Getting cancer services back on track during the COVID-19 pandemic

Conversations about COVID-19 are changing. While the impact of COVID-19 on healthcare services across the UK is likely to continue for many months to come, talk is shifting to how to restore healthcare services.

But at a time when our health services are recovering from one major health crisis, we are in danger of creating another – a cancer crisis. Over 2 million people in the UK were left waiting for cancer screening, tests and treatments in the first 10 weeks of lockdown, and that figure is growing.

Cancer services are beginning to get up and running across the country, but we’re still a long way from either restoring capacity or addressing the backlog of people waiting for tests and treatment.

And we can’t just focus on the next few weeks or months. Without a clear plan in each UK nation that looks not just at restoring cancer services over the next few months, but at how we fully recover services and get back on track to transform cancer care, progress on cancer survival could stall.

Here’s what we think needs to happen to make sure patients get the care they need, when they need it.

Creating COVID-protected safe spaces for cancer care

The first, and most pressing, issue is to create COVID-protected safe spaces in hospitals – free, as far as possible, from the COVID-19 virus – to ensure that people can be diagnosed and treated safely and be reassured enough to come forward for care. This requires frequent testing for COVID-19 in all patients and staff working in these spaces, whether they have COVID-19 symptoms or not.

The good news is that COVID-protected safe spaces are being rolled out across the UK. But some hospitals are still struggling to carry out as many tests as they need and get the results quickly enough. For safe spaces to exist, we need to remove the ambiguity.

Each UK nation needs a national strategy to uplift hospital testing capacity, ensure tests are turned around quickly enough and that healthcare workings are tested frequently, prioritising the most needy services first.

We’ve estimated that between 21,000 – 37,000 tests per day, combined with other infection control measures, are required to ensure there are COVID-protected safe spaces for cancer diagnosis and treatment.

> Help us secure safe spaces for cancer services by emailing your MP

Ensuring these COVID-protected safe spaces are fully functional will be vital to managing the backlog and rebuilding trust in cancer services. But it must be combined with awareness campaigns so that people with potential cancer symptoms are encouraged to seek help from health professionals and feel safe doing so.

At the beginning of the coronavirus outbreak, the number of people being urgently referred for suspected cancer dropped by up to 75%, meaning far fewer people were getting diagnostic tests, equating to some 2,300 cancers a week not being diagnosed through this route. And while the number of urgent referrals is steadily rising, they remain lower than usual, and the backlog of patients requiring diagnostic tests continues to build.

And it’s not just urgent cancer referrals that have been affected. All national cancer screening programmes were effectively paused in each UK nation by the coronavirus pandemic, which means up to 1.2 million invitations to take part in bowel, breast and cervical screening were not being sent out each month. And chemotherapy, radiotherapy and surgery cases dropped, leaving thousands of patients waiting for life-saving cancer treatment.

So far, we have estimates of how many people are affected. But for local services to plan how they will catch up, and the capacity they will need, health services need to provide clear and high-quality data on the scale of the disruption over the past 4 months and a detailed assessment of who will need tests or treatment most urgently.

As the UK could face multiple waves of COVID-19 cases – these figures will also help health services to prepare for these scenarios, with the aim of keeping cancer services running as much and as safely as possible.

Restarting clinical trials

A vital part of getting cancer services back on track is restarting clinical trials. COVID-19 has had a huge impact on the UK’s ability to run clinical trials, with the number of new patients being recruit on to UK-based trials falling by 95% in April 2020 compared with April 2019.

Without clinical trials, the potential pipeline of new or improved cancer treatment options stalls, so restarting clinical trials should be a priority.

Things are starting to move in the right direction – the National Institute for Health Research has published a framework outlining conditions that must be met before clinical trials start as well as criteria for prioritising which trials should be restarted first.

But while cancer trials are starting to re-open to new patients, right now the highest priority level is reserved for COVID-19 trials. To ensure that cancer clinical trials are not seen as less of a priority when it comes to getting trials back up and running, we believe the highest priority level should be expanded to include urgent non-COVID studies, especially studies that provide safer alternatives treatments in a COVID-19 environment.

Preventing cancer

For healthcare to truly be back on track, we need to think bigger than cancer diagnosis and treatment. Smoking continues to be the biggest preventable cause of cancer, illness and death in the UK, and recent research suggests that people who smoke are more likely to experience severe COVID-19 symptoms than non-smokers.

Most stop smoking services in the UK responded quickly to the COVID-19 pandemic and have adapted their service to ensure people could continue receiving behavioural support over the phone, through videoconference or via email, text messaging or apps.

Many services have also found innovative ways of delivering stop smoking therapies to people during the period of lockdown, including sending prescriptions to pharmacies for collection or posting these medications directly to people who need them. It’s vital that people who smoke continue to be provided with professional support to give them the best chance of stopping smoking, with support delivered virtually. This relies on specialist support receiving enough funding on a national and local level.

Workforce and innovation

Healthcare staff are central to the recovery of cancer services and action must be taken to increase and retain staff working in cancer care. This is not a new issue, before the COVID-19 crisis there were around 1 in 10 diagnostic posts unfilled across the health service. But it’s become even more pressing during the pandemic, as the backlog of people waiting for tests or treatment has grown.

To manage this, there must be a clear understanding of how COVID-19 has affected the number of staff in specific cancer professions, and health services must take steps to train and increase the workforce where it’s most needed. In the longer term, each UK nation needs a fully-funded workforce plan to make sure there are enough staff in the future to support the rising incidence of cancer.

While the crisis has placed unimaginable strain on the healthcare service, it’s also forced services to find new and innovative ways of working, by reconfiguring services and embracing technology.

We must make sure that we learn from these changes, scaling up innovations that have worked well. As much of this has been driven at a local level, we need national health leaders, hospitals and clinicians to work together to make this happen.

Moving forward

COVID-19 has changed the game, and health services and governments need to act now to ensure that cancer tests, treatment and care can recover following the COVID-19 peak. Our chief executive officer, Michelle Mitchell, alongside other charities, has written to the Prime Minister to help kickstart a national conversation about our longer-term ambitions in cancer. And our teams in Scotland, Wales and Northern Ireland will work with the relevant governments to deliver our ambitions in each UK nation.

We know that cancer survival and outcomes can improve, despite COVID-19, and we should be aiming to catch up with others in the world. But in order to give patients the care they deserve, the UK and devolved governments must commit to an ambitious cancer agenda.

Khruti Shrotri is a policy manager at Cancer Research UK

We need your help to secure safe spaces for cancer services.

> Demand urgent action now 



from Cancer Research UK – Science blog https://ift.tt/3fLYdd9

Conversations about COVID-19 are changing. While the impact of COVID-19 on healthcare services across the UK is likely to continue for many months to come, talk is shifting to how to restore healthcare services.

But at a time when our health services are recovering from one major health crisis, we are in danger of creating another – a cancer crisis. Over 2 million people in the UK were left waiting for cancer screening, tests and treatments in the first 10 weeks of lockdown, and that figure is growing.

Cancer services are beginning to get up and running across the country, but we’re still a long way from either restoring capacity or addressing the backlog of people waiting for tests and treatment.

And we can’t just focus on the next few weeks or months. Without a clear plan in each UK nation that looks not just at restoring cancer services over the next few months, but at how we fully recover services and get back on track to transform cancer care, progress on cancer survival could stall.

Here’s what we think needs to happen to make sure patients get the care they need, when they need it.

Creating COVID-protected safe spaces for cancer care

The first, and most pressing, issue is to create COVID-protected safe spaces in hospitals – free, as far as possible, from the COVID-19 virus – to ensure that people can be diagnosed and treated safely and be reassured enough to come forward for care. This requires frequent testing for COVID-19 in all patients and staff working in these spaces, whether they have COVID-19 symptoms or not.

The good news is that COVID-protected safe spaces are being rolled out across the UK. But some hospitals are still struggling to carry out as many tests as they need and get the results quickly enough. For safe spaces to exist, we need to remove the ambiguity.

Each UK nation needs a national strategy to uplift hospital testing capacity, ensure tests are turned around quickly enough and that healthcare workings are tested frequently, prioritising the most needy services first.

We’ve estimated that between 21,000 – 37,000 tests per day, combined with other infection control measures, are required to ensure there are COVID-protected safe spaces for cancer diagnosis and treatment.

> Help us secure safe spaces for cancer services by emailing your MP

Ensuring these COVID-protected safe spaces are fully functional will be vital to managing the backlog and rebuilding trust in cancer services. But it must be combined with awareness campaigns so that people with potential cancer symptoms are encouraged to seek help from health professionals and feel safe doing so.

At the beginning of the coronavirus outbreak, the number of people being urgently referred for suspected cancer dropped by up to 75%, meaning far fewer people were getting diagnostic tests, equating to some 2,300 cancers a week not being diagnosed through this route. And while the number of urgent referrals is steadily rising, they remain lower than usual, and the backlog of patients requiring diagnostic tests continues to build.

And it’s not just urgent cancer referrals that have been affected. All national cancer screening programmes were effectively paused in each UK nation by the coronavirus pandemic, which means up to 1.2 million invitations to take part in bowel, breast and cervical screening were not being sent out each month. And chemotherapy, radiotherapy and surgery cases dropped, leaving thousands of patients waiting for life-saving cancer treatment.

So far, we have estimates of how many people are affected. But for local services to plan how they will catch up, and the capacity they will need, health services need to provide clear and high-quality data on the scale of the disruption over the past 4 months and a detailed assessment of who will need tests or treatment most urgently.

As the UK could face multiple waves of COVID-19 cases – these figures will also help health services to prepare for these scenarios, with the aim of keeping cancer services running as much and as safely as possible.

Restarting clinical trials

A vital part of getting cancer services back on track is restarting clinical trials. COVID-19 has had a huge impact on the UK’s ability to run clinical trials, with the number of new patients being recruit on to UK-based trials falling by 95% in April 2020 compared with April 2019.

Without clinical trials, the potential pipeline of new or improved cancer treatment options stalls, so restarting clinical trials should be a priority.

Things are starting to move in the right direction – the National Institute for Health Research has published a framework outlining conditions that must be met before clinical trials start as well as criteria for prioritising which trials should be restarted first.

But while cancer trials are starting to re-open to new patients, right now the highest priority level is reserved for COVID-19 trials. To ensure that cancer clinical trials are not seen as less of a priority when it comes to getting trials back up and running, we believe the highest priority level should be expanded to include urgent non-COVID studies, especially studies that provide safer alternatives treatments in a COVID-19 environment.

Preventing cancer

For healthcare to truly be back on track, we need to think bigger than cancer diagnosis and treatment. Smoking continues to be the biggest preventable cause of cancer, illness and death in the UK, and recent research suggests that people who smoke are more likely to experience severe COVID-19 symptoms than non-smokers.

Most stop smoking services in the UK responded quickly to the COVID-19 pandemic and have adapted their service to ensure people could continue receiving behavioural support over the phone, through videoconference or via email, text messaging or apps.

Many services have also found innovative ways of delivering stop smoking therapies to people during the period of lockdown, including sending prescriptions to pharmacies for collection or posting these medications directly to people who need them. It’s vital that people who smoke continue to be provided with professional support to give them the best chance of stopping smoking, with support delivered virtually. This relies on specialist support receiving enough funding on a national and local level.

Workforce and innovation

Healthcare staff are central to the recovery of cancer services and action must be taken to increase and retain staff working in cancer care. This is not a new issue, before the COVID-19 crisis there were around 1 in 10 diagnostic posts unfilled across the health service. But it’s become even more pressing during the pandemic, as the backlog of people waiting for tests or treatment has grown.

To manage this, there must be a clear understanding of how COVID-19 has affected the number of staff in specific cancer professions, and health services must take steps to train and increase the workforce where it’s most needed. In the longer term, each UK nation needs a fully-funded workforce plan to make sure there are enough staff in the future to support the rising incidence of cancer.

While the crisis has placed unimaginable strain on the healthcare service, it’s also forced services to find new and innovative ways of working, by reconfiguring services and embracing technology.

We must make sure that we learn from these changes, scaling up innovations that have worked well. As much of this has been driven at a local level, we need national health leaders, hospitals and clinicians to work together to make this happen.

Moving forward

COVID-19 has changed the game, and health services and governments need to act now to ensure that cancer tests, treatment and care can recover following the COVID-19 peak. Our chief executive officer, Michelle Mitchell, alongside other charities, has written to the Prime Minister to help kickstart a national conversation about our longer-term ambitions in cancer. And our teams in Scotland, Wales and Northern Ireland will work with the relevant governments to deliver our ambitions in each UK nation.

We know that cancer survival and outcomes can improve, despite COVID-19, and we should be aiming to catch up with others in the world. But in order to give patients the care they deserve, the UK and devolved governments must commit to an ambitious cancer agenda.

Khruti Shrotri is a policy manager at Cancer Research UK

We need your help to secure safe spaces for cancer services.

> Demand urgent action now 



from Cancer Research UK – Science blog https://ift.tt/3fLYdd9

Young moon after sunset June 22, 23 and 24

By June 22, 2020, the annular solar eclipse has passed. From the Americas, it might have been possible to catch the skinniest of lunar crescents at dusk June 21, though binoculars would have been needed to glimpse the frail crescent that’s only about 0.5 percent illuminated in sunshine. For most of us, the young moon will return to the west after sunset on June 22, 23 and 24. Finding an unobstructed western horizon will be most helpful – especially on June 22 – when a whisker-thin lunar crescent will sit low in the west at sunset and will follow the sun beneath the horizon shortly thereafter. Most likely, on June 22, the thin crescent will set before nightfall. On the following evenings – June 23 and 24 – the young moon will be higher up after sunset and easier to see, but don’t delay. These young crescent moons all follow the sun below the western horizon in early evening.

Find out when the moon sets in your sky via TimeandDate.com

The moon swept to its new phase on June 21, 2020, at 06:41 UTC, giving birth to the new lunar month (Brown Lunation Number 1206).

Normally, the moon is not seen from Earth at new phase. At that time, the moon’s dark side is facing Earth, with the moon as a whole traveling near the sun in our daytime sky, lost in the sun’s glare. You’ll typically see the young moon return to the evening sky a day or two after new moon.

At the June 21 new moon, a number of people living in the world’s Eastern Hemisphere did see the moon during daylight hours. That’s because the new moon swung smack-dab in front of the sun, causing a solar eclipse. A small slice of the world saw this annular – or ring – solar eclipse. At mid-eclipse, the new moon silhouette was surrounded by a thin ring – or annulus – of the sun’s surface. A much larger swath of the world saw the new moon take a bite out of the solar disk: a partial eclipse of the sun.

Read more: Annular solar eclipse on June 21, 2020

Those who watched the June 21 solar eclipse – either in the sky or online – were viewing the moon’s night side. Now daylight is returning to the side of the moon we see. Assuming you don’t see the moon in your evening sky on June 21 (and most of us won’t), the first thin slice of illumination on the near side of the moon will be visible after sunset June 22.

Day by day, the moon moves a little over 12 degrees eastward of the setting sun. (For reference, the moon’s angular diameter spans about 1/2 degree of sky, and your fist at arm’s length measures approximately 10 degrees.) That means a wider lunar crescent will be higher in the sky at sunset, and will stay out longer after dark. In other words, the moon will be easier to catch after sundown on June 23 than on June 22, and on June 24 than June 23.

Thin yellow crescent, partly behind a wooded hill, in a dark orange twilight sky, with rest of moon showing dimly.

Above photo: Peter Lowenstein of Mutare, Zimbabwe, caught the young moon, with its dark side all aglow in earthshine, after sunset September 29, 2019.

While you’re enjoying the beauty of a young moon these next several days, note the soft glow of earthshine on the dark side of the moon. Earthshine is twice-reflected sunlight, with sunlight reflected from Earth hitting the moon, and then bouncing back to Earth.

Read more: What is earthshine?

Bottom line: These next several days – June 22, 23 and 24, 2020 – watch for the young moon to adorn your western twilight sky.



from EarthSky https://ift.tt/31hWetl

By June 22, 2020, the annular solar eclipse has passed. From the Americas, it might have been possible to catch the skinniest of lunar crescents at dusk June 21, though binoculars would have been needed to glimpse the frail crescent that’s only about 0.5 percent illuminated in sunshine. For most of us, the young moon will return to the west after sunset on June 22, 23 and 24. Finding an unobstructed western horizon will be most helpful – especially on June 22 – when a whisker-thin lunar crescent will sit low in the west at sunset and will follow the sun beneath the horizon shortly thereafter. Most likely, on June 22, the thin crescent will set before nightfall. On the following evenings – June 23 and 24 – the young moon will be higher up after sunset and easier to see, but don’t delay. These young crescent moons all follow the sun below the western horizon in early evening.

Find out when the moon sets in your sky via TimeandDate.com

The moon swept to its new phase on June 21, 2020, at 06:41 UTC, giving birth to the new lunar month (Brown Lunation Number 1206).

Normally, the moon is not seen from Earth at new phase. At that time, the moon’s dark side is facing Earth, with the moon as a whole traveling near the sun in our daytime sky, lost in the sun’s glare. You’ll typically see the young moon return to the evening sky a day or two after new moon.

At the June 21 new moon, a number of people living in the world’s Eastern Hemisphere did see the moon during daylight hours. That’s because the new moon swung smack-dab in front of the sun, causing a solar eclipse. A small slice of the world saw this annular – or ring – solar eclipse. At mid-eclipse, the new moon silhouette was surrounded by a thin ring – or annulus – of the sun’s surface. A much larger swath of the world saw the new moon take a bite out of the solar disk: a partial eclipse of the sun.

Read more: Annular solar eclipse on June 21, 2020

Those who watched the June 21 solar eclipse – either in the sky or online – were viewing the moon’s night side. Now daylight is returning to the side of the moon we see. Assuming you don’t see the moon in your evening sky on June 21 (and most of us won’t), the first thin slice of illumination on the near side of the moon will be visible after sunset June 22.

Day by day, the moon moves a little over 12 degrees eastward of the setting sun. (For reference, the moon’s angular diameter spans about 1/2 degree of sky, and your fist at arm’s length measures approximately 10 degrees.) That means a wider lunar crescent will be higher in the sky at sunset, and will stay out longer after dark. In other words, the moon will be easier to catch after sundown on June 23 than on June 22, and on June 24 than June 23.

Thin yellow crescent, partly behind a wooded hill, in a dark orange twilight sky, with rest of moon showing dimly.

Above photo: Peter Lowenstein of Mutare, Zimbabwe, caught the young moon, with its dark side all aglow in earthshine, after sunset September 29, 2019.

While you’re enjoying the beauty of a young moon these next several days, note the soft glow of earthshine on the dark side of the moon. Earthshine is twice-reflected sunlight, with sunlight reflected from Earth hitting the moon, and then bouncing back to Earth.

Read more: What is earthshine?

Bottom line: These next several days – June 22, 23 and 24, 2020 – watch for the young moon to adorn your western twilight sky.



from EarthSky https://ift.tt/31hWetl

Saturn’s large moon Titan is drifting away 100 times faster than anyone knew

Large banded sphere with dark curved lines, a long thin straight line and smaller darker sphere in front of it, on black background.

Titan orbiting Saturn, as seen by the Cassini spacecraft on May 12, 2012. Image via NASA/ JPL-Caltech/ Space Science Institute.

Researchers knew Saturn’s moon, Titan, was moving away from its planet, just as Earth’s moon gradually orbits farther from Earth. But – while Titan’s outward drift is still extremely slow – this large moon is now known to be moving away from Saturn 100 times faster than previously thought. That’s according to a June 2020 announcement by scientists in the U.S., France and Italy.

The peer-reviewed findings were published on June 8 in the journal Nature Astronomy.

The rate of Titan’s movement away from Saturn had been thought to be well understood, but as often happens in science, a new discovery has upended that idea. The discovery was made via a new analysis of data from the Cassini spacecraft, which orbited Saturn from 2004 to 2017. The data show Titan moving outward at about 4 inches (11 centimeters) per year.

That might not sound like a lot, but it’s significantly faster than the rate at which our moon drifts away from Earth. Our moon is drifting outward at only about 1.5 inches (3.8 centimeters) each year.

Mottled green and brown sphere on black background.

Titan’s surface as seen in infrared via Cassini on November 13, 2015. Titan is completely surrounded by thick haze, but Cassini’s radar penetrated the haze to reveal surface details. Image via NASA/ JPL/ University of Arizona/ University of Idaho.

The researchers reached this conclusion after studying images of stars sent back by Cassini. They mapped the background stars and tracked the position of Titan among them. Those images were then compared to a completely separate dataset, Cassini’s radio science data. Cassini sent radio waves back to Earth during 10 close flybys that the spacecraft conducted of Titan between 2006 and 2016. By examining how the frequency of the radio signals was affected by interactions with its environment in space, the researchers could estimate how Titan’s orbit evolved and changed over the past few billion years. Study coauthor Paolo Tortora, of Italy’s University of Bologna, explained in a statement:

By using two completely different datasets, we obtained results that are in full agreement, and also in agreement with Jim Fuller’s theory, which predicted a much faster migration of Titan.

Why do moons move away from their planets, anyway?

Large sphere with rings and line of very tiny spheres, with text annotations, on grayish background.

Titan is one of the outer moons of Saturn, orbiting well beyond the main rings and out past Rhea. Image via NASA/ JPL/ Wikipedia.

As a moon orbits a planet, its gravity tugs a bit on the planet – a process called tidal friction – creating strain and a resulting very slight bulge on the planet. On Earth, this bulge happens most noticably in our oceans – called a tidal bulge – and causes the cycle of high and low tides, but planets without oceans can bulge, too. This cyclic process of bulging and then subsequent relaxing creates a lot of energy over a long period of time. Tidal friction, however, also prevents the tidal bulge on Earth from remaining directly beneath the moon; instead it is carried along with the rotation of the Earth. The energy, created by mutual attraction between the moon and the material in the bulge, accelerates the moon slightly in its orbit. This causes the moon to drift a tiny bit farther away from Earth over time.

The new result also has implications for the age of the entire Saturn system. It’s still uncertain just how old Saturn’s rings are, as well as the planet’s moons. Right now, Titan is 759,000 miles (1.2 million kilometers) from Saturn; if the new measurement of the moon’s drift rate is correct, it means that Titan must have once been closer to Saturn than previously understood, and that Titan has migrated to its current position far out from the planet. In other words, Titan must have gone from being an inner moon to being an outer moon.

The new result further implies that the entire Saturn system of moons expanded faster than thought. Valery Lainey, lead author of the new study, formerly a scientist at the Jet Propulsion Laboratory (JPL) and now at the Paris Observatory at PSL University, stated:

This result brings an important new piece of the puzzle for the highly debated question of the age of the Saturn system and how its moons formed.

Large banded sphere with rings, a smaller reddish sphere and spacecraft with dish antenna and long solar panel, on black background.

Artist’s concept of Cassini near Titan. Image via Kevin Gill/ Flickr/ Smithsonian Magazine.

Plus, the findings offer validation for a theory about how planets affect the orbits of their moons. Previous theories have stated that moons farther out from a planet migrate more slowly than moons closer in. The assumption was that the planet’s gravity would have a greater affect on moons that were closer, which sounds logical. But that view came into dispute four years ago, thanks to theoretical astrophysicist Jim Fuller at Caltech. He predicted that outer moons and inner moons should actually migrate at similar rates, because outer moons have a different orbit pattern linked to the “wobble” of a planet. That wobble can sling inner moons outward. Fuller said:

The new measurements imply that these kind of planet-moon interactions can be more prominent than prior expectations and that they can apply to many systems, such as other planetary moon systems, exoplanets – those outside our solar system – and even binary star systems, where stars orbit each other.

Man in blue shirt with brown terrain behind him.

Valery Lainey at JPL and the Paris Observatory, lead author of the new study. Image via ResearchGate.

Cassini orbited Saturn for more than 13 years, collecting vast amounts of data and taking thousands of images. The mission ended in September 2017 after the spacecraft finally ran out of fuel. By design, Cassini plummeted into Saturn’s deep, tumultuous clouds to burn up so as to not risk contaminating any of the moons, especially Enceladus or Titan, with any stray microbes from Earth that may have still been onboard. Cassini revolutionized our knowledge about the Saturn system, and as this study shows, there is still much to learn.

Bottom line: New study shows that Titan is moving away from Saturn 100 times faster than first thought.

Source: Resonance locking in giant planets indicated by the rapid orbital expansion of Titan

Via Jet Propulsion Laboratory



from EarthSky https://ift.tt/3dujkPS
Large banded sphere with dark curved lines, a long thin straight line and smaller darker sphere in front of it, on black background.

Titan orbiting Saturn, as seen by the Cassini spacecraft on May 12, 2012. Image via NASA/ JPL-Caltech/ Space Science Institute.

Researchers knew Saturn’s moon, Titan, was moving away from its planet, just as Earth’s moon gradually orbits farther from Earth. But – while Titan’s outward drift is still extremely slow – this large moon is now known to be moving away from Saturn 100 times faster than previously thought. That’s according to a June 2020 announcement by scientists in the U.S., France and Italy.

The peer-reviewed findings were published on June 8 in the journal Nature Astronomy.

The rate of Titan’s movement away from Saturn had been thought to be well understood, but as often happens in science, a new discovery has upended that idea. The discovery was made via a new analysis of data from the Cassini spacecraft, which orbited Saturn from 2004 to 2017. The data show Titan moving outward at about 4 inches (11 centimeters) per year.

That might not sound like a lot, but it’s significantly faster than the rate at which our moon drifts away from Earth. Our moon is drifting outward at only about 1.5 inches (3.8 centimeters) each year.

Mottled green and brown sphere on black background.

Titan’s surface as seen in infrared via Cassini on November 13, 2015. Titan is completely surrounded by thick haze, but Cassini’s radar penetrated the haze to reveal surface details. Image via NASA/ JPL/ University of Arizona/ University of Idaho.

The researchers reached this conclusion after studying images of stars sent back by Cassini. They mapped the background stars and tracked the position of Titan among them. Those images were then compared to a completely separate dataset, Cassini’s radio science data. Cassini sent radio waves back to Earth during 10 close flybys that the spacecraft conducted of Titan between 2006 and 2016. By examining how the frequency of the radio signals was affected by interactions with its environment in space, the researchers could estimate how Titan’s orbit evolved and changed over the past few billion years. Study coauthor Paolo Tortora, of Italy’s University of Bologna, explained in a statement:

By using two completely different datasets, we obtained results that are in full agreement, and also in agreement with Jim Fuller’s theory, which predicted a much faster migration of Titan.

Why do moons move away from their planets, anyway?

Large sphere with rings and line of very tiny spheres, with text annotations, on grayish background.

Titan is one of the outer moons of Saturn, orbiting well beyond the main rings and out past Rhea. Image via NASA/ JPL/ Wikipedia.

As a moon orbits a planet, its gravity tugs a bit on the planet – a process called tidal friction – creating strain and a resulting very slight bulge on the planet. On Earth, this bulge happens most noticably in our oceans – called a tidal bulge – and causes the cycle of high and low tides, but planets without oceans can bulge, too. This cyclic process of bulging and then subsequent relaxing creates a lot of energy over a long period of time. Tidal friction, however, also prevents the tidal bulge on Earth from remaining directly beneath the moon; instead it is carried along with the rotation of the Earth. The energy, created by mutual attraction between the moon and the material in the bulge, accelerates the moon slightly in its orbit. This causes the moon to drift a tiny bit farther away from Earth over time.

The new result also has implications for the age of the entire Saturn system. It’s still uncertain just how old Saturn’s rings are, as well as the planet’s moons. Right now, Titan is 759,000 miles (1.2 million kilometers) from Saturn; if the new measurement of the moon’s drift rate is correct, it means that Titan must have once been closer to Saturn than previously understood, and that Titan has migrated to its current position far out from the planet. In other words, Titan must have gone from being an inner moon to being an outer moon.

The new result further implies that the entire Saturn system of moons expanded faster than thought. Valery Lainey, lead author of the new study, formerly a scientist at the Jet Propulsion Laboratory (JPL) and now at the Paris Observatory at PSL University, stated:

This result brings an important new piece of the puzzle for the highly debated question of the age of the Saturn system and how its moons formed.

Large banded sphere with rings, a smaller reddish sphere and spacecraft with dish antenna and long solar panel, on black background.

Artist’s concept of Cassini near Titan. Image via Kevin Gill/ Flickr/ Smithsonian Magazine.

Plus, the findings offer validation for a theory about how planets affect the orbits of their moons. Previous theories have stated that moons farther out from a planet migrate more slowly than moons closer in. The assumption was that the planet’s gravity would have a greater affect on moons that were closer, which sounds logical. But that view came into dispute four years ago, thanks to theoretical astrophysicist Jim Fuller at Caltech. He predicted that outer moons and inner moons should actually migrate at similar rates, because outer moons have a different orbit pattern linked to the “wobble” of a planet. That wobble can sling inner moons outward. Fuller said:

The new measurements imply that these kind of planet-moon interactions can be more prominent than prior expectations and that they can apply to many systems, such as other planetary moon systems, exoplanets – those outside our solar system – and even binary star systems, where stars orbit each other.

Man in blue shirt with brown terrain behind him.

Valery Lainey at JPL and the Paris Observatory, lead author of the new study. Image via ResearchGate.

Cassini orbited Saturn for more than 13 years, collecting vast amounts of data and taking thousands of images. The mission ended in September 2017 after the spacecraft finally ran out of fuel. By design, Cassini plummeted into Saturn’s deep, tumultuous clouds to burn up so as to not risk contaminating any of the moons, especially Enceladus or Titan, with any stray microbes from Earth that may have still been onboard. Cassini revolutionized our knowledge about the Saturn system, and as this study shows, there is still much to learn.

Bottom line: New study shows that Titan is moving away from Saturn 100 times faster than first thought.

Source: Resonance locking in giant planets indicated by the rapid orbital expansion of Titan

Via Jet Propulsion Laboratory



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The secrets of night-shining clouds

High, rippled, shining clouds above waterway in twilight, man standing on beach.

View at EarthSky Community Photos. | Noctilucent – or night-shining – clouds just after midnight on June 16, 2020. Nature photographer Ruslan Merzlyakov in Limfjord, Denmark, said these clouds were: ” … disturbed by the high-altitude turbulence.” Thank you, Ruslan!

Every year – from May through August in the Northern Hemisphere, and from November through February in the Southern Hemisphere – people at high latitudes report seeing noctilucent or night-shining clouds. We read at SpaceWeather.com this weekend that these beautiful clouds have now descended to their lowest latitude of the 2020 season so far: +44 degrees north in Bend, Oregon. Bend resident Roy Reynolds, who photographed the glowing clouds on June 18, 2020, told SpaceWeather:

I woke up at 3:30 a.m. to a very bright sky shining through the shades. I got up to take a look and was surprised to find noctilucent clouds. I live in Bend Oregon and since living here (18 years) have seen this only two other times. Beautiful.

Noctilucent clouds typically descend even lower after the summer solstice, according to Tony Phillips of SpaceWeather.com. If you’re at a northerly latitude, now is a good time to watch for them!

Close shot of swirling narrow light blue clouds against a dark blue sky.

View at EarthSky Community Photos. | Menno van der Haven reported from Waddinxveen, the Netherlands, on June 21, 2020: “Last night, the ‘evening view’ of noctilucent clouds in the northwest was quite small and weak. However, if you use a zoom lens and overexpose with a certain amount, you often see some pretty curls. One in particular resembled a corkscrew and also behaved like this …” Thank you, Meeno!

Diagram of light shining from the sun, bouncing off high clouds to a location over the horizon from the sun.

When the sun is below the ground horizon but visible from the high altitude of noctilucent clouds, sunlight illuminates these clouds, causing them to glow in the dark night sky. Illustration via NASA.

What are noctilucent clouds? Noctilucent clouds form in the highest reaches of the atmosphere – the mesosphere – as much as 50 miles (80 km) above the Earth’s surface. They’re thought to be made of ice crystals that form on fine dust particles from meteors. They can only form when temperatures are incredibly low and when there’s water available to form ice crystals.

Why do these clouds – which require such cold temperatures – form in the summer? It’s because of the dynamics of the atmosphere. You actually get the coldest temperatures of the year near the poles in summer at that height in the mesosphere.

Here’s how it works: during summer, air close to the ground gets heated and rises. Since atmospheric pressure decreases with altitude, the rising air expands. When the air expands, it also cools down. This, along with other processes in the upper atmosphere, drives the air even higher causing it to cool even more. As a result, temperatures in the mesosphere can plunge to as low as -210 degrees Fahrenheit (-134 degrees Celsius).

In the Northern Hemisphere, the mesosphere often reaches these temperatures by mid-May, in most years.

Since the clouds are so sensitive to the atmospheric temperatures, they can act as a proxy for information about the wind circulation that causes these temperatures. First of all, they can tell scientists that the circulation exists, and also tell us something about the strength of the circulation.

How can I see noctilucent clouds? If you want to see the clouds, what steps should you take? Remember, you have to be at a relatively high latitude on Earth to see them: typically between about 45 degrees and 60 degrees north or south latitude, although the clouds can sometimes be seen at lower latitudes, particularly following the solstices.

For best results, look for these clouds from about May through August in the Northern Hemisphere, and from November through February in the Southern Hemisphere.

Noctilucent clouds are primarily visible when the sun is just below the horizon, say, from about 90 minutes to about two hours after sunset or before sunrise. At such times, when the sun is below the ground horizon but visible from the high altitude of noctilucent clouds, sunlight illuminates these clouds, causing them to glow in the dark night sky.

Shimmery pale blue to white clouds in a night sky, with silhouetted trees in foreground.

View at EarthSky Community Photos. | Marek Nikodem captured this image at 11:59 p.m. on June 16, 2020, near Szubin, Poland. He wrote: “The noctilucent clouds were visible all night, from dusk to dawn.”

Scientists studying these clouds have included those from NASA’s Aeronomy of Ice in the Mesosphere (AIM) satellite. This satellite, launched in 2007, has observed noctilucent clouds using several onboard instruments to collect information such as temperature, atmospheric gases, ice crystal size and changes in the clouds, as well as the amount of meteoric space dust that enters the atmosphere. You can find out what they are learning at NASA’s AIM page.

Black space, shining ripply layer of clouds, dark orange narrow stripe above black silhouette of Earth.

Noctilucent clouds can be seen from space, too. Astronauts in the International Space Station (ISS) took this photo on January 5, 2013, when ISS was over the Pacific Ocean south of French Polynesia. Below the brightly-lit noctilucent clouds, across the center of the image, the pale orange band is the stratosphere. Image via NASA.

Bottom line: Noctilucent or night-shining clouds are seen during summer in Earth’s high-latitude regions. They form in the highest reaches of the atmosphere – the mesosphere – as much as 50 miles (80 km) above the surface.

Visit SpaceWeather’s RealTime Noctilucent Cloud Gallery

Visit the Facebook page Noctilucent Clouds Around the World



from EarthSky https://ift.tt/3dhviw0
High, rippled, shining clouds above waterway in twilight, man standing on beach.

View at EarthSky Community Photos. | Noctilucent – or night-shining – clouds just after midnight on June 16, 2020. Nature photographer Ruslan Merzlyakov in Limfjord, Denmark, said these clouds were: ” … disturbed by the high-altitude turbulence.” Thank you, Ruslan!

Every year – from May through August in the Northern Hemisphere, and from November through February in the Southern Hemisphere – people at high latitudes report seeing noctilucent or night-shining clouds. We read at SpaceWeather.com this weekend that these beautiful clouds have now descended to their lowest latitude of the 2020 season so far: +44 degrees north in Bend, Oregon. Bend resident Roy Reynolds, who photographed the glowing clouds on June 18, 2020, told SpaceWeather:

I woke up at 3:30 a.m. to a very bright sky shining through the shades. I got up to take a look and was surprised to find noctilucent clouds. I live in Bend Oregon and since living here (18 years) have seen this only two other times. Beautiful.

Noctilucent clouds typically descend even lower after the summer solstice, according to Tony Phillips of SpaceWeather.com. If you’re at a northerly latitude, now is a good time to watch for them!

Close shot of swirling narrow light blue clouds against a dark blue sky.

View at EarthSky Community Photos. | Menno van der Haven reported from Waddinxveen, the Netherlands, on June 21, 2020: “Last night, the ‘evening view’ of noctilucent clouds in the northwest was quite small and weak. However, if you use a zoom lens and overexpose with a certain amount, you often see some pretty curls. One in particular resembled a corkscrew and also behaved like this …” Thank you, Meeno!

Diagram of light shining from the sun, bouncing off high clouds to a location over the horizon from the sun.

When the sun is below the ground horizon but visible from the high altitude of noctilucent clouds, sunlight illuminates these clouds, causing them to glow in the dark night sky. Illustration via NASA.

What are noctilucent clouds? Noctilucent clouds form in the highest reaches of the atmosphere – the mesosphere – as much as 50 miles (80 km) above the Earth’s surface. They’re thought to be made of ice crystals that form on fine dust particles from meteors. They can only form when temperatures are incredibly low and when there’s water available to form ice crystals.

Why do these clouds – which require such cold temperatures – form in the summer? It’s because of the dynamics of the atmosphere. You actually get the coldest temperatures of the year near the poles in summer at that height in the mesosphere.

Here’s how it works: during summer, air close to the ground gets heated and rises. Since atmospheric pressure decreases with altitude, the rising air expands. When the air expands, it also cools down. This, along with other processes in the upper atmosphere, drives the air even higher causing it to cool even more. As a result, temperatures in the mesosphere can plunge to as low as -210 degrees Fahrenheit (-134 degrees Celsius).

In the Northern Hemisphere, the mesosphere often reaches these temperatures by mid-May, in most years.

Since the clouds are so sensitive to the atmospheric temperatures, they can act as a proxy for information about the wind circulation that causes these temperatures. First of all, they can tell scientists that the circulation exists, and also tell us something about the strength of the circulation.

How can I see noctilucent clouds? If you want to see the clouds, what steps should you take? Remember, you have to be at a relatively high latitude on Earth to see them: typically between about 45 degrees and 60 degrees north or south latitude, although the clouds can sometimes be seen at lower latitudes, particularly following the solstices.

For best results, look for these clouds from about May through August in the Northern Hemisphere, and from November through February in the Southern Hemisphere.

Noctilucent clouds are primarily visible when the sun is just below the horizon, say, from about 90 minutes to about two hours after sunset or before sunrise. At such times, when the sun is below the ground horizon but visible from the high altitude of noctilucent clouds, sunlight illuminates these clouds, causing them to glow in the dark night sky.

Shimmery pale blue to white clouds in a night sky, with silhouetted trees in foreground.

View at EarthSky Community Photos. | Marek Nikodem captured this image at 11:59 p.m. on June 16, 2020, near Szubin, Poland. He wrote: “The noctilucent clouds were visible all night, from dusk to dawn.”

Scientists studying these clouds have included those from NASA’s Aeronomy of Ice in the Mesosphere (AIM) satellite. This satellite, launched in 2007, has observed noctilucent clouds using several onboard instruments to collect information such as temperature, atmospheric gases, ice crystal size and changes in the clouds, as well as the amount of meteoric space dust that enters the atmosphere. You can find out what they are learning at NASA’s AIM page.

Black space, shining ripply layer of clouds, dark orange narrow stripe above black silhouette of Earth.

Noctilucent clouds can be seen from space, too. Astronauts in the International Space Station (ISS) took this photo on January 5, 2013, when ISS was over the Pacific Ocean south of French Polynesia. Below the brightly-lit noctilucent clouds, across the center of the image, the pale orange band is the stratosphere. Image via NASA.

Bottom line: Noctilucent or night-shining clouds are seen during summer in Earth’s high-latitude regions. They form in the highest reaches of the atmosphere – the mesosphere – as much as 50 miles (80 km) above the surface.

Visit SpaceWeather’s RealTime Noctilucent Cloud Gallery

Visit the Facebook page Noctilucent Clouds Around the World



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Emperor penguins are good dads

Close-up view of an egg resting on the feet of a male penguin with his head bent to touoh it with his beak.

Emperor penguin dad keeps his egg warm while waiting for his chick to hatch. Image via Tony Bojkovski/ Australian Antarctic Division.

We know there are some awesome dads out there among you humans. But the nominees for best dad must surely include emperor penguin males, who go to extraordinary extremes for their offspring, enduring bitter cold and darkness during winter on Earth’s coldest continent, Antarctica. It’s winter in Antarctica now. If you could visit, you’d find emperor penguin males gathered in colonies near the coast. They’re tightly huddled together to stay warm in temperatures that can dip as low as -40 degrees F (-40 degrees C), with winds as strong as 90 miles per hour (144 km/ hour). For the next two months, these devoted dads will each incubate a single egg that holds his offspring. Each dad will also care for his chick when it first hatches. Penguin dads do all this while surviving only on fat reserves from the previous summer.

Penguins, with brooding fathers in the foreground and males' and females' routes back and forth to the sea.

A diagram of the emperor penguin’s breeding schedule. Image via Zina Deretsky/ NSF/ Wikimedia Commons.

Many emperor penguins standing close together leaning into the wind and almost obscured by blowing snow.

Emperor penguins huddle during a blizzard. Image via Frederique Olivier/ Australian Antarctic Division.

For much of the summer, male and female emperor penguins are at sea, feeding on fish, squid, and krill. For the males, it’s an opportunity to accumulate fat reserves they’ll need to survive in winter.

In April, autumn in the Southern Hemisphere, adult emperor penguins begin congregating at their respective nesting areas, traveling inland as much as 30 to 75 miles (50 to 120 kilometers) from the pack ice.

Following courtship displays, the birds form pairs and mate. In May and early June, the female lays a single egg. The egg is pear-shaped with a pale greenish-white tint, almost 5 inches long and 3 inches wide (12 and 8 cm, respectively). The female penguin passes the egg to her mate, then heads back to sea. She’ll be back in two months to continue her parental duties.

Until then, the males are on their own for winter in Antarctica. Their dense insulating feathers and fat accumulations, however, aren’t enough to keep them alive. To conserve heat, the emperor penguin males huddle close together. Each colony varies in size, and could number several hundred birds. They take turns moving from the edge of the colony, which is colder, to the warmer center.

The egg, meanwhile, is snugly tucked away in dad’s brood pouch, resting on his feet. If all goes well, the chick will hatch in 65 to 75 days. Hatching will likely happen a few days before mom returns. During this time, the chick, weighing just 11 ounces (312 grams) with only a thin layer of down feathers, is completely dependent on dad for warmth and protection. Until mom returns to start feeding the chick, he also provides his offspring with what’s called crop milk, a high fat and protein secretion.

Mom returns to the colony, sometime between mid-July and early August, after spending the last two months feeding at sea. She takes over caring for the chick while dad, having not eaten for about 120 days, heads to the ocean to start feeding. By now, he has dropped in weight to around 50 pounds (23 kilograms) from his summer weight of about 84 pounds (38 kilograms).

Dad will spend about three to four weeks feeding at sea, then return to his mate. From then on, the pair takes turns caring for their little one, keeping it warm and feeding it regurgitated krill, fish, and squid.

Two adult emperor penguins standing very close together with a little chick between them.

An emperor penguin pair with their chick. Image via Gary Miller / Australian Antarctic Division.

About 50 days after hatching, the colony’s chicks, now sporting a thick downy coat, are corralled together for warmth and protection in what’s called a crèche – that’s emperor penguin daycare where the chicks wait for their parents to return from the sea to feed them.

In early November, as spring yields to summer in Antarctica, the chicks undergo a two-month moult, replacing their downy chick feathers with juvenile plumage that will enable them to swim.

By December and January, the chicks are nearly as big as their parents. At this point, mom and dad have done their job and will stop feeding the kids. The youngsters will then venture to sea to start foraging on their own. In about three to four years, they will be old enough to start breeding.

A close-up view of a fuzzy gray, black and white chick sitting atop a parent's legs.

An emperor penguin chick. Image via Robin Mundy/ Australian Antarctic Division.

Bottom line: Male emperor penguins are some of the best dads in the world. They incubate their eggs for over two months in the frigid Antarctic winter.



from EarthSky https://ift.tt/3ep5Zto
Close-up view of an egg resting on the feet of a male penguin with his head bent to touoh it with his beak.

Emperor penguin dad keeps his egg warm while waiting for his chick to hatch. Image via Tony Bojkovski/ Australian Antarctic Division.

We know there are some awesome dads out there among you humans. But the nominees for best dad must surely include emperor penguin males, who go to extraordinary extremes for their offspring, enduring bitter cold and darkness during winter on Earth’s coldest continent, Antarctica. It’s winter in Antarctica now. If you could visit, you’d find emperor penguin males gathered in colonies near the coast. They’re tightly huddled together to stay warm in temperatures that can dip as low as -40 degrees F (-40 degrees C), with winds as strong as 90 miles per hour (144 km/ hour). For the next two months, these devoted dads will each incubate a single egg that holds his offspring. Each dad will also care for his chick when it first hatches. Penguin dads do all this while surviving only on fat reserves from the previous summer.

Penguins, with brooding fathers in the foreground and males' and females' routes back and forth to the sea.

A diagram of the emperor penguin’s breeding schedule. Image via Zina Deretsky/ NSF/ Wikimedia Commons.

Many emperor penguins standing close together leaning into the wind and almost obscured by blowing snow.

Emperor penguins huddle during a blizzard. Image via Frederique Olivier/ Australian Antarctic Division.

For much of the summer, male and female emperor penguins are at sea, feeding on fish, squid, and krill. For the males, it’s an opportunity to accumulate fat reserves they’ll need to survive in winter.

In April, autumn in the Southern Hemisphere, adult emperor penguins begin congregating at their respective nesting areas, traveling inland as much as 30 to 75 miles (50 to 120 kilometers) from the pack ice.

Following courtship displays, the birds form pairs and mate. In May and early June, the female lays a single egg. The egg is pear-shaped with a pale greenish-white tint, almost 5 inches long and 3 inches wide (12 and 8 cm, respectively). The female penguin passes the egg to her mate, then heads back to sea. She’ll be back in two months to continue her parental duties.

Until then, the males are on their own for winter in Antarctica. Their dense insulating feathers and fat accumulations, however, aren’t enough to keep them alive. To conserve heat, the emperor penguin males huddle close together. Each colony varies in size, and could number several hundred birds. They take turns moving from the edge of the colony, which is colder, to the warmer center.

The egg, meanwhile, is snugly tucked away in dad’s brood pouch, resting on his feet. If all goes well, the chick will hatch in 65 to 75 days. Hatching will likely happen a few days before mom returns. During this time, the chick, weighing just 11 ounces (312 grams) with only a thin layer of down feathers, is completely dependent on dad for warmth and protection. Until mom returns to start feeding the chick, he also provides his offspring with what’s called crop milk, a high fat and protein secretion.

Mom returns to the colony, sometime between mid-July and early August, after spending the last two months feeding at sea. She takes over caring for the chick while dad, having not eaten for about 120 days, heads to the ocean to start feeding. By now, he has dropped in weight to around 50 pounds (23 kilograms) from his summer weight of about 84 pounds (38 kilograms).

Dad will spend about three to four weeks feeding at sea, then return to his mate. From then on, the pair takes turns caring for their little one, keeping it warm and feeding it regurgitated krill, fish, and squid.

Two adult emperor penguins standing very close together with a little chick between them.

An emperor penguin pair with their chick. Image via Gary Miller / Australian Antarctic Division.

About 50 days after hatching, the colony’s chicks, now sporting a thick downy coat, are corralled together for warmth and protection in what’s called a crèche – that’s emperor penguin daycare where the chicks wait for their parents to return from the sea to feed them.

In early November, as spring yields to summer in Antarctica, the chicks undergo a two-month moult, replacing their downy chick feathers with juvenile plumage that will enable them to swim.

By December and January, the chicks are nearly as big as their parents. At this point, mom and dad have done their job and will stop feeding the kids. The youngsters will then venture to sea to start foraging on their own. In about three to four years, they will be old enough to start breeding.

A close-up view of a fuzzy gray, black and white chick sitting atop a parent's legs.

An emperor penguin chick. Image via Robin Mundy/ Australian Antarctic Division.

Bottom line: Male emperor penguins are some of the best dads in the world. They incubate their eggs for over two months in the frigid Antarctic winter.



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It’s summer. What’s noon to you?

Sun in blue sky between 3 buildings.

Image via ©iStockphoto.com/ KavalenkavaVolha/ timeanddate

When is it noon for you? That’s not as easy a question to answer as you might think! What do you mean by noon? Do you define it by your clock or wristwatch? Or the gnawing in your stomach that says it’s time for lunch? Well, you might want to think again!

We in the Northern Hemisphere typically say the first day of summer comes at the June solstice, which, in 2020, fell on June 20. But – no matter what day it is – when noon occurs depends in part on your location and in part on your definition of noon. On the day of a June solstice, noontime shadows are just a hair shorter than the day before. That’s because, at the June solstice, Earth’s Northern Hemisphere is tilted most sunward for the year, and the sun rises highest in our Northern Hemisphere sky, yielding the year’s shortest midday shadows.

Photo by EarthSky Facebook friend Muhammad Mohsin Jameel. He wrote,

Photo by EarthSky Facebook friend Muhammad Mohsin Jameel. He wrote: “Shortest shadows at noon, summer solstice — in Islamabad, Pakistan!”

Notice that I said midday, rather than just noon. Usually when most of us say noon, we mean 12 p.m. on the clock. But that may not be what astronomers mean by noon.

Around the time of the June solstice, shadows are shortest when the sun is due south in the sky. We say that the sun is crossing the meridian. But the sun’s meridian crossing rarely occurs at exactly straight-up noon, according to the clock. The time at which the sun crosses the meridian used to be called high noon because that is when the sun is highest in the sky. Today we astronomers sometimes refer to it as transit time or local solar noon.

I have assigned my students a project in which they compare the height of the sun at local solar noon to that in another location in New Mexico. This simulates an observation by Eratosthenes more than 2,000 years ago, through which he obtained the first accurate measurement of the size of the Earth.

You can construct a simple device called a gnomon (pronounced NO-mun) or shadow stick to calculate how high the sun is, with simple trigonometry. Just measure the height of the gnomon (H) and the length of the shadow (L) at local solar noon. Then the angular height of the sun is the arctangent of H/L. For accuracy, the gnomon must be very straight, the ground level, and the measurements precise. Here in Denver, it will be about 73.75 degrees high. How high is it where you live?

But before you can make the measurement, you need to know when local solar noon occurs where you are located. Before the invention of the telegraph in the 19th century, every locality defined noon by the time when the sun crossed the meridian. Because of geographical location, when the sun crosses the meridian as seen in Denver, in Grand Junction (about 180 miles to the west) the sun hasn’t reached the meridian yet, and won’t for another 14 minutes or so. It takes about 14 minutes for the Earth to turn far enough to bring the sun to the meridian in Grand Junction after it passes the meridian in Denver.

At a time when the fastest form of communication was a stagecoach or the Pony Express, this difference in time did not matter. But when near-instantaneous communication became available with the telegraph, people gradually realized that a standardization of time was necessary. Thus the concept of time zones was developed in 1884, but not adopted officially in the U.S. until 1918.

But even considering time zones, the actual time of transit varies through the year because of the Earth’s varying speed in its orbit around the sun. At times the planet has to turn a bit more from one transit to the next, and at times it needs to turn a bit less. This is because the change in Earth’s speed (due to varying distance to the sun through the year) causes the sun’s apparent motion across the sky to change. There is also a variation due to the tilt of the Earth and how that affects the sun’s apparent motion in the sky. That means that the real sun (which crosses the meridian at local solar noon) is as much as 16 minutes faster or slower than the steady but fictitious mean sun that defines clock-time noon for the various time zones.

And then of course there is the complication of “Daylight Saving Time,” which really saves nothing but merely offsets the clocks by an hour.

Now you can make all the calculations to figure out transit time or local solar noon for yourself, but you don’t need to go to the trouble. Just go to the U.S. Naval Observatory website and have it calculate it for you.

Here are some examples of typical transit times, or local solar noons, for June 21, as calculated by the Naval Observatory website:

Eastern Time Zone Central Time Zone Mountain Time Zone Pacific Time Zone
New York 12:57 p.m Chicago 12:53 p.m. Denver 1:02 p.m. Los Angeles 12:55 p.m.
Miami 1:23 p.m. Little Rock 1:11 p.m. Albuquerque 1:08 p.m. Seattle 1:11 p.m.
Detroit 1:34 p.m. Kansas City (KS) 1:21 p.m. Salt Lake City 1:29 p.m. San Francisco 1:12 p.m.
Atlanta 1:39 p.m. Houston 1:23 p.m. Phoenix 12:30 p.m. * Portland 1:12 p.m.

* Note that Phoenix is on Standard, not Daylight, Time. Also note that the exact moment of the summer solstice is not related to the time of local solar noon.

Oh, and by the way, if you’re out in the sun – contemplating the passage of the sun and the time of noon for you – don’t forget your sunscreen.

Bottom line: What is the definition of noon? An exploration of how astronomers think about noontime.



from EarthSky https://ift.tt/2V4icMk
Sun in blue sky between 3 buildings.

Image via ©iStockphoto.com/ KavalenkavaVolha/ timeanddate

When is it noon for you? That’s not as easy a question to answer as you might think! What do you mean by noon? Do you define it by your clock or wristwatch? Or the gnawing in your stomach that says it’s time for lunch? Well, you might want to think again!

We in the Northern Hemisphere typically say the first day of summer comes at the June solstice, which, in 2020, fell on June 20. But – no matter what day it is – when noon occurs depends in part on your location and in part on your definition of noon. On the day of a June solstice, noontime shadows are just a hair shorter than the day before. That’s because, at the June solstice, Earth’s Northern Hemisphere is tilted most sunward for the year, and the sun rises highest in our Northern Hemisphere sky, yielding the year’s shortest midday shadows.

Photo by EarthSky Facebook friend Muhammad Mohsin Jameel. He wrote,

Photo by EarthSky Facebook friend Muhammad Mohsin Jameel. He wrote: “Shortest shadows at noon, summer solstice — in Islamabad, Pakistan!”

Notice that I said midday, rather than just noon. Usually when most of us say noon, we mean 12 p.m. on the clock. But that may not be what astronomers mean by noon.

Around the time of the June solstice, shadows are shortest when the sun is due south in the sky. We say that the sun is crossing the meridian. But the sun’s meridian crossing rarely occurs at exactly straight-up noon, according to the clock. The time at which the sun crosses the meridian used to be called high noon because that is when the sun is highest in the sky. Today we astronomers sometimes refer to it as transit time or local solar noon.

I have assigned my students a project in which they compare the height of the sun at local solar noon to that in another location in New Mexico. This simulates an observation by Eratosthenes more than 2,000 years ago, through which he obtained the first accurate measurement of the size of the Earth.

You can construct a simple device called a gnomon (pronounced NO-mun) or shadow stick to calculate how high the sun is, with simple trigonometry. Just measure the height of the gnomon (H) and the length of the shadow (L) at local solar noon. Then the angular height of the sun is the arctangent of H/L. For accuracy, the gnomon must be very straight, the ground level, and the measurements precise. Here in Denver, it will be about 73.75 degrees high. How high is it where you live?

But before you can make the measurement, you need to know when local solar noon occurs where you are located. Before the invention of the telegraph in the 19th century, every locality defined noon by the time when the sun crossed the meridian. Because of geographical location, when the sun crosses the meridian as seen in Denver, in Grand Junction (about 180 miles to the west) the sun hasn’t reached the meridian yet, and won’t for another 14 minutes or so. It takes about 14 minutes for the Earth to turn far enough to bring the sun to the meridian in Grand Junction after it passes the meridian in Denver.

At a time when the fastest form of communication was a stagecoach or the Pony Express, this difference in time did not matter. But when near-instantaneous communication became available with the telegraph, people gradually realized that a standardization of time was necessary. Thus the concept of time zones was developed in 1884, but not adopted officially in the U.S. until 1918.

But even considering time zones, the actual time of transit varies through the year because of the Earth’s varying speed in its orbit around the sun. At times the planet has to turn a bit more from one transit to the next, and at times it needs to turn a bit less. This is because the change in Earth’s speed (due to varying distance to the sun through the year) causes the sun’s apparent motion across the sky to change. There is also a variation due to the tilt of the Earth and how that affects the sun’s apparent motion in the sky. That means that the real sun (which crosses the meridian at local solar noon) is as much as 16 minutes faster or slower than the steady but fictitious mean sun that defines clock-time noon for the various time zones.

And then of course there is the complication of “Daylight Saving Time,” which really saves nothing but merely offsets the clocks by an hour.

Now you can make all the calculations to figure out transit time or local solar noon for yourself, but you don’t need to go to the trouble. Just go to the U.S. Naval Observatory website and have it calculate it for you.

Here are some examples of typical transit times, or local solar noons, for June 21, as calculated by the Naval Observatory website:

Eastern Time Zone Central Time Zone Mountain Time Zone Pacific Time Zone
New York 12:57 p.m Chicago 12:53 p.m. Denver 1:02 p.m. Los Angeles 12:55 p.m.
Miami 1:23 p.m. Little Rock 1:11 p.m. Albuquerque 1:08 p.m. Seattle 1:11 p.m.
Detroit 1:34 p.m. Kansas City (KS) 1:21 p.m. Salt Lake City 1:29 p.m. San Francisco 1:12 p.m.
Atlanta 1:39 p.m. Houston 1:23 p.m. Phoenix 12:30 p.m. * Portland 1:12 p.m.

* Note that Phoenix is on Standard, not Daylight, Time. Also note that the exact moment of the summer solstice is not related to the time of local solar noon.

Oh, and by the way, if you’re out in the sun – contemplating the passage of the sun and the time of noon for you – don’t forget your sunscreen.

Bottom line: What is the definition of noon? An exploration of how astronomers think about noontime.



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Solstice sun near Taurus-Gemini border

At the June 20, 2020, solstice, the sun is in front of the constellation Taurus the Bull. On June 21, at around 09:00 UTC, the sun moves out of the constellation Taurus and into the constellation Gemini the Twins. In other words, the sun on the June solstice shines very close to the Taurus-Gemini border.

Relative to the backdrop stars of the zodiac, the sun on the solstice always appears a tiny bit westward of the previous year’s solstice sun.

Star chart of constellation Gemini with stars black on white background and ecliptic running across.

As seen from Earth, the sun travels in front of the constellation Gemini the Twins from June 22, 2019 at around 03:00 UTC, until July 21 at about 07:00 UTC. Translate UTC to your time. The solstice point is at the intersection of 6h with the ecliptic.

Thirty-one years ago, in the year 1989, the sun was in front of the constellation Gemini on the June solstice. Then in the following year, in 1990, the June solstice sun shone in front of the constellation Taurus, the constellation to the immediate west of Gemini. The sun on the June solstice will continue to shine in front of Taurus until the year 4609, when the June solstice sun will finally move into the constellation Aries, the constellation to the immediate west of Taurus.

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Sign versus constellation

Please keep in mind that we’re talking about constellations – not astrological signs – of the zodiac.

By definition, the sun occupies the first point of (the sign) Cancer on the June solstice, irrespective of which constellation backdrops the sun at this time. Also, the sun reaches the first point of (the sign) Leo when it resides 30 degrees east of the June solstice point along the ecliptic – regardless of which constellation backdrops the sun.

Signs are fixed relative to the solstice and equinox points. On the other hand, the solstice and equinox points slowly but surely move westward relative to the zodiacal constellations.

The solstice and equinox points go full circle through the constellations of the zodiac in about 26,000 years.

Bottom line: On June 21, 2020, at around 09:00 UTC, the sun moves out of the constellation Taurus the Bull and into Gemini the Twins.

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At the June 20, 2020, solstice, the sun is in front of the constellation Taurus the Bull. On June 21, at around 09:00 UTC, the sun moves out of the constellation Taurus and into the constellation Gemini the Twins. In other words, the sun on the June solstice shines very close to the Taurus-Gemini border.

Relative to the backdrop stars of the zodiac, the sun on the solstice always appears a tiny bit westward of the previous year’s solstice sun.

Star chart of constellation Gemini with stars black on white background and ecliptic running across.

As seen from Earth, the sun travels in front of the constellation Gemini the Twins from June 22, 2019 at around 03:00 UTC, until July 21 at about 07:00 UTC. Translate UTC to your time. The solstice point is at the intersection of 6h with the ecliptic.

Thirty-one years ago, in the year 1989, the sun was in front of the constellation Gemini on the June solstice. Then in the following year, in 1990, the June solstice sun shone in front of the constellation Taurus, the constellation to the immediate west of Gemini. The sun on the June solstice will continue to shine in front of Taurus until the year 4609, when the June solstice sun will finally move into the constellation Aries, the constellation to the immediate west of Taurus.

Enjoying EarthSky so far? Sign up for our free daily newsletter today!

Sign versus constellation

Please keep in mind that we’re talking about constellations – not astrological signs – of the zodiac.

By definition, the sun occupies the first point of (the sign) Cancer on the June solstice, irrespective of which constellation backdrops the sun at this time. Also, the sun reaches the first point of (the sign) Leo when it resides 30 degrees east of the June solstice point along the ecliptic – regardless of which constellation backdrops the sun.

Signs are fixed relative to the solstice and equinox points. On the other hand, the solstice and equinox points slowly but surely move westward relative to the zodiacal constellations.

The solstice and equinox points go full circle through the constellations of the zodiac in about 26,000 years.

Bottom line: On June 21, 2020, at around 09:00 UTC, the sun moves out of the constellation Taurus the Bull and into Gemini the Twins.

EarthSky astronomy kits are perfect for beginners. Order today from the EarthSky store

Donate: Your support means the world to us



from EarthSky https://ift.tt/2NjkC5j