Why fireflies light up

Photo via Fiona M. Donnelly in Smiths Falls, Ontario.

Fireflies are sometimes called lightning bugs. Many a child has spent a summer evening chasing them. And maybe you’ve wondered how and why these insects are able to light up? The answer is that the light of a firefly is a chemical reaction caused by an organic compound in their abdomens.

Image via Matt Pollock in upstate New York.

The compound is called luciferin. As air rushes into a firefly’s abdomen, it reacts with the luciferin, and a chemical reaction gives off the firefly’s familiar glow. This light is sometimes called “cold light” because it generates so little heat. The firefly can regulate the airflow into the abdomen to create a pulsating pattern.

Did you ever do this? Image via Flickr user jamelah e.

Some experts think the firefly’s flashy style may warn predators of the insect’s bitter taste. On the other hand, some frogs don’t seem to mind. They eat so many fireflies that they themselves begin to glow. Male fireflies also light up to signal their desire for mates, and willing females attract the males with flashes of their own.

“Fireflies on top of the wave of grass and overflowing. Biggest firefly show in years.” Image via Eileen Claffey in West Brookfield, Massachusetts, June 2015.

But not all the flashing of fireflies is motivated by romance. While each firefly species has its own pattern of flashing, some females imitate the patterns of other species. Males land next to them, only to be eaten alive.

Cool firefly photo – a 30-second exposure – from astrophotographer Tom Wildoner. Astrophotographers often capture fireflies when trying to photograph the night sky.

So the next time you see a firefly, keep in mind that its flickering isn’t just a wonder of the night. It’s also a unique love language … that can be deadly.

You can see what looks like trails made by fireflies, via long-exposure photography from Jack Fusco Photography. There’s also a single meteor in the upper left of this photo. See it? It’s straighter than the firefly trails.

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Fireflies and star trails from Michael A Rosinski.

Bottom line: Fireflies – aka lightning bugs – light up because of a chemical reaction between an organic compound in the fireflies’ abdomens – called luciferin – and the air.

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

Photo via Fiona M. Donnelly in Smiths Falls, Ontario.

Fireflies are sometimes called lightning bugs. Many a child has spent a summer evening chasing them. And maybe you’ve wondered how and why these insects are able to light up? The answer is that the light of a firefly is a chemical reaction caused by an organic compound in their abdomens.

Image via Matt Pollock in upstate New York.

The compound is called luciferin. As air rushes into a firefly’s abdomen, it reacts with the luciferin, and a chemical reaction gives off the firefly’s familiar glow. This light is sometimes called “cold light” because it generates so little heat. The firefly can regulate the airflow into the abdomen to create a pulsating pattern.

Did you ever do this? Image via Flickr user jamelah e.

Some experts think the firefly’s flashy style may warn predators of the insect’s bitter taste. On the other hand, some frogs don’t seem to mind. They eat so many fireflies that they themselves begin to glow. Male fireflies also light up to signal their desire for mates, and willing females attract the males with flashes of their own.

“Fireflies on top of the wave of grass and overflowing. Biggest firefly show in years.” Image via Eileen Claffey in West Brookfield, Massachusetts, June 2015.

But not all the flashing of fireflies is motivated by romance. While each firefly species has its own pattern of flashing, some females imitate the patterns of other species. Males land next to them, only to be eaten alive.

Cool firefly photo – a 30-second exposure – from astrophotographer Tom Wildoner. Astrophotographers often capture fireflies when trying to photograph the night sky.

So the next time you see a firefly, keep in mind that its flickering isn’t just a wonder of the night. It’s also a unique love language … that can be deadly.

You can see what looks like trails made by fireflies, via long-exposure photography from Jack Fusco Photography. There’s also a single meteor in the upper left of this photo. See it? It’s straighter than the firefly trails.

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

Fireflies and star trails from Michael A Rosinski.

Bottom line: Fireflies – aka lightning bugs – light up because of a chemical reaction between an organic compound in the fireflies’ abdomens – called luciferin – and the air.

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

10 years of the sun in 1 hour

On June 24, 2020, NASA released this incredible timelapse of the sun that condenses an entire solar cycle into one hour. The video uses images of the sun taken by NASA’s Solar Dynamics Observatory – SDO – every hour continuously over 10 years.

As of June 2020, the SDO spacecraft has been watching the sun non-stop for over a full decade. From its orbit in space around the Earth, SDO has gathered 425 million high-resolution images of the sun, amassing 20 million gigabytes of data over the past 10 years.

Every second of the 61-minute video represents images taken over a single day, starting on June 2, 2010, with the last frame captured on June 1, 2020.

According to NASA:

With a triad of instruments, SDO captures an image of the sun every 0.75 seconds. The Atmospheric Imaging Assembly (AIA) instrument alone captures images every 12 seconds at 10 different wavelengths of light. This 10-year time lapse showcases photos taken at a wavelength of 17.1 nanometers, which is an extreme ultraviolet wavelength that shows the sun’s outermost atmospheric layer – the corona. Compiling one photo every hour, the movie condenses a decade of the sun into 61 minutes. The video shows the rise and fall in activity that occurs as part of the sun’s 11-year solar cycle and notable events, like transiting planets and eruptions.

While SDO has kept an unblinking eye pointed towards the sun, there have been a few moments it missed. The dark frames in the video are caused by Earth or the moon eclipsing SDO as they pass between the spacecraft and the sun. A longer blackout in 2016 was caused by a temporary issue with the AIA instrument that was successfully resolved after a week. The images where the sun is off-center were observed when SDO was calibrating its instruments.

Some noteworthy events appear briefly in this timelapse. Use the time links below to jump to each event.

6:20 June 7, 2011 – A massive prominence eruption explodes from the lower right of the sun.

12:24 June 5, 2012 – The transit of Venus across the face of the sun. Won’t happen again until 2117.

13:06 July 19, 2012 – A complex loop of magnetic fields and plasma forms and lasts for hours.

13:50 August 31, 2012 – The most iconic eruption of this solar cycle bursts from the lower left of the sun.

20:25 September 29, 2013 – A prominence eruption forms a long ‘canyon’ that is then covered with loops of plasma.

26:39 October 8, 2014 – Active regions on the sun resemble a jack o’ lantern just in time for Halloween.

36:18 May 9, 2016 – Mercury transits across the face of the sun. Smaller and more distant than Venus, it is hard to spot.

43:20 July 5, 2017 – A large sunspot group spends two weeks crossing the face of the sun

44:20 September 6, 2017 – The most powerful sequence of flares during this solar cycle crackle for several days, peaking at X9.3.

57:38 November 11, 2019 – Mercury transits the sun once more for SDO. The next transit won’t be until 2032.

The music for the video, titled Solar Observer, was composed by Lars Leonhard.

Bottom line: Watch a video that condenses an entire solar cycle into one hour.

Via NASA

from EarthSky https://ift.tt/3iB3vuu

On June 24, 2020, NASA released this incredible timelapse of the sun that condenses an entire solar cycle into one hour. The video uses images of the sun taken by NASA’s Solar Dynamics Observatory – SDO – every hour continuously over 10 years.

As of June 2020, the SDO spacecraft has been watching the sun non-stop for over a full decade. From its orbit in space around the Earth, SDO has gathered 425 million high-resolution images of the sun, amassing 20 million gigabytes of data over the past 10 years.

Every second of the 61-minute video represents images taken over a single day, starting on June 2, 2010, with the last frame captured on June 1, 2020.

According to NASA:

With a triad of instruments, SDO captures an image of the sun every 0.75 seconds. The Atmospheric Imaging Assembly (AIA) instrument alone captures images every 12 seconds at 10 different wavelengths of light. This 10-year time lapse showcases photos taken at a wavelength of 17.1 nanometers, which is an extreme ultraviolet wavelength that shows the sun’s outermost atmospheric layer – the corona. Compiling one photo every hour, the movie condenses a decade of the sun into 61 minutes. The video shows the rise and fall in activity that occurs as part of the sun’s 11-year solar cycle and notable events, like transiting planets and eruptions.

While SDO has kept an unblinking eye pointed towards the sun, there have been a few moments it missed. The dark frames in the video are caused by Earth or the moon eclipsing SDO as they pass between the spacecraft and the sun. A longer blackout in 2016 was caused by a temporary issue with the AIA instrument that was successfully resolved after a week. The images where the sun is off-center were observed when SDO was calibrating its instruments.

Some noteworthy events appear briefly in this timelapse. Use the time links below to jump to each event.

6:20 June 7, 2011 – A massive prominence eruption explodes from the lower right of the sun.

12:24 June 5, 2012 – The transit of Venus across the face of the sun. Won’t happen again until 2117.

13:06 July 19, 2012 – A complex loop of magnetic fields and plasma forms and lasts for hours.

13:50 August 31, 2012 – The most iconic eruption of this solar cycle bursts from the lower left of the sun.

20:25 September 29, 2013 – A prominence eruption forms a long ‘canyon’ that is then covered with loops of plasma.

26:39 October 8, 2014 – Active regions on the sun resemble a jack o’ lantern just in time for Halloween.

36:18 May 9, 2016 – Mercury transits across the face of the sun. Smaller and more distant than Venus, it is hard to spot.

43:20 July 5, 2017 – A large sunspot group spends two weeks crossing the face of the sun

44:20 September 6, 2017 – The most powerful sequence of flares during this solar cycle crackle for several days, peaking at X9.3.

57:38 November 11, 2019 – Mercury transits the sun once more for SDO. The next transit won’t be until 2032.

The music for the video, titled Solar Observer, was composed by Lars Leonhard.

Bottom line: Watch a video that condenses an entire solar cycle into one hour.

Via NASA

from EarthSky https://ift.tt/3iB3vuu

‘Astonishing discovery’ of massive prehistoric circle near Stonehenge

A team of archaeologists have discovered a massive ring of prehistoric trenches at the site of an ancient village about two miles (3.2 km) from the famous Stonehenge monument in the UK. The team believes the circle of pits – carbon dated to about 2,500 BC – could have guided people towards the religious sites and warned others not to cross the boundary.

The find also makes the site the largest prehistoric structure in Britain and possibly in Europe. That’s according to University of Bradford archaeologist Vincent Gaffney, lead author of the analysis, which was published online in Internet Archaeology. Bradford told the New York Times:

It has completely transformed how we understand this landscape — there is no doubt about it.

The 1.2 mile-wide (2 km-wide) ring of shafts – up to 33 feet (10 meters) across and 16 feet (5 meters) deep – was discovered around the ancient village known as the Durrington Walls henge monument. Researchers have identified up to 20 shafts but estimate there may have been more than 30 originally.

This low-level aerial photograph clearly shows the earlier circular earthwork that surrounds the stone monument. Image via English Heritage.

Nick Snashall is National Trust archaeologist for the Stonehenge and Avebury World Heritage Site. She said:

As the place where the builders of Stonehenge lived and feasted, Durrington Walls is key to unlocking the story of the wider Stonehenge landscape, and this astonishing discovery offers us new insights into the lives and beliefs of our Neolithic ancestors.

Archaeologists believe the circle of shaft marks a boundary around the massive henge at Durrington. the features, along with an internal post line, could have guided people towards the religious sites and warned others not to cross the boundary. Gaffney told the New York Times:

Stonehenge was for the dead, Durrington was for the living. But now, what we are probably looking at was this great big boundary around them probably warning people of what they are approaching.

Image via The Guardian.

Gaffney said it was extraordinary such a major find had been made so close to Stonehenge. He said in a statement:

The area around Stonehenge is amongst the most studied archaeological landscapes on earth and it is remarkable that the application of new technology can still lead to the discovery of such a massive prehistoric structure which, currently, is significantly larger than any comparative prehistoric monument that we know of in Britain, at least.

When these pits were first noted it was thought they might be natural features – solution hollows in the chalk. Only when the larger picture emerged, through the geophysical surveys undertaken as part of the Stonehenge Hidden Landscape Project, could we join the dots and see there was a pattern on a massive scale.

Stonehenge closed on March 18, 2020 as the British government introduced measures to combat the coronavirus pandemic. But English Heritage has announced that Stonehenge is now open for visitors, although tickets, and other safety measures are required. If you can’t visit, take a virtual tour instead. Image via The Salsbury Journal

Gaffney said:

The size of the shafts and circuit surrounding Durrington Walls is without precedent within the UK. It demonstrates the significance of Durrington Walls Henge, the complexity of the monumental structures within the Stonehenge landscape, and the capacity and desire of Neolithic communities to record their cosmological belief systems in ways, and at a scale, that we had never previously anticipated.

The research on the pits at Durrington was undertaken by a consortium of archaeologists as part of the Stonehenge Hidden Landscape Project.

? Watch the sunrise live over Stonehenge! #summersolstice https://t.co/NlVYtUYIu4

— English Heritage (@EnglishHeritage) June 21, 2020

Source: A Massive, Late Neolithic Pit Structure associated with Durrington Walls Henge

Via University of Bradford

Image via EarthSky Facebook friend Buddy Puckhaber.

Bottom line: A team of archaeologists have discovered a massive ring of prehistoric trenches at the site of an ancient village about 2 miles from the famous Stonehenge monument in the UK.

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

A team of archaeologists have discovered a massive ring of prehistoric trenches at the site of an ancient village about two miles (3.2 km) from the famous Stonehenge monument in the UK. The team believes the circle of pits – carbon dated to about 2,500 BC – could have guided people towards the religious sites and warned others not to cross the boundary.

The find also makes the site the largest prehistoric structure in Britain and possibly in Europe. That’s according to University of Bradford archaeologist Vincent Gaffney, lead author of the analysis, which was published online in Internet Archaeology. Bradford told the New York Times:

It has completely transformed how we understand this landscape — there is no doubt about it.

The 1.2 mile-wide (2 km-wide) ring of shafts – up to 33 feet (10 meters) across and 16 feet (5 meters) deep – was discovered around the ancient village known as the Durrington Walls henge monument. Researchers have identified up to 20 shafts but estimate there may have been more than 30 originally.

This low-level aerial photograph clearly shows the earlier circular earthwork that surrounds the stone monument. Image via English Heritage.

Nick Snashall is National Trust archaeologist for the Stonehenge and Avebury World Heritage Site. She said:

As the place where the builders of Stonehenge lived and feasted, Durrington Walls is key to unlocking the story of the wider Stonehenge landscape, and this astonishing discovery offers us new insights into the lives and beliefs of our Neolithic ancestors.

Archaeologists believe the circle of shaft marks a boundary around the massive henge at Durrington. the features, along with an internal post line, could have guided people towards the religious sites and warned others not to cross the boundary. Gaffney told the New York Times:

Stonehenge was for the dead, Durrington was for the living. But now, what we are probably looking at was this great big boundary around them probably warning people of what they are approaching.

Image via The Guardian.

Gaffney said it was extraordinary such a major find had been made so close to Stonehenge. He said in a statement:

The area around Stonehenge is amongst the most studied archaeological landscapes on earth and it is remarkable that the application of new technology can still lead to the discovery of such a massive prehistoric structure which, currently, is significantly larger than any comparative prehistoric monument that we know of in Britain, at least.

When these pits were first noted it was thought they might be natural features – solution hollows in the chalk. Only when the larger picture emerged, through the geophysical surveys undertaken as part of the Stonehenge Hidden Landscape Project, could we join the dots and see there was a pattern on a massive scale.

Stonehenge closed on March 18, 2020 as the British government introduced measures to combat the coronavirus pandemic. But English Heritage has announced that Stonehenge is now open for visitors, although tickets, and other safety measures are required. If you can’t visit, take a virtual tour instead. Image via The Salsbury Journal

Gaffney said:

The size of the shafts and circuit surrounding Durrington Walls is without precedent within the UK. It demonstrates the significance of Durrington Walls Henge, the complexity of the monumental structures within the Stonehenge landscape, and the capacity and desire of Neolithic communities to record their cosmological belief systems in ways, and at a scale, that we had never previously anticipated.

The research on the pits at Durrington was undertaken by a consortium of archaeologists as part of the Stonehenge Hidden Landscape Project.

? Watch the sunrise live over Stonehenge! #summersolstice https://t.co/NlVYtUYIu4

— English Heritage (@EnglishHeritage) June 21, 2020

Source: A Massive, Late Neolithic Pit Structure associated with Durrington Walls Henge

Via University of Bradford

Image via EarthSky Facebook friend Buddy Puckhaber.

Bottom line: A team of archaeologists have discovered a massive ring of prehistoric trenches at the site of an ancient village about 2 miles from the famous Stonehenge monument in the UK.

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

How do fireworks get their colors?

Different kinds of metal salts produce different colors in fireworks. Image via NASA.

On Wednesday, July 1, 2020, Canadians celebrated Canada Day, and Saturday, July 4 is Independence Day – commonly referred to as the Fourth of July – in the United States. And that means – whether you love or hate it – it’s fireworks season in North America.

For fireworks (a type of pyrotechnics) enthusiasts, the red, orange, yellow, green, blue and purple colors exploding in the skies create a lot of “ohhhhs” and “ahhhhs.” But what actually creates those brilliant colors?

As might be expected, science has the answer and it is simple: pure chemistry. The beautiful colors in fireworks are created by the use of metal salts. These salts are different from table salt, and in chemistry ‘salt’ refers to any compound that contains metal and non-metal atoms. Some of these compounds produce intense colors when they are burned, which makes them ideal for fireworks. Others, like potassium nitrate, sulfur and charcoal are often used to help the fireworks burn. Nitrates, chlorates and perchlorates provide oxygen for the combustion of the fuel. Dextrin, often used as a starch, holds the mixture together. Some colors can be strengthened with the use of chlorine donors.

A more detailed overview as to how fireworks get their vibrant colors. Image via Compound Interest 2015.

Metal salts commonly used in firework displays include: strontium carbonate (red fireworks), calcium chloride (orange fireworks), sodium nitrate (yellow fireworks), barium chloride (green fireworks) and copper chloride (blue fireworks). Purple fireworks are typically produced by use of a mixture of strontium (red) and copper (blue) compounds.

The metal salts are packed into small pea- to plum-sized pellets called “stars” or “pyrotechnic stars.”

After a firework is ignited, a lift charge propels it into the sky. That’s just explosive black powder in a confined space that, when lit, causes a fast increase of heat and gas that can send a firework as high as 1,000 feet (300 meters) into the air.

Meanwhile, a time-delay fuse burns slowly into the interior of the firework shell. After about 5 seconds, as the shell is soaring overhead, the fuse kindles a charge that reaches the core of the firework, explodes and ignites the stars that contain the metal salts.

Fireworks in Austin, Texas, on July 4, 2013. Photo via our friend Sergio Garcia Rill.

Voila! A beautiful and colorful fireworks display.

By the way, the people who create fireworks are precise, expert craftsmen. Putting on a fireworks display is a complex process, and must be done safely. If even one thing is off — too much black powder, stars that aren’t aligned correctly or a trigger that fires too soon or too late — can cause everything else to go wrong.

Bottom line: The red, orange, yellow, green, blue and purple colors exploding in the night sky during a fireworks festival are created by the use of metal salts.

Read more: The Chemistry of Fireworks Colors

Read more: The Chemistry of Fireworks

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

from EarthSky https://ift.tt/2ZAbYW3

Different kinds of metal salts produce different colors in fireworks. Image via NASA.

On Wednesday, July 1, 2020, Canadians celebrated Canada Day, and Saturday, July 4 is Independence Day – commonly referred to as the Fourth of July – in the United States. And that means – whether you love or hate it – it’s fireworks season in North America.

For fireworks (a type of pyrotechnics) enthusiasts, the red, orange, yellow, green, blue and purple colors exploding in the skies create a lot of “ohhhhs” and “ahhhhs.” But what actually creates those brilliant colors?

As might be expected, science has the answer and it is simple: pure chemistry. The beautiful colors in fireworks are created by the use of metal salts. These salts are different from table salt, and in chemistry ‘salt’ refers to any compound that contains metal and non-metal atoms. Some of these compounds produce intense colors when they are burned, which makes them ideal for fireworks. Others, like potassium nitrate, sulfur and charcoal are often used to help the fireworks burn. Nitrates, chlorates and perchlorates provide oxygen for the combustion of the fuel. Dextrin, often used as a starch, holds the mixture together. Some colors can be strengthened with the use of chlorine donors.

A more detailed overview as to how fireworks get their vibrant colors. Image via Compound Interest 2015.

Metal salts commonly used in firework displays include: strontium carbonate (red fireworks), calcium chloride (orange fireworks), sodium nitrate (yellow fireworks), barium chloride (green fireworks) and copper chloride (blue fireworks). Purple fireworks are typically produced by use of a mixture of strontium (red) and copper (blue) compounds.

The metal salts are packed into small pea- to plum-sized pellets called “stars” or “pyrotechnic stars.”

After a firework is ignited, a lift charge propels it into the sky. That’s just explosive black powder in a confined space that, when lit, causes a fast increase of heat and gas that can send a firework as high as 1,000 feet (300 meters) into the air.

Meanwhile, a time-delay fuse burns slowly into the interior of the firework shell. After about 5 seconds, as the shell is soaring overhead, the fuse kindles a charge that reaches the core of the firework, explodes and ignites the stars that contain the metal salts.

Fireworks in Austin, Texas, on July 4, 2013. Photo via our friend Sergio Garcia Rill.

Voila! A beautiful and colorful fireworks display.

By the way, the people who create fireworks are precise, expert craftsmen. Putting on a fireworks display is a complex process, and must be done safely. If even one thing is off — too much black powder, stars that aren’t aligned correctly or a trigger that fires too soon or too late — can cause everything else to go wrong.

Bottom line: The red, orange, yellow, green, blue and purple colors exploding in the night sky during a fireworks festival are created by the use of metal salts.

Read more: The Chemistry of Fireworks Colors

Read more: The Chemistry of Fireworks

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

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Full moon, faint eclipse, on July 4-5

For us in the Americas, the moon will turn precisely full during the nighttime hours on July 4-5, 2020, to present a partial penumbral eclipse of the moon. It’ll be such a faint eclipse – so nearly imperceptible – that some of you will swear nothing is happening even while staring straight at it. Then again … very observant people might notice something strange happening on the moon, even without knowing an eclipse is taking place. Who will see it (or not) in this post. But first …

On the night of July 4-5, there’s another astronomical event taking place that we all can see. This July full moon will shine near on the sky’s dome to the very bright planet Jupiter, and also to the ringed planet Saturn. You need a telescope to see Saturn’s rings. But you’ll get a kick out of seeing Jupiter and Saturn close together!

What’s more, Jupiter and Saturn are now at their best. Later this month, Earth will pass between each of these worlds and the sun, so that both Jupiter and Saturn reach their oppositions, Jupiter on July 13-14 and Saturn on July 20.

Don’t miss these worlds near the moon on July 4 and 5!

Read more: Jupiter at opposition on July 13-14, 2020

Read more: Saturn at opposition on July 20, 2020

Read more: Before 2020 ends, a great conjunction of Jupiter and Saturn

Now about that penumbral lunar eclipse on the night of July 4-5 … The eclipse happens for everyone at the same time worldwide. The time on your clock will depend on your location.

To find eclipse times for your location for the July 4-5 eclipse, visit TimeandDate.com

Day and night sides of Earth at the instant of full moon (July 5, 2020 at 04:44 UTC). The shadow line at left – crossing the Pacific Ocean and northern North America – depicts sunset July 4. The shadow line at right – running through Spain and Africa – depicts sunrise July 5. Notice North America. This faintest of eclipses will occur in our night sky on July 4-5. How well you see it will depend on your sky conditions, eyesight and ability to observe subtle details. Worldwide map via Fourmilab.

We in the Americas are well situated to view this extremely faint, partial penumbral eclipse of the moon on the night of July 4-5.

The chance is there … but will you notice anything even if you catch the eclipse? That depends in part on your eyesight, in part on your experience watching eclipses, and in part on your powers of observation.

So of course many will watch it! Just don’t be disappointed if it’s, shall we say, lacking in drama? At best, it’ll be a subtle shading on the moon.

This eclipse wins some distinction because it’s the third of three eclipses in one eclipse season. More often than not, an eclipse season only harbors two eclipses.

Read more: What is an eclipse season?

Read more: Middle of eclipse season June 20, 2020

To find eclipse times for your location for the July 4-5 eclipse, visit TimeandDate.com

Not only does the moon completely miss the Earth’s dark umbral shadow at this July 4-5 eclipse, but the moon barely clips the fainter penumbral shadow. Thus, at greatest eclipse (July 5, 2020, at 04:30 Universal Time), you might – or might not – note a subtle shading on the northern side of the lunar disk. Read more: Penumbral lunar eclipse of July 5, 2020.

What about the rest of the world? For most of the world’s Eastern Hemisphere, the moon will turn precisely full during daylight hours on July 5, when the moon is still below the horizon.

From the westernmost parts of Africa, people might spot this partial penumbral eclipse just before dawn July 5, but for most of the eclipse area in western Africa (and Spain and Portugal), the eclipse will be obscured by the glow of morning twilight. For reference, see the worldwide map above.

To find eclipse times for your location for the July 4-5 eclipse, visit TimeandDate.com

A lunar eclipse can only happen at full moon, but more often than not the full moon swings above or below the Earth’s shadow. On the night of July 4-5, 2020, the full moon swings south of the dark umbra but partially passes through the faint penumbra.

Astronomers say the moon is full when it’s precisely 180 degrees opposite the sun in ecliptic longitude. Although the moon turns full at the same instant worldwide, the time of day or local clock time of the full moon varies across the globe. Full moon happens on July 5 at 04:44 Universal Time. At United States time zones, that places the full moon at 12:44 a.m. EDT (on July 5) – yet on July 4 at 11:44 p.m. CDT, 10:44 p.m. MDT and 9:44 p.m. PDT.

Moon’s present position in front of the constellations of the zodiac via Heavens-Above

Generally speaking, half the globe won’t see the moon at the instant it turns precisely full. Still, from almost everywhere worldwide, the moon will appear plenty full to the eye on the nights of July 4-5 and 5-6. That’s because, for several days around full moon, the moon remains more or less opposite the sun and appears in Earth’s sky for most hours of the night.

Look for the moon to appear low in your eastern sky around sunset July 4. It’ll climb highest up for the night around midnight and will shine low in your western sky at dawn July 5. In other words, look for the moon to light up the sky from dusk till dawn.

The full moon lies almost opposite the sun, so the path of the July full moon across the nighttime sky will resemble that of the January sun across the daytime sky. Therefore, far-northern regions of the globe won’t see the moon at all these next few nights. That’s because the July full moon, like the January sun, resides too far south on the sky’s dome to be seen from northern Arctic latitudes.

In North America, we often call the July full moon the Buck Moon, Thunder Moon or Hay Moon. At this time of year, buck deer begin to grow velvety antlers, while farmers are working to put hay in their barns, and trying to avoid the summer season’s frequent thunder showers.

Bottom line: The penumbral lunar eclipse of July 4-5, 2020, will be so nearly imperceptible that some will see nothing even while staring at it. Then again … very observant people will notice something strange happening on the moon, without knowing an eclipse is taking place.

To find eclipse times for your location for the July 4-5 eclipse, visit TimeandDate.com

from EarthSky https://ift.tt/2BVg6I0

For us in the Americas, the moon will turn precisely full during the nighttime hours on July 4-5, 2020, to present a partial penumbral eclipse of the moon. It’ll be such a faint eclipse – so nearly imperceptible – that some of you will swear nothing is happening even while staring straight at it. Then again … very observant people might notice something strange happening on the moon, even without knowing an eclipse is taking place. Who will see it (or not) in this post. But first …

On the night of July 4-5, there’s another astronomical event taking place that we all can see. This July full moon will shine near on the sky’s dome to the very bright planet Jupiter, and also to the ringed planet Saturn. You need a telescope to see Saturn’s rings. But you’ll get a kick out of seeing Jupiter and Saturn close together!

What’s more, Jupiter and Saturn are now at their best. Later this month, Earth will pass between each of these worlds and the sun, so that both Jupiter and Saturn reach their oppositions, Jupiter on July 13-14 and Saturn on July 20.

Don’t miss these worlds near the moon on July 4 and 5!

Read more: Jupiter at opposition on July 13-14, 2020

Read more: Saturn at opposition on July 20, 2020

Read more: Before 2020 ends, a great conjunction of Jupiter and Saturn

Now about that penumbral lunar eclipse on the night of July 4-5 … The eclipse happens for everyone at the same time worldwide. The time on your clock will depend on your location.

To find eclipse times for your location for the July 4-5 eclipse, visit TimeandDate.com

Day and night sides of Earth at the instant of full moon (July 5, 2020 at 04:44 UTC). The shadow line at left – crossing the Pacific Ocean and northern North America – depicts sunset July 4. The shadow line at right – running through Spain and Africa – depicts sunrise July 5. Notice North America. This faintest of eclipses will occur in our night sky on July 4-5. How well you see it will depend on your sky conditions, eyesight and ability to observe subtle details. Worldwide map via Fourmilab.

We in the Americas are well situated to view this extremely faint, partial penumbral eclipse of the moon on the night of July 4-5.

The chance is there … but will you notice anything even if you catch the eclipse? That depends in part on your eyesight, in part on your experience watching eclipses, and in part on your powers of observation.

So of course many will watch it! Just don’t be disappointed if it’s, shall we say, lacking in drama? At best, it’ll be a subtle shading on the moon.

This eclipse wins some distinction because it’s the third of three eclipses in one eclipse season. More often than not, an eclipse season only harbors two eclipses.

Read more: What is an eclipse season?

Read more: Middle of eclipse season June 20, 2020

To find eclipse times for your location for the July 4-5 eclipse, visit TimeandDate.com

Not only does the moon completely miss the Earth’s dark umbral shadow at this July 4-5 eclipse, but the moon barely clips the fainter penumbral shadow. Thus, at greatest eclipse (July 5, 2020, at 04:30 Universal Time), you might – or might not – note a subtle shading on the northern side of the lunar disk. Read more: Penumbral lunar eclipse of July 5, 2020.

What about the rest of the world? For most of the world’s Eastern Hemisphere, the moon will turn precisely full during daylight hours on July 5, when the moon is still below the horizon.

From the westernmost parts of Africa, people might spot this partial penumbral eclipse just before dawn July 5, but for most of the eclipse area in western Africa (and Spain and Portugal), the eclipse will be obscured by the glow of morning twilight. For reference, see the worldwide map above.

To find eclipse times for your location for the July 4-5 eclipse, visit TimeandDate.com

A lunar eclipse can only happen at full moon, but more often than not the full moon swings above or below the Earth’s shadow. On the night of July 4-5, 2020, the full moon swings south of the dark umbra but partially passes through the faint penumbra.

Astronomers say the moon is full when it’s precisely 180 degrees opposite the sun in ecliptic longitude. Although the moon turns full at the same instant worldwide, the time of day or local clock time of the full moon varies across the globe. Full moon happens on July 5 at 04:44 Universal Time. At United States time zones, that places the full moon at 12:44 a.m. EDT (on July 5) – yet on July 4 at 11:44 p.m. CDT, 10:44 p.m. MDT and 9:44 p.m. PDT.

Moon’s present position in front of the constellations of the zodiac via Heavens-Above

Generally speaking, half the globe won’t see the moon at the instant it turns precisely full. Still, from almost everywhere worldwide, the moon will appear plenty full to the eye on the nights of July 4-5 and 5-6. That’s because, for several days around full moon, the moon remains more or less opposite the sun and appears in Earth’s sky for most hours of the night.

Look for the moon to appear low in your eastern sky around sunset July 4. It’ll climb highest up for the night around midnight and will shine low in your western sky at dawn July 5. In other words, look for the moon to light up the sky from dusk till dawn.

The full moon lies almost opposite the sun, so the path of the July full moon across the nighttime sky will resemble that of the January sun across the daytime sky. Therefore, far-northern regions of the globe won’t see the moon at all these next few nights. That’s because the July full moon, like the January sun, resides too far south on the sky’s dome to be seen from northern Arctic latitudes.

In North America, we often call the July full moon the Buck Moon, Thunder Moon or Hay Moon. At this time of year, buck deer begin to grow velvety antlers, while farmers are working to put hay in their barns, and trying to avoid the summer season’s frequent thunder showers.

Bottom line: The penumbral lunar eclipse of July 4-5, 2020, will be so nearly imperceptible that some will see nothing even while staring at it. Then again … very observant people will notice something strange happening on the moon, without knowing an eclipse is taking place.

To find eclipse times for your location for the July 4-5 eclipse, visit TimeandDate.com

from EarthSky https://ift.tt/2BVg6I0

News digest – naked mole-rats, junk food deals, ovarian cancer drug and glowing surgery dye

With news about the coronavirus pandemic developing daily, we want to make sure everyone affected by cancer gets the information they need during this time.

We’re pulling together the latest government and NHS health updates from across the UK in a separate blog post, which we’re updating regularly.

Naked mole-rats and cancer resistance

Research into naked mole-rat’s resistance to cancer could open the door to new ways of preventing cancer in humans. Scientists have long been fascinated by this remarkable rodent, which is immune to certain types of pain, can survive 18 minutes without oxygen and resists the biological laws of ageing. For a long time, scientists believed that naked mole-rats almost never got cancer because their cells were resistant to becoming cancerous. But new research funded by Cancer Research UK suggests that it’s the environment around cells that stop them dividing. Read more at The Independent and in our press release.

‘Buy one get one free deals’ fuel obesity

As part of its renewed, pandemic-inspired interest in getting the nation fitter, the UK Government is considering restrictions on multi-buy promotions. New restrictions would be introduced as a means of reducing obesity levels, which have doubled over the last 20 years and now affects 13 million people in England alone. Experts say that rather than saving money, multi-buy deals encourage us to buy more in the long-term, especially of unhealthy foods. And restricting such deals could encourage promotions on healthier produce. More on this at iNews.

Ovarian cancer drug could reduce fertility in mice

A drug used to treat people with advanced ovarian and breast cancer has been shown to damage immature eggs stored in primary ovarian follicles in mice. Olaparib has not been used for long enough to know if the drug could have the same effect on women’s fertility. Daily Mail has the full story.

And finally…

A glowing dye used to light up breast cancer cells in dogs could help doctors remove more cancerous cells during surgery, reports New Atlas. Using the technique would allow cancers to be more safely removed via surgery, with fewer cells left behind, reducing the likelihood that the cancer will return or spread to other parts of the body. Scientists are now investigating the best way to deliver this type of florescent dye to tumours in humans. It’s not the first time that fluorescent dyes have been used during surgery, in 2019 a ‘pink drink’ to help guide brain surgery was rolled out across the NHS.

Scarlett Sangster is a writer for PA Media Group

from Cancer Research UK – Science blog https://ift.tt/2Bsl3s0

With news about the coronavirus pandemic developing daily, we want to make sure everyone affected by cancer gets the information they need during this time.

We’re pulling together the latest government and NHS health updates from across the UK in a separate blog post, which we’re updating regularly.

Naked mole-rats and cancer resistance

Research into naked mole-rat’s resistance to cancer could open the door to new ways of preventing cancer in humans. Scientists have long been fascinated by this remarkable rodent, which is immune to certain types of pain, can survive 18 minutes without oxygen and resists the biological laws of ageing. For a long time, scientists believed that naked mole-rats almost never got cancer because their cells were resistant to becoming cancerous. But new research funded by Cancer Research UK suggests that it’s the environment around cells that stop them dividing. Read more at The Independent and in our press release.

‘Buy one get one free deals’ fuel obesity

As part of its renewed, pandemic-inspired interest in getting the nation fitter, the UK Government is considering restrictions on multi-buy promotions. New restrictions would be introduced as a means of reducing obesity levels, which have doubled over the last 20 years and now affects 13 million people in England alone. Experts say that rather than saving money, multi-buy deals encourage us to buy more in the long-term, especially of unhealthy foods. And restricting such deals could encourage promotions on healthier produce. More on this at iNews.

Ovarian cancer drug could reduce fertility in mice

A drug used to treat people with advanced ovarian and breast cancer has been shown to damage immature eggs stored in primary ovarian follicles in mice. Olaparib has not been used for long enough to know if the drug could have the same effect on women’s fertility. Daily Mail has the full story.

And finally…

A glowing dye used to light up breast cancer cells in dogs could help doctors remove more cancerous cells during surgery, reports New Atlas. Using the technique would allow cancers to be more safely removed via surgery, with fewer cells left behind, reducing the likelihood that the cancer will return or spread to other parts of the body. Scientists are now investigating the best way to deliver this type of florescent dye to tumours in humans. It’s not the first time that fluorescent dyes have been used during surgery, in 2019 a ‘pink drink’ to help guide brain surgery was rolled out across the NHS.

Scarlett Sangster is a writer for PA Media Group

from Cancer Research UK – Science blog https://ift.tt/2Bsl3s0

For the 1st time, a visible light explosion from a black hole merger

Artist’s concept of a peculiar black hole system, in which 2 small black holes are merging in the disk surrounding a 3rd, supermassive black hole. Astronomers think that, when the 2 smaller holes merged, they sent a newly formed black hole flying through the gaseous disk, disturbing the gas and producing a visible light flare. Image via Caltech/ R. Hurt (IPAC).

Astronomers long believed – and in recent years they’ve observed – that 2 black holes orbiting each other sometimes spiral closer and then merge. Until now, they’ve never seen visible light from such a merger. What they observe are elusive signals from black hole mergers called gravitational waves: ripples in spacetime. Meanwhile, theorists have proposed ways that black hole mergers might explode with visible light. This month, for the first time, astronomers in California announced evidence that they’ve now seen one of these light-producing scenarios.

The new study describing the origin of the light explosion, or flare, was published June 25, 2020, in the peer-reviewed journal Physical Review Letters.

The evidence comes from Caltech’s robotic Zwicky Transient Facility (ZTF), located at Palomar Observatory near San Diego. ZTF’s job is to survey the night sky, capturing a multiplicity of unexpected flares and eruptions, lighting up like cosmic fireflies in the night. On May 21, 2019, the ZTF robot telescope detected a flare generated by a distant active supermassive black hole, or quasar, called J1249+3449. This object is an estimated 12.8 billion light-years away.

Around that same time, two gravitational wave detectors – the Laser Interferometer Gravitational-wave Observatory (LIGO) and the European Virgo detector – also detected an event. They labeled the gravitational wave event S190521g.

Now, more than a year later, astronomers have done the careful analysis, coordination and review needed to say that, yes, these two events – one in visible light, one in gravitational waves – likely spring from the same black hole merger. Matthew Graham of Caltech is lead author of the new research and ZTF project scientist. He said in a statement from Caltech:

This supermassive black hole was burbling along for years before this more abrupt flare.

The flare occurred on the right timescale, and in the right location, to be coincident with the gravitational-wave event. In our study, we conclude that the flare is likely the result of a black hole merger, but we cannot completely rule out other possibilities.

Astronomer Matthew Graham of Caltech is project scientist of the robotic Zwicky Transient Facility and lead author of the new research.

How do two merging black holes erupt with light? Graham and his fellow astronomers believe that two small black holes resided within a disk surrounding a much-larger black hole. A co-author of the new research, Kathleen E. Saavik Ford of the Graduate Center at City University New York (CUNY), explained:

At the center of most galaxies lurks a supermassive black hole. It’s surrounded by a swarm of stars and dead stars, including [other] black holes. These objects swarm like angry bees around the monstrous queen bee at the center. They can briefly find gravitational partners and pair up but usually lose their partners quickly to the mad dance. But in a supermassive black hole’s disk, the flowing gas converts the mosh pit of the swarm to a classical minuet, organizing the black holes so they can pair up.

Astrophysicist Kathleen E. Saavik Ford of CUNY is a co-author of the new research.

According to the scenario described by these scientists, once the two smaller black holes merged into a new black hole, that new black hole experienced a “kick” that sent it flying off in a random direction within the gaseous disk of the supermassive black hole. Astronomer Barry McKernan, also of CUNY, said:

It is the reaction of the gas to this speeding bullet [the newly formed black hole] that creates a bright flare, visible with telescopes.

Such a flare is predicted to begin days to weeks after the initial splash of gravitational waves produced during the merger, these astronomers said. Their statement explained:

In this case, ZTF did not catch the event right away, but when the scientists went back and looked through archival ZTF images months later, they found a signal that started days after the May 2019 gravitational-wave event. ZTF observed the flare slowly fade over the period of a month.

The scientists attempted to get a more detailed look at the light of the supermassive black hole, called a spectrum, but by the time they looked, the flare had already faded. A spectrum would have offered more support for the idea that the flare came from merging black holes within the disk of the supermassive black hole. However, the researchers say they were able to largely rule out other possible causes for the observed flare, including a supernova or a tidal disruption event, which occurs when a black hole essentially eats a star.

What is more, the team says it is not likely that the flare came from the usual rumblings of the supermassive black hole, which regularly feeds off its surrounding disk. Using the Catalina Real-Time Transient Survey, led by Caltech, they were able to assess the behavior of the black hole over the past 15 years, and found that its activity was relatively normal until May of 2019, when it suddenly intensified.

Another co-author, astronomer Mansi Kasliwal of Caltech, said:

Supermassive black holes like this one have flares all the time. They are not quiet objects, but the timing, size, and location of this flare was spectacular

The reason looking for flares like this is so important is that it helps enormously with astrophysics and cosmology questions. If we can do this again and detect light from the mergers of other black holes, then we can nail down the homes of these black holes and learn more about their origins.

These astronomers believe the newly formed black hole should cause another flare in the next few years. The same process that sent the newly formed black hole flying – after the two smaller black holes coalesced into one – should cause the new black hole to enter the supermassive black hole’s disk again:

… producing another flash of light that ZTF should be able to see.

Astronomer Mansi Kasliwal.

Bottom line: In recent years, black hole mergers in our universe have been detected via ripples in spacetime known as gravitational waves. Now, for the first time, astronomers believe they’ve observed visible light from a black hole merger, in a peculiar 3-black-hole system.

Source: Candidate Electromagnetic Counterpart to the Binary Black Hole Merger Gravitational-Wave Event S190521g

Via Caltech

Via CUNY

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

Artist’s concept of a peculiar black hole system, in which 2 small black holes are merging in the disk surrounding a 3rd, supermassive black hole. Astronomers think that, when the 2 smaller holes merged, they sent a newly formed black hole flying through the gaseous disk, disturbing the gas and producing a visible light flare. Image via Caltech/ R. Hurt (IPAC).

Astronomers long believed – and in recent years they’ve observed – that 2 black holes orbiting each other sometimes spiral closer and then merge. Until now, they’ve never seen visible light from such a merger. What they observe are elusive signals from black hole mergers called gravitational waves: ripples in spacetime. Meanwhile, theorists have proposed ways that black hole mergers might explode with visible light. This month, for the first time, astronomers in California announced evidence that they’ve now seen one of these light-producing scenarios.

The new study describing the origin of the light explosion, or flare, was published June 25, 2020, in the peer-reviewed journal Physical Review Letters.

The evidence comes from Caltech’s robotic Zwicky Transient Facility (ZTF), located at Palomar Observatory near San Diego. ZTF’s job is to survey the night sky, capturing a multiplicity of unexpected flares and eruptions, lighting up like cosmic fireflies in the night. On May 21, 2019, the ZTF robot telescope detected a flare generated by a distant active supermassive black hole, or quasar, called J1249+3449. This object is an estimated 12.8 billion light-years away.

Around that same time, two gravitational wave detectors – the Laser Interferometer Gravitational-wave Observatory (LIGO) and the European Virgo detector – also detected an event. They labeled the gravitational wave event S190521g.

Now, more than a year later, astronomers have done the careful analysis, coordination and review needed to say that, yes, these two events – one in visible light, one in gravitational waves – likely spring from the same black hole merger. Matthew Graham of Caltech is lead author of the new research and ZTF project scientist. He said in a statement from Caltech:

This supermassive black hole was burbling along for years before this more abrupt flare.

The flare occurred on the right timescale, and in the right location, to be coincident with the gravitational-wave event. In our study, we conclude that the flare is likely the result of a black hole merger, but we cannot completely rule out other possibilities.

Astronomer Matthew Graham of Caltech is project scientist of the robotic Zwicky Transient Facility and lead author of the new research.

How do two merging black holes erupt with light? Graham and his fellow astronomers believe that two small black holes resided within a disk surrounding a much-larger black hole. A co-author of the new research, Kathleen E. Saavik Ford of the Graduate Center at City University New York (CUNY), explained:

At the center of most galaxies lurks a supermassive black hole. It’s surrounded by a swarm of stars and dead stars, including [other] black holes. These objects swarm like angry bees around the monstrous queen bee at the center. They can briefly find gravitational partners and pair up but usually lose their partners quickly to the mad dance. But in a supermassive black hole’s disk, the flowing gas converts the mosh pit of the swarm to a classical minuet, organizing the black holes so they can pair up.

Astrophysicist Kathleen E. Saavik Ford of CUNY is a co-author of the new research.

According to the scenario described by these scientists, once the two smaller black holes merged into a new black hole, that new black hole experienced a “kick” that sent it flying off in a random direction within the gaseous disk of the supermassive black hole. Astronomer Barry McKernan, also of CUNY, said:

It is the reaction of the gas to this speeding bullet [the newly formed black hole] that creates a bright flare, visible with telescopes.

Such a flare is predicted to begin days to weeks after the initial splash of gravitational waves produced during the merger, these astronomers said. Their statement explained:

In this case, ZTF did not catch the event right away, but when the scientists went back and looked through archival ZTF images months later, they found a signal that started days after the May 2019 gravitational-wave event. ZTF observed the flare slowly fade over the period of a month.

The scientists attempted to get a more detailed look at the light of the supermassive black hole, called a spectrum, but by the time they looked, the flare had already faded. A spectrum would have offered more support for the idea that the flare came from merging black holes within the disk of the supermassive black hole. However, the researchers say they were able to largely rule out other possible causes for the observed flare, including a supernova or a tidal disruption event, which occurs when a black hole essentially eats a star.

What is more, the team says it is not likely that the flare came from the usual rumblings of the supermassive black hole, which regularly feeds off its surrounding disk. Using the Catalina Real-Time Transient Survey, led by Caltech, they were able to assess the behavior of the black hole over the past 15 years, and found that its activity was relatively normal until May of 2019, when it suddenly intensified.

Another co-author, astronomer Mansi Kasliwal of Caltech, said:

Supermassive black holes like this one have flares all the time. They are not quiet objects, but the timing, size, and location of this flare was spectacular

The reason looking for flares like this is so important is that it helps enormously with astrophysics and cosmology questions. If we can do this again and detect light from the mergers of other black holes, then we can nail down the homes of these black holes and learn more about their origins.

These astronomers believe the newly formed black hole should cause another flare in the next few years. The same process that sent the newly formed black hole flying – after the two smaller black holes coalesced into one – should cause the new black hole to enter the supermassive black hole’s disk again:

… producing another flash of light that ZTF should be able to see.

Astronomer Mansi Kasliwal.

Bottom line: In recent years, black hole mergers in our universe have been detected via ripples in spacetime known as gravitational waves. Now, for the first time, astronomers believe they’ve observed visible light from a black hole merger, in a peculiar 3-black-hole system.

Source: Candidate Electromagnetic Counterpart to the Binary Black Hole Merger Gravitational-Wave Event S190521g

Via Caltech

Via CUNY

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