How frigid polar vortex blasts are connected to global warming

Bundled up against the cold in downtown Chicago, Sunday, January 27, 2019. Image via AP Photo/Nam Y. Huh.

By Jennifer Francis, Rutgers University

A record-breaking cold wave is sending literal shivers down the spines of millions of Americans. Temperatures across the upper Midwest are forecast to fall an astonishing 50 degrees Fahrenheit (28 degrees C) below normal this week – as low as 35 degrees below zero. Pile a gusty wind on top, and the air will feel like -60 degrees F (-51 degrees C).

Predicted near-surface air temperatures (F) for Wednesday morning, January 30, 2019. Forecast by NOAA’s Global Forecast System model. Image via Pivotal Weather.

This cold is nothing to sneeze at. The National Weather Service is warning of brutal, life-threatening conditions. Frostbite will strike fast on any exposed skin. At the same time, the North Pole is facing a heat wave with temperatures approaching the freezing point – about 25 degrees Fahrenheit (14 degrees C) above normal.

Predicted near-surface air temperature differences (C) from normal, relative to 1981-2010. Image via Pivotal Weather.

What is causing this topsy-turvy pattern? You guessed it: the polar vortex.

In the past several years, thanks to previous cold waves, the polar vortex has become entrenched in our everyday vocabulary and served as a butt of jokes for late-night TV hosts and politicians. But what is it really? Is it escaping from its usual Arctic haunts more often? And a question that looms large in my work: How does global warming fit into the story?

Rivers of air

Actually, there are two polar vortices in the Northern Hemisphere, stacked on top of each other. The lower one is usually and more accurately called the jet stream. It’s a meandering river of strong westerly winds around the Northern Hemisphere, about seven miles above Earth’s surface, near the height where jets fly.

The jet stream exists all year, and is responsible for creating and steering the high- and low-pressure systems that bring us our day-to-day weather: storms and blue skies, warm and cold spells. Way above the jet stream, around 30 miles above the Earth, is the stratospheric polar vortex. This river of wind also rings the North Pole, but only forms during winter, and is usually fairly circular.

Dark arrows indicate rotation of the polar vortex in the Arctic; light arrows indicate the location of the polar jet stream when meanders form and cold, Arctic air dips down to mid-latitudes. Image via L.S. Gardiner/UCAR.

Both of these wind features exist because of the large temperature difference between the cold Arctic and warmer areas farther south, known as the mid-latitudes. Uneven heating creates pressure differences, and air flows from high-pressure to low-pressure areas, creating winds. The spinning Earth then turns winds to the right in the northern hemisphere, creating these belts of westerlies.

Why cold air plunges south

Greenhouse gas emissions from human activities have warmed the globe by about 1.8 degrees Fahrenheit (1 degree C) over the past 50 years. However, the Arctic has warmed more than twice as much. Amplified Arctic warming is due mainly to dramatic melting of ice and snow in recent decades, which exposes darker ocean and land surfaces that absorb a lot more of the sun’s heat.

Because of rapid Arctic warming, the north/south temperature difference has diminished. This reduces pressure differences between the Arctic and mid-latitudes, weakening jet stream winds. And just as slow-moving rivers typically take a winding route, a slower-flowing jet stream tends to meander.

Large north/south undulations in the jet stream generate wave energy in the atmosphere. If they are wavy and persistent enough, the energy can travel upward and disrupt the stratospheric polar vortex. Sometimes this upper vortex becomes so distorted that it splits into two or more swirling eddies.

These “daughter” vortices tend to wander southward, bringing their very cold air with them and leaving behind a warmer-than-normal Arctic. One of these eddies will sit over North America this week, delivering bone-chilling temperatures to much of the nation.

Here it comes! Thanks to ? #GOESEast and #GOES17, we can visually see the #polar air set to bring potentially historic and dangerous cold air over the Upper Midwest this week. The numbers in the loop? Those are wind chills. Why yes, they are low. As low as -81 degrees F in fact. ? pic.twitter.com/5U5F6wQTgm

— NWS Grand Forks (@NWSGrandForks) January 28, 2019

Deep freezes in a warming world

Splits in the stratospheric polar vortex do happen naturally, but should we expect to see them more often thanks to climate change and rapid Arctic warming? It is possible that these cold intrusions could become a more regular winter story. This is a hot research topic and is by no means settled, but a handful of studies offer compelling evidence that the stratospheric polar vortex is changing, and that this trend can explain bouts of unusually cold winter weather.

Undoubtedly this new polar vortex attack will unleash fresh claims that global warming is a hoax. But this ridiculous notion can be quickly dispelled with a look at predicted temperature departures around the globe for early this week. The lobe of cold air over North America is far outweighed by areas elsewhere in the United States and worldwide that are warmer than normal.

Predicted daily mean, near-surface temperature (C) differences from normal (relative to 1979-2000) for January 28-30, 2019. Data from NOAA’s Global Forecast System model. Image via Climate Reanalyzer, Climate Change Institute, University of Maine.

Symptoms of a changing climate are not always obvious or easy to understand, but their causes and future behaviors are increasingly coming into focus. And it’s clear that at times, coping with global warming means arming ourselves with extra scarfs, mittens and long underwear.

Jennifer Francis, Visiting Professor, Rutgers University

Bottom line: A scientist explains how the frigid polar vortex of January 2019 is connected to global warming.

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

from EarthSky http://bit.ly/2BepRh7

Bundled up against the cold in downtown Chicago, Sunday, January 27, 2019. Image via AP Photo/Nam Y. Huh.

By Jennifer Francis, Rutgers University

A record-breaking cold wave is sending literal shivers down the spines of millions of Americans. Temperatures across the upper Midwest are forecast to fall an astonishing 50 degrees Fahrenheit (28 degrees C) below normal this week – as low as 35 degrees below zero. Pile a gusty wind on top, and the air will feel like -60 degrees F (-51 degrees C).

Predicted near-surface air temperatures (F) for Wednesday morning, January 30, 2019. Forecast by NOAA’s Global Forecast System model. Image via Pivotal Weather.

This cold is nothing to sneeze at. The National Weather Service is warning of brutal, life-threatening conditions. Frostbite will strike fast on any exposed skin. At the same time, the North Pole is facing a heat wave with temperatures approaching the freezing point – about 25 degrees Fahrenheit (14 degrees C) above normal.

Predicted near-surface air temperature differences (C) from normal, relative to 1981-2010. Image via Pivotal Weather.

What is causing this topsy-turvy pattern? You guessed it: the polar vortex.

In the past several years, thanks to previous cold waves, the polar vortex has become entrenched in our everyday vocabulary and served as a butt of jokes for late-night TV hosts and politicians. But what is it really? Is it escaping from its usual Arctic haunts more often? And a question that looms large in my work: How does global warming fit into the story?

Rivers of air

Actually, there are two polar vortices in the Northern Hemisphere, stacked on top of each other. The lower one is usually and more accurately called the jet stream. It’s a meandering river of strong westerly winds around the Northern Hemisphere, about seven miles above Earth’s surface, near the height where jets fly.

The jet stream exists all year, and is responsible for creating and steering the high- and low-pressure systems that bring us our day-to-day weather: storms and blue skies, warm and cold spells. Way above the jet stream, around 30 miles above the Earth, is the stratospheric polar vortex. This river of wind also rings the North Pole, but only forms during winter, and is usually fairly circular.

Dark arrows indicate rotation of the polar vortex in the Arctic; light arrows indicate the location of the polar jet stream when meanders form and cold, Arctic air dips down to mid-latitudes. Image via L.S. Gardiner/UCAR.

Both of these wind features exist because of the large temperature difference between the cold Arctic and warmer areas farther south, known as the mid-latitudes. Uneven heating creates pressure differences, and air flows from high-pressure to low-pressure areas, creating winds. The spinning Earth then turns winds to the right in the northern hemisphere, creating these belts of westerlies.

Why cold air plunges south

Greenhouse gas emissions from human activities have warmed the globe by about 1.8 degrees Fahrenheit (1 degree C) over the past 50 years. However, the Arctic has warmed more than twice as much. Amplified Arctic warming is due mainly to dramatic melting of ice and snow in recent decades, which exposes darker ocean and land surfaces that absorb a lot more of the sun’s heat.

Because of rapid Arctic warming, the north/south temperature difference has diminished. This reduces pressure differences between the Arctic and mid-latitudes, weakening jet stream winds. And just as slow-moving rivers typically take a winding route, a slower-flowing jet stream tends to meander.

Large north/south undulations in the jet stream generate wave energy in the atmosphere. If they are wavy and persistent enough, the energy can travel upward and disrupt the stratospheric polar vortex. Sometimes this upper vortex becomes so distorted that it splits into two or more swirling eddies.

These “daughter” vortices tend to wander southward, bringing their very cold air with them and leaving behind a warmer-than-normal Arctic. One of these eddies will sit over North America this week, delivering bone-chilling temperatures to much of the nation.

Here it comes! Thanks to ? #GOESEast and #GOES17, we can visually see the #polar air set to bring potentially historic and dangerous cold air over the Upper Midwest this week. The numbers in the loop? Those are wind chills. Why yes, they are low. As low as -81 degrees F in fact. ? pic.twitter.com/5U5F6wQTgm

— NWS Grand Forks (@NWSGrandForks) January 28, 2019

Deep freezes in a warming world

Splits in the stratospheric polar vortex do happen naturally, but should we expect to see them more often thanks to climate change and rapid Arctic warming? It is possible that these cold intrusions could become a more regular winter story. This is a hot research topic and is by no means settled, but a handful of studies offer compelling evidence that the stratospheric polar vortex is changing, and that this trend can explain bouts of unusually cold winter weather.

Undoubtedly this new polar vortex attack will unleash fresh claims that global warming is a hoax. But this ridiculous notion can be quickly dispelled with a look at predicted temperature departures around the globe for early this week. The lobe of cold air over North America is far outweighed by areas elsewhere in the United States and worldwide that are warmer than normal.

Predicted daily mean, near-surface temperature (C) differences from normal (relative to 1979-2000) for January 28-30, 2019. Data from NOAA’s Global Forecast System model. Image via Climate Reanalyzer, Climate Change Institute, University of Maine.

Symptoms of a changing climate are not always obvious or easy to understand, but their causes and future behaviors are increasingly coming into focus. And it’s clear that at times, coping with global warming means arming ourselves with extra scarfs, mittens and long underwear.

Jennifer Francis, Visiting Professor, Rutgers University

Bottom line: A scientist explains how the frigid polar vortex of January 2019 is connected to global warming.

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

from EarthSky http://bit.ly/2BepRh7

Some summertime for you

View larger at EarthSky Community Photos. | This tiger lily bloomed in Antoni Williams’ garden in Tokoroa, New Zealand, in January 2019. “We have a wonderful garden. Taken 30 years to complete (if it`s ever possible to complete a garden). This is one of my favorites.”

View larger at EarthSky Community Photos. | Antoni’s garden also hosts a brilliant red volunteer sunflower. Antoni said, “Couldn’t capture it complete. Too tall! We didn’t plant these sunflowers, so don’t know where they came from.”

from EarthSky http://bit.ly/2MFx0eS

View larger at EarthSky Community Photos. | This tiger lily bloomed in Antoni Williams’ garden in Tokoroa, New Zealand, in January 2019. “We have a wonderful garden. Taken 30 years to complete (if it`s ever possible to complete a garden). This is one of my favorites.”

View larger at EarthSky Community Photos. | Antoni’s garden also hosts a brilliant red volunteer sunflower. Antoni said, “Couldn’t capture it complete. Too tall! We didn’t plant these sunflowers, so don’t know where they came from.”

from EarthSky http://bit.ly/2MFx0eS

Small telescopes detect missing link in planet evolution

View larger. | Artist’s concept of newly discovered small object far from our sun, in the outer solar system, via NAOJ.

Astronomers in Japan report that they’ve detected a very small body – only 1.6 miles wide (2.6-km diameter) – at the edge of our solar system. They’re calling it a missing link in planet evolution. We know of multiple small bodies orbiting far from the sun, in the realm of what astronomers call the Kuiper Belt. The largest of the known Kuiper Belt Objects, or KBOs, are hundreds of miles wide. Some are smaller, like Ultima Thule, recently passed by the New Horizons spacecraft. However, this is the first time a body this small has been found. It’s so small that even the Hubble Space Telescope would not be able to spot it. Instead, astronomers detected it using two small, amateur telescopes, with the help of a distant star.

The astronomers described their work January 28, 2019, in the peer-reviewed journal Nature Astronomy. It was made possible by grants-in-aid from the Japan Society for the Promotion of Science and the support of the Miyako open-air school and the local community in Miyakojima-shi.

Ko Arimatsu at the National Astronomical Observatory of Japan led the research. His statement explained:

Kilometer-sized bodies like the one discovered have been predicted to exist for more than 70 years. These objects acted as an important step in the planet formation process between small initial amalgamations of dust and ice and the planets we see today.

The Edgeworth-Kuiper Belt is a collection of small celestial bodies located beyond Neptune’s orbit. The most famous Edgeworth-Kuiper Belt Object is Pluto. Edgeworth-Kuiper Belt Objects are believed to be remnants left over from the formation of the solar system. While small bodies like asteroids in the inner solar system have been altered by solar radiation, collisions, and the gravity of the planets over time; objects in the cold, dark, lonely Edgeworth-Kuiper Belt preserve the pristine conditions of the early solar system. Thus astronomers study them to learn about the beginning of the planet formation process.

Here’s Ultima Thule, a Kuiper Belt Object passed on January 1, 2019, by the New Horizons spacecraft. It’s roughly 19 miles (30 km) long, or about 1/60th the diameter of Pluto. Image via NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute/Spaceflight Insider.

Kuiper Belt Objects as small as the one just discovered – only a few miles across – have been predicted to exist. But even the world’s largest telescopes can’t pick them up by looking directly at them; they are just too small and too dim. Ko Arimatsu and his team instead used the technique of watching for stellar occultations – the blocking of starlight by objects closer to us than the stars – to find this object. They monitored a large number of stars, watching for telltale dips in the stars’ light that would indicate unknown objects.

They called their team OASES (Organized Autotelescopes for Serendipitous Event Survey) and placed two small (28 cm – 11 inch) telescopes on the roof of the Miyako open-air school on Miyako Island, Miyakojima-shi, Okinawa Prefecture, Japan. They monitored approximately 2,000 stars for a total of 60 hours.

Analyzing the data, the team found an event consistent with a star appearing to dim as it is occulted by a 1.6-mile-wide (2.6-km-wide) object in the Kuiper Belt. They said this detection indicates that kilometer-sized Kuiper Belt Objects are more numerous than previously thought.

If so, this fact would support models where planetesimals – the early building blocks of planets – first grow slowly into kilometer-sized objects before runaway growth causes them to merge into planets.

Arimatsu said:

This is a real victory for little projects. Our team had less than 0.3 percent of the budget of large international projects. We didn’t even have enough money to build a second dome to protect our second telescope! Yet we still managed to make a discovery that is impossible for the big projects. Now that we know our system works, we will investigate the Edgeworth-Kuiper Belt in more detail. We also have our sights set on the still undiscovered Oort Cloud out beyond that.

Artist’s concept of the Kuiper Belt and the Oort Cloud, the distant icy realm of the solar system. Image via NASA.

Bottom line: Astronomers in Japan used two amateur-sized telescopes to discover a very small body in the Kuiper Belt.

Source: A kilometre-sized Kuiper belt object discovered by stellar occultation using amateur telescopes

Via National Astronomical Observatory of Japan

from EarthSky http://bit.ly/2sUT1gK

View larger. | Artist’s concept of newly discovered small object far from our sun, in the outer solar system, via NAOJ.

Astronomers in Japan report that they’ve detected a very small body – only 1.6 miles wide (2.6-km diameter) – at the edge of our solar system. They’re calling it a missing link in planet evolution. We know of multiple small bodies orbiting far from the sun, in the realm of what astronomers call the Kuiper Belt. The largest of the known Kuiper Belt Objects, or KBOs, are hundreds of miles wide. Some are smaller, like Ultima Thule, recently passed by the New Horizons spacecraft. However, this is the first time a body this small has been found. It’s so small that even the Hubble Space Telescope would not be able to spot it. Instead, astronomers detected it using two small, amateur telescopes, with the help of a distant star.

The astronomers described their work January 28, 2019, in the peer-reviewed journal Nature Astronomy. It was made possible by grants-in-aid from the Japan Society for the Promotion of Science and the support of the Miyako open-air school and the local community in Miyakojima-shi.

Ko Arimatsu at the National Astronomical Observatory of Japan led the research. His statement explained:

Kilometer-sized bodies like the one discovered have been predicted to exist for more than 70 years. These objects acted as an important step in the planet formation process between small initial amalgamations of dust and ice and the planets we see today.

The Edgeworth-Kuiper Belt is a collection of small celestial bodies located beyond Neptune’s orbit. The most famous Edgeworth-Kuiper Belt Object is Pluto. Edgeworth-Kuiper Belt Objects are believed to be remnants left over from the formation of the solar system. While small bodies like asteroids in the inner solar system have been altered by solar radiation, collisions, and the gravity of the planets over time; objects in the cold, dark, lonely Edgeworth-Kuiper Belt preserve the pristine conditions of the early solar system. Thus astronomers study them to learn about the beginning of the planet formation process.

Here’s Ultima Thule, a Kuiper Belt Object passed on January 1, 2019, by the New Horizons spacecraft. It’s roughly 19 miles (30 km) long, or about 1/60th the diameter of Pluto. Image via NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute/Spaceflight Insider.

Kuiper Belt Objects as small as the one just discovered – only a few miles across – have been predicted to exist. But even the world’s largest telescopes can’t pick them up by looking directly at them; they are just too small and too dim. Ko Arimatsu and his team instead used the technique of watching for stellar occultations – the blocking of starlight by objects closer to us than the stars – to find this object. They monitored a large number of stars, watching for telltale dips in the stars’ light that would indicate unknown objects.

They called their team OASES (Organized Autotelescopes for Serendipitous Event Survey) and placed two small (28 cm – 11 inch) telescopes on the roof of the Miyako open-air school on Miyako Island, Miyakojima-shi, Okinawa Prefecture, Japan. They monitored approximately 2,000 stars for a total of 60 hours.

Analyzing the data, the team found an event consistent with a star appearing to dim as it is occulted by a 1.6-mile-wide (2.6-km-wide) object in the Kuiper Belt. They said this detection indicates that kilometer-sized Kuiper Belt Objects are more numerous than previously thought.

If so, this fact would support models where planetesimals – the early building blocks of planets – first grow slowly into kilometer-sized objects before runaway growth causes them to merge into planets.

Arimatsu said:

This is a real victory for little projects. Our team had less than 0.3 percent of the budget of large international projects. We didn’t even have enough money to build a second dome to protect our second telescope! Yet we still managed to make a discovery that is impossible for the big projects. Now that we know our system works, we will investigate the Edgeworth-Kuiper Belt in more detail. We also have our sights set on the still undiscovered Oort Cloud out beyond that.

Artist’s concept of the Kuiper Belt and the Oort Cloud, the distant icy realm of the solar system. Image via NASA.

Bottom line: Astronomers in Japan used two amateur-sized telescopes to discover a very small body in the Kuiper Belt.

Source: A kilometre-sized Kuiper belt object discovered by stellar occultation using amateur telescopes

Via National Astronomical Observatory of Japan

from EarthSky http://bit.ly/2sUT1gK

How Titan cooked its atmosphere

Saturn’s large moon Titan, with its smaller moon Mimas in the foreground, as seen by the Cassini spacecraft in 2013. Titan’s atmosphere is thick and hazy, and mostly nitrogen, like Earth’s. Where did the nitrogen come from? Image via NASA/JPL-Caltech/Space Science Institute.

Titan is Saturn’s largest moon and, in many ways, seems more like a planet than a moon. It is eerily Earth-like, yet a very different world from Earth, with extreme cold and rivers, lakes and seas of liquid methane/ethane. Also, Titan is the only moon in the solar system that has a thick atmosphere, and, in that way, too, it’s reminiscent of the major planets in our solar system. Titan’s atmosphere is composed primarily of nitrogen, like Earth’s. Just how Titan’s atmosphere developed has been one of the long-standing mysteries of this bizarre world. 

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A new peer-reviewed study sheds some light on this question. The study was published online in The Astrophysical Journal on January 22, 2019. The study – from the Southwest Research Institute (SwRI) – suggests that the nitrogen in Titan’s atmosphere originated from the “cooking” of organic material in the interior of the moon. Kelly Miller, a research scientist in SwRI’s Space Science and Engineering Division and lead author of the study, provided some background:

Titan is a very interesting moon because it has this very thick atmosphere, which makes it unique among moons in our solar system. It is also the only body in the solar system, other than Earth, that has large quantities of liquid on the surface. Titan, however, has liquid hydrocarbons instead of water.

A lot of organic chemistry is no doubt happening on Titan, so it’s an undeniable source of curiosity.

The main theory about Titan’s atmosphere has been that ammonia ice from comets was converted, by impacts or photochemistry, into nitrogen to form Titan’s atmosphere. While that may still be an important process, it neglects the effects of what we now know is a very substantial portion of comets: complex organic material.

Artist’s concept of the Huygens probe descending through Titan’s thick atmosphere before landing, in 2005. Image via NASA.

Miller’s study was inspired by a mission to a very different object – comet 67P/Churyumov-Gerasimenko – studied in detail by the European Space Agency’s Rosetta spacecraft. It turned out that the composition of the comet was about half-ice, one-quarter rock and one-quarter organic material. The comet’s composition could be significant in terms of figuring out how Titan’s atmosphere came to be, according to Miller:

Comets and primitive bodies in the outer solar system are really interesting because they’re thought to be leftover building blocks of the solar system. Those small bodies could be incorporated into larger bodies, like Titan, and the dense, organic-rich rocky material could be found in its core.

Titan as seen by Cassini’s radar, showing methane clouds in the atmosphere. Image via NASA/JPL-Caltech.

How exactly does all this apply to Titan? Miller compared thermal models of Titan’s interior to data from organic material in meteorites. The idea was to see how much gaseous material could be produced from meteorite impacts into Titan when it was first forming.

The result was that about half of the moon’s nitrogen and perhaps also most of its methane could be accounted for in this scenario. The organics would be “cooked” into Titan as it was forming a few billion years ago.

While primarily nitrogen, Titan’s atmosphere also contains about 5% methane, which can form organic compounds. Those organics are all over Titan today – both in the atmosphere (as haze) and coating the surface (including massive “dunes” of organic material).

Structure of Titan’s atmosphere, which is composed primarily of nitrogen and methane. Image via Anthony J. Colozza.

But Titan’s atmospheric methane supply still needs to be replenished somehow since the gas breaks down over time, and scientists are still not sure how that happens. On Earth, most methane comes from biology, but on Titan – given the extreme conditions – it is more likely to be primordial methane left over from when the moon first formed, similar to that found in the atmospheres of the ice giants Uranus and Neptune.

Some scientists, however, do think that primitive life of some kind is possible on Titan, perhaps in its methane/ethane lakes and seas or in the subsurface water ocean.

Bottom line: Titan’s thick nitrogen atmosphere is unique among moons in the solar system. The nitrogen may have been “cooked” inside Titan.

Source: Contributions from Accreted Organics to Titan’s Atmosphere: New Insights from Cometary and Chondritic Data

Via SwRI

from EarthSky http://bit.ly/2TlfDCu

Saturn’s large moon Titan, with its smaller moon Mimas in the foreground, as seen by the Cassini spacecraft in 2013. Titan’s atmosphere is thick and hazy, and mostly nitrogen, like Earth’s. Where did the nitrogen come from? Image via NASA/JPL-Caltech/Space Science Institute.

Titan is Saturn’s largest moon and, in many ways, seems more like a planet than a moon. It is eerily Earth-like, yet a very different world from Earth, with extreme cold and rivers, lakes and seas of liquid methane/ethane. Also, Titan is the only moon in the solar system that has a thick atmosphere, and, in that way, too, it’s reminiscent of the major planets in our solar system. Titan’s atmosphere is composed primarily of nitrogen, like Earth’s. Just how Titan’s atmosphere developed has been one of the long-standing mysteries of this bizarre world. 

EarthSky lunar calendars are cool! They make great gifts. Order now. Going fast!

A new peer-reviewed study sheds some light on this question. The study was published online in The Astrophysical Journal on January 22, 2019. The study – from the Southwest Research Institute (SwRI) – suggests that the nitrogen in Titan’s atmosphere originated from the “cooking” of organic material in the interior of the moon. Kelly Miller, a research scientist in SwRI’s Space Science and Engineering Division and lead author of the study, provided some background:

Titan is a very interesting moon because it has this very thick atmosphere, which makes it unique among moons in our solar system. It is also the only body in the solar system, other than Earth, that has large quantities of liquid on the surface. Titan, however, has liquid hydrocarbons instead of water.

A lot of organic chemistry is no doubt happening on Titan, so it’s an undeniable source of curiosity.

The main theory about Titan’s atmosphere has been that ammonia ice from comets was converted, by impacts or photochemistry, into nitrogen to form Titan’s atmosphere. While that may still be an important process, it neglects the effects of what we now know is a very substantial portion of comets: complex organic material.

Artist’s concept of the Huygens probe descending through Titan’s thick atmosphere before landing, in 2005. Image via NASA.

Miller’s study was inspired by a mission to a very different object – comet 67P/Churyumov-Gerasimenko – studied in detail by the European Space Agency’s Rosetta spacecraft. It turned out that the composition of the comet was about half-ice, one-quarter rock and one-quarter organic material. The comet’s composition could be significant in terms of figuring out how Titan’s atmosphere came to be, according to Miller:

Comets and primitive bodies in the outer solar system are really interesting because they’re thought to be leftover building blocks of the solar system. Those small bodies could be incorporated into larger bodies, like Titan, and the dense, organic-rich rocky material could be found in its core.

Titan as seen by Cassini’s radar, showing methane clouds in the atmosphere. Image via NASA/JPL-Caltech.

How exactly does all this apply to Titan? Miller compared thermal models of Titan’s interior to data from organic material in meteorites. The idea was to see how much gaseous material could be produced from meteorite impacts into Titan when it was first forming.

The result was that about half of the moon’s nitrogen and perhaps also most of its methane could be accounted for in this scenario. The organics would be “cooked” into Titan as it was forming a few billion years ago.

While primarily nitrogen, Titan’s atmosphere also contains about 5% methane, which can form organic compounds. Those organics are all over Titan today – both in the atmosphere (as haze) and coating the surface (including massive “dunes” of organic material).

Structure of Titan’s atmosphere, which is composed primarily of nitrogen and methane. Image via Anthony J. Colozza.

But Titan’s atmospheric methane supply still needs to be replenished somehow since the gas breaks down over time, and scientists are still not sure how that happens. On Earth, most methane comes from biology, but on Titan – given the extreme conditions – it is more likely to be primordial methane left over from when the moon first formed, similar to that found in the atmospheres of the ice giants Uranus and Neptune.

Some scientists, however, do think that primitive life of some kind is possible on Titan, perhaps in its methane/ethane lakes and seas or in the subsurface water ocean.

Bottom line: Titan’s thick nitrogen atmosphere is unique among moons in the solar system. The nitrogen may have been “cooked” inside Titan.

Source: Contributions from Accreted Organics to Titan’s Atmosphere: New Insights from Cometary and Chondritic Data

Via SwRI

from EarthSky http://bit.ly/2TlfDCu

Moon slides past 3 morning planets

Starting around January 30, 2019 – and through the morning of February 1 and possibly even February 2 – watch the slender waning crescent moon slide by the planets Jupiter, Venus and then Saturn.

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On January 30, the moon rises first, followed by Jupiter, then Venus and then Saturn. Given clear skies and an unobstructed horizon in the direction of sunrise, it’ll be easy to catch the moon, Venus and Jupiter. These worlds rank as the second-brightest, third-brightest and fourth-brightest celestial bodies to light up the heavens, respectively, after the sun.

Then just keep watching. The planets and moon will still be there – and the lit side of the moon will still be pointing in the direction of Saturn – on January 31 and February 1.

Eliot Herman caught Venus (brighter) and Jupiter on the morning of their conjunction (January 22, 2019). Note that, on the morning, Jupiter was below Venus as seen from U.S. latitudes. By the end of January, Jupiter is above Venus as seen from around the world.

Saturn is just now returning to the east before dawn, to begin its yearly trek across Earth’s skies. It’s not very prominent yet, and you might encounter haze or other murk near the horizon.

Thus Saturn will present more of a challenge, sitting, as it does, much closer to the sunrise horizon, with its luster tarnished by the glow of morning dawn. Although Saturn will be nowhere near as bright as the moon, Venus or Jupiter, the ringed planet nonetheless now shines as brightly as a 1st-magnitude star.

On any of these mornings, draw an imaginary line between Venus and Jupiter to spot Saturn near the horizon an hour or so before sunrise. That imaginary line will continue to work for you for awhile, even after the moon has disappeared into the sunrise glare.

If you can’t catch Saturn with the eye alone, try your luck with binoculars.

Want to know when the moon and planets rise into your sky? Click here if you live in the U.S. or Canada.

If you live elsewhere worldwide, click here.

The planets of the solar system are scaled by size but not distance. Click here to find out planetary distances in astronomical units. Image via International Astronomical Union.

Note that – day by day – the moon shifts eastward (in the direction of sunrise). The lit side of the waning moon always points in the moon’s direction of travel in front of the stars and planets of the zodiac. In other words, the daily change of the moon’s position relative to the backdrop stars reveals how far the moon has traveled in its orbit around Earth.

In the time frame of one month, the moon swings through all the constellations of the zodiac and sweeps by every planet of the solar system. The moon does not actually come close to any of these planets, however. For a day or two each month, the moon and a particular planet more or less align on the sky’s dome, but are not truly close together in space. Click here to know the present distance of the moon (in Earth-radii) from Earth and the present distances of the planets (in astronomical units) from Earth. Incidentally, one astronomical unit = 23,455 Earth-radii.

Now and again, the moon occults – passes directly in front of – a bright star or solar system planet. The moon will occult Venus on January 31, 2019; click here for more about the Venus occultation.

For the most part, the lunar occultation of Venus takes place over the Pacific Ocean. The red dotted line depicts where the occultation occurs in daytime, blue at twilight and white in a dark sky. Worldwide map via IOTA.

The moon will occult Saturn on February 2, 2019; click here for more about the Saturn occultation.

Note that you have to be at just the right place on Earth to witness either occultation.

From some parts of the world, the moon passed in front of Venus on September 18, 2017. Mazamir Mazlan of Telok Kemang Observatory in Malaysia caught the near occultation – with Venus sweeping to one side of the moon. Beautiful, yes? On January 31, 2019, from some parts of the world, the moon will occult Venus again. Click here for more about the Venus occultation.

Bottom line: No matter where you live on Earth, let the slender waning crescent moon guide your eye to Jupiter and Venus (and possibly Saturn) before sunup in late January and early February 2019.

from EarthSky http://bit.ly/2DH1ASG

Starting around January 30, 2019 – and through the morning of February 1 and possibly even February 2 – watch the slender waning crescent moon slide by the planets Jupiter, Venus and then Saturn.

Keep track of moon phases with EarthSky lunar calendars. Order now. Going fast!

On January 30, the moon rises first, followed by Jupiter, then Venus and then Saturn. Given clear skies and an unobstructed horizon in the direction of sunrise, it’ll be easy to catch the moon, Venus and Jupiter. These worlds rank as the second-brightest, third-brightest and fourth-brightest celestial bodies to light up the heavens, respectively, after the sun.

Then just keep watching. The planets and moon will still be there – and the lit side of the moon will still be pointing in the direction of Saturn – on January 31 and February 1.

Eliot Herman caught Venus (brighter) and Jupiter on the morning of their conjunction (January 22, 2019). Note that, on the morning, Jupiter was below Venus as seen from U.S. latitudes. By the end of January, Jupiter is above Venus as seen from around the world.

Saturn is just now returning to the east before dawn, to begin its yearly trek across Earth’s skies. It’s not very prominent yet, and you might encounter haze or other murk near the horizon.

Thus Saturn will present more of a challenge, sitting, as it does, much closer to the sunrise horizon, with its luster tarnished by the glow of morning dawn. Although Saturn will be nowhere near as bright as the moon, Venus or Jupiter, the ringed planet nonetheless now shines as brightly as a 1st-magnitude star.

On any of these mornings, draw an imaginary line between Venus and Jupiter to spot Saturn near the horizon an hour or so before sunrise. That imaginary line will continue to work for you for awhile, even after the moon has disappeared into the sunrise glare.

If you can’t catch Saturn with the eye alone, try your luck with binoculars.

Want to know when the moon and planets rise into your sky? Click here if you live in the U.S. or Canada.

If you live elsewhere worldwide, click here.

The planets of the solar system are scaled by size but not distance. Click here to find out planetary distances in astronomical units. Image via International Astronomical Union.

Note that – day by day – the moon shifts eastward (in the direction of sunrise). The lit side of the waning moon always points in the moon’s direction of travel in front of the stars and planets of the zodiac. In other words, the daily change of the moon’s position relative to the backdrop stars reveals how far the moon has traveled in its orbit around Earth.

In the time frame of one month, the moon swings through all the constellations of the zodiac and sweeps by every planet of the solar system. The moon does not actually come close to any of these planets, however. For a day or two each month, the moon and a particular planet more or less align on the sky’s dome, but are not truly close together in space. Click here to know the present distance of the moon (in Earth-radii) from Earth and the present distances of the planets (in astronomical units) from Earth. Incidentally, one astronomical unit = 23,455 Earth-radii.

Now and again, the moon occults – passes directly in front of – a bright star or solar system planet. The moon will occult Venus on January 31, 2019; click here for more about the Venus occultation.

For the most part, the lunar occultation of Venus takes place over the Pacific Ocean. The red dotted line depicts where the occultation occurs in daytime, blue at twilight and white in a dark sky. Worldwide map via IOTA.

The moon will occult Saturn on February 2, 2019; click here for more about the Saturn occultation.

Note that you have to be at just the right place on Earth to witness either occultation.

From some parts of the world, the moon passed in front of Venus on September 18, 2017. Mazamir Mazlan of Telok Kemang Observatory in Malaysia caught the near occultation – with Venus sweeping to one side of the moon. Beautiful, yes? On January 31, 2019, from some parts of the world, the moon will occult Venus again. Click here for more about the Venus occultation.

Bottom line: No matter where you live on Earth, let the slender waning crescent moon guide your eye to Jupiter and Venus (and possibly Saturn) before sunup in late January and early February 2019.

from EarthSky http://bit.ly/2DH1ASG

Star-hop from Orion to Planet 9

Above image of Planet 9’s path via Wikipedia

Tonight, let the constellation Orion the Hunter show you the approximate position of the hypothetical Planet 9 in the starry sky. As of now, nobody has yet seen this hypothetical solar system planet, which, if it exists, is large and very distant. But – still, hypothetically speaking – there are reasons to believe it does exist, and so for astronomers and citizen scientists … the hunt is on.

Two Caltech astronomers – Mike Brown and Konstantin Batygin – claim to have solid theoretical evidence for a 9th major planet in the outer solar system moving in a bizarre, highly elongated orbit. Recently, however, some astronomers have offered an alternative explanation to their data, saying it doesn’t necessitate the presence of a Planet 9.

Mystery orbits don’t require a Planet 9, researchers say

The astronomer Scott S. Sheppard guesses this planet might shine somewhere between 23rd and 25th magnitude, making this world about 6 to 40 million times fainter than the faintest celestial object visible to the unaided eye. Still, it’s fun to imagine the place in the sky where astronomers are searching for Planet 9.

The sky chart at the top of this post shows that location. The chart, which is via Wikipedia, shows Planet 9‘s possible path across our sky, in front of the backdrop stars, from the years 1000 to 3000 AD.

Although this world, if it exits, is way beyond the range of our backyard telescopes, we can still star-hop from the constellation Orion to Planet 9’s possible location in the starry sky.

From around the world at this time of year, the constellation Orion climbs highest up for the night around mid-evening (9 to 10 p.m.) local time. From temperate latitudes in the Northern Hemisphere, Orion appears in the southern sky at mid-evening. From the equator, Orion appears high overhead, and from temperate regions in the Southern Hemisphere, an “upside-down” Orion shines in the northern sky.

Some of you may know how to star-hop from Orion’s Belt to Aldebaran, the brightest star in the constellation Taurus the Bull. If not, refer to the sky chart below. Once you’ve found Aldebaran, you’ve pretty much found the proposed location of Planet 9, which – again, if it exists, and if astronomers are right about its location in our solar system – lodges pretty much directly east of Orion’s Belt and directly south of the star Aldebaran.

Use Orion’s Belt to star-hop to the star Aldebaran.

Caltech astronomers first announced a hypothetical Planet 9 on January 20, 2016. What they called “solid theoretical evidence” exists for a giant planet – a 9th major planet in the outer solar system – moving in what they called a “bizarre, highly elongated orbit.” They nicknamed it Planet 9 then, and they said hoped other astronomers would search for it.

If it exists, the planet has a mass about 10 times that of Earth and orbits about 20 times farther from the sun on average than Neptune, which is currently the 8th major planet and which orbits the sun at an average distance of 2.8 billion miles (4.5 billion km).

The astronomers say it would take this new planet between 10,000 and 20,000 years to make just one full orbit around the sun.

The orbits of 6 extreme trans-Neptunian objects (in magenta), all mysteriously aligned in one direction. These orbits were used by Caltech astronomers to hypothesize a Planet 9 (in orange). Image via Caltech/ R. Hurt (IPAC).

Read more: Solid evidence for a 9th planet

Bottom line: Astronomers are searching for a hypothetical Planet 9 in the starry sky. You can use the constellation Orion to show you approximately where they’re looking.

from EarthSky http://bit.ly/2WoEkjv

Above image of Planet 9’s path via Wikipedia

Tonight, let the constellation Orion the Hunter show you the approximate position of the hypothetical Planet 9 in the starry sky. As of now, nobody has yet seen this hypothetical solar system planet, which, if it exists, is large and very distant. But – still, hypothetically speaking – there are reasons to believe it does exist, and so for astronomers and citizen scientists … the hunt is on.

Two Caltech astronomers – Mike Brown and Konstantin Batygin – claim to have solid theoretical evidence for a 9th major planet in the outer solar system moving in a bizarre, highly elongated orbit. Recently, however, some astronomers have offered an alternative explanation to their data, saying it doesn’t necessitate the presence of a Planet 9.

Mystery orbits don’t require a Planet 9, researchers say

The astronomer Scott S. Sheppard guesses this planet might shine somewhere between 23rd and 25th magnitude, making this world about 6 to 40 million times fainter than the faintest celestial object visible to the unaided eye. Still, it’s fun to imagine the place in the sky where astronomers are searching for Planet 9.

The sky chart at the top of this post shows that location. The chart, which is via Wikipedia, shows Planet 9‘s possible path across our sky, in front of the backdrop stars, from the years 1000 to 3000 AD.

Although this world, if it exits, is way beyond the range of our backyard telescopes, we can still star-hop from the constellation Orion to Planet 9’s possible location in the starry sky.

From around the world at this time of year, the constellation Orion climbs highest up for the night around mid-evening (9 to 10 p.m.) local time. From temperate latitudes in the Northern Hemisphere, Orion appears in the southern sky at mid-evening. From the equator, Orion appears high overhead, and from temperate regions in the Southern Hemisphere, an “upside-down” Orion shines in the northern sky.

Some of you may know how to star-hop from Orion’s Belt to Aldebaran, the brightest star in the constellation Taurus the Bull. If not, refer to the sky chart below. Once you’ve found Aldebaran, you’ve pretty much found the proposed location of Planet 9, which – again, if it exists, and if astronomers are right about its location in our solar system – lodges pretty much directly east of Orion’s Belt and directly south of the star Aldebaran.

Use Orion’s Belt to star-hop to the star Aldebaran.

Caltech astronomers first announced a hypothetical Planet 9 on January 20, 2016. What they called “solid theoretical evidence” exists for a giant planet – a 9th major planet in the outer solar system – moving in what they called a “bizarre, highly elongated orbit.” They nicknamed it Planet 9 then, and they said hoped other astronomers would search for it.

If it exists, the planet has a mass about 10 times that of Earth and orbits about 20 times farther from the sun on average than Neptune, which is currently the 8th major planet and which orbits the sun at an average distance of 2.8 billion miles (4.5 billion km).

The astronomers say it would take this new planet between 10,000 and 20,000 years to make just one full orbit around the sun.

The orbits of 6 extreme trans-Neptunian objects (in magenta), all mysteriously aligned in one direction. These orbits were used by Caltech astronomers to hypothesize a Planet 9 (in orange). Image via Caltech/ R. Hurt (IPAC).

Read more: Solid evidence for a 9th planet

Bottom line: Astronomers are searching for a hypothetical Planet 9 in the starry sky. You can use the constellation Orion to show you approximately where they’re looking.

from EarthSky http://bit.ly/2WoEkjv

Michael Peres on how to photograph snowflakes

Michael Peres uses a black velvet catch tray to capture falling snowflakes. Photo appears courtesy of Michael Peres.

Michael Peres is a professor of biomedical photographic communications at the Rochester Institute of Technology in New York. He’s also an award-winning photo-educator, author, and science photographer, with work featured by CNN, Time, the Weather Channel, Nikon, and Mashable. EarthSky spoke with him via email in January, 2019, to learn more about his amazing photographs.

How did you get interested in photographing snowflakes?

In the winter of 2003–2004, one of my students visited an exhibition of Wilson Snowflake Bentley photographs on display at the Buffalo Museum and Science Center. Her excitement about trying to photograph snowflakes was contagious and within a short period of time on a wintry day in January, my microscopy class moved our gear outside and we tried. Little did I know how infectious the experience would be for me personally. Now, more than 15 years later, I am obsessed with the challenge during the long and snowy Rochester, New York, winters. Rochester on average can receive more than 105 inches of snow per season. One could speculate that amount of snow would provide ample subjects and chances to photograph unique and interesting ice crystals.

Snowflake photographed by Michael Peres during a January 19, 2019, snowstorm. Photo appears courtesy of Michael Peres.

Plate-shaped snow crystal photographed by Michael Peres during a January 19, 2019, snowstorm. Photo appears courtesy of Michael Peres.

Dendritic-shaped snow crystal photographed by Michael Peres during a January 19, 2019, snowstorm. Photo appears courtesy of Michael Peres.

Snowflakes come in a variety of different shapes. What are some of your favorite shapes to photograph?

During the course of any winter, a wide variety of crystal types fall. My methods and equipment are focused towards photographing crystals that are 1 to 2 millimeters in size and are dendritic [“tree-like”]. All snowflakes start out as water molecules that form hexagons in the right conditions. These embryonic crystals are called stellar plates. They can be infinitely small, but they grow and add water molecules over time. At some time during their formation, they grow wings and other intricate structures. When this happens they become dendritic flakes. They are my favorite crystals to photograph. It has been my experience that I have the best luck when the air temperatures are between 15 and 25 degrees Fahrenheit [about -10 to -5 degrees Celsius].. During the course of a winter, each storm can bring a wide range of crystal types including columns, capped columns, needles, and granular snow to share a few types of crystals that can fall.

Technique used to select a snowflake to photograph. Photo appears courtesy of Michael Peres.

The microscope used by Professor Peres to photograph snowflakes. Photo appears courtesy of Michael Peres.

Can you describe the general process you use to take a photograph of a snowflake?

My process starts by frequently watching the weather forecasts. My equipment is kept outside in the garage. Photographing ice crystals requires that everything I use be kept below 32 degrees Fahrenheit [0 Celsius]. I keep an inventory of glass slides with my microscope, and I use a fiber optic light source. Being a snowflake photographer is much like being a fireman and ready at a moment’s notice when things happen. These events can be at night, in the day, when I am at work, and when I am indisposed or when I am ready. When good crystals fall and I am available, I start my photographing.

I catch crystals that are falling using a baking tray with a piece of black velvet draped over the tray. Velvet is useful for isolating the best crystals but also allows for easy retrieval using a small needle taped to a pencil. Depending on the humidity and air temperatures, there is a natural static electricity in the needle and crystal. It allows me to lift the crystal using the needle because they are attracted to one another giving me a chance to position the crystal onto a clear glass slide. It is possible to photograph the crystals in the tray on the fabric but I prefer the isolation against a lighter background and have the opportunity to light from underneath.

I use a low power simple microscope. Basically, the microscope is a repurposed industrial macro stand. I use a 16- or 25-millimeter macro lens and the camera has a bellows. Attached to the bellows (extension tubes can also be used) is a DSLR camera body without a lens.

Once an interesting crystal has been identified in my catch tray, I move it to a glass slide using the needle on the pencil. The slide is placed onto the microscope’s focusing stage where I can compose and focus the image in the viewfinder of the camera.

I use a fiber optic illuminator with a bifurcated gooseneck light guide that illuminates the crystals. I shine light onto a variety of materials located below the stage to provide contrast and color to the light that is refracted into the crystal used to reveal the crystal’s facets.

Snowflake photograph from Michael Peres’s RIT snowflake gallery. Image via Michael Peres, RIT.

Any tips for those of us who have been trying to capture a good snowflake photograph with a macro lens? I for one am wondering if some temperatures are better than others for taking snowflake photos, and how on Earth do I keep my hands warm?

It is possible to photograph snowflakes with a smartphone or DSLR. The features and advantages of each camera are pretty clear. The smartphone has a pretty good sensor but focusing the lens, exposure management, and ability to magnify sometimes 1-millimeter crystals are real obstacles. There are accessory lenses that can be added to the smartphone. Photojojo is an excellent vendor of such lenses.

DSLR cameras are significantly better choices for this work and are equipped with a macro lens capable of at least 1:1. Canon sells a 65-millimeter macro lens that can achieve 5:1 magnification. Adding extension tubes or by using a simple bellows, you can increase the image size that the camera system produces. My typical crystals benefit from a 3 to 6x magnification.

I dress warmly for this work wearing many layers including insulated boots. I use gloves with finger holes but because of the delicate nature of focusing a microscope, moving the crystal in small increments, I benefit from more control and feel having nothing on my hands. Because of the adrenaline, I can typically work for up to 30 minutes before my hands cannot tolerate the conditions any longer.

I photograph using a medium aperture such as ƒ/5.6. Diffraction at these image sizes can cause the crystals to become less defined if I use a smaller aperture. Often I photograph wide open and create increased DOF images.

Snowflake photograph from Michael Peres’s RIT snowflake gallery. Image via Michael Peres, RIT.

Many thanks to Professor Peres for discussing his snowflake photography with EarthSky. More examples of his work can be viewed on his Instagram account @michael_peres and on his website at the Rochester Institute of Technology (RIT).

Want more? You can read about the attempts one of EarthSky’s intrepid contributors to photograph snowflakes in the archive here.

See some recent favorite snowflake photos from the EarthSky Community

If this post inspires you to give snowflake photography a shot, please submit your photos to EarthSky Community Photos! We love seeing and sharing your recent captures of the natural world!

Bottom line: How to take photos of snowflakes with Professor Michael Peres of the Rochester Institute of Technology.

from EarthSky http://bit.ly/2B9Uhku

Michael Peres uses a black velvet catch tray to capture falling snowflakes. Photo appears courtesy of Michael Peres.

Michael Peres is a professor of biomedical photographic communications at the Rochester Institute of Technology in New York. He’s also an award-winning photo-educator, author, and science photographer, with work featured by CNN, Time, the Weather Channel, Nikon, and Mashable. EarthSky spoke with him via email in January, 2019, to learn more about his amazing photographs.

How did you get interested in photographing snowflakes?

In the winter of 2003–2004, one of my students visited an exhibition of Wilson Snowflake Bentley photographs on display at the Buffalo Museum and Science Center. Her excitement about trying to photograph snowflakes was contagious and within a short period of time on a wintry day in January, my microscopy class moved our gear outside and we tried. Little did I know how infectious the experience would be for me personally. Now, more than 15 years later, I am obsessed with the challenge during the long and snowy Rochester, New York, winters. Rochester on average can receive more than 105 inches of snow per season. One could speculate that amount of snow would provide ample subjects and chances to photograph unique and interesting ice crystals.

Snowflake photographed by Michael Peres during a January 19, 2019, snowstorm. Photo appears courtesy of Michael Peres.

Plate-shaped snow crystal photographed by Michael Peres during a January 19, 2019, snowstorm. Photo appears courtesy of Michael Peres.

Dendritic-shaped snow crystal photographed by Michael Peres during a January 19, 2019, snowstorm. Photo appears courtesy of Michael Peres.

Snowflakes come in a variety of different shapes. What are some of your favorite shapes to photograph?

During the course of any winter, a wide variety of crystal types fall. My methods and equipment are focused towards photographing crystals that are 1 to 2 millimeters in size and are dendritic [“tree-like”]. All snowflakes start out as water molecules that form hexagons in the right conditions. These embryonic crystals are called stellar plates. They can be infinitely small, but they grow and add water molecules over time. At some time during their formation, they grow wings and other intricate structures. When this happens they become dendritic flakes. They are my favorite crystals to photograph. It has been my experience that I have the best luck when the air temperatures are between 15 and 25 degrees Fahrenheit [about -10 to -5 degrees Celsius].. During the course of a winter, each storm can bring a wide range of crystal types including columns, capped columns, needles, and granular snow to share a few types of crystals that can fall.

Technique used to select a snowflake to photograph. Photo appears courtesy of Michael Peres.

The microscope used by Professor Peres to photograph snowflakes. Photo appears courtesy of Michael Peres.

Can you describe the general process you use to take a photograph of a snowflake?

My process starts by frequently watching the weather forecasts. My equipment is kept outside in the garage. Photographing ice crystals requires that everything I use be kept below 32 degrees Fahrenheit [0 Celsius]. I keep an inventory of glass slides with my microscope, and I use a fiber optic light source. Being a snowflake photographer is much like being a fireman and ready at a moment’s notice when things happen. These events can be at night, in the day, when I am at work, and when I am indisposed or when I am ready. When good crystals fall and I am available, I start my photographing.

I catch crystals that are falling using a baking tray with a piece of black velvet draped over the tray. Velvet is useful for isolating the best crystals but also allows for easy retrieval using a small needle taped to a pencil. Depending on the humidity and air temperatures, there is a natural static electricity in the needle and crystal. It allows me to lift the crystal using the needle because they are attracted to one another giving me a chance to position the crystal onto a clear glass slide. It is possible to photograph the crystals in the tray on the fabric but I prefer the isolation against a lighter background and have the opportunity to light from underneath.

I use a low power simple microscope. Basically, the microscope is a repurposed industrial macro stand. I use a 16- or 25-millimeter macro lens and the camera has a bellows. Attached to the bellows (extension tubes can also be used) is a DSLR camera body without a lens.

Once an interesting crystal has been identified in my catch tray, I move it to a glass slide using the needle on the pencil. The slide is placed onto the microscope’s focusing stage where I can compose and focus the image in the viewfinder of the camera.

I use a fiber optic illuminator with a bifurcated gooseneck light guide that illuminates the crystals. I shine light onto a variety of materials located below the stage to provide contrast and color to the light that is refracted into the crystal used to reveal the crystal’s facets.

Snowflake photograph from Michael Peres’s RIT snowflake gallery. Image via Michael Peres, RIT.

Any tips for those of us who have been trying to capture a good snowflake photograph with a macro lens? I for one am wondering if some temperatures are better than others for taking snowflake photos, and how on Earth do I keep my hands warm?

It is possible to photograph snowflakes with a smartphone or DSLR. The features and advantages of each camera are pretty clear. The smartphone has a pretty good sensor but focusing the lens, exposure management, and ability to magnify sometimes 1-millimeter crystals are real obstacles. There are accessory lenses that can be added to the smartphone. Photojojo is an excellent vendor of such lenses.

DSLR cameras are significantly better choices for this work and are equipped with a macro lens capable of at least 1:1. Canon sells a 65-millimeter macro lens that can achieve 5:1 magnification. Adding extension tubes or by using a simple bellows, you can increase the image size that the camera system produces. My typical crystals benefit from a 3 to 6x magnification.

I dress warmly for this work wearing many layers including insulated boots. I use gloves with finger holes but because of the delicate nature of focusing a microscope, moving the crystal in small increments, I benefit from more control and feel having nothing on my hands. Because of the adrenaline, I can typically work for up to 30 minutes before my hands cannot tolerate the conditions any longer.

I photograph using a medium aperture such as ƒ/5.6. Diffraction at these image sizes can cause the crystals to become less defined if I use a smaller aperture. Often I photograph wide open and create increased DOF images.

Snowflake photograph from Michael Peres’s RIT snowflake gallery. Image via Michael Peres, RIT.

Many thanks to Professor Peres for discussing his snowflake photography with EarthSky. More examples of his work can be viewed on his Instagram account @michael_peres and on his website at the Rochester Institute of Technology (RIT).

Want more? You can read about the attempts one of EarthSky’s intrepid contributors to photograph snowflakes in the archive here.

See some recent favorite snowflake photos from the EarthSky Community

If this post inspires you to give snowflake photography a shot, please submit your photos to EarthSky Community Photos! We love seeing and sharing your recent captures of the natural world!

Bottom line: How to take photos of snowflakes with Professor Michael Peres of the Rochester Institute of Technology.

from EarthSky http://bit.ly/2B9Uhku