When is my earliest sunset?

Adrian Strand captured this photo on a beach in northwest England.

The winter solstice is the shortest day. It offers the shortest period of daylight. But, unless you live close to the Arctic Circle or Antarctic Circle, your earliest sunsets aren’t on or even near the solstice itself. Instead, your earliest sunsets will come before the winter solstice. The exact date of earliest sunset depends on your latitude. If you live in the southernmost U.S., or a comparable latitude (say, around 25 or 26 degrees north latitude), your earliest sunsets are in late November. If you’re farther north – say, around 40 degrees north latitude – your earliest sunsets are around December 7.

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

Stephen Aman shares his map of the United States that lists the dates of the year’s earliest sunset for various latitudes. Thank you, Stephen!

And if you live in the Southern Hemisphere, your earliest sunrises are coming around now. Southern Hemisphere? Click here.

Why isn’t the earliest sunset on the year’s shortest day? To understand it, try thinking about it in terms of solar noon or midday, the time midway between sunrise and sunset, when the sun reaches its highest point for the day.

A clock ticks off exactly 24 hours from one noon to the next. But the actual days – as measured by the spin of the Earth – are rarely exactly 24 hours long.

So the exact time of solar noon, as measured by Earth’s spin, shifts in a seasonal way. If you measured Earth’s spin from one solar noon to the next, you’d find that – around the time of the December solstice – the time period between consecutive solar noons is actually half a minute longer than 24 hours.

So – two weeks before the solstice, for example – the sun reaches its noontime position at 11:52 a.m. local standard time. Two weeks later – on the winter solstice – the sun reaches its noontime position at 11:59 a.m. That’s 7 minutes later.

The later clock time for solar noon also means a later clock time for sunrise and sunset.

Visit Sunrise Sunset Calendars for the December 2019 calendar, giving you the clock time for solar noon (check the solar noon box).

The result: earlier sunsets before the winter solstice and increasingly later sunrises for a few weeks after the winter solstice.

The exact date of earliest sunset varies with latitude. But the sequence is always the same. For the Northern Hemisphere, earliest sunset in early December, winter solstice, latest sunrise in early January.

In early December, the Southern Hemisphere is approaching its summer solstice. Sunset on that part of Earth will continue coming later until early January. Photo of sunset with crepuscular rays by Phil Rettke Photography in Ipswich, Queensland, Australia.

Meanwhile, if you’re in the Southern Hemisphere, take nearly everything we say here and apply it to your winter solstice in June. For the Southern Hemisphere, the earliest sunsets come prior to the winter solstice, which is typically around June 21. The latest sunrises occur after the June winter solstice.

During the month of December, it’s nearly summer in the Southern Hemisphere; the summer solstice comes this month for that hemisphere. So sunsets and sunrises are shifting in a similar way. For both hemispheres, the sequence in summer is: earliest sunrises before the summer solstice, then the summer solstice itself, then latest sunsets after the summer solstice.

As always, things get tricky if you look closely. Assuming you’re at a mid-temperate latitude, the earliest sunset for the Northern Hemisphere – and earliest sunrise for the Southern Hemisphere – come about two weeks before the December solstice, and the latest sunrise/latest sunset happen about two weeks after.

But at the other end of the year, in June and July, the time period is not equivalent. Again assuming a mid-temperate latitude, the earliest sunrise for the Northern Hemisphere – and earliest sunset for the Southern Hemisphere – comes only about one week before the June solstice, and the latest sunset/latest sunrise happens about one week after.

The time difference is due to the fact that the December solstice occurs when Earth is near its perihelion – or closest point to the sun – around which time we’re moving fastest in orbit. Meanwhile, the June solstice occurs when Earth is near aphelion – our farthest point from the sun – around which time we’re moving at our slowest in orbit.

View larger. | Computed position of the sun looking eastward at the same time each morning from the Northern Hemisphere. December solstice point at lower right and June solstice point at upper left. Solar days are longer than 24 hours long at the solstices, yet less than 24 hours long at the equinoxes. Roughly midway between a solstice and an equinox, or vice versa, the solar day is exactly 24 hours long.

In short, the earliest sunset/winter solstice/latest sunrise and earliest sunrise/summer solstice/latest sunset phenomena are due to the fact that true solar days are longer than 24 hours long for several weeks before and after the solstices. At and around the solstices, the Earth must rotate farther on its axis for the sun to return to its daily noontime position, primarily because the sun is appreciably north or south of the Earth’s equator.

However, perihelion accentuates the effect around the December solstice, giving a day length of 24 hours 30 seconds. And aphelion lessens the effect around the June solstice, giving a day length of 24 hours 13 seconds.

Read more: Year’s earliest solar noon on November 3

Bottom line: The earliest sunsets and latest sunrises don’t come on the winter solstice, the shortest day of the year. Instead, earliest sunsets come some weeks before the winter solstice. Latest sunrises come some weeks after it.

Here are more details about the earliest sunsets.

from EarthSky https://ift.tt/2G2Ot1p

Adrian Strand captured this photo on a beach in northwest England.

The winter solstice is the shortest day. It offers the shortest period of daylight. But, unless you live close to the Arctic Circle or Antarctic Circle, your earliest sunsets aren’t on or even near the solstice itself. Instead, your earliest sunsets will come before the winter solstice. The exact date of earliest sunset depends on your latitude. If you live in the southernmost U.S., or a comparable latitude (say, around 25 or 26 degrees north latitude), your earliest sunsets are in late November. If you’re farther north – say, around 40 degrees north latitude – your earliest sunsets are around December 7.

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

Stephen Aman shares his map of the United States that lists the dates of the year’s earliest sunset for various latitudes. Thank you, Stephen!

And if you live in the Southern Hemisphere, your earliest sunrises are coming around now. Southern Hemisphere? Click here.

Why isn’t the earliest sunset on the year’s shortest day? To understand it, try thinking about it in terms of solar noon or midday, the time midway between sunrise and sunset, when the sun reaches its highest point for the day.

A clock ticks off exactly 24 hours from one noon to the next. But the actual days – as measured by the spin of the Earth – are rarely exactly 24 hours long.

So the exact time of solar noon, as measured by Earth’s spin, shifts in a seasonal way. If you measured Earth’s spin from one solar noon to the next, you’d find that – around the time of the December solstice – the time period between consecutive solar noons is actually half a minute longer than 24 hours.

So – two weeks before the solstice, for example – the sun reaches its noontime position at 11:52 a.m. local standard time. Two weeks later – on the winter solstice – the sun reaches its noontime position at 11:59 a.m. That’s 7 minutes later.

The later clock time for solar noon also means a later clock time for sunrise and sunset.

Visit Sunrise Sunset Calendars for the December 2019 calendar, giving you the clock time for solar noon (check the solar noon box).

The result: earlier sunsets before the winter solstice and increasingly later sunrises for a few weeks after the winter solstice.

The exact date of earliest sunset varies with latitude. But the sequence is always the same. For the Northern Hemisphere, earliest sunset in early December, winter solstice, latest sunrise in early January.

In early December, the Southern Hemisphere is approaching its summer solstice. Sunset on that part of Earth will continue coming later until early January. Photo of sunset with crepuscular rays by Phil Rettke Photography in Ipswich, Queensland, Australia.

Meanwhile, if you’re in the Southern Hemisphere, take nearly everything we say here and apply it to your winter solstice in June. For the Southern Hemisphere, the earliest sunsets come prior to the winter solstice, which is typically around June 21. The latest sunrises occur after the June winter solstice.

During the month of December, it’s nearly summer in the Southern Hemisphere; the summer solstice comes this month for that hemisphere. So sunsets and sunrises are shifting in a similar way. For both hemispheres, the sequence in summer is: earliest sunrises before the summer solstice, then the summer solstice itself, then latest sunsets after the summer solstice.

As always, things get tricky if you look closely. Assuming you’re at a mid-temperate latitude, the earliest sunset for the Northern Hemisphere – and earliest sunrise for the Southern Hemisphere – come about two weeks before the December solstice, and the latest sunrise/latest sunset happen about two weeks after.

But at the other end of the year, in June and July, the time period is not equivalent. Again assuming a mid-temperate latitude, the earliest sunrise for the Northern Hemisphere – and earliest sunset for the Southern Hemisphere – comes only about one week before the June solstice, and the latest sunset/latest sunrise happens about one week after.

The time difference is due to the fact that the December solstice occurs when Earth is near its perihelion – or closest point to the sun – around which time we’re moving fastest in orbit. Meanwhile, the June solstice occurs when Earth is near aphelion – our farthest point from the sun – around which time we’re moving at our slowest in orbit.

View larger. | Computed position of the sun looking eastward at the same time each morning from the Northern Hemisphere. December solstice point at lower right and June solstice point at upper left. Solar days are longer than 24 hours long at the solstices, yet less than 24 hours long at the equinoxes. Roughly midway between a solstice and an equinox, or vice versa, the solar day is exactly 24 hours long.

In short, the earliest sunset/winter solstice/latest sunrise and earliest sunrise/summer solstice/latest sunset phenomena are due to the fact that true solar days are longer than 24 hours long for several weeks before and after the solstices. At and around the solstices, the Earth must rotate farther on its axis for the sun to return to its daily noontime position, primarily because the sun is appreciably north or south of the Earth’s equator.

However, perihelion accentuates the effect around the December solstice, giving a day length of 24 hours 30 seconds. And aphelion lessens the effect around the June solstice, giving a day length of 24 hours 13 seconds.

Read more: Year’s earliest solar noon on November 3

Bottom line: The earliest sunsets and latest sunrises don’t come on the winter solstice, the shortest day of the year. Instead, earliest sunsets come some weeks before the winter solstice. Latest sunrises come some weeks after it.

Here are more details about the earliest sunsets.

from EarthSky https://ift.tt/2G2Ot1p

Let the moon show you Saturn

At nightfall these next few evenings – November 29 and 30, 2019 – let the waxing crescent moon show you Saturn, the 6th planet outward from the sun. Look first for the moon and that nearby bright star will be Saturn. At dusk, or before nightfall, you might also see the brighter planets Venus and Jupiter beneath the moon and Saturn.

This artist’s concept depicts the relative sizes of the planets. Jupiter’s diameter is about 11 times that of Earth whereas Saturn’s diameter is about 9.5 times greater.

Saturn is the farthest world that you can easily with the naked eye. What’s more, with nothing more than a modest backyard telescope, you can zoom in on Saturn and view its glorious rings. Day by day, however, Saturn is sinking closer to the setting sun and will fade into the evening twilight in a month or so. Nightfall and early evening present the best chance to see Saturn’s majestic rings. Now’s the time!

Contrasting the size of Saturn and its rings with our planet Earth via Hubble Heritage Team.

We often talk about Saturn’s rings but perhaps we should also pay homage to Saturn’s intriguing moon, Titan. Titan boasts of being Saturn’s largest moon and the second biggest moon in the solar system, after Jupiter’s Ganymede. Titan stands all by itself in that it’s the only solar system moon known to harbor a substantial atmosphere – which, moreover, is even denser than Earth’s.

This exotic world is Earth-like in that the respect that Titan’s surface is alive with clouds, rain, rivers, lakes and seas, though these flowing bodies are composed primarily of hydrocarbons (methane and ethane) instead of water. Beneath Titan’s cold exterior, though, may be a vast ocean of subsurface water. Some scientists think the complex organic materials making up Titan’s atmosphere may be similar to those of Earth’s long-past atmosphere, when Earth’s prebiotic environment was a precursor to life.

Read more: Dragonfly aims for Saturn’s moon Titan

Possibly, some primitive forms of life might already populate Titan. NASA is planning on launching The Dragonfly spacecraft in 2026 that’s to arrive at Titan in 2034 to investigate this wildly mysterious world. Scientists will use Titan’s dense atmosphere to their advantage, because this drone-like rotocraft will have an easier time flying at Titan’s heavy atmosphere than it would on Earth.

This illustration shows NASA’s Dragonfly rotorcraft-lander approaching a site on Saturn’s exotic moon, Titan. Taking advantage of Titan’s dense atmosphere and low gravity, Dragonfly will explore dozens of locations across the icy world, sampling and measuring the compositions of Titan’s organic surface materials to characterize the habitability of Titan’s environment and investigate the progression of prebiotic chemistry. Credits: NASA/JHU-APL

At nightfall these next few evenings – November 29 and 30, 2019 – use the waxing crescent moon to find Saturn, the parent planet of Titan, the only solar system moon known to harbor a substantial atmosphere.

from EarthSky https://ift.tt/34y7L6q

At nightfall these next few evenings – November 29 and 30, 2019 – let the waxing crescent moon show you Saturn, the 6th planet outward from the sun. Look first for the moon and that nearby bright star will be Saturn. At dusk, or before nightfall, you might also see the brighter planets Venus and Jupiter beneath the moon and Saturn.

This artist’s concept depicts the relative sizes of the planets. Jupiter’s diameter is about 11 times that of Earth whereas Saturn’s diameter is about 9.5 times greater.

Saturn is the farthest world that you can easily with the naked eye. What’s more, with nothing more than a modest backyard telescope, you can zoom in on Saturn and view its glorious rings. Day by day, however, Saturn is sinking closer to the setting sun and will fade into the evening twilight in a month or so. Nightfall and early evening present the best chance to see Saturn’s majestic rings. Now’s the time!

Contrasting the size of Saturn and its rings with our planet Earth via Hubble Heritage Team.

We often talk about Saturn’s rings but perhaps we should also pay homage to Saturn’s intriguing moon, Titan. Titan boasts of being Saturn’s largest moon and the second biggest moon in the solar system, after Jupiter’s Ganymede. Titan stands all by itself in that it’s the only solar system moon known to harbor a substantial atmosphere – which, moreover, is even denser than Earth’s.

This exotic world is Earth-like in that the respect that Titan’s surface is alive with clouds, rain, rivers, lakes and seas, though these flowing bodies are composed primarily of hydrocarbons (methane and ethane) instead of water. Beneath Titan’s cold exterior, though, may be a vast ocean of subsurface water. Some scientists think the complex organic materials making up Titan’s atmosphere may be similar to those of Earth’s long-past atmosphere, when Earth’s prebiotic environment was a precursor to life.

Read more: Dragonfly aims for Saturn’s moon Titan

Possibly, some primitive forms of life might already populate Titan. NASA is planning on launching The Dragonfly spacecraft in 2026 that’s to arrive at Titan in 2034 to investigate this wildly mysterious world. Scientists will use Titan’s dense atmosphere to their advantage, because this drone-like rotocraft will have an easier time flying at Titan’s heavy atmosphere than it would on Earth.

This illustration shows NASA’s Dragonfly rotorcraft-lander approaching a site on Saturn’s exotic moon, Titan. Taking advantage of Titan’s dense atmosphere and low gravity, Dragonfly will explore dozens of locations across the icy world, sampling and measuring the compositions of Titan’s organic surface materials to characterize the habitability of Titan’s environment and investigate the progression of prebiotic chemistry. Credits: NASA/JHU-APL

At nightfall these next few evenings – November 29 and 30, 2019 – use the waxing crescent moon to find Saturn, the parent planet of Titan, the only solar system moon known to harbor a substantial atmosphere.

from EarthSky https://ift.tt/34y7L6q

Poo tests: looking for cancer clues in poo

It’s a substance most people try not to think about. But it could be a vital tool when it comes to detecting bowel cancer early.

We need to talk about poo.

In diagnosing some cancers, poo has a particular advantage. Professor Chris Probert, a Cancer Research UK-funded bowel cancer expert at the University of Liverpool, explains why it’s such an important tool.

“For bowel cancer, where in the body is the action happening? It’s in the gut. And where are those chemicals that we want to detect most likely to go? In the stool.”

Current tests for bowel cancer screening already take advantage of this fact, using poo to look for early signs of bowel cancer.

“The beauty of looking at the faeces is that it’s right up against the cancer, making it very likely what you’re looking at came from that cancer,” says Probert. “Whereas if I find a compound in the urine, it may have been filtered from the blood, and excreted in the urine, having come from anywhere else.”

In other words, poo can provide very specific information about the state of someone’s gut.

Getting FIT

Until recently, faecal occult blood tests (FOBt) were used to screen for bowel cancer across the UK.

“The bowel cancer screening programme aims to find polyps, and because some polyps bleed, the detection is based on finding traces of blood in people’s stool.”

But this test has its problems.

• It detects any blood, not just human blood, so results can be skewed by a person’s diet.
• FOBt also require 6 samples (2 samples from 3 separate poos) to flag if more tests are needed.
• The test also relies on technicians judging colour changes when the samples are processed, which can cause errors in how results are interpreted.

But as of June this year in England, September this year in Wales and in November 2017 in Scotland, FOBt has been replaced by a better test, the Faecal Immunochemical Test (FIT). Northern Ireland are still using FOBt, but the plan is to begin switching to using FIT in 2020.

And unlike FOBt, FIT only detects human blood, requires just one sample and uses an automatic analysis process that provides a number to indicate how much blood is in a sample.

Since FIT was introduced, more people in Scotland have taken part in bowel screening. It’s thought this could be because FIT is an easier test to complete

An expanding field

The recent switch from FOBt to FIT exemplifies the improvements made in using poo to detect cancer. But it’s not the only progress being made. Scientists are investigating if there are other cancer clues that can be picked up in poo samples.

For example, a Cancer Research UK-funded team at Cardiff University are exploring if detecting a certain safe strain of salmonella can help to locate polyps and help to pick up bowel cancer earlier.

Probert and his team are taking a different approach. They’re investigating if chemicals that come from the gut can help doctors detect the early signs of cancer, in a project called VODECA (Volatile Organic compounds for the DEtection of Colorectal cAncer).

The team detect volatile organic compounds, or VOCs (which are essentially odours), to see if any of them could help indicate if a patient has cancer.

VODECA – smelling the problem

Probert’s research started off as anecdotal evidence.

“Historically patients in my clinic have reported that when they’re unwell, they notice a change in what some may call bathroom odours.”

Gases from poo come from all sorts of places. Some come from diet, but other gases come from the chemical reactions taking place in our gut.

“We thought that these smells could be telling us something about the biology of the gut, and it might provide a useful signature.”

A few months ago, Probert’s team discovered that the molecules found in people with bowel cancer’s poo are different from those found in people without the disease. “This means that potentially, from a stool sample, you can get quite an interesting insight to what is going on in the gut.”

VODECA, though promising, is still in its early phases. But Probert can see this research working alongside FIT tests to aid early diagnosis.

“Early diagnosis might become a two-step analysis, where you look for things that bleed and then within the things that bleed you look for what is most likely to be cancer.”

And, the added benefit of using these VOCs for Probert is “it’s, quite literally, a lot cleaner to work with.”

“Nothing is insurmountable, but there is an aesthetic issue”

Studying the digestive system and what it produces is clearly rich with scientific capability to improve the early detection of cancer. But there’s an ongoing issue.

According to Probert, it’s quite hard to get people involved. “I know from my earlier research that if you just want a healthy volunteer to give you a stool sample for research, they are not as willing as someone who thinks it might be useful for them and understands the need to make a diagnosis for bowel cancer.”

Probert is optimistic about this problem, saying that more and more people are willing to donate poo samples, which is providing essential data for their research.

“People think nothing of giving blood samples, and I think with more time, it will become more mainstream to look at faecal samples too.”

Which can only be a good thing for detecting cancer earlier.

Ethan

Follow our early detection series to find out all the other ways – and bodily fluids – our scientists are looking for cancer in to detect it earlier and boost the chance of people surviving the disease.

from Cancer Research UK – Science blog https://ift.tt/34ukeI6

It’s a substance most people try not to think about. But it could be a vital tool when it comes to detecting bowel cancer early.

We need to talk about poo.

In diagnosing some cancers, poo has a particular advantage. Professor Chris Probert, a Cancer Research UK-funded bowel cancer expert at the University of Liverpool, explains why it’s such an important tool.

“For bowel cancer, where in the body is the action happening? It’s in the gut. And where are those chemicals that we want to detect most likely to go? In the stool.”

Current tests for bowel cancer screening already take advantage of this fact, using poo to look for early signs of bowel cancer.

“The beauty of looking at the faeces is that it’s right up against the cancer, making it very likely what you’re looking at came from that cancer,” says Probert. “Whereas if I find a compound in the urine, it may have been filtered from the blood, and excreted in the urine, having come from anywhere else.”

In other words, poo can provide very specific information about the state of someone’s gut.

Getting FIT

Until recently, faecal occult blood tests (FOBt) were used to screen for bowel cancer across the UK.

“The bowel cancer screening programme aims to find polyps, and because some polyps bleed, the detection is based on finding traces of blood in people’s stool.”

But this test has its problems.

• It detects any blood, not just human blood, so results can be skewed by a person’s diet.
• FOBt also require 6 samples (2 samples from 3 separate poos) to flag if more tests are needed.
• The test also relies on technicians judging colour changes when the samples are processed, which can cause errors in how results are interpreted.

But as of June this year in England, September this year in Wales and in November 2017 in Scotland, FOBt has been replaced by a better test, the Faecal Immunochemical Test (FIT). Northern Ireland are still using FOBt, but the plan is to begin switching to using FIT in 2020.

And unlike FOBt, FIT only detects human blood, requires just one sample and uses an automatic analysis process that provides a number to indicate how much blood is in a sample.

Since FIT was introduced, more people in Scotland have taken part in bowel screening. It’s thought this could be because FIT is an easier test to complete

An expanding field

The recent switch from FOBt to FIT exemplifies the improvements made in using poo to detect cancer. But it’s not the only progress being made. Scientists are investigating if there are other cancer clues that can be picked up in poo samples.

For example, a Cancer Research UK-funded team at Cardiff University are exploring if detecting a certain safe strain of salmonella can help to locate polyps and help to pick up bowel cancer earlier.

Probert and his team are taking a different approach. They’re investigating if chemicals that come from the gut can help doctors detect the early signs of cancer, in a project called VODECA (Volatile Organic compounds for the DEtection of Colorectal cAncer).

The team detect volatile organic compounds, or VOCs (which are essentially odours), to see if any of them could help indicate if a patient has cancer.

VODECA – smelling the problem

Probert’s research started off as anecdotal evidence.

“Historically patients in my clinic have reported that when they’re unwell, they notice a change in what some may call bathroom odours.”

Gases from poo come from all sorts of places. Some come from diet, but other gases come from the chemical reactions taking place in our gut.

“We thought that these smells could be telling us something about the biology of the gut, and it might provide a useful signature.”

A few months ago, Probert’s team discovered that the molecules found in people with bowel cancer’s poo are different from those found in people without the disease. “This means that potentially, from a stool sample, you can get quite an interesting insight to what is going on in the gut.”

VODECA, though promising, is still in its early phases. But Probert can see this research working alongside FIT tests to aid early diagnosis.

“Early diagnosis might become a two-step analysis, where you look for things that bleed and then within the things that bleed you look for what is most likely to be cancer.”

And, the added benefit of using these VOCs for Probert is “it’s, quite literally, a lot cleaner to work with.”

“Nothing is insurmountable, but there is an aesthetic issue”

Studying the digestive system and what it produces is clearly rich with scientific capability to improve the early detection of cancer. But there’s an ongoing issue.

According to Probert, it’s quite hard to get people involved. “I know from my earlier research that if you just want a healthy volunteer to give you a stool sample for research, they are not as willing as someone who thinks it might be useful for them and understands the need to make a diagnosis for bowel cancer.”

Probert is optimistic about this problem, saying that more and more people are willing to donate poo samples, which is providing essential data for their research.

“People think nothing of giving blood samples, and I think with more time, it will become more mainstream to look at faecal samples too.”

Which can only be a good thing for detecting cancer earlier.

Ethan

Follow our early detection series to find out all the other ways – and bodily fluids – our scientists are looking for cancer in to detect it earlier and boost the chance of people surviving the disease.

from Cancer Research UK – Science blog https://ift.tt/34ukeI6

Young moon and 3 planets after sunset

Depending on where you live worldwide, you might – or might not – catch the tiniest sliver of a young moon in the western sky after sunset on November 27, 2019. The moon will be sitting in the afterglow of sunset, beneath the dazzling planets Venus and Jupiter – the third-brightest and fourth-brightest celestial objects to light up the heavens, respectively, after the sun and moon – fresh from their conjunction last Sunday.

Then, in the days ahead, get ready for some spectacular views of the young moon near Venus and Jupiter. It’ll be much easier to catch the young moon after sunset on November 28 than on November 27. And it’ll be easier on November 29 than on November 28. That’s because, day by day, the moon goes eastward in its orbit, thus appearing farther and farther east of the sunset, exhibiting a wider crescent after sundown and staying out later after dark.

On the evening of Thanksgiving here in the U.S. – Thursday evening, November 28 – you can amaze your family and friends by taking them outside to see the young moon, Venus and Jupiter.

Think photo opportunity! In the coming days, check out EarthSky Community Photos. There are sure to be some great ones there. If you’d like to submit a photo, you can do so here. Also, watch for photos in EarthSky’s feeds on Facebook, Twitter and Instagram.

EarthSky lunar calendars make great gifts for astronomy-minded friends and family. Order now. Going fast!

November 19, 2017 young moon from Patrick Casaert in Meaux, France.

Also, while you’re out there watching the moon, Venus and Jupiter, look for Saturn. Notice on our chart at top that Saturn is located approximately on a line with Venus, Jupiter and the moon. This line across our sky – shown on our charts in green – is the ecliptic. Saturn is no slouch in brightness, either; it shines as brilliantly as a 1st-magnitude star, that is, as one of the brightest stars visible in Earth’s sky.

But Saturn is no match in brightness for Venus or Jupiter. Jupiter is nine times brighter than Saturn, while Venus is about seven times brighter than Jupiter (meaning Venus is some 63 times brighter than Saturn). However, Saturn should be fairly easy to view despite its lesser brilliance, because Saturn – unlike Venus and Jupiter – stays out well past nightfall.

Looking for a sky almanac? Click here.

The day and night sides of Earth when the moon is one day past the November 26 new moon (November 27, 2019, at 15:06 Universal Time), The shadow line at right depicts sunset November 27, 2019, and the shadow line at left depicts sunrise November 27, 2019. Image via Fourmilab.

About seeing the very young moon on November 27. At new moon on November 26, the moon was 0 degrees away from the sun and 0 percent illuminated as seen from Earth. One day after new moon, the moon is nearly 13 degrees (26 moon diameters) east of the sun and 1.2 percent illuminated as seen from Earth.

Generally, it’s quite difficult to spot a young moon that’s less than 24 hours old (even with binoculars). As the sun sets on November 27 in the Middle East, Asia, Indonesia, Australia and New Zealand, the moon will be less than one day old; for western Europe and the most of Africa, the moon will be a touch older than one day in age at sunset November 27.

By the time that the sun sets over the Americas, the moon will be 1 1/3 days (32 hours) old. The lunar crescent will be 17 degrees east of the sun and 2.2 percent illuminated. So, on November 27, there’s a better chance of catching the young moon in the Americas than in the world’s Eastern Hemisphere.

To find out when the moon sets in your sky, visit Sunrise Sunset Calendars and check the moonrise and moonset box.

Visit Unitarium to find out the moon’s elongation (angular separation) from the sun and its illumination.

Want to know the moon’s position on the zodiac? Check Heavens-Above.

Day and night sides of Earth at 1 1/3 days (30 hours) after new moon November 27, 2019, at 23:06 Universal Time). The shadow line at left (going through the Americas) depicts sunset November 27, 2019.

So watch for the moon and planets, beginning on November 27 and for the next few days. Find an unobstructed horizon in the direction of sunset, and, if possible, stand atop a hill or balcony. That way you peek a little farther over the horizon. Binoculars aways enhance the view. Be sure to note the soft glow of earthshine – twice-reflected sunlight – on the dark side of the moon, with either the eye alone or an optical aid.

Good luck! Clear skies …

Bottom line: There will be a picturesque scene in your western sky after sunset on November 27, 28 and 29, 2019. Watch for the moon, Venus, Jupiter and Saturn.

from EarthSky https://ift.tt/2OSayk2

Depending on where you live worldwide, you might – or might not – catch the tiniest sliver of a young moon in the western sky after sunset on November 27, 2019. The moon will be sitting in the afterglow of sunset, beneath the dazzling planets Venus and Jupiter – the third-brightest and fourth-brightest celestial objects to light up the heavens, respectively, after the sun and moon – fresh from their conjunction last Sunday.

Then, in the days ahead, get ready for some spectacular views of the young moon near Venus and Jupiter. It’ll be much easier to catch the young moon after sunset on November 28 than on November 27. And it’ll be easier on November 29 than on November 28. That’s because, day by day, the moon goes eastward in its orbit, thus appearing farther and farther east of the sunset, exhibiting a wider crescent after sundown and staying out later after dark.

On the evening of Thanksgiving here in the U.S. – Thursday evening, November 28 – you can amaze your family and friends by taking them outside to see the young moon, Venus and Jupiter.

Think photo opportunity! In the coming days, check out EarthSky Community Photos. There are sure to be some great ones there. If you’d like to submit a photo, you can do so here. Also, watch for photos in EarthSky’s feeds on Facebook, Twitter and Instagram.

EarthSky lunar calendars make great gifts for astronomy-minded friends and family. Order now. Going fast!

November 19, 2017 young moon from Patrick Casaert in Meaux, France.

Also, while you’re out there watching the moon, Venus and Jupiter, look for Saturn. Notice on our chart at top that Saturn is located approximately on a line with Venus, Jupiter and the moon. This line across our sky – shown on our charts in green – is the ecliptic. Saturn is no slouch in brightness, either; it shines as brilliantly as a 1st-magnitude star, that is, as one of the brightest stars visible in Earth’s sky.

But Saturn is no match in brightness for Venus or Jupiter. Jupiter is nine times brighter than Saturn, while Venus is about seven times brighter than Jupiter (meaning Venus is some 63 times brighter than Saturn). However, Saturn should be fairly easy to view despite its lesser brilliance, because Saturn – unlike Venus and Jupiter – stays out well past nightfall.

Looking for a sky almanac? Click here.

The day and night sides of Earth when the moon is one day past the November 26 new moon (November 27, 2019, at 15:06 Universal Time), The shadow line at right depicts sunset November 27, 2019, and the shadow line at left depicts sunrise November 27, 2019. Image via Fourmilab.

About seeing the very young moon on November 27. At new moon on November 26, the moon was 0 degrees away from the sun and 0 percent illuminated as seen from Earth. One day after new moon, the moon is nearly 13 degrees (26 moon diameters) east of the sun and 1.2 percent illuminated as seen from Earth.

Generally, it’s quite difficult to spot a young moon that’s less than 24 hours old (even with binoculars). As the sun sets on November 27 in the Middle East, Asia, Indonesia, Australia and New Zealand, the moon will be less than one day old; for western Europe and the most of Africa, the moon will be a touch older than one day in age at sunset November 27.

By the time that the sun sets over the Americas, the moon will be 1 1/3 days (32 hours) old. The lunar crescent will be 17 degrees east of the sun and 2.2 percent illuminated. So, on November 27, there’s a better chance of catching the young moon in the Americas than in the world’s Eastern Hemisphere.

To find out when the moon sets in your sky, visit Sunrise Sunset Calendars and check the moonrise and moonset box.

Visit Unitarium to find out the moon’s elongation (angular separation) from the sun and its illumination.

Want to know the moon’s position on the zodiac? Check Heavens-Above.

Day and night sides of Earth at 1 1/3 days (30 hours) after new moon November 27, 2019, at 23:06 Universal Time). The shadow line at left (going through the Americas) depicts sunset November 27, 2019.

So watch for the moon and planets, beginning on November 27 and for the next few days. Find an unobstructed horizon in the direction of sunset, and, if possible, stand atop a hill or balcony. That way you peek a little farther over the horizon. Binoculars aways enhance the view. Be sure to note the soft glow of earthshine – twice-reflected sunlight – on the dark side of the moon, with either the eye alone or an optical aid.

Good luck! Clear skies …

Bottom line: There will be a picturesque scene in your western sky after sunset on November 27, 28 and 29, 2019. Watch for the moon, Venus, Jupiter and Saturn.

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Late November and December planet guide

The Venus-Jupiter conjunction was this past Sunday (November 24, 2019). In late November, watch for the young moon to fly by Jupiter, Venus and Saturn in the west after sunset. Throughout December, Venus will be climbing upward, away from the sunset, while Jupiter is sinking downward. Jupiter will disappear in the sunset glare around mid-December.

Click the name of a planet to learn more about its visibility in November 2019: Venus, Jupiter, Saturn, Mars and Mercury.

Try Stellarium Online for a precise view from your location.

Venus – the brightest planet – reclaims her mantle as the evening “star” in December 2019. Last month, in November 2019, Venus assumed a low profile, lurking over the western horizon after sunset, beneath the planets Jupiter and Saturn. But Venus came into prominence in late November, when the queen planet finally met up with the king planet Jupiter for a stunning conjunction on November 24, 2019.

Next, Venus will catch up with Saturn for a conjunction on December 10, 2019. In the second half of December, Venus lords over Saturn and Jupiter in the evening sky. Jupiter and Saturn will soon fade away in the evening twilight, whereas dazzling Venus will grace the evening sky for several months to come.

At mid-northern latitudes in early December, Venus sets about two hours after sunset; but by the month’s end, that’ll increase to nearly three hours.

At temperate latitudes in the Southern Hemisphere, Venus sets about two hours after sunset throughout the month.

Watch for the young waxing crescent moon to pair up with Venus on or near December 28, as shown on the chart below.

Look for the young waxing crescent moon to couple up with Venus on or near December 28, 2019. Read more.

Jupiter – the second-brightest planet after Venus – can be found low in the west at dusk (beneath brighter Venus) during the first week or so of December 2019. Seek for Jupiter shortly after sunset because the king planet follows the sun the sun beneath the horizon before nightfall.

Jupiter should be visible to the eye alone during the first several days of December. Day by day, however, this world sinks closer the glow of sunset, and you’ll probably need binoculars to view Jupiter in the second week of December. By mid-month, Jupiter will probably disappear from view altogether.

Around the world, Jupiter sets around nightfall in early December. Then, by around December 7, Jupiter plunges beneath the horizon about one hour after the sun. Near the month’s end, Jupiter will transition out of the evening sky and into the morning sky. Jupiter will probably return to visibility in the east before sunrise in late January 2020.

EarthSky 2020 lunar calendars are available! They make great gifts. Order now. Going fast!

For North America, Venus and Saturn have their conjunction on the evening of December 10, 2019. Read more.

Saturn. After you find Venus at dusk and nightfall, use Venus, the sky’s brightest planet, to find the nearby fainter planet, Saturn. Although Saturn nowhere matches Venus in brilliance, Saturn does shine on par with the 1st-magnitude stars, or the sky’s brightest stars.

You really can’t mistake Saturn for Venus. The queen planet Venus ranks as the third-brightest celestial object in all the heavens, after the sun and moon. Venus outshines Saturn by more than 60 times.

Look for Saturn above Venus during the first part of December, and beneath Venus in the second half of the month. Throughout December, Venus climbs upward day by day, away from the sunset direction, while Saturn sinks downward and sunward. Look for these two worlds to meet up for a conjunction on or near December 10, as shown on the above sky chart.

By the month’s end, Saturn will sit low in the glow of evening twilight, and may be hard to see – even with binoculars. The first half of December presents the last good viewing of Saturn in the evening sky, before this world is submerged in the sun’s afterglow in late December.

Saturn will swing directly behind the sun on January 13, 2020, to transition out of the evening sky and into morning sky. After December passes, you might not see Saturn again until the ringed planet reappears in the eastern morning sky in February 2020.

Around the wold, Saturn plunges below the horizon about 3 hours after sunset in early December. Near the month’s end, Saturn sets about an hour after the sun.

If you’re up for a big challenge, try your luck at catching the young moon with Saturn after sunset on or near December 27, 2019, as shown on the sky chart below.

Look for the young waxing crescent moon to couple up with Saturn on or near December 27, 2019. Read more.

Mercury, the solar system’s innermost planet, recently reached its greatest elongation from the sun in the morning sky on November 28, 2019. Mercury remains a fine morning object as viewed from the Northern Hemisphere for the first week or two in December. Get up before dawn to see the 1st-magnitude star Spica lining up with the 2nd-magnitude planet Mars. Then, as the predawn darkness gives way to dawn, look for Mercury to climb above the horizon, more or less on line with Spica and Mars.

An imaginary line from Spica and past Mars, and down to the horizon, lets you know Mercury’s approximate rising point on the horizon, as shown on the sky chart below. Be mindful that Mars (and possibly Spica) will fade from view by the time that Mercury climbs above your horizon. Binoculars always come in handy for any Mercury quest.

Live in the Northern Hemisphere.? At northerly latitudes, the first week or so of December 2019 presents a fine opportunity for catching Mercury, the solar system’s innermost planet, in the predawn/dawn morning sky. Read more.

Where is Mars? From around the world, modestly-bright Mars now rises before dawn’s first light in the morning sky. At mid-northern latitudes, Mars rises about 2 1/2 hours before the sun in early December, and by the month’s end, rises some 3 hours before.

At temperate latitudes in the Southern Hemisphere, Mars comes up about 1 1/2 hours before the sun in early December, and about 2 1/2 hours before sunrise at the month’s end.

Let the old waning crescent moon help guide your eye to Mars for several mornings, centered on or near December 22, as shown on the sky chart below.

Are you a morning person? Around the time of the December solstice, watch for the moon to go by the celestial line-up: Spica, the brightest star in the constellation Virgo, Zubenelgenubi, the constellation Libra’s alpha star, and Mars, the 4th planet from the sun. Read more.

What do we mean by bright planet? By bright planet, we mean any solar system planet that is easily visible without an optical aid and that has been watched by our ancestors since time immemorial. In their outward order from the sun, the five bright planets are Mercury, Venus, Mars, Jupiter and Saturn. These planets actually do appear bright in our sky. They are typically as bright as – or brighter than – the brightest stars. Plus, these relatively nearby worlds tend to shine with a steadier light than the distant, twinkling stars. You can spot them, and come to know them as faithful friends, if you try.

Skywatcher, by Predrag Agatonovic.

Bottom line: In December 2019, a lineup of three planets – Saturn, Venus, and Jupiter – adorns the western sky at dusk/nightfall, with Saturn at top and Jupiter at bottom. Day by day, Venus climbs upward toward Saturn, until Venus and Saturn meet up for a conjunction on December 10. Mercury and Mars are morning planets, coming up before sun in the eastern sky. Click here for recommended almanacs; they can help you know when the planets rise and set in your sky.

Don’t miss anything. Subscribe to EarthSky News by email

Visit EarthSky’s Best Places to Stargaze, and recommend a place we can all enjoy.

Help EarthSky keep going! Donate now.

Post your planet photos at EarthSky Community Photos

from EarthSky https://ift.tt/1YD00CF

The Venus-Jupiter conjunction was this past Sunday (November 24, 2019). In late November, watch for the young moon to fly by Jupiter, Venus and Saturn in the west after sunset. Throughout December, Venus will be climbing upward, away from the sunset, while Jupiter is sinking downward. Jupiter will disappear in the sunset glare around mid-December.

Click the name of a planet to learn more about its visibility in November 2019: Venus, Jupiter, Saturn, Mars and Mercury.

Try Stellarium Online for a precise view from your location.

Venus – the brightest planet – reclaims her mantle as the evening “star” in December 2019. Last month, in November 2019, Venus assumed a low profile, lurking over the western horizon after sunset, beneath the planets Jupiter and Saturn. But Venus came into prominence in late November, when the queen planet finally met up with the king planet Jupiter for a stunning conjunction on November 24, 2019.

Next, Venus will catch up with Saturn for a conjunction on December 10, 2019. In the second half of December, Venus lords over Saturn and Jupiter in the evening sky. Jupiter and Saturn will soon fade away in the evening twilight, whereas dazzling Venus will grace the evening sky for several months to come.

At mid-northern latitudes in early December, Venus sets about two hours after sunset; but by the month’s end, that’ll increase to nearly three hours.

At temperate latitudes in the Southern Hemisphere, Venus sets about two hours after sunset throughout the month.

Watch for the young waxing crescent moon to pair up with Venus on or near December 28, as shown on the chart below.

Look for the young waxing crescent moon to couple up with Venus on or near December 28, 2019. Read more.

Jupiter – the second-brightest planet after Venus – can be found low in the west at dusk (beneath brighter Venus) during the first week or so of December 2019. Seek for Jupiter shortly after sunset because the king planet follows the sun the sun beneath the horizon before nightfall.

Jupiter should be visible to the eye alone during the first several days of December. Day by day, however, this world sinks closer the glow of sunset, and you’ll probably need binoculars to view Jupiter in the second week of December. By mid-month, Jupiter will probably disappear from view altogether.

Around the world, Jupiter sets around nightfall in early December. Then, by around December 7, Jupiter plunges beneath the horizon about one hour after the sun. Near the month’s end, Jupiter will transition out of the evening sky and into the morning sky. Jupiter will probably return to visibility in the east before sunrise in late January 2020.

EarthSky 2020 lunar calendars are available! They make great gifts. Order now. Going fast!

For North America, Venus and Saturn have their conjunction on the evening of December 10, 2019. Read more.

Saturn. After you find Venus at dusk and nightfall, use Venus, the sky’s brightest planet, to find the nearby fainter planet, Saturn. Although Saturn nowhere matches Venus in brilliance, Saturn does shine on par with the 1st-magnitude stars, or the sky’s brightest stars.

You really can’t mistake Saturn for Venus. The queen planet Venus ranks as the third-brightest celestial object in all the heavens, after the sun and moon. Venus outshines Saturn by more than 60 times.

Look for Saturn above Venus during the first part of December, and beneath Venus in the second half of the month. Throughout December, Venus climbs upward day by day, away from the sunset direction, while Saturn sinks downward and sunward. Look for these two worlds to meet up for a conjunction on or near December 10, as shown on the above sky chart.

By the month’s end, Saturn will sit low in the glow of evening twilight, and may be hard to see – even with binoculars. The first half of December presents the last good viewing of Saturn in the evening sky, before this world is submerged in the sun’s afterglow in late December.

Saturn will swing directly behind the sun on January 13, 2020, to transition out of the evening sky and into morning sky. After December passes, you might not see Saturn again until the ringed planet reappears in the eastern morning sky in February 2020.

Around the wold, Saturn plunges below the horizon about 3 hours after sunset in early December. Near the month’s end, Saturn sets about an hour after the sun.

If you’re up for a big challenge, try your luck at catching the young moon with Saturn after sunset on or near December 27, 2019, as shown on the sky chart below.

Look for the young waxing crescent moon to couple up with Saturn on or near December 27, 2019. Read more.

Mercury, the solar system’s innermost planet, recently reached its greatest elongation from the sun in the morning sky on November 28, 2019. Mercury remains a fine morning object as viewed from the Northern Hemisphere for the first week or two in December. Get up before dawn to see the 1st-magnitude star Spica lining up with the 2nd-magnitude planet Mars. Then, as the predawn darkness gives way to dawn, look for Mercury to climb above the horizon, more or less on line with Spica and Mars.

An imaginary line from Spica and past Mars, and down to the horizon, lets you know Mercury’s approximate rising point on the horizon, as shown on the sky chart below. Be mindful that Mars (and possibly Spica) will fade from view by the time that Mercury climbs above your horizon. Binoculars always come in handy for any Mercury quest.

Live in the Northern Hemisphere.? At northerly latitudes, the first week or so of December 2019 presents a fine opportunity for catching Mercury, the solar system’s innermost planet, in the predawn/dawn morning sky. Read more.

Where is Mars? From around the world, modestly-bright Mars now rises before dawn’s first light in the morning sky. At mid-northern latitudes, Mars rises about 2 1/2 hours before the sun in early December, and by the month’s end, rises some 3 hours before.

At temperate latitudes in the Southern Hemisphere, Mars comes up about 1 1/2 hours before the sun in early December, and about 2 1/2 hours before sunrise at the month’s end.

Let the old waning crescent moon help guide your eye to Mars for several mornings, centered on or near December 22, as shown on the sky chart below.

Are you a morning person? Around the time of the December solstice, watch for the moon to go by the celestial line-up: Spica, the brightest star in the constellation Virgo, Zubenelgenubi, the constellation Libra’s alpha star, and Mars, the 4th planet from the sun. Read more.

What do we mean by bright planet? By bright planet, we mean any solar system planet that is easily visible without an optical aid and that has been watched by our ancestors since time immemorial. In their outward order from the sun, the five bright planets are Mercury, Venus, Mars, Jupiter and Saturn. These planets actually do appear bright in our sky. They are typically as bright as – or brighter than – the brightest stars. Plus, these relatively nearby worlds tend to shine with a steadier light than the distant, twinkling stars. You can spot them, and come to know them as faithful friends, if you try.

Skywatcher, by Predrag Agatonovic.

Bottom line: In December 2019, a lineup of three planets – Saturn, Venus, and Jupiter – adorns the western sky at dusk/nightfall, with Saturn at top and Jupiter at bottom. Day by day, Venus climbs upward toward Saturn, until Venus and Saturn meet up for a conjunction on December 10. Mercury and Mars are morning planets, coming up before sun in the eastern sky. Click here for recommended almanacs; they can help you know when the planets rise and set in your sky.

Don’t miss anything. Subscribe to EarthSky News by email

Visit EarthSky’s Best Places to Stargaze, and recommend a place we can all enjoy.

Help EarthSky keep going! Donate now.

Post your planet photos at EarthSky Community Photos

from EarthSky https://ift.tt/1YD00CF

Thanksgiving turkey: light meat or dark?

Turkeys do a lot of standing and milling around, not a lot of flying. Image via Richard Wozniak/Shutterstock.com.

By Joshua Selsby, Iowa State University

As families gather together this holiday season, the lucky ones will avoid impassioned discussions about religion and politics. But another argument is almost inevitable: white meat versus dark meat.

Light meat lovers claim dark meat is greasy; dark meat devotees complain that light meat is dry and lacks flavor. Few meat eaters are ambivalent on the matter.

But why do these different types of meat exist, and what underlies these differences? As a muscle physiologist, I can tell you it comes down to the metabolic and functional differences between various types of muscle.

Consider how turkeys move. Have you ever seen a flock of turkeys fly by? Of course not! If a turkey is threatened, it can take flight for brief periods in an attempt to escape. But these birds spend most of their time standing and walking.

These activities – walking and standing versus brief, panicked flight – are quite different. They’re supported by different kinds of muscles geared to these different functions, and you can see those differences on your dinner plate.

Deliciously dark or grotesquely greasy? Image via Andrii Ridnyi/Shutterstock.com.

What makes dark meat dark?

Consider first the dark meat, which is found largely in the legs. This type of meat comes from muscles that get lots of use as turkeys spend their time walking around being turkeys.

Muscle physiologists call these sorts of muscles slow twitch or type I muscles. They are also called oxidative muscles, which refers to how they produce adenosine triphosphate, abbreviated as ATP. Think of ATP as a cell’s energy currency for performing a given function. Cells don’t need a job to earn this cash; they simply produce it.

The muscles’ metabolism must be able to support them throughout their long, sustained activities. In this case, because lots of ATP must be produced over extended periods of time, the muscle cells rely on their organelles called mitochondria. The mitochondria are like factories that manufacture ATP.

It’s the mitochondria that lend dark meat one of its distinguishing (disgusting?) characteristics. They can use fat to produce ATP. Because of its higher muscle fat content, some people may perceive dark muscle as greasy, while others deem it delicious.

Mitochondria also require oxygen in order to function. They rely on an iron-containing protein called myoglobin, which shuttles oxygen from the blood to the mitochondria found inside muscle. Because of the large amount of myoglobin, these muscles appear dark.

Lusciously lean or depressingly dry? Image via Paul Cowan/Shutterstock.com.

What makes white meat light?

What about that drier, white meat? Again, it’s useful to first consider its function.

White meat is found largely in the breast muscles, which are used to create the explosive force needed for flight. But keep in mind that for turkeys, this flight is very short in duration: just long enough to escape a predator. This job is ideally suited for what physiologists call type II or fast twitch muscle.

This sort of activity is supported by a different means of ATP production – one that does not heavily rely on mitochondria or require oxygen. White muscles use a process called glycolysis, which requires carbohydrates to create ATP. They are light in color because of their low capacity to use oxygen during exercise; there is simply no need for a high abundance of the iron-rich oxygen shuttle, myoglobin.

White muscles have a low fat content because they don’t need and don’t have a large amount of mitochondria required to make ATP from fat. That’s why some people find this meat to be dry.

Different species of animals perform different jobs with their muscles. For instance, duck breast muscles must support very long duration flights, and like turkey legs, are dark in color and loaded with fat.

In case you’re wondering, people’s muscles are a bit more complicated than just light or dark. Most human muscles are what physiologists consider mixed, with a variety of oxidative and slow muscle fibers. People with proportionally more of one than another might excel at different activities – think sprinters versus marathon runners.

Next time you sit down to enjoy your holiday meal, have confidence that you know why your meat choice tastes delicious. Now, can you believe what those D.C. politicians are up to?

Joshua Selsby, Professor of Animal Science, Iowa State University

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

Bottom line: Dark turkey meat vs white turkey meat.

from EarthSky https://ift.tt/2P1yX7d

Turkeys do a lot of standing and milling around, not a lot of flying. Image via Richard Wozniak/Shutterstock.com.

By Joshua Selsby, Iowa State University

As families gather together this holiday season, the lucky ones will avoid impassioned discussions about religion and politics. But another argument is almost inevitable: white meat versus dark meat.

Light meat lovers claim dark meat is greasy; dark meat devotees complain that light meat is dry and lacks flavor. Few meat eaters are ambivalent on the matter.

But why do these different types of meat exist, and what underlies these differences? As a muscle physiologist, I can tell you it comes down to the metabolic and functional differences between various types of muscle.

Consider how turkeys move. Have you ever seen a flock of turkeys fly by? Of course not! If a turkey is threatened, it can take flight for brief periods in an attempt to escape. But these birds spend most of their time standing and walking.

These activities – walking and standing versus brief, panicked flight – are quite different. They’re supported by different kinds of muscles geared to these different functions, and you can see those differences on your dinner plate.

Deliciously dark or grotesquely greasy? Image via Andrii Ridnyi/Shutterstock.com.

What makes dark meat dark?

Consider first the dark meat, which is found largely in the legs. This type of meat comes from muscles that get lots of use as turkeys spend their time walking around being turkeys.

Muscle physiologists call these sorts of muscles slow twitch or type I muscles. They are also called oxidative muscles, which refers to how they produce adenosine triphosphate, abbreviated as ATP. Think of ATP as a cell’s energy currency for performing a given function. Cells don’t need a job to earn this cash; they simply produce it.

The muscles’ metabolism must be able to support them throughout their long, sustained activities. In this case, because lots of ATP must be produced over extended periods of time, the muscle cells rely on their organelles called mitochondria. The mitochondria are like factories that manufacture ATP.

It’s the mitochondria that lend dark meat one of its distinguishing (disgusting?) characteristics. They can use fat to produce ATP. Because of its higher muscle fat content, some people may perceive dark muscle as greasy, while others deem it delicious.

Mitochondria also require oxygen in order to function. They rely on an iron-containing protein called myoglobin, which shuttles oxygen from the blood to the mitochondria found inside muscle. Because of the large amount of myoglobin, these muscles appear dark.

Lusciously lean or depressingly dry? Image via Paul Cowan/Shutterstock.com.

What makes white meat light?

What about that drier, white meat? Again, it’s useful to first consider its function.

White meat is found largely in the breast muscles, which are used to create the explosive force needed for flight. But keep in mind that for turkeys, this flight is very short in duration: just long enough to escape a predator. This job is ideally suited for what physiologists call type II or fast twitch muscle.

This sort of activity is supported by a different means of ATP production – one that does not heavily rely on mitochondria or require oxygen. White muscles use a process called glycolysis, which requires carbohydrates to create ATP. They are light in color because of their low capacity to use oxygen during exercise; there is simply no need for a high abundance of the iron-rich oxygen shuttle, myoglobin.

White muscles have a low fat content because they don’t need and don’t have a large amount of mitochondria required to make ATP from fat. That’s why some people find this meat to be dry.

Different species of animals perform different jobs with their muscles. For instance, duck breast muscles must support very long duration flights, and like turkey legs, are dark in color and loaded with fat.

In case you’re wondering, people’s muscles are a bit more complicated than just light or dark. Most human muscles are what physiologists consider mixed, with a variety of oxidative and slow muscle fibers. People with proportionally more of one than another might excel at different activities – think sprinters versus marathon runners.

Next time you sit down to enjoy your holiday meal, have confidence that you know why your meat choice tastes delicious. Now, can you believe what those D.C. politicians are up to?

Joshua Selsby, Professor of Animal Science, Iowa State University

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

Bottom line: Dark turkey meat vs white turkey meat.

from EarthSky https://ift.tt/2P1yX7d

Cranberries are more than just a holiday condiment

Image Credit: Rene Schwietzke

My first encounters with cranberries were in the form of cranberry sauce, specifically the canned variety. The product, a homogenous, sweetened gel, bore little resemblance to fruit. It emerged from its container like a Bundt cake from a mould, a perfect can-shaped lump, still bearing ringed indents from the metal. To my childish palette, it was the best thing ever, and for years attempts to persuade me to eat homemade cranberry sauce with actual chunks of real cranberries were met with sour moods and bitter disapproval.

Behold the spleandor of “can-berry” sauce. Image via Mr. T in DC.

As an adult, I learned to appreciate more authentic and even creative versions of the classic holiday condiment. Novel cranberry sauces with ingredients like walnuts and jalapeños are now welcome on my plate. Cranberries too have broadened their horizons over the years. From their simple beginnings in sauces and “juice cocktail”, they’ve branched out into dried snacks, muffin and cookie ingredients, and nutritional supplement pills. Not bad for a fruit that is, by many standards, inedibly sour in its raw form. Though a reputation for providing health benefits also helped, the cranberry owes much of its success to some basic biological quirks that make it ideal for cultivation.

Better off bitter

The American cranberry is an evergreen shrub native to the eastern part of North America. While the common cranberry (Vaccinium oxycoccos) has a broader distribution, including northern Europe and Asia, it is not as heavily cultivated as the new world version of the fruit.

Floatation device. Image via TheDeliciousLife.

A relative of the blueberry, cranberries differ from this sweeter cousin in habitat. The American cranberry grows in bogs with acidic soil. Cranberries don’t actually grow underwater, just near it. However, growing in wet environments made it possible for them to use the water as a means of seed dispersal. Air pockets inside the berries allow them to float.* Since they don’t rely on animals to disperse their seeds (and prefer to grow close to water), cranberries need to avoid being too delicious. Tannins lend the fruit its tartness. These are the same chemicals that give unripe bananas that awful mouth-drying effect.† Having rendered themselves unappetizing to most critters, cranberries are left alone until they fall from their vines and are ferried to new locations by water.

Bobbing for berries

Watery harvest. Image via Elaine Ashton.

Its ability to float would eventually also make the cranberry a popular fruit for cultivation. In the early days of cranberry farming, the crop was “dry harvested” – that is, the berries were hand-picked from the shrubs, which was slow and labor intensive. But in the mid 20th century someone realized that it would be easier to flood the bogs in which cranberries were grown, rattle the branches a bit, and then skim the buoyant berries from the top of the water. This “wet harvesting” technique is now used for the bulk of cranberry farming. Most farmed cranberries make their way into juices and other processed products. Some are still sold fresh, and these are typically dry-harvested to assure that they’re fresher and not too battered.

A Thanksgiving tradition
Somewhere during the month of November, U.S. schoolchildren receive a (greatly simplified) history lesson on the holiday for which they are about to get two full days of reprieve from education. As the story goes, the nation’s settlers, having (barely) survived a brutal first winter and successfully harvested enough food to perhaps live through a second one, sat down to a celebratory feast with Native Americans (whose farming know-how helped to make said harvesting possible in the first). And thus American Thanksgiving was born. ‡

Flooded fruit. Image via Keith Weller.

Well, the funny thing about that “first” Thanksgiving – other than the fact that harvest festivals had long been common fare in Europe, and that Plymouth pilgrims weren’t exactly the first Europeans to make their way to the new world – is that we don’t have the recipe cards from the event. What was served at the 1621 celebration is largely speculation. We know that they had deer, courtesy of the Wampanoag tribe. Pies were probably not on the menu as the settlers’ sugar stash was pretty low by that point. And there is no record of mashed potatoes and gravy, marshmallow yams, or cranberry sauce. Since Native Americans regularly used cranberries for food and dye and such, it’s possible the sour fruit made an appearance at the dinner table. Let’s hope so, as vitamin-C-rich cranberries would certainly have done the pilgrims some good, scurvy being a major problem back then.

Here’s to your health

Good for what ails you? Image via Dana Deskiewicz.

Speaking of maladies, here’s a fine topic for holiday dinner conversations: urinary tract infections (UTI). While UTIs were surely the least of the pilgrims’ health woes, they’re fairly common in modern times (especially among women) and there’s some evidence that cranberries may be helpful in preventing them.

UTIs are caused by bacteria (usually E. coli) getting into the urinary system. In most cases, such infections are contained to the urethra and bladder and can be treated with antibiotics. However, they can cause an array of uncomfortable symptoms (pelvic pain, burning sensation while urinating, etc.) and, in unluckier individuals, they have a tendency to recur.

Maybe you’ve heard that studies have suggested that regular consumption of cranberry juice may help prevent their recurrence. But it turns out that more recent suggest say that cranberries may not be much of UTI fighter after all. The research results are mixed and the mechanism of action is still a little fuzzy. For a while it was thought that cranberries worked by rendering urine too acidic for bacteria to set up camp in the urethra. More recently, the idea was that chemicals found in cranberries called proanthocyanidins (PACs) prevented bacteria from adhering to the cells lining the urinary tract. Essentially, it’s complicated.

But maybe you just like cranberries and want to give preventative medicine a shot. What have you got to lose, right? Well, a few considerations might be in order. First, go easy on the dosage, especially if you’re working with pure cranberry juice (most often, the stuff is sold in highly dilute “juice cocktail” form). Like Thanksgiving itself, excessive amounts of cranberries can cause stomach upset. Additionally, the fruit may (this too is still in the “more research is needed” category) have an undesired interaction with the prescription anticoagulant (translation: blood clot preventing drug) warfarin. While it hasn’t been demonstrated with any certainty, coupling daily cranberry juice consumption with your warfarin regimen may put you at greater risk for bruising and bleeding.§

But you might be over-thinking all this. Maybe you should just relax and have a glass of cranberry wine. You can even make it at home. Though you should probably start immediately as the fermenting and “racking” process takes about a year. And then, it should probably sit for another year. If you get your act together quickly enough, you might be able to enjoy cranberry wine at Thanksgiving 2013. Something to look forward to.

* While they’re not the only floating fruit, cranberries are particularly skilled at it. As for other fruits, I can report that (according to internet research) lemons float, whereas limes sink, and that (according to kitchen experiments) red grapefruits float, but not by much.

† Tannins also provide a much more welcome dryness to wine.

‡ Thanksgiving did not become official in the U.S. until 1863 – almost two and a half centuries after the settlers’ famous party – when Abraham Lincoln made it a national holiday.

§ These are already side effects of warfarin (it does impede blood from clotting after all), cranberry juice might just amplify them. Maybe. Bonus trivia: warfarin can also be used as rat poison.

This post was originally published in November 2011

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

Image Credit: Rene Schwietzke

My first encounters with cranberries were in the form of cranberry sauce, specifically the canned variety. The product, a homogenous, sweetened gel, bore little resemblance to fruit. It emerged from its container like a Bundt cake from a mould, a perfect can-shaped lump, still bearing ringed indents from the metal. To my childish palette, it was the best thing ever, and for years attempts to persuade me to eat homemade cranberry sauce with actual chunks of real cranberries were met with sour moods and bitter disapproval.

Behold the spleandor of “can-berry” sauce. Image via Mr. T in DC.

As an adult, I learned to appreciate more authentic and even creative versions of the classic holiday condiment. Novel cranberry sauces with ingredients like walnuts and jalapeños are now welcome on my plate. Cranberries too have broadened their horizons over the years. From their simple beginnings in sauces and “juice cocktail”, they’ve branched out into dried snacks, muffin and cookie ingredients, and nutritional supplement pills. Not bad for a fruit that is, by many standards, inedibly sour in its raw form. Though a reputation for providing health benefits also helped, the cranberry owes much of its success to some basic biological quirks that make it ideal for cultivation.

Better off bitter

The American cranberry is an evergreen shrub native to the eastern part of North America. While the common cranberry (Vaccinium oxycoccos) has a broader distribution, including northern Europe and Asia, it is not as heavily cultivated as the new world version of the fruit.

Floatation device. Image via TheDeliciousLife.

A relative of the blueberry, cranberries differ from this sweeter cousin in habitat. The American cranberry grows in bogs with acidic soil. Cranberries don’t actually grow underwater, just near it. However, growing in wet environments made it possible for them to use the water as a means of seed dispersal. Air pockets inside the berries allow them to float.* Since they don’t rely on animals to disperse their seeds (and prefer to grow close to water), cranberries need to avoid being too delicious. Tannins lend the fruit its tartness. These are the same chemicals that give unripe bananas that awful mouth-drying effect.† Having rendered themselves unappetizing to most critters, cranberries are left alone until they fall from their vines and are ferried to new locations by water.

Bobbing for berries

Watery harvest. Image via Elaine Ashton.

Its ability to float would eventually also make the cranberry a popular fruit for cultivation. In the early days of cranberry farming, the crop was “dry harvested” – that is, the berries were hand-picked from the shrubs, which was slow and labor intensive. But in the mid 20th century someone realized that it would be easier to flood the bogs in which cranberries were grown, rattle the branches a bit, and then skim the buoyant berries from the top of the water. This “wet harvesting” technique is now used for the bulk of cranberry farming. Most farmed cranberries make their way into juices and other processed products. Some are still sold fresh, and these are typically dry-harvested to assure that they’re fresher and not too battered.

A Thanksgiving tradition
Somewhere during the month of November, U.S. schoolchildren receive a (greatly simplified) history lesson on the holiday for which they are about to get two full days of reprieve from education. As the story goes, the nation’s settlers, having (barely) survived a brutal first winter and successfully harvested enough food to perhaps live through a second one, sat down to a celebratory feast with Native Americans (whose farming know-how helped to make said harvesting possible in the first). And thus American Thanksgiving was born. ‡

Flooded fruit. Image via Keith Weller.

Well, the funny thing about that “first” Thanksgiving – other than the fact that harvest festivals had long been common fare in Europe, and that Plymouth pilgrims weren’t exactly the first Europeans to make their way to the new world – is that we don’t have the recipe cards from the event. What was served at the 1621 celebration is largely speculation. We know that they had deer, courtesy of the Wampanoag tribe. Pies were probably not on the menu as the settlers’ sugar stash was pretty low by that point. And there is no record of mashed potatoes and gravy, marshmallow yams, or cranberry sauce. Since Native Americans regularly used cranberries for food and dye and such, it’s possible the sour fruit made an appearance at the dinner table. Let’s hope so, as vitamin-C-rich cranberries would certainly have done the pilgrims some good, scurvy being a major problem back then.

Here’s to your health

Good for what ails you? Image via Dana Deskiewicz.

Speaking of maladies, here’s a fine topic for holiday dinner conversations: urinary tract infections (UTI). While UTIs were surely the least of the pilgrims’ health woes, they’re fairly common in modern times (especially among women) and there’s some evidence that cranberries may be helpful in preventing them.

UTIs are caused by bacteria (usually E. coli) getting into the urinary system. In most cases, such infections are contained to the urethra and bladder and can be treated with antibiotics. However, they can cause an array of uncomfortable symptoms (pelvic pain, burning sensation while urinating, etc.) and, in unluckier individuals, they have a tendency to recur.

Maybe you’ve heard that studies have suggested that regular consumption of cranberry juice may help prevent their recurrence. But it turns out that more recent suggest say that cranberries may not be much of UTI fighter after all. The research results are mixed and the mechanism of action is still a little fuzzy. For a while it was thought that cranberries worked by rendering urine too acidic for bacteria to set up camp in the urethra. More recently, the idea was that chemicals found in cranberries called proanthocyanidins (PACs) prevented bacteria from adhering to the cells lining the urinary tract. Essentially, it’s complicated.

But maybe you just like cranberries and want to give preventative medicine a shot. What have you got to lose, right? Well, a few considerations might be in order. First, go easy on the dosage, especially if you’re working with pure cranberry juice (most often, the stuff is sold in highly dilute “juice cocktail” form). Like Thanksgiving itself, excessive amounts of cranberries can cause stomach upset. Additionally, the fruit may (this too is still in the “more research is needed” category) have an undesired interaction with the prescription anticoagulant (translation: blood clot preventing drug) warfarin. While it hasn’t been demonstrated with any certainty, coupling daily cranberry juice consumption with your warfarin regimen may put you at greater risk for bruising and bleeding.§

But you might be over-thinking all this. Maybe you should just relax and have a glass of cranberry wine. You can even make it at home. Though you should probably start immediately as the fermenting and “racking” process takes about a year. And then, it should probably sit for another year. If you get your act together quickly enough, you might be able to enjoy cranberry wine at Thanksgiving 2013. Something to look forward to.

* While they’re not the only floating fruit, cranberries are particularly skilled at it. As for other fruits, I can report that (according to internet research) lemons float, whereas limes sink, and that (according to kitchen experiments) red grapefruits float, but not by much.

† Tannins also provide a much more welcome dryness to wine.

‡ Thanksgiving did not become official in the U.S. until 1863 – almost two and a half centuries after the settlers’ famous party – when Abraham Lincoln made it a national holiday.

§ These are already side effects of warfarin (it does impede blood from clotting after all), cranberry juice might just amplify them. Maybe. Bonus trivia: warfarin can also be used as rat poison.

This post was originally published in November 2011

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