Summer solstice tale of 2 cities

Sunset over Manhattan, June 5, 2016, by Jennifer Khordi. Visit Khordi Photography on Facebook.

Around the time of the June solstice, the sun sets at virtually the same time in both New York City, New York, and St. Augustine, Florida. On June 20, 2020, the sun sets around 8:30 p.m. Eastern Daylight Time (EDT) in both places.

What’s going on here? Doesn’t the sun set later farther north at this time of year? What about the phenomenon of midnight twilight and midnight sun, after all? It’s true that – for places farther north in summer – the sun stays out longer. But St. Augustine lodges about 7.5 degrees of longitude to the west of New York City. Our planet takes about 30 minutes to rotate this 7.5 degrees.

Therefore, on any day of the year, the sun reaches its noontime position some 30 minutes later in St. Augustine than it does in New York City. For instance, on June 20, 2020, the noonday sun reaches its high point for the day at 12:57 p.m. EDT in New York City – yet in St. Augustine, solar noon comes about 30 minutes later, at 1:27 p.m. EDT.

Because New York is appreciably north of St. Augustine, New York’s afternoon daylight (from solar noon to sunset) lasts some 30 minutes longer on the day of the June solstice than it does in St. Augustine.

Thus, the longer period of daylight in New York cancels out the later noontime appearance of the sun in St. Augustine, to give both localities the same sunset time on the day of the June solstice. The table below helps to clarify.

Sunrise/solar noon/sunset times on June 20, 2020

City	Sunrise	Solar Noon	Sunset
New York	5:24 a.m.	12:57 p.m.	8:30 p.m.
St. Augustine	6:24 a.m.	1:27 p.m.	8:29 p.m.

NYC and St. Augustine both use Eastern time. But the noonday sun comes 30 minutes later to St. Augustine because it resides 7.5 degrees of longitude west of New York City.

In other words, from sunrise to sunset on the June solstice, New York City has about an hour more daylight than St. Augustine does. (That’s 30 minutes more morning daylight and 30 minutes more afternoon daylight.) Although the sunset occurs at virtually the same time for both cities, the sunrise happens an hour earlier in New York City. Look again at the sunrise/solar noon/sunset table above.

Earth’s terminator – line of sunset – nearly parallels the Eastern Seaboard on the day of the June solstice.

The image above is a simulated view of Earth as the sun is setting around the time of the June summer solstice. Note that the terminator pretty much aligns with the U. S. East Coast, providing a similar sunset time for coastal dwellers.

Enter the equinoxes

Some three – and nine – months after the June solstice, St. Augustine and New York City receive the same amount of daylight on the days of the September and March equinoxes. On the equinoxes, noontime as well as sunrise and sunset come 30 minutes later in St. Augustine than they do in New York City. The simulated view of Earth below shows the terminator – the sunrise line – running due north and south on the equinox. Neither the sunrise terminator nor sunset terminator comes anywhere close to aligning with the U.S. East Coast at either equinox.

Sunrise/solar noon/sunset times on September 22, 2020

City	Sunrise	Solar Noon	Sunset
New York	6:42 a.m.	12:49 p.m.	6:55 p.m.
St. Augustine	7:12 a.m.	1:18 p.m.	7:23 p.m.

The terminator – sunrise line – runs due north and south on the equinoxes. The sunset line, though not shown, also runs north and south. Image via Earth and Moon Viewer.

Sunrise/solar noon/sunset times on March 20, 2021

City	Sunrise	Solar Noon	Sunset
New York	6:58 a.m.	1:03 p.m.	7:08 p.m.
St. Augustine	7:28 a.m.	1:32 p.m.	7:36 p.m.

Enter the December solstice

Six months after the June solstice, it’s the December winter solstice for the Northern Hemisphere, coming yearly on or near December 21. Now, the situation is reversed from the June solstice, with St. Augustine receiving an hour more daylight than New York City.

Because St. Augustine lies appreciably south of New York City, St. Augustine’s morning daylight (from sunrise to solar noon) lasts 30 minutes longer than in New York City on the day of the December winter solstice. Thus, the more daylight in St. Augustine cancels out the earlier noontime in New York City, to give both localities the same sunrise time on the December solstice. (See sunrise/solar noon/sunset table below.)

Simulation of the line of sunrise as it hits the U.S. eastern seaboard around the December solstice. Image via U.S. Naval Observatory.

Look above at the simulated view of Earth as the sun is rising over the Eastern Seaboard of the United States on the day of the winter solstice. Note that the terminator – the sunrise line – pretty much coincides with the East Coast, giving a similar sunrise time for residents along the Atlantic Seaboard.

Sunrise/solar noon/sunset times on December 21, 2020

City	Sunrise	Solar Noon	Sunset
New York	7:16 a.m.	11:54 a.m.	4:32 p.m.
St. Augustine	7:16 a.m.	12:24 p.m.	5:30 p.m.

From sunrise to sunset on the day of the winter solstice, St. Augustine residents enjoy about an hour more daylight than those in New York City. Although the sunrise occurs at about the same time for both cities, the sunset happens an hour later in St. Augustine on the day of the winter solstice.

Bottom Line: On the day of the June summer solstice, the sun sets at the same time in both St. Augustine, Florida, and New York City, New York. However, New York City enjoys an hour more daylight. Six months later, on the day of the December solstice, it’s the exact opposite. It’s the sunrise that happens at the same time in both places, yet it’s then St. Augustine’s turn to enjoy an extra hour of sunshine.

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Sunset over Manhattan, June 5, 2016, by Jennifer Khordi. Visit Khordi Photography on Facebook.

Around the time of the June solstice, the sun sets at virtually the same time in both New York City, New York, and St. Augustine, Florida. On June 20, 2020, the sun sets around 8:30 p.m. Eastern Daylight Time (EDT) in both places.

What’s going on here? Doesn’t the sun set later farther north at this time of year? What about the phenomenon of midnight twilight and midnight sun, after all? It’s true that – for places farther north in summer – the sun stays out longer. But St. Augustine lodges about 7.5 degrees of longitude to the west of New York City. Our planet takes about 30 minutes to rotate this 7.5 degrees.

Therefore, on any day of the year, the sun reaches its noontime position some 30 minutes later in St. Augustine than it does in New York City. For instance, on June 20, 2020, the noonday sun reaches its high point for the day at 12:57 p.m. EDT in New York City – yet in St. Augustine, solar noon comes about 30 minutes later, at 1:27 p.m. EDT.

Because New York is appreciably north of St. Augustine, New York’s afternoon daylight (from solar noon to sunset) lasts some 30 minutes longer on the day of the June solstice than it does in St. Augustine.

Thus, the longer period of daylight in New York cancels out the later noontime appearance of the sun in St. Augustine, to give both localities the same sunset time on the day of the June solstice. The table below helps to clarify.

Sunrise/solar noon/sunset times on June 20, 2020

City	Sunrise	Solar Noon	Sunset
New York	5:24 a.m.	12:57 p.m.	8:30 p.m.
St. Augustine	6:24 a.m.	1:27 p.m.	8:29 p.m.

NYC and St. Augustine both use Eastern time. But the noonday sun comes 30 minutes later to St. Augustine because it resides 7.5 degrees of longitude west of New York City.

In other words, from sunrise to sunset on the June solstice, New York City has about an hour more daylight than St. Augustine does. (That’s 30 minutes more morning daylight and 30 minutes more afternoon daylight.) Although the sunset occurs at virtually the same time for both cities, the sunrise happens an hour earlier in New York City. Look again at the sunrise/solar noon/sunset table above.

Earth’s terminator – line of sunset – nearly parallels the Eastern Seaboard on the day of the June solstice.

The image above is a simulated view of Earth as the sun is setting around the time of the June summer solstice. Note that the terminator pretty much aligns with the U. S. East Coast, providing a similar sunset time for coastal dwellers.

Enter the equinoxes

Some three – and nine – months after the June solstice, St. Augustine and New York City receive the same amount of daylight on the days of the September and March equinoxes. On the equinoxes, noontime as well as sunrise and sunset come 30 minutes later in St. Augustine than they do in New York City. The simulated view of Earth below shows the terminator – the sunrise line – running due north and south on the equinox. Neither the sunrise terminator nor sunset terminator comes anywhere close to aligning with the U.S. East Coast at either equinox.

Sunrise/solar noon/sunset times on September 22, 2020

City	Sunrise	Solar Noon	Sunset
New York	6:42 a.m.	12:49 p.m.	6:55 p.m.
St. Augustine	7:12 a.m.	1:18 p.m.	7:23 p.m.

The terminator – sunrise line – runs due north and south on the equinoxes. The sunset line, though not shown, also runs north and south. Image via Earth and Moon Viewer.

Sunrise/solar noon/sunset times on March 20, 2021

City	Sunrise	Solar Noon	Sunset
New York	6:58 a.m.	1:03 p.m.	7:08 p.m.
St. Augustine	7:28 a.m.	1:32 p.m.	7:36 p.m.

Enter the December solstice

Six months after the June solstice, it’s the December winter solstice for the Northern Hemisphere, coming yearly on or near December 21. Now, the situation is reversed from the June solstice, with St. Augustine receiving an hour more daylight than New York City.

Because St. Augustine lies appreciably south of New York City, St. Augustine’s morning daylight (from sunrise to solar noon) lasts 30 minutes longer than in New York City on the day of the December winter solstice. Thus, the more daylight in St. Augustine cancels out the earlier noontime in New York City, to give both localities the same sunrise time on the December solstice. (See sunrise/solar noon/sunset table below.)

Simulation of the line of sunrise as it hits the U.S. eastern seaboard around the December solstice. Image via U.S. Naval Observatory.

Look above at the simulated view of Earth as the sun is rising over the Eastern Seaboard of the United States on the day of the winter solstice. Note that the terminator – the sunrise line – pretty much coincides with the East Coast, giving a similar sunrise time for residents along the Atlantic Seaboard.

Sunrise/solar noon/sunset times on December 21, 2020

City	Sunrise	Solar Noon	Sunset
New York	7:16 a.m.	11:54 a.m.	4:32 p.m.
St. Augustine	7:16 a.m.	12:24 p.m.	5:30 p.m.

From sunrise to sunset on the day of the winter solstice, St. Augustine residents enjoy about an hour more daylight than those in New York City. Although the sunrise occurs at about the same time for both cities, the sunset happens an hour later in St. Augustine on the day of the winter solstice.

Bottom Line: On the day of the June summer solstice, the sun sets at the same time in both St. Augustine, Florida, and New York City, New York. However, New York City enjoys an hour more daylight. Six months later, on the day of the December solstice, it’s the exact opposite. It’s the sunrise that happens at the same time in both places, yet it’s then St. Augustine’s turn to enjoy an extra hour of sunshine.

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Celebrate solstice sunrise at Stonehenge live online

View of the Heel Stone at summer solstice sunrise, as seen from inside the Stonehenge monument. Image via mysticrealms.org.

Wherever you are in the world, you can celebrate the 2020 June solstice by watching the sun rise at Stonehenge.

Every year, thousands of visitors gather at the neolithic Stonehenge monument in Wiltshire, England, to celebrate the first sunrise of the Northern Hemisphere summer. However, this year’s event has been canceled; Stonehenge is currently closed due to Covid-19. While this news is disappointing, there’s good news: For the first time, English Heritage – which has provided access to the event since 2000 – will instead stream the solstice event online.

The event starts at sunset on Saturday (20:26 UTC on June 20) and goes through sunrise on Sunday (03:53 UTC on June 21). Translate UTC to your time. Here is the official Facebook event page, where you’ll be able to watch the livestream. You can also access the event via Stonehenge on Twitter.

Experience the solstice at Stonehenge – live online – beginning at sunset on Saturday (20:26 UTC on June 20) and lasting through sunrise on Sunday (03:52 UTC on June 21). Translate UTC to your time.

For everyone's safety and wellbeing, we've had to cancel this year's summer solstice celebrations at Stonehenge.

We know how special this occasion is to so many of you, and we'll be live streaming it for free online. pic.twitter.com/zMi0NzCmbO

— English Heritage (@EnglishHeritage) May 12, 2020

Stonehenge director Nichola Tasker told The Salisbury Journal:

We hope that our live stream offers an alternative opportunity for people near and far to connect with this spiritual place at such a special time of year and we look forward to welcoming everyone back next year.

We know how strong the draw to come is for some people, but I would take this opportunity to say please do not travel to Stonehenge this summer solstice, but watch it online instead.

Stonehenge has been closed since March 18, 2020, as the British government introduced measures to combat the coronavirus pandemic. Image via The Salisbury Journal

Stonehenge, in England, was built in three phases between about 3,000 B.C. and 1,600 B.C., and its purpose remains under study. However, it’s known that if you stand in just the right place inside the Stonehenge monument on the day of the northern summer solstice, facing northeast through the entrance towards a rough-hewn stone outside the circle – known as the Heel Stone – you will see the sun rise above the Heel Stone, as illustrated in the image at the top.

Here’s a video tour of Stonehenge from English Heritage on Facebook:

The BBC reported that about 12,000 people attended the neolithic site in Wiltshire to watch the sun rise at on June 20, 2016. Image via BBC.

In the Northern Hemisphere at this time of year, the sun is shining on us most directly at midday. Except at high northerly latitudes, above the Arctic Circle – where daylight is continuous for many months – the day on which the summer solstice occurs is the day of the year with the longest period of daylight. Meanwhile, it is the shortest day for Earth’s Southern Hemisphere.

At the northern summer solstice – always around June 20 – the sun’s path stops moving northward in the sky. For us in the Northern Hemisphere, it’s the day on which the days stop growing longer and will soon begin to shorten again. For this reason, the summer solstice is a time of festivals and celebrations around this hemisphere of Earth.

Summer solstice at Stonehenge via stonehengetrips.com.

The Stonehenge Free Festival was a British free festival from 1974 to 1984 held at Stonehenge during the month of June, and culminating on the summer solstice. The festival was a celebration of various alternative cultures. The Tibetan Ukrainian Mountain Troupe, The Tepee People, Circus Normal, the Peace Convoy, New Age Travellers and the Wallys were notable counterculture attendees. Image via Wikipedia.

Stonehenge is tied to the winter solstice, too. At Stonehenge on the day of the northern winter solstice (always around December 20), people watch as the sun sets in the midst of three great stones – known as the Trilithon – consisting of two large vertical stones supporting a third, horizontal stone across the top.

In the case of Stonehenge, this great Trilithon faces outwards from the center of the monument, with its smooth flat face turned toward the midwinter sun. In fact, the primary axis of Stonehenge seems to have been carefully aligned on a sight-line pointing to the winter solstice sunset.

EarthSky Facebook friend Buddy Puckhaber of South Carolina took this photo of Stonehenge in the early morning, while visiting. He said, “My wife and I were among the first visitors of the day.” Thank you, Buddy!

This huge megalithic monument shows how carefully our ancestors watched the sun. Astronomical observations such as these surely controlled human activities such as the mating of animals, the sowing of crops and the metering of winter reserves between harvests. Stonehenge is perhaps the most famous of of the ancient astronomical monuments found around the world.

When Stonehenge was first opened to the public it was possible to walk among the stones – even climb on them.

The stones were roped off in 1977 as a result of serious erosion. Today, visitors to the monument are not permitted to touch the stones, but, if you go, you will be able to walk around the monument from a short distance away. Visitors can also make special bookings to access the stones throughout the year.

Another beautiful shot of Stonehenge from our friend Buddy Puckhaber. Thank you, Buddy.

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

Bottom line: How to celebrate the 2020 June solstice sunrise at Stonehenge live online.

from EarthSky https://ift.tt/3fBO0Qx

View of the Heel Stone at summer solstice sunrise, as seen from inside the Stonehenge monument. Image via mysticrealms.org.

Wherever you are in the world, you can celebrate the 2020 June solstice by watching the sun rise at Stonehenge.

Every year, thousands of visitors gather at the neolithic Stonehenge monument in Wiltshire, England, to celebrate the first sunrise of the Northern Hemisphere summer. However, this year’s event has been canceled; Stonehenge is currently closed due to Covid-19. While this news is disappointing, there’s good news: For the first time, English Heritage – which has provided access to the event since 2000 – will instead stream the solstice event online.

The event starts at sunset on Saturday (20:26 UTC on June 20) and goes through sunrise on Sunday (03:53 UTC on June 21). Translate UTC to your time. Here is the official Facebook event page, where you’ll be able to watch the livestream. You can also access the event via Stonehenge on Twitter.

Experience the solstice at Stonehenge – live online – beginning at sunset on Saturday (20:26 UTC on June 20) and lasting through sunrise on Sunday (03:52 UTC on June 21). Translate UTC to your time.

For everyone's safety and wellbeing, we've had to cancel this year's summer solstice celebrations at Stonehenge.

We know how special this occasion is to so many of you, and we'll be live streaming it for free online. pic.twitter.com/zMi0NzCmbO

— English Heritage (@EnglishHeritage) May 12, 2020

Stonehenge director Nichola Tasker told The Salisbury Journal:

We hope that our live stream offers an alternative opportunity for people near and far to connect with this spiritual place at such a special time of year and we look forward to welcoming everyone back next year.

We know how strong the draw to come is for some people, but I would take this opportunity to say please do not travel to Stonehenge this summer solstice, but watch it online instead.

Stonehenge has been closed since March 18, 2020, as the British government introduced measures to combat the coronavirus pandemic. Image via The Salisbury Journal

Stonehenge, in England, was built in three phases between about 3,000 B.C. and 1,600 B.C., and its purpose remains under study. However, it’s known that if you stand in just the right place inside the Stonehenge monument on the day of the northern summer solstice, facing northeast through the entrance towards a rough-hewn stone outside the circle – known as the Heel Stone – you will see the sun rise above the Heel Stone, as illustrated in the image at the top.

Here’s a video tour of Stonehenge from English Heritage on Facebook:

The BBC reported that about 12,000 people attended the neolithic site in Wiltshire to watch the sun rise at on June 20, 2016. Image via BBC.

In the Northern Hemisphere at this time of year, the sun is shining on us most directly at midday. Except at high northerly latitudes, above the Arctic Circle – where daylight is continuous for many months – the day on which the summer solstice occurs is the day of the year with the longest period of daylight. Meanwhile, it is the shortest day for Earth’s Southern Hemisphere.

At the northern summer solstice – always around June 20 – the sun’s path stops moving northward in the sky. For us in the Northern Hemisphere, it’s the day on which the days stop growing longer and will soon begin to shorten again. For this reason, the summer solstice is a time of festivals and celebrations around this hemisphere of Earth.

Summer solstice at Stonehenge via stonehengetrips.com.

The Stonehenge Free Festival was a British free festival from 1974 to 1984 held at Stonehenge during the month of June, and culminating on the summer solstice. The festival was a celebration of various alternative cultures. The Tibetan Ukrainian Mountain Troupe, The Tepee People, Circus Normal, the Peace Convoy, New Age Travellers and the Wallys were notable counterculture attendees. Image via Wikipedia.

Stonehenge is tied to the winter solstice, too. At Stonehenge on the day of the northern winter solstice (always around December 20), people watch as the sun sets in the midst of three great stones – known as the Trilithon – consisting of two large vertical stones supporting a third, horizontal stone across the top.

In the case of Stonehenge, this great Trilithon faces outwards from the center of the monument, with its smooth flat face turned toward the midwinter sun. In fact, the primary axis of Stonehenge seems to have been carefully aligned on a sight-line pointing to the winter solstice sunset.

EarthSky Facebook friend Buddy Puckhaber of South Carolina took this photo of Stonehenge in the early morning, while visiting. He said, “My wife and I were among the first visitors of the day.” Thank you, Buddy!

This huge megalithic monument shows how carefully our ancestors watched the sun. Astronomical observations such as these surely controlled human activities such as the mating of animals, the sowing of crops and the metering of winter reserves between harvests. Stonehenge is perhaps the most famous of of the ancient astronomical monuments found around the world.

When Stonehenge was first opened to the public it was possible to walk among the stones – even climb on them.

The stones were roped off in 1977 as a result of serious erosion. Today, visitors to the monument are not permitted to touch the stones, but, if you go, you will be able to walk around the monument from a short distance away. Visitors can also make special bookings to access the stones throughout the year.

Another beautiful shot of Stonehenge from our friend Buddy Puckhaber. Thank you, Buddy.

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

Bottom line: How to celebrate the 2020 June solstice sunrise at Stonehenge live online.

from EarthSky https://ift.tt/3fBO0Qx

SOHO’s 4,000th comet

The NASA/ESA Solar and Heliospheric Observatory – affectionately called SOHO – is easily history’s greatest comet discoverer. This space observatory is designed to study the sun, but it now also has 4,000 comets to its credit, with the 4,000th discovered this week. SOHO’s abundance of comet discoveries is in part thanks to the dedication of citizen scientists, who pore through its data, seeking the moving fuzzballs near the sun that turn out to be sun-grazing comets. Amateur astronomer and geophysics graduate Trygve Prestgard – originally from Norway, now in Grenoble, France – spotted the 4,000th comet in the SOHO data on June 15, 2020. NASA reported:

The comet is nicknamed SOHO-4000, pending an official designation from the Minor Planet Center.

The 3,999th and 4,000th comets discovered by the SOHO spacecraft as they sped toward the sun. The spacecraft’s coronagraph, LASCO, uses a metal disk to block out the sun itself. This obscuring disk helps the instrument focus on the sun’s outer atmosphere or corona, and it allows SOHO to find comets! Image via ESA/ NASA/ SOHO/ Karl Battams.

Like most other SOHO-discovered comets, SOHO-4000 is part of the Kreutz family of sungrazers. The Kreutz family of comets all follow the same general trajectory, one that carries them skimming through the outer atmosphere of the sun. SOHO-4000 is on the small side, with a diameter in the range of 15-30 feet [4.5 to 9 meters], and it was extremely faint and close to the sun when discovered – meaning SOHO is the only observatory that has spotted the comet, as it’s impossible to see from Earth with or without a telescope.

Trygve Prestgard said:

I feel very fortunate to have found SOHO’s 4,000th comet. Although I knew that SOHO was nearing its 4,000th comet discovery, I did not initially think that this sungrazer would be it. It was only after discussing with other SOHO comet hunters, and counting through the most recent sungrazer discoveries, that the idea sunk in. I am honored to be part of such an amazing collaborative effort.

I'm super, SUPER excited to announce that on June 15th, the @ESA/@NASASun SOHO satellite made its 4,000th comet discovery!!

Many congrats to @TrygvePrestgard for finding the 4,000th comet, and a huge THANK YOU to all the citizen scientists who have contributed to the project! pic.twitter.com/FKJrlMIoKC

— Karl Battams (@SungrazerComets) June 17, 2020

Karl Battams, a space scientist at the U.S. Naval Research Lab in Washington, D.C., who works on SOHO and manages its comet-finding program, said:

Not only has SOHO rewritten the history books in terms of solar physics, but, unexpectedly, it’s rewritten the books in terms of comets as well.

NASA explained:

SOHO’s comet-hunting prowess comes from a combination of its long lifespan, its sensitive instruments focused on the solar corona, and the tireless work of citizen scientists who scour SOHO’s data for previously-undiscovered comets, which are clumps of frozen gases, rock and dust that orbit the sun.

The vast majority of comets found in SOHO’s data are from its coronagraph instrument, called LASCO, short for Large Angle and Spectrometric Coronagraph. Like other coronagraphs, LASCO uses a solid object – in this case, a metal disk – to block out the sun’s bright face, allowing its cameras to focus on the relatively faint outer atmosphere, the corona. The corona is critical to understanding how the sun’s changes propagate out into the solar system, making LASCO a key part of SOHO’s scientific quest to understand the sun and its influence.

But focusing on this faint region also means LASCO can do something other telescopes can’t – it can see comets flying extremely close to the sun, called sungrazers, which are otherwise blotted out by the sun’s intense light and impossible to see. This is why nearly all of SOHO’s 4,000 comet discoveries have come from LASCO’s data.

SOHO orbits the sun at the Lagrangian 1 point (L1) in the Earth-sun system. It’s about a million miles from Earth, and has an uninterrupted view from its vantage point between the sun and Earth. In this animation, Earth is blue, and the sun is yellow. The green dots are the L1 to L5 points: relativity stable places to park a (moving) spacecraft. Image via Wikimedia Commons.

Citizen scientist Trygve Prestgard, who has discovered around 120 previously-unknown comets using data from SOHO and NASA’s STEREO mission, commented:

I have been actively involved in the Sungrazer Project for about eight years … I enjoy the feeling of discovering something previously unknown, whether this is a nice ‘real time’ comet or a ‘long-gone’ overlooked one in the archives.

Read more about SOHO’s copious comets from NASA

The 4,000th comet discovered by the ESA/NASA SOHO sun observatory is seen here in an image from the spacecraft. Alongside is SOHO’s 3,999th comet discovery. The 2 comets are relatively close at approximately 1 million miles apart, suggesting that they could have been connected together as recently as a few years ago. Image via ESA/ NASA/ SOHO/ Karl Battams.

Bottom line: On June 15, 2020, citizen scientist Trygve Prestgard spotted a never-before-seen comet in data from the sun-observing SOHO spacecraft. It was SOHO’s 4,000th comet discovery.

Via NASA

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The NASA/ESA Solar and Heliospheric Observatory – affectionately called SOHO – is easily history’s greatest comet discoverer. This space observatory is designed to study the sun, but it now also has 4,000 comets to its credit, with the 4,000th discovered this week. SOHO’s abundance of comet discoveries is in part thanks to the dedication of citizen scientists, who pore through its data, seeking the moving fuzzballs near the sun that turn out to be sun-grazing comets. Amateur astronomer and geophysics graduate Trygve Prestgard – originally from Norway, now in Grenoble, France – spotted the 4,000th comet in the SOHO data on June 15, 2020. NASA reported:

The comet is nicknamed SOHO-4000, pending an official designation from the Minor Planet Center.

The 3,999th and 4,000th comets discovered by the SOHO spacecraft as they sped toward the sun. The spacecraft’s coronagraph, LASCO, uses a metal disk to block out the sun itself. This obscuring disk helps the instrument focus on the sun’s outer atmosphere or corona, and it allows SOHO to find comets! Image via ESA/ NASA/ SOHO/ Karl Battams.

Like most other SOHO-discovered comets, SOHO-4000 is part of the Kreutz family of sungrazers. The Kreutz family of comets all follow the same general trajectory, one that carries them skimming through the outer atmosphere of the sun. SOHO-4000 is on the small side, with a diameter in the range of 15-30 feet [4.5 to 9 meters], and it was extremely faint and close to the sun when discovered – meaning SOHO is the only observatory that has spotted the comet, as it’s impossible to see from Earth with or without a telescope.

Trygve Prestgard said:

I feel very fortunate to have found SOHO’s 4,000th comet. Although I knew that SOHO was nearing its 4,000th comet discovery, I did not initially think that this sungrazer would be it. It was only after discussing with other SOHO comet hunters, and counting through the most recent sungrazer discoveries, that the idea sunk in. I am honored to be part of such an amazing collaborative effort.

I'm super, SUPER excited to announce that on June 15th, the @ESA/@NASASun SOHO satellite made its 4,000th comet discovery!!

Many congrats to @TrygvePrestgard for finding the 4,000th comet, and a huge THANK YOU to all the citizen scientists who have contributed to the project! pic.twitter.com/FKJrlMIoKC

— Karl Battams (@SungrazerComets) June 17, 2020

Karl Battams, a space scientist at the U.S. Naval Research Lab in Washington, D.C., who works on SOHO and manages its comet-finding program, said:

Not only has SOHO rewritten the history books in terms of solar physics, but, unexpectedly, it’s rewritten the books in terms of comets as well.

NASA explained:

SOHO’s comet-hunting prowess comes from a combination of its long lifespan, its sensitive instruments focused on the solar corona, and the tireless work of citizen scientists who scour SOHO’s data for previously-undiscovered comets, which are clumps of frozen gases, rock and dust that orbit the sun.

The vast majority of comets found in SOHO’s data are from its coronagraph instrument, called LASCO, short for Large Angle and Spectrometric Coronagraph. Like other coronagraphs, LASCO uses a solid object – in this case, a metal disk – to block out the sun’s bright face, allowing its cameras to focus on the relatively faint outer atmosphere, the corona. The corona is critical to understanding how the sun’s changes propagate out into the solar system, making LASCO a key part of SOHO’s scientific quest to understand the sun and its influence.

But focusing on this faint region also means LASCO can do something other telescopes can’t – it can see comets flying extremely close to the sun, called sungrazers, which are otherwise blotted out by the sun’s intense light and impossible to see. This is why nearly all of SOHO’s 4,000 comet discoveries have come from LASCO’s data.

SOHO orbits the sun at the Lagrangian 1 point (L1) in the Earth-sun system. It’s about a million miles from Earth, and has an uninterrupted view from its vantage point between the sun and Earth. In this animation, Earth is blue, and the sun is yellow. The green dots are the L1 to L5 points: relativity stable places to park a (moving) spacecraft. Image via Wikimedia Commons.

Citizen scientist Trygve Prestgard, who has discovered around 120 previously-unknown comets using data from SOHO and NASA’s STEREO mission, commented:

I have been actively involved in the Sungrazer Project for about eight years … I enjoy the feeling of discovering something previously unknown, whether this is a nice ‘real time’ comet or a ‘long-gone’ overlooked one in the archives.

Read more about SOHO’s copious comets from NASA

The 4,000th comet discovered by the ESA/NASA SOHO sun observatory is seen here in an image from the spacecraft. Alongside is SOHO’s 3,999th comet discovery. The 2 comets are relatively close at approximately 1 million miles apart, suggesting that they could have been connected together as recently as a few years ago. Image via ESA/ NASA/ SOHO/ Karl Battams.

Bottom line: On June 15, 2020, citizen scientist Trygve Prestgard spotted a never-before-seen comet in data from the sun-observing SOHO spacecraft. It was SOHO’s 4,000th comet discovery.

Via NASA

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Sally Ride: 1st American woman in space

Sally Ride on the space shuttle Challenger in 1983. Image via NASA/ Mental Floss.

On June 18, 1983, physicist Sally Ride (1951-2012) became the first American woman to go into space, blasting off onboard the space shuttle Challenger for the STS-7 mission. Although it was a historic achievement for NASA, Ride was actually the third woman in space overall. Soviet cosmonaut Valentina Tereshkova was the first, in 1963, and fellow cosmonaut Svetlana Savitskaya was the second, in 1982. STS-7 was NASA’s seventh space shuttle mission and the second mission for Challenger.

Ride was selected as a mission specialist for the mission, after becoming eligible for space shuttle missions in 1979. She helped to operate the shuttle’s robotic arm, deploy the ANIK C-2 and PALAPA B-1 satellites, conduct the first formation flying of the shuttle with a free-flying satellite (SPAS-01), carry and operate the first U.S./ German cooperative materials science payload (OSTA-2), and operate the Continuous Flow Electrophoresis System (CFES) and the Monodisperse Latex Reactor (MLR) experiments. STS-7 also had the largest crew to fly in a single spacecraft up to that point (5 astronauts). Ride enjoyed the experience, saying simply:

The thing that I’ll remember most about the flight is that it was fun. In fact, I’m sure it was the most fun I’ll ever have in my life.

The crew of the STS-7 space shuttle Challenger mission in 1983. Front row, left to right: Sally K. Ride (mission specialist), Robert L. Crippen (commander), and Frederick H. Hauck (pilot). Back row, left to right: John M. Fabian and Norman E. Thagard (mission specialists). Image via NASA/ Wikipedia.

The mission lasted 6 days, 2 hours, 23 minutes, and 59 seconds, with Challenger landing on a lakebed runway at Edwards Air Force Base in California, on June 24, 1983.

The successful flight made Ride a hero for young women and girls, showing that they could break barriers that they previously might have thought to be impossible.

Ride later flew on the space shuttle again for mission STS-41G in 1984, the 13th shuttle flight overall. STS 41-G launched from Kennedy Space Center on October 5, 1984. She was also supposed to join shuttle mission STS-61M, but that mission was canceled due to the 1986 Challenger disaster.

Sally’s Story

Sally Ride was born in Los Angeles, California, on May 26, 1951. As a young girl, she was fascinated by science, and grew up playing with a telescope and chemistry set. As a teenager, she also loved sports such as running, volleyball, softball and, especially, tennis, winning a tennis scholarship to Westlake School for Girls in Los Angeles. After receiving undergraduate degrees in physics and in English from Stanford University in 1973, she obtained her Ph.D. in physics.

Portrait of Sally Ride. Image via NASA/ Wikipedia.

Sally Ride as a teenager. She was passionate about tennis and participated in national championships. Image via Afflictor.com.

In 1977, NASA was looking for new astronauts, including women. Ride saw an ad in the school newspaper inviting women to apply to the astronaut program and decided to apply. Out of 8,000 applicants, she was one of six women chosen as an astronaut candidate in January 1978. In 1979, she began training as a mission specialist for future space flights, which included parachute jumping, water survival, weightlessness, radio communications, and navigation. She was also part of the team that developed the robot arm used by shuttle crews to deploy and retrieve satellites.

In 1986, as part of the Rogers Commission, Ride later assisted in the investigation of the Challenger space shuttle disaster. According to a 2016 article in Popular Mechanics, it was Ride who revealed to General Donald Kutyna – another member of the Rogers Commission – that the O-rings used in the shuttle became stiff at low temperatures. This eventually led to the identification of the cause of the explosion that killed the seven astronauts. After the investigation was finished, she was assigned to NASA headquarters as special assistant to the administrator for long-range and strategic planning. She wrote an influential report entitled “Leadership and America’s Future in Space,” and became the first director of NASA’s Office of Exploration.

Ride retired from NASA in 1987, becoming a science fellow at the Center for International Security and Arms Control at Stanford University. She kept very busy in her post-astronaut career. In 1989, she became a professor of physics at the University of California, San Diego and director of the California Space Institute.

Sally Ride, left, and her partner, Tam O’Shaughnessy, discuss the role of women in science and Earth’s changing climate during a 2008 American Library Association conference in Anaheim, California, in 2008. Image via American Library Association/ NBC News.

President Obama greets former astronaut Sally Ride prior to the launch of the “Educate to Innovate” Campaign for Excellence in Science, Technology, Engineering & Math (STEM) Education, in the South Court Auditorium of the White House, Nov. 23, 2009. Image via Pete Souza/ White House/ Obama White House Archives.

In 2001, she founded Sally Ride Science, a company she co-founded with her partner, Tam O’Shaughnessy, to inspire other young women to pursue STEM careers. Her company targeted middle school students and their parents. Ride wrote seven science books for children, including To Space and Back (with Sue Okie); Voyager; The Third Planet; The Mystery of Mars; Exploring Our Solar System; Mission Planet Earth; and Mission Save the Planet (all with Tam O’Shaughnessy).

Ride died on July 23, 2012, after a 17-month battle with pancreatic cancer. In November 2013, she was posthumously awarded the Presidential Medal of Freedom in a White House ceremony. O’Shaughnessy accepted the medal on her behalf. Sally’s mother, Joyce Ride, and her sister, Bear Ride, attended along with other 2013 medal recipients including President Bill Clinton, Gloria Steinem, and Oprah Winfrey. She will always be remembered as a true pioneer for female astronauts and women in science.

Bottom line: Sally Ride became the first American woman to go into space on June 18, 1983.

Read Sally Ride’s biography from NASA

Read more about her at Sally Ride Science

from EarthSky https://ift.tt/3fBtC1X

Sally Ride on the space shuttle Challenger in 1983. Image via NASA/ Mental Floss.

On June 18, 1983, physicist Sally Ride (1951-2012) became the first American woman to go into space, blasting off onboard the space shuttle Challenger for the STS-7 mission. Although it was a historic achievement for NASA, Ride was actually the third woman in space overall. Soviet cosmonaut Valentina Tereshkova was the first, in 1963, and fellow cosmonaut Svetlana Savitskaya was the second, in 1982. STS-7 was NASA’s seventh space shuttle mission and the second mission for Challenger.

Ride was selected as a mission specialist for the mission, after becoming eligible for space shuttle missions in 1979. She helped to operate the shuttle’s robotic arm, deploy the ANIK C-2 and PALAPA B-1 satellites, conduct the first formation flying of the shuttle with a free-flying satellite (SPAS-01), carry and operate the first U.S./ German cooperative materials science payload (OSTA-2), and operate the Continuous Flow Electrophoresis System (CFES) and the Monodisperse Latex Reactor (MLR) experiments. STS-7 also had the largest crew to fly in a single spacecraft up to that point (5 astronauts). Ride enjoyed the experience, saying simply:

The thing that I’ll remember most about the flight is that it was fun. In fact, I’m sure it was the most fun I’ll ever have in my life.

The crew of the STS-7 space shuttle Challenger mission in 1983. Front row, left to right: Sally K. Ride (mission specialist), Robert L. Crippen (commander), and Frederick H. Hauck (pilot). Back row, left to right: John M. Fabian and Norman E. Thagard (mission specialists). Image via NASA/ Wikipedia.

The mission lasted 6 days, 2 hours, 23 minutes, and 59 seconds, with Challenger landing on a lakebed runway at Edwards Air Force Base in California, on June 24, 1983.

The successful flight made Ride a hero for young women and girls, showing that they could break barriers that they previously might have thought to be impossible.

Ride later flew on the space shuttle again for mission STS-41G in 1984, the 13th shuttle flight overall. STS 41-G launched from Kennedy Space Center on October 5, 1984. She was also supposed to join shuttle mission STS-61M, but that mission was canceled due to the 1986 Challenger disaster.

Sally’s Story

Sally Ride was born in Los Angeles, California, on May 26, 1951. As a young girl, she was fascinated by science, and grew up playing with a telescope and chemistry set. As a teenager, she also loved sports such as running, volleyball, softball and, especially, tennis, winning a tennis scholarship to Westlake School for Girls in Los Angeles. After receiving undergraduate degrees in physics and in English from Stanford University in 1973, she obtained her Ph.D. in physics.

Portrait of Sally Ride. Image via NASA/ Wikipedia.

Sally Ride as a teenager. She was passionate about tennis and participated in national championships. Image via Afflictor.com.

In 1977, NASA was looking for new astronauts, including women. Ride saw an ad in the school newspaper inviting women to apply to the astronaut program and decided to apply. Out of 8,000 applicants, she was one of six women chosen as an astronaut candidate in January 1978. In 1979, she began training as a mission specialist for future space flights, which included parachute jumping, water survival, weightlessness, radio communications, and navigation. She was also part of the team that developed the robot arm used by shuttle crews to deploy and retrieve satellites.

In 1986, as part of the Rogers Commission, Ride later assisted in the investigation of the Challenger space shuttle disaster. According to a 2016 article in Popular Mechanics, it was Ride who revealed to General Donald Kutyna – another member of the Rogers Commission – that the O-rings used in the shuttle became stiff at low temperatures. This eventually led to the identification of the cause of the explosion that killed the seven astronauts. After the investigation was finished, she was assigned to NASA headquarters as special assistant to the administrator for long-range and strategic planning. She wrote an influential report entitled “Leadership and America’s Future in Space,” and became the first director of NASA’s Office of Exploration.

Ride retired from NASA in 1987, becoming a science fellow at the Center for International Security and Arms Control at Stanford University. She kept very busy in her post-astronaut career. In 1989, she became a professor of physics at the University of California, San Diego and director of the California Space Institute.

Sally Ride, left, and her partner, Tam O’Shaughnessy, discuss the role of women in science and Earth’s changing climate during a 2008 American Library Association conference in Anaheim, California, in 2008. Image via American Library Association/ NBC News.

President Obama greets former astronaut Sally Ride prior to the launch of the “Educate to Innovate” Campaign for Excellence in Science, Technology, Engineering & Math (STEM) Education, in the South Court Auditorium of the White House, Nov. 23, 2009. Image via Pete Souza/ White House/ Obama White House Archives.

In 2001, she founded Sally Ride Science, a company she co-founded with her partner, Tam O’Shaughnessy, to inspire other young women to pursue STEM careers. Her company targeted middle school students and their parents. Ride wrote seven science books for children, including To Space and Back (with Sue Okie); Voyager; The Third Planet; The Mystery of Mars; Exploring Our Solar System; Mission Planet Earth; and Mission Save the Planet (all with Tam O’Shaughnessy).

Ride died on July 23, 2012, after a 17-month battle with pancreatic cancer. In November 2013, she was posthumously awarded the Presidential Medal of Freedom in a White House ceremony. O’Shaughnessy accepted the medal on her behalf. Sally’s mother, Joyce Ride, and her sister, Bear Ride, attended along with other 2013 medal recipients including President Bill Clinton, Gloria Steinem, and Oprah Winfrey. She will always be remembered as a true pioneer for female astronauts and women in science.

Bottom line: Sally Ride became the first American woman to go into space on June 18, 1983.

Read Sally Ride’s biography from NASA

Read more about her at Sally Ride Science

from EarthSky https://ift.tt/3fBtC1X

Picking out the sound of tumours

For the longest time, scientists have been trying to find ways to use blood to better understand how cancer progresses inside the body.

As a tumour grows inside the body, it releases DNA into the bloodstream. And over the last decade, this circulating tumour DNA (ctDNA) has been the focus of researchers aiming to detect or monitor cancer.

This technique (known as a liquid biopsy) allows doctors to find out more about a patient’s cancer without the need for surgery. Although these ctDNA-based tests aren’t yet common, their use has been rapidly growing over the last few years.

The potential benefits are huge, both for designing clinical trials and for patients. Monitoring patients – particularly after they’ve received treatment – allows doctors to assess if treatment was successful and monitor for signs that the cancer might return.

Now, a team of Cancer Research UK scientists led by Dr Nitzan Rosenfeld at the University of Cambridge have developed a new experimental liquid biopsy that is up to ten times more sensitive than those being tested currently and has the potential to change how cancer is treated.

Cancelling out the noise

We’ve blogged before about the challenges with developing a blood test to pick up cancer. And a big issue is the complexity of changes to cancer cell’s DNA.

Cancer isn’t caused by just one error, it’s a culmination of many mutations that will vary from cancer to cancer and person to person. One of the ways that researchers can get around this complexity problem is to make the test more tailored. By analysing the individual genetic makeup of a person’s tumour, liquid biopsies can home in on a specific set of mutations and use them as a starting point to monitor the progression of cancer.

But knowing what to look for is just the start – because these tiny fragments of tumour DNA aren’t alone in the blood, they’re floating amongst millions of fragments of DNA from other cells.

Various methods have been proposed to reduce noise and improve signal to noise. In the last few months there’s been an explosion of methods that are based on tumour-informed analysis and personalized panels, with several exciting advances presented or published very recently.

– Dr Nitzan Rosenfeld

Scientists have worked to cut through this noise by looking for more than one DNA error, designing tests that pick up anything between 10 and 100 mutations. Using this approach, some tests are able to detect 1 mutant molecule amongst 30,000 pieces of DNA. But while the numbers seem impressive, they’re not good enough – particularly when there’s only a tube of blood to work with. This insensitivity means that even if the patient has enough cancer in their body to lead to a potential relapse, the test can come back negative.

Rosenfeld’s team thought they could do better.

According to Dr Rosenfeld this came about by “a combination of developing a lab process, which generates data from patient samples and control samples, and computational methods that have been developed to take advantage of the dataset that this generates”

The key was to combine data generated from personally profiling a patient’s tumour (looking for hundreds and sometimes thousands of mutations in each blood sample) with a clever computational solution.

It’s like listening to a quiet song on a pair of noise-cancelling headphones. Their new computational technique uses their data to “learn” the pattern of background noise – the molecular equivalent of a crowded street – in order to filter it out and better analyse the mutations that have been made clearer.

This uses control data to “learn” the pattern of background noise, and a series of filters and statistical methods that remove noise, define the detection classification algorithms and improve their confidence margins

– Dr Nitzan Rosenfeld

Putting their new techniques to the test on samples from 105 cancer patients, across 5 different cancer types and multiple stages of disease, they found the new technique was able to detect ctDNA at high sensitivity in patients with advanced breast and melanoma cancer, as well as patients with glioblastoma (a cancer traditionally difficult to detect in blood).

Compared to the traditional techniques, this new method can pick up 1 mutant molecule in amongst 100,000 – 1,000,000 pieces of DNA.

This sensitivity boost meant the test could detect tumour DNA in the blood of patients with earlier stage disease, included patients with early-stage lung and breast cancers, as well as those who had already undergone surgery for melanoma, despite the levels being much lower and more difficult to find.

Monitoring the future

Although it might be several years before this type of approach is ready to be used with patients, the team are still excited by what might come.

Further increases in sensitivity could lead to tests that would only require a drop of blood – meaning that patients could do it at home and send it off to the lab themselves. This would allow for more patients to have their cancers more continually monitored while not having to go to as many hospital appointments.

In future studies, the team and their collaborators plan to use this technique to measure ctDNA levels in people who are at high risk of developing cancer and hope that the information they will generate can be used to help refine future tests for cancer early detection.

Alex

Reference

Wan, J.C.M., Heider, K., Gale, D., Murphy, S., Fisher, E., Mouliere, F., Ruiz-Valdepenas, A., Santonja, A., Morris, J., Chandrananda, D., Marshall, A., Gill, A.B., Chan, P.Y., Barker, E., Young, G., Cooper, W.N., Hudecova, I., Marass, F., Mair, R., Brindle, K.M., Stewart, G.D., Abraham, J.E., Caldas, C., Rassl, D.M., Rintoul, R.C., Alifrangis, C., Middleton, M.R., Gallagher, F.A., Parkinson, C., Durrani, A., McDermott, U., Smith, C.G., Massie, C., Corrie, P.G., Rosenfeld, N., 2020. ctDNA monitoring using patient-specific sequencing and integration of variant reads. Science Translational Medicine 12, eaaz8084. https://doi.org/10.1126/scitranslmed.aaz8084

from Cancer Research UK – Science blog https://ift.tt/2Vc1Hht

For the longest time, scientists have been trying to find ways to use blood to better understand how cancer progresses inside the body.

As a tumour grows inside the body, it releases DNA into the bloodstream. And over the last decade, this circulating tumour DNA (ctDNA) has been the focus of researchers aiming to detect or monitor cancer.

This technique (known as a liquid biopsy) allows doctors to find out more about a patient’s cancer without the need for surgery. Although these ctDNA-based tests aren’t yet common, their use has been rapidly growing over the last few years.

The potential benefits are huge, both for designing clinical trials and for patients. Monitoring patients – particularly after they’ve received treatment – allows doctors to assess if treatment was successful and monitor for signs that the cancer might return.

Now, a team of Cancer Research UK scientists led by Dr Nitzan Rosenfeld at the University of Cambridge have developed a new experimental liquid biopsy that is up to ten times more sensitive than those being tested currently and has the potential to change how cancer is treated.

Cancelling out the noise

We’ve blogged before about the challenges with developing a blood test to pick up cancer. And a big issue is the complexity of changes to cancer cell’s DNA.

Cancer isn’t caused by just one error, it’s a culmination of many mutations that will vary from cancer to cancer and person to person. One of the ways that researchers can get around this complexity problem is to make the test more tailored. By analysing the individual genetic makeup of a person’s tumour, liquid biopsies can home in on a specific set of mutations and use them as a starting point to monitor the progression of cancer.

But knowing what to look for is just the start – because these tiny fragments of tumour DNA aren’t alone in the blood, they’re floating amongst millions of fragments of DNA from other cells.

Various methods have been proposed to reduce noise and improve signal to noise. In the last few months there’s been an explosion of methods that are based on tumour-informed analysis and personalized panels, with several exciting advances presented or published very recently.

– Dr Nitzan Rosenfeld

Scientists have worked to cut through this noise by looking for more than one DNA error, designing tests that pick up anything between 10 and 100 mutations. Using this approach, some tests are able to detect 1 mutant molecule amongst 30,000 pieces of DNA. But while the numbers seem impressive, they’re not good enough – particularly when there’s only a tube of blood to work with. This insensitivity means that even if the patient has enough cancer in their body to lead to a potential relapse, the test can come back negative.

Rosenfeld’s team thought they could do better.

According to Dr Rosenfeld this came about by “a combination of developing a lab process, which generates data from patient samples and control samples, and computational methods that have been developed to take advantage of the dataset that this generates”

The key was to combine data generated from personally profiling a patient’s tumour (looking for hundreds and sometimes thousands of mutations in each blood sample) with a clever computational solution.

It’s like listening to a quiet song on a pair of noise-cancelling headphones. Their new computational technique uses their data to “learn” the pattern of background noise – the molecular equivalent of a crowded street – in order to filter it out and better analyse the mutations that have been made clearer.

This uses control data to “learn” the pattern of background noise, and a series of filters and statistical methods that remove noise, define the detection classification algorithms and improve their confidence margins

– Dr Nitzan Rosenfeld

Putting their new techniques to the test on samples from 105 cancer patients, across 5 different cancer types and multiple stages of disease, they found the new technique was able to detect ctDNA at high sensitivity in patients with advanced breast and melanoma cancer, as well as patients with glioblastoma (a cancer traditionally difficult to detect in blood).

Compared to the traditional techniques, this new method can pick up 1 mutant molecule in amongst 100,000 – 1,000,000 pieces of DNA.

This sensitivity boost meant the test could detect tumour DNA in the blood of patients with earlier stage disease, included patients with early-stage lung and breast cancers, as well as those who had already undergone surgery for melanoma, despite the levels being much lower and more difficult to find.

Monitoring the future

Although it might be several years before this type of approach is ready to be used with patients, the team are still excited by what might come.

Further increases in sensitivity could lead to tests that would only require a drop of blood – meaning that patients could do it at home and send it off to the lab themselves. This would allow for more patients to have their cancers more continually monitored while not having to go to as many hospital appointments.

In future studies, the team and their collaborators plan to use this technique to measure ctDNA levels in people who are at high risk of developing cancer and hope that the information they will generate can be used to help refine future tests for cancer early detection.

Alex

Reference

Wan, J.C.M., Heider, K., Gale, D., Murphy, S., Fisher, E., Mouliere, F., Ruiz-Valdepenas, A., Santonja, A., Morris, J., Chandrananda, D., Marshall, A., Gill, A.B., Chan, P.Y., Barker, E., Young, G., Cooper, W.N., Hudecova, I., Marass, F., Mair, R., Brindle, K.M., Stewart, G.D., Abraham, J.E., Caldas, C., Rassl, D.M., Rintoul, R.C., Alifrangis, C., Middleton, M.R., Gallagher, F.A., Parkinson, C., Durrani, A., McDermott, U., Smith, C.G., Massie, C., Corrie, P.G., Rosenfeld, N., 2020. ctDNA monitoring using patient-specific sequencing and integration of variant reads. Science Translational Medicine 12, eaaz8084. https://doi.org/10.1126/scitranslmed.aaz8084

from Cancer Research UK – Science blog https://ift.tt/2Vc1Hht

New moon is June 21, 2020

Youngest possible lunar crescent, with the moon’s age being exactly zero when this photo was taken – at the instant of new moon – 07:14 UTC on July 8, 2013. Image by Thierry Legault.

When the moon is new, it’s most nearly between the Earth and sun for any particular month. There’s a new moon about once a month, because the moon takes about a month to orbit Earth. Most of the time, the new moon passes not in front of the sun, but simply near it in our sky. That’s why, in most months, there’s no solar eclipse. In June 2020, however, the moon will pass dead-on in front of the sun, causing an annular – or ring – solar eclipse. Read more about the solar eclipse here.

View at EarthSky Community Photos. | Annular solar eclipse of December 26, 2019. Alexander Krivenyshev of the website WorldTimeZone.com caught it at Al Hofuf, Saudi Arabia. Thank you, Alexander! Read more about the June 21, 2020 annular solar eclipse.

The photo of a new moon at the top of this page shows the moon as it passed near the sun on July 8, 2013. There was no eclipse that day; it was an ordinary new moon.

New moons typically can’t be seen, or at least they can’t without special equipment and a lot of moon-photography experience. Thierry Legault was able to catch the photo at top – the moon at the instant it was new – because the moon that month passed to one side of the sun, and the faintest of lunar crescents was visible.

Either way – in front of the sun or just near it – on the day of new moon, the moon travels across the sky with the sun during the day, hidden in the sun’s glare.

Some people use the term new moon for a thin crescent moon visible in the west after sunset. You always see these little crescents – which set shortly after the sun – a day or two after each month’s new moon. Astronomers don’t call these little crescent moons new moons, however. In the language of astronomy, this slim crescent is called a young moon.

The June 2020 young moon will sweep from the twin stars Castor and Pollux toward Regulus in the few days following new moon.

The young moon and stars in June, 2020. Beginning around June 22, watch day by day for a wider waxing crescent moon to be higher up at sunset, and to stay out longer after sundown.

New moons, and young moons, are fascinating to many. The Farmer’s Almanac, for example, still offers information on gardening by the moon. And many cultures have holidays based on moon phases.

Bottom line: New moons generally can’t be seen. They cross the sky with the sun during the day. This month’s new moon happens on June 21 at 06:41 UTC. It will cause an annular solar eclipse on that date. Afterward – beginning around June 22 – the moon will return to the evening sky.

Read more: What’s the youngest moon you can see?

Read more: Top 4 keys to understanding moon phases

Help EarthSky keep going! Please donate.

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

Youngest possible lunar crescent, with the moon’s age being exactly zero when this photo was taken – at the instant of new moon – 07:14 UTC on July 8, 2013. Image by Thierry Legault.

When the moon is new, it’s most nearly between the Earth and sun for any particular month. There’s a new moon about once a month, because the moon takes about a month to orbit Earth. Most of the time, the new moon passes not in front of the sun, but simply near it in our sky. That’s why, in most months, there’s no solar eclipse. In June 2020, however, the moon will pass dead-on in front of the sun, causing an annular – or ring – solar eclipse. Read more about the solar eclipse here.

View at EarthSky Community Photos. | Annular solar eclipse of December 26, 2019. Alexander Krivenyshev of the website WorldTimeZone.com caught it at Al Hofuf, Saudi Arabia. Thank you, Alexander! Read more about the June 21, 2020 annular solar eclipse.

The photo of a new moon at the top of this page shows the moon as it passed near the sun on July 8, 2013. There was no eclipse that day; it was an ordinary new moon.

New moons typically can’t be seen, or at least they can’t without special equipment and a lot of moon-photography experience. Thierry Legault was able to catch the photo at top – the moon at the instant it was new – because the moon that month passed to one side of the sun, and the faintest of lunar crescents was visible.

Either way – in front of the sun or just near it – on the day of new moon, the moon travels across the sky with the sun during the day, hidden in the sun’s glare.

Some people use the term new moon for a thin crescent moon visible in the west after sunset. You always see these little crescents – which set shortly after the sun – a day or two after each month’s new moon. Astronomers don’t call these little crescent moons new moons, however. In the language of astronomy, this slim crescent is called a young moon.

The June 2020 young moon will sweep from the twin stars Castor and Pollux toward Regulus in the few days following new moon.

The young moon and stars in June, 2020. Beginning around June 22, watch day by day for a wider waxing crescent moon to be higher up at sunset, and to stay out longer after sundown.

New moons, and young moons, are fascinating to many. The Farmer’s Almanac, for example, still offers information on gardening by the moon. And many cultures have holidays based on moon phases.

Bottom line: New moons generally can’t be seen. They cross the sky with the sun during the day. This month’s new moon happens on June 21 at 06:41 UTC. It will cause an annular solar eclipse on that date. Afterward – beginning around June 22 – the moon will return to the evening sky.

Read more: What’s the youngest moon you can see?

Read more: Top 4 keys to understanding moon phases

Help EarthSky keep going! Please donate.

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

Dance of 3 stars confirms Einstein’s ‘most fortunate thought’

Artist’s concept of the system known as PSR J0337+1715. It’s triple system, consisting of a millisecond pulsar with 2 white dwarf companions. The green mesh illustrates the curvature of space-time caused by the different masses of these 3 stars. Size and distances of the 3 components are not to scale. Image via Michael Kramer/ MPIfR.

It’s part of science legend that Galileo dropped objects of different masses from Italy’s Leaning Tower of Pisa in order to contradict the long-held notion that heavier and lighter objects fall at different rates. In fact, all objects – irrespective of mass – fall at the same rate in a vacuum. This is called the universality of free fall, confirmed since then both on Earth and in space. Einstein himself called the universality of free fall his “most fortunate thought” since it led him eventually to the general theory of relativity. Now researchers in Europe have confirmed this fact of nature again, with extremely high precision, by tracking the motion of a triple star system containing a millisecond pulsar.

The findings were published in the peer-reviewed journal Astronomy & Astrophysics on June 10, 2020. A statement from the Max Planck Institute for Radio Astronomy (MPIfR) in Bonn, Germany, whose researchers participated in the study, said:

[The] findings – achieved by a new rigorous method and a combination of radio telescope data with latest insight from gravitational wave detectors – provide the strongest test ever of one of the most fundamental predictions of general relativity: that gravity attracts all objects with the same acceleration, without regard for their composition, density or the strength of their own gravitational field.

The pulsar in the system they studied – a highly compact neutron star – is called PSR J0337+1715. It orbits in a triple system with two white dwarfs, objects less compact than a neutron star, but more compact than our sun.

As described by general relativity theory, very compact objects like neutron stars curve spacetime many trillion times more strongly than planets or than our sun. These scientists said:

Perhaps more than any previous test, this result indicates that general relativity, based on the simplicity of Einstein’s most fortunate thought, really captures something fundamental about nature.

How can we understand what these scientists studied? Consider the universality of free fall in our own Earth/moon system – in the video below – which shows what’s sometimes called the Apollo 15 Hammer Feather Drop. The video shows that, on an airless world like the moon, a hammer and a feather fall at the same rate.

Much as in the video above, the new work is about a test of the universality of free fall. The scientists’ statement explained:

Pulsar PSR J0337+1715, located in the constellation Taurus, is a neutron star of 1.44 solar masses, showing regular radio pulses as it rotates 366 times per second around its own axis. It is a member of an unusual triple star system, in mutual interaction with two other stars, both of which are white dwarfs. A white dwarf is already quite exotic – a star typically the size of the Earth with a density of many hundred kilograms per cubic centimeter at its center. Compared to white dwarfs, a neutron star is truly extreme, having more mass than the sun squashed into a radius of just 12 kilometers [7 1/2 miles] and by this reaching densities of more than a billion tons within the volume of a sugar cube.

A research team, led by Guillaume Voisin (Jodrell Bank Centre for Astrophysics/UK and Observatoire de Paris), including MPIfR astronomers Paulo Freire, Norbert Wex and Michael Kramer, and astronomers from several institutions in France, used the Nançay radio telescope, located in the Sologne region of France, to precisely measure the arrival times of the radio pulses from PSR J0337+1715 over a time interval of eight years. They can show that neutron stars and white dwarf stars fall with the same acceleration within two parts per million.

What does it mean that the neutron star and white dwarf stars fall with the same acceleration? What does falling have to do with the orbits of objects in this triple system? In fact, you can look at objects in orbit around one another as being in a state of free fall. The object with less mass is falling toward the object with more mass. However, if the less massive object has enough tangential velocity – enough speed – it won’t fall into the other body. Instead, it’ll follow a curved path around the other body. The less massive object is then said to be orbiting the more massive one. To understand more about orbits, try this post on Newton’s cannonball.

Artist’s concept of 2 bodies orbiting a common center of gravity (red cross). You can consider the less massive body as “falling” toward the more massive one. It never reaches the more massive body, though, because it’s moving too fast. Image via Wikipedia.

What these scientists showed – to a high degree of precision – was that the orbits of the objects in the pulsar/white dwarf triple system are all “falling” at the same rate, as they pursue their mutual orbit. Since the pulsar is more massive than the white dwarf stars, this result confirms the universality of free fall: it shows that objects of different masses fall at the same rate. Guillaume Voisin commented:

Confirming it to this precision constitutes one of the most stringent tests of Einstein’s theory ever made – and the theory passes the test with flying colors. Moreover, the results also provide very stringent constraints on alternative theories of gravity, which compete with Einstein’s general relativity to explain gravity and, for example, dark energy.

Einstein’s Most Fortunate Thought

The scientists’ statement explained:

After the 1905 publication of the special theory of relativity, Einstein started thinking about how to combine his new theory with gravity, since Newton’s law of gravity is incompatible with his new principle of relativity. In the fall of 1907, an idea came to his mind: that for someone in free fall it is as if gravity has been turned off, since due to the universality of free fall everything in his environment accelerates the same way.

This simple but profound insight led Einstein eventually to understand that gravity is a manifestation of curved space-time acting on all masses the same way, a concept which is at the heart of his general theory of relativity. He later described this sudden inspiration as ‘the most fortunate thought in my life.’

Read more about some of the applications of the new work, via MPIfR.

The scientists also pointed out that this triple system containing the pulsar PSR J0337+1715 illustrates something very profound. It shows that Einstein’s “ingenious insight” also applies to such extreme cosmic objects as neutron stars, which were discovered for the first time only 50 years after the publication of the general theory of relativity. Paulo Freire, another co-author from MPIfR, commented:

Perhaps more than any previous test, this result indicates that Einstein’s most fortunate thought really captures something fundamental about gravity and the inner workings of nature.

Bottom line: The universality of free fall describes the fact that objects of unequal mass fall at the same rate (in a vacuum). Einstein called the universality of free fall “my most fortunate thought.” Researchers in Europe have now confirmed this fact of nature with extremely high precision, using a triple star system containing the millisecond pulsar PSR J0337+1715.

Source: An improved test of the strong equivalence principle with the pulsar in a triple star system

Via MPIfR

from EarthSky https://ift.tt/3hLC9RU

Artist’s concept of the system known as PSR J0337+1715. It’s triple system, consisting of a millisecond pulsar with 2 white dwarf companions. The green mesh illustrates the curvature of space-time caused by the different masses of these 3 stars. Size and distances of the 3 components are not to scale. Image via Michael Kramer/ MPIfR.

It’s part of science legend that Galileo dropped objects of different masses from Italy’s Leaning Tower of Pisa in order to contradict the long-held notion that heavier and lighter objects fall at different rates. In fact, all objects – irrespective of mass – fall at the same rate in a vacuum. This is called the universality of free fall, confirmed since then both on Earth and in space. Einstein himself called the universality of free fall his “most fortunate thought” since it led him eventually to the general theory of relativity. Now researchers in Europe have confirmed this fact of nature again, with extremely high precision, by tracking the motion of a triple star system containing a millisecond pulsar.

The findings were published in the peer-reviewed journal Astronomy & Astrophysics on June 10, 2020. A statement from the Max Planck Institute for Radio Astronomy (MPIfR) in Bonn, Germany, whose researchers participated in the study, said:

[The] findings – achieved by a new rigorous method and a combination of radio telescope data with latest insight from gravitational wave detectors – provide the strongest test ever of one of the most fundamental predictions of general relativity: that gravity attracts all objects with the same acceleration, without regard for their composition, density or the strength of their own gravitational field.

The pulsar in the system they studied – a highly compact neutron star – is called PSR J0337+1715. It orbits in a triple system with two white dwarfs, objects less compact than a neutron star, but more compact than our sun.

As described by general relativity theory, very compact objects like neutron stars curve spacetime many trillion times more strongly than planets or than our sun. These scientists said:

Perhaps more than any previous test, this result indicates that general relativity, based on the simplicity of Einstein’s most fortunate thought, really captures something fundamental about nature.

How can we understand what these scientists studied? Consider the universality of free fall in our own Earth/moon system – in the video below – which shows what’s sometimes called the Apollo 15 Hammer Feather Drop. The video shows that, on an airless world like the moon, a hammer and a feather fall at the same rate.

Much as in the video above, the new work is about a test of the universality of free fall. The scientists’ statement explained:

Pulsar PSR J0337+1715, located in the constellation Taurus, is a neutron star of 1.44 solar masses, showing regular radio pulses as it rotates 366 times per second around its own axis. It is a member of an unusual triple star system, in mutual interaction with two other stars, both of which are white dwarfs. A white dwarf is already quite exotic – a star typically the size of the Earth with a density of many hundred kilograms per cubic centimeter at its center. Compared to white dwarfs, a neutron star is truly extreme, having more mass than the sun squashed into a radius of just 12 kilometers [7 1/2 miles] and by this reaching densities of more than a billion tons within the volume of a sugar cube.

A research team, led by Guillaume Voisin (Jodrell Bank Centre for Astrophysics/UK and Observatoire de Paris), including MPIfR astronomers Paulo Freire, Norbert Wex and Michael Kramer, and astronomers from several institutions in France, used the Nançay radio telescope, located in the Sologne region of France, to precisely measure the arrival times of the radio pulses from PSR J0337+1715 over a time interval of eight years. They can show that neutron stars and white dwarf stars fall with the same acceleration within two parts per million.

What does it mean that the neutron star and white dwarf stars fall with the same acceleration? What does falling have to do with the orbits of objects in this triple system? In fact, you can look at objects in orbit around one another as being in a state of free fall. The object with less mass is falling toward the object with more mass. However, if the less massive object has enough tangential velocity – enough speed – it won’t fall into the other body. Instead, it’ll follow a curved path around the other body. The less massive object is then said to be orbiting the more massive one. To understand more about orbits, try this post on Newton’s cannonball.

Artist’s concept of 2 bodies orbiting a common center of gravity (red cross). You can consider the less massive body as “falling” toward the more massive one. It never reaches the more massive body, though, because it’s moving too fast. Image via Wikipedia.

What these scientists showed – to a high degree of precision – was that the orbits of the objects in the pulsar/white dwarf triple system are all “falling” at the same rate, as they pursue their mutual orbit. Since the pulsar is more massive than the white dwarf stars, this result confirms the universality of free fall: it shows that objects of different masses fall at the same rate. Guillaume Voisin commented:

Confirming it to this precision constitutes one of the most stringent tests of Einstein’s theory ever made – and the theory passes the test with flying colors. Moreover, the results also provide very stringent constraints on alternative theories of gravity, which compete with Einstein’s general relativity to explain gravity and, for example, dark energy.

Einstein’s Most Fortunate Thought

The scientists’ statement explained:

After the 1905 publication of the special theory of relativity, Einstein started thinking about how to combine his new theory with gravity, since Newton’s law of gravity is incompatible with his new principle of relativity. In the fall of 1907, an idea came to his mind: that for someone in free fall it is as if gravity has been turned off, since due to the universality of free fall everything in his environment accelerates the same way.

This simple but profound insight led Einstein eventually to understand that gravity is a manifestation of curved space-time acting on all masses the same way, a concept which is at the heart of his general theory of relativity. He later described this sudden inspiration as ‘the most fortunate thought in my life.’

Read more about some of the applications of the new work, via MPIfR.

The scientists also pointed out that this triple system containing the pulsar PSR J0337+1715 illustrates something very profound. It shows that Einstein’s “ingenious insight” also applies to such extreme cosmic objects as neutron stars, which were discovered for the first time only 50 years after the publication of the general theory of relativity. Paulo Freire, another co-author from MPIfR, commented:

Perhaps more than any previous test, this result indicates that Einstein’s most fortunate thought really captures something fundamental about gravity and the inner workings of nature.

Bottom line: The universality of free fall describes the fact that objects of unequal mass fall at the same rate (in a vacuum). Einstein called the universality of free fall “my most fortunate thought.” Researchers in Europe have now confirmed this fact of nature with extremely high precision, using a triple star system containing the millisecond pulsar PSR J0337+1715.

Source: An improved test of the strong equivalence principle with the pulsar in a triple star system

Via MPIfR

from EarthSky https://ift.tt/3hLC9RU