better luck, a wager to help assure a future?
Please let us know if you're aware of an article you think may be of interest for Skeptical Science research news, or if we've missed something that may be important. Send your input to Skeptical Science via our contact form.
The previous edition of Skeptical Science new research may be found here.
Diagnosing cancer at its earliest and most treatable stages is vital to help more people survive their cancer. But it requires the Government to ensure there are enough NHS staff in place.
Dawn Chaplin, a consultant radiographer, has seen her clinics get busier and busier over the years.
Dawn Chaplin, a consultant radiographer who diagnoses breast cancer, shares her experiences of working for a short-staffed and overstretched NHS.
“It’s very, very difficult – rewarding and unrewarding. I love my job and what I do, but the expectations are unrealistic,” she says.
Chaplin’s role involves taking breast scans and interpreting results, as well as taking biopsies of any lumps she sees. She worked full-time for the NHS for 10 years, before switching to work short-term contracts. She says the pressures have increased year on year.
“It’s completely changed over the last few years, the number of patients we’re expected to deal with has just increased beyond belief for the number of staff.”
Too many patients, not enough time
Chaplin typically runs two clinics a day, one in the morning and one in the afternoon.
“My clinics are enormous now, I’m expected see around 22 patients in my clinic, whereas I would be seeing 12-14 before.”
Despite the increase in numbers, Chaplin says she’s expected to complete each clinic in the same amount of time. This often means one clinic runs into another.
“Last Thursday, the clinic that was due to finish at 12.30pm actually finished at 2pm. But my afternoon clinic was supposed to start at 1.30pm, so already there were patients waiting for the next clinic while you’re still doing the first.”
This isn’t unusual. It means Chaplin rarely has time for a break, leaving her feeling that she’s “on a hamster wheel all the time”. This means more evening and weekend work to catch up.
But it’s not just her wellbeing that’s being affected, she thinks it’s having a big impact on patients too.
“They don’t get as much time with us as they used to be able to get. You try to give the patient as much time as you can but you’re always aware that there are 10 patients waiting outside to come in as well.”
And for Chaplin, the potential consequences are huge.
“Ultimately, I’m worried that people are going to die, because there’s just not enough people to diagnose the cancers in a timely manner.”
Chaplin fears a delay in cancer diagnosis could mean cancers present when they’re bigger, more advanced and more difficult to treat. “I worry it may lead to people dying earlier than they should,” she adds.
‘It’s the same across the country’
This isn’t an isolated problem, says Chaplin, having worked in many hospitals across the country and had the same conversations with colleagues. And it’s having a big impact on staff.
“People with fantastic skills, lovely, hardworking and dedicated people, are leaving to go and work elsewhere – outside the NHS and overseas – for more money and half the amount of stress,” she says.
It’s in the hands of the Government to make sure there are enough staff to diagnose and treat cancer early. And with cancer rates increasing and the government target to diagnose 3 in 4 cancers early by 2028, the pressure faced by NHS staff is only going to grow.
“I think the NHS is definitely in crisis, despite what the Government is saying. We need more staff.”
from Cancer Research UK – Science blog https://ift.tt/2A4Z9qb
Diagnosing cancer at its earliest and most treatable stages is vital to help more people survive their cancer. But it requires the Government to ensure there are enough NHS staff in place.
Dawn Chaplin, a consultant radiographer, has seen her clinics get busier and busier over the years.
Dawn Chaplin, a consultant radiographer who diagnoses breast cancer, shares her experiences of working for a short-staffed and overstretched NHS.
“It’s very, very difficult – rewarding and unrewarding. I love my job and what I do, but the expectations are unrealistic,” she says.
Chaplin’s role involves taking breast scans and interpreting results, as well as taking biopsies of any lumps she sees. She worked full-time for the NHS for 10 years, before switching to work short-term contracts. She says the pressures have increased year on year.
“It’s completely changed over the last few years, the number of patients we’re expected to deal with has just increased beyond belief for the number of staff.”
Too many patients, not enough time
Chaplin typically runs two clinics a day, one in the morning and one in the afternoon.
“My clinics are enormous now, I’m expected see around 22 patients in my clinic, whereas I would be seeing 12-14 before.”
Despite the increase in numbers, Chaplin says she’s expected to complete each clinic in the same amount of time. This often means one clinic runs into another.
“Last Thursday, the clinic that was due to finish at 12.30pm actually finished at 2pm. But my afternoon clinic was supposed to start at 1.30pm, so already there were patients waiting for the next clinic while you’re still doing the first.”
This isn’t unusual. It means Chaplin rarely has time for a break, leaving her feeling that she’s “on a hamster wheel all the time”. This means more evening and weekend work to catch up.
But it’s not just her wellbeing that’s being affected, she thinks it’s having a big impact on patients too.
“They don’t get as much time with us as they used to be able to get. You try to give the patient as much time as you can but you’re always aware that there are 10 patients waiting outside to come in as well.”
And for Chaplin, the potential consequences are huge.
“Ultimately, I’m worried that people are going to die, because there’s just not enough people to diagnose the cancers in a timely manner.”
Chaplin fears a delay in cancer diagnosis could mean cancers present when they’re bigger, more advanced and more difficult to treat. “I worry it may lead to people dying earlier than they should,” she adds.
‘It’s the same across the country’
This isn’t an isolated problem, says Chaplin, having worked in many hospitals across the country and had the same conversations with colleagues. And it’s having a big impact on staff.
“People with fantastic skills, lovely, hardworking and dedicated people, are leaving to go and work elsewhere – outside the NHS and overseas – for more money and half the amount of stress,” she says.
It’s in the hands of the Government to make sure there are enough staff to diagnose and treat cancer early. And with cancer rates increasing and the government target to diagnose 3 in 4 cancers early by 2028, the pressure faced by NHS staff is only going to grow.
“I think the NHS is definitely in crisis, despite what the Government is saying. We need more staff.”
