The Crow, Cup and Water Snake appear on June evenings.
At nightfall tonight, or any June evening, look in a general southward direction for Spica, the brightest star in the constellation Virgo the Maiden. If you live in the Southern Hemisphere, Spica appears overhead or high in the north. Spica is your jumping off point to 3 faint constellations: Corvus the Crow, Crater the Cup and Hydra the Water Snake.
Use the Big Dipper to find Spica
Check out the 2 charts below. If you’re familiar with the Big Dipper, use it to star-hop to Spica, as shown in the first chart.
Then you can use Spica to find the constellation Corvus. And alternatively, use Corvus to confirm that you’ve found Spica, as shown in the second chart.
Use the Big Dipper to locate the stars Arcturus and Spica for months to come.Here’s another way to verify that you’re looking at Spica, the brightest star in the constellation Virgo.
Okay … got Spica? Now, as nightfall deepens into later evening, watch for a number of fainter stars to become visible. That’s when the Crow, Cup and Water Snake will come into view.
Crow, Cup and Water Snake in skylore
In Greek mythology, Apollo sent the crow to fetch a cup of water. But the crow, Corvus, got distracted eating figs. It was only after much delay that he finally remembered his mission. The crow knew Apollo would be angry, so he plucked a snake from the water and concocted a story about how it had attacked and delayed him.
Apollo was not fooled and angrily flung the Crow, Cup and Snake into the sky, placing the Crow and Cup on the Snake’s back. Then the god ordered Hydra to never let the Crow drink from the Cup. As a further punishment, he ordered that the Crow could never sing again, only screech and caw.
None of these constellations have any bright stars, but Hydra holds the distinction of being the longest constellation in the heavens.
The Crow, Cup and Water Snake appear on June evenings.
At nightfall tonight, or any June evening, look in a general southward direction for Spica, the brightest star in the constellation Virgo the Maiden. If you live in the Southern Hemisphere, Spica appears overhead or high in the north. Spica is your jumping off point to 3 faint constellations: Corvus the Crow, Crater the Cup and Hydra the Water Snake.
Use the Big Dipper to find Spica
Check out the 2 charts below. If you’re familiar with the Big Dipper, use it to star-hop to Spica, as shown in the first chart.
Then you can use Spica to find the constellation Corvus. And alternatively, use Corvus to confirm that you’ve found Spica, as shown in the second chart.
Use the Big Dipper to locate the stars Arcturus and Spica for months to come.Here’s another way to verify that you’re looking at Spica, the brightest star in the constellation Virgo.
Okay … got Spica? Now, as nightfall deepens into later evening, watch for a number of fainter stars to become visible. That’s when the Crow, Cup and Water Snake will come into view.
Crow, Cup and Water Snake in skylore
In Greek mythology, Apollo sent the crow to fetch a cup of water. But the crow, Corvus, got distracted eating figs. It was only after much delay that he finally remembered his mission. The crow knew Apollo would be angry, so he plucked a snake from the water and concocted a story about how it had attacked and delayed him.
Apollo was not fooled and angrily flung the Crow, Cup and Snake into the sky, placing the Crow and Cup on the Snake’s back. Then the god ordered Hydra to never let the Crow drink from the Cup. As a further punishment, he ordered that the Crow could never sing again, only screech and caw.
None of these constellations have any bright stars, but Hydra holds the distinction of being the longest constellation in the heavens.
A LCVP (Landing Craft, Vehicle, Personnel) from the U.S. Coast Guard-manned USS Samuel Chase disembarks troops of Company A, 16th Infantry, 1st Infantry Division (the Big Red One) wading onto the Fox Green section of Omaha Beach (Calvados, Basse-Normandie, France) on the morning of June 6, 1944. American soldiers encountered the newly formed German 352nd Division when landing. During the initial landing two-thirds of Company E became casualties. Credit Wikipedia/Chief Photographer’s Mate (CPHoM) Robert F. Sargent
Today is D-day’s 80th anniversary. It’s the anniversary of when – in 1944 – World War II’s allied armies began landing on the beaches of Normandy, France during Operation Overlord.
Beneath the roar of gunfire and the chaos of D-day, an unlikely hero played a vital role — wetland science. Often overlooked amid military strategies and troop movements, the study of mud proved critical to the success of the largest amphibious invasion in history.
Much has been written about the events of June 6 1944 and the extensive planning that led up to Operation Overlord on that pivotal day. The success of the Normandy landings involved expertise from a vast array of military, espionage, engineering and communication groups. My new report explains how scientists with knowledge of sediments and substrate formation, such as peat found in bogs and fens, were also instrumental in the planning and execution of D-day.
Following the evacuation of the British Expeditionary Force from Dunkirk during Operation Dynamo in 1940, Britain and its allies began meticulously planning for the invasion of mainland Europe. Gathering intelligence about the French coast and where the invasion would probably occur, was a vital component of these preparations.
The allies concluded that any landing site needed to be within range of their fighter aircraft, sheltered from harsh weather, and near a port to facilitate the landing of additional troops and equipment. These criteria led to the selection of the coast north of Caen in Normandy, France.
However, initial intelligence had raised concerns about whether the beaches were suitable for a successful invasion. Geological maps smuggled out of Paris by the French Resistance suggested that the beaches might be underlain by peat, which could destabilise the landing. Staggeringly, one of these maps is believed to have dated back to Roman times, when they surveyed the entire empire for peat, as it was used as a fuel source.
Peat, a semi-decomposed organic matter that accumulates over millennia in wetland habitats, can be soft and unstable. Professor John Desmond Bernal, an important scientific adviser to the allies, warned that the beaches might not support the heavy vehicles and equipment of the invasion force.
This is how Normandy, France looks today. Arromanches-les-Bains is once again a peaceful seaside village. The remains of a portable temporary Mulberry harbor still sits in its bay, used by Allied forces for Operation Neptune, the invasion of Europe on June 6, 1944. Credit: Myrabella via Wikimedia Commons
Commandos gathered sediment samples during covert raid
Aerial photography was inconclusive, so physical analysis of the beaches was deemed necessary. The task fell to Lieutenant Commander Nigel Clogstoun-Willmott of the Royal Navy, who had expertise in covert coastal surveying. He had previously created the Combined Operations Pilotage Parties (COPP) to gather detailed information about potential landing sites earlier in the war.
After training and a test mission, COPP swung into action. On December 31, two commandos — 24-year-old Major Logan “Scottie” Scott-Bowden and 25-year-old Sergeant Bruce Ogden-Smith — were chosen to land covertly on the Normandy landing beach codenamed Gold Beach. Their task was to collect sediment samples.
On New Year’s Eve 1943, Scott-Bowden and Ogden-Smith swam ashore under the cover of darkness, having been dropped off by a small boat 300 meters from the French coast. Alongside their swimming suits, rather like modern-day dry-suits, they were equipped with a torch, compass, watch, a fighting knife and a .45 Colt revolver. They also took a soil corer, or auger, for taking soil samples and ten tubes for storing the samples.
When they eventually reached the predetermined point on Gold Beach, they crawled in a W pattern, collecting samples. They recorded their positions on waterproof writing tablets strapped to their wrists. When they had finished sampling the area, they waded into the surf and swam back out to sea. Reaching what they hoped was their rendezvous point, they signalled with their torches fitted with a directional cone and waterproofed with a condom until they were picked up by the rest of the COPP team.
Upon their return to England, the samples were analysed by soil and wetland scientists to determine the peat and clay content. It was crucial for assessing the suitability of the beaches as landing sites.
Wetlands study led to specialized vehicles – ‘funnies’ – for D-Day
Over the following months, COPP surveyed many areas of the Normandy landing beaches, looking for soft clay and peat deposits. It is understood that some of the places were found to be acceptable for wheeled vehicles while other areas weren’t.
In some cases, specialised vehicles and tanks – so-called “funnies” – were specifically designed to cope with the substrate conditions detected by members of COPP. One example of this was the “Bobbin” carpet layer, which laid its own path over soft clay, mud and peat.
The bravery of the COPP commandos and the application of wetland science were instrumental in ensuring the success of D-day. Without their efforts the allies could literally have been bogged down, making them easy targets for German defences. As Admiral Sir Bertram Ramsay, the allied naval commander, stated after the Normandy landings: “On these operations depends to a very great extent the final success of Operation Overlord.”
The actions of the commandos and scientists involved must not be forgotten as we honor the 80th anniversary of D-day. Their work ensured that the beaches of Normandy could support the weight of freedom, changing the course of history.
Bottom line: Wetland science and covert raids helped Allied forces gather critical information prior to the D-Day landing in Normandy, France on June 6, 1944.
A LCVP (Landing Craft, Vehicle, Personnel) from the U.S. Coast Guard-manned USS Samuel Chase disembarks troops of Company A, 16th Infantry, 1st Infantry Division (the Big Red One) wading onto the Fox Green section of Omaha Beach (Calvados, Basse-Normandie, France) on the morning of June 6, 1944. American soldiers encountered the newly formed German 352nd Division when landing. During the initial landing two-thirds of Company E became casualties. Credit Wikipedia/Chief Photographer’s Mate (CPHoM) Robert F. Sargent
Today is D-day’s 80th anniversary. It’s the anniversary of when – in 1944 – World War II’s allied armies began landing on the beaches of Normandy, France during Operation Overlord.
Beneath the roar of gunfire and the chaos of D-day, an unlikely hero played a vital role — wetland science. Often overlooked amid military strategies and troop movements, the study of mud proved critical to the success of the largest amphibious invasion in history.
Much has been written about the events of June 6 1944 and the extensive planning that led up to Operation Overlord on that pivotal day. The success of the Normandy landings involved expertise from a vast array of military, espionage, engineering and communication groups. My new report explains how scientists with knowledge of sediments and substrate formation, such as peat found in bogs and fens, were also instrumental in the planning and execution of D-day.
Following the evacuation of the British Expeditionary Force from Dunkirk during Operation Dynamo in 1940, Britain and its allies began meticulously planning for the invasion of mainland Europe. Gathering intelligence about the French coast and where the invasion would probably occur, was a vital component of these preparations.
The allies concluded that any landing site needed to be within range of their fighter aircraft, sheltered from harsh weather, and near a port to facilitate the landing of additional troops and equipment. These criteria led to the selection of the coast north of Caen in Normandy, France.
However, initial intelligence had raised concerns about whether the beaches were suitable for a successful invasion. Geological maps smuggled out of Paris by the French Resistance suggested that the beaches might be underlain by peat, which could destabilise the landing. Staggeringly, one of these maps is believed to have dated back to Roman times, when they surveyed the entire empire for peat, as it was used as a fuel source.
Peat, a semi-decomposed organic matter that accumulates over millennia in wetland habitats, can be soft and unstable. Professor John Desmond Bernal, an important scientific adviser to the allies, warned that the beaches might not support the heavy vehicles and equipment of the invasion force.
This is how Normandy, France looks today. Arromanches-les-Bains is once again a peaceful seaside village. The remains of a portable temporary Mulberry harbor still sits in its bay, used by Allied forces for Operation Neptune, the invasion of Europe on June 6, 1944. Credit: Myrabella via Wikimedia Commons
Commandos gathered sediment samples during covert raid
Aerial photography was inconclusive, so physical analysis of the beaches was deemed necessary. The task fell to Lieutenant Commander Nigel Clogstoun-Willmott of the Royal Navy, who had expertise in covert coastal surveying. He had previously created the Combined Operations Pilotage Parties (COPP) to gather detailed information about potential landing sites earlier in the war.
After training and a test mission, COPP swung into action. On December 31, two commandos — 24-year-old Major Logan “Scottie” Scott-Bowden and 25-year-old Sergeant Bruce Ogden-Smith — were chosen to land covertly on the Normandy landing beach codenamed Gold Beach. Their task was to collect sediment samples.
On New Year’s Eve 1943, Scott-Bowden and Ogden-Smith swam ashore under the cover of darkness, having been dropped off by a small boat 300 meters from the French coast. Alongside their swimming suits, rather like modern-day dry-suits, they were equipped with a torch, compass, watch, a fighting knife and a .45 Colt revolver. They also took a soil corer, or auger, for taking soil samples and ten tubes for storing the samples.
When they eventually reached the predetermined point on Gold Beach, they crawled in a W pattern, collecting samples. They recorded their positions on waterproof writing tablets strapped to their wrists. When they had finished sampling the area, they waded into the surf and swam back out to sea. Reaching what they hoped was their rendezvous point, they signalled with their torches fitted with a directional cone and waterproofed with a condom until they were picked up by the rest of the COPP team.
Upon their return to England, the samples were analysed by soil and wetland scientists to determine the peat and clay content. It was crucial for assessing the suitability of the beaches as landing sites.
Wetlands study led to specialized vehicles – ‘funnies’ – for D-Day
Over the following months, COPP surveyed many areas of the Normandy landing beaches, looking for soft clay and peat deposits. It is understood that some of the places were found to be acceptable for wheeled vehicles while other areas weren’t.
In some cases, specialised vehicles and tanks – so-called “funnies” – were specifically designed to cope with the substrate conditions detected by members of COPP. One example of this was the “Bobbin” carpet layer, which laid its own path over soft clay, mud and peat.
The bravery of the COPP commandos and the application of wetland science were instrumental in ensuring the success of D-day. Without their efforts the allies could literally have been bogged down, making them easy targets for German defences. As Admiral Sir Bertram Ramsay, the allied naval commander, stated after the Normandy landings: “On these operations depends to a very great extent the final success of Operation Overlord.”
The actions of the commandos and scientists involved must not be forgotten as we honor the 80th anniversary of D-day. Their work ensured that the beaches of Normandy could support the weight of freedom, changing the course of history.
Bottom line: Wetland science and covert raids helped Allied forces gather critical information prior to the D-Day landing in Normandy, France on June 6, 1944.
Artist’s depiction of the new dinosaur species Musankwa sanyatiensis (left), with a metoposaur (right). Image via Atashni Moopen/ EurekaAlert.
A new dinosaur from Zimbabwe
Scientists said on May 30, 2024, they’ve discovered a new dinosaur species from fossils found near Lake Kariba in Zimbabwe, Africa. The new species – Musankwa sanyatiensis – is the 4th dinosaur species discovery in the country. It was a plant-eater that lived around 210 million years ago.
The dinosaur’s genus name, “Musankwa,” was the name of the houseboat scientists used during their expeditions to the research site. Moreover, in the Tonga dialect, it means “boy close to marriage.” In addition, its species name “sanyatiensis” alludes to the Sanyati River that flows into Lake Kariba.
The researchers published their peer-reviewed findings in the journal Acta Palaeontologica Polonica on May 30, 2024.
Identifying a new species from leg bones
In 2018, scientists found the fossils embedded in sandy siltstone on the shoreline of Lake Kariba in Zimbabwe. The rocks that held those fossils dated to the late Triassic period, about 210 million years ago.
They recovered a hind leg that included thigh, shin and ankle bones. Those bones alone were enough to identify it as a sauropodomorpha. These Triassic sauropodomorpha were plant-eaters with long necks that walked on their hind legs.
The leg bones of Musankwa sanyatiensis. This photograph shows them on the shoreline of Lake Kariba in Zimbabwe, the site of their discovery. Image via Paul Barrett/ EurekaAlert.
This new species likely weighed about 850 lbs (386 kg), about the size of a medium-sized horse. Also, scientists think it was one of the larger dinosaurs of that era. It was closely related to other late Triassic sauropodomorpha found in South Africa and Argentina.
Moreover, its fossilized hind leg had features researchers had not seen in other sauropodomorpha. As a result, scientists were able to identify it as a new species. Co-author Kimberley Chapelle of Stony Brook University said:
Despite the limited fossil material, these bones possess unique features that distinguish them from those of other dinosaurs living at the same time.
Dinosaurs in Africa
The first dinosaur discovery from the continent of Africa was in South Africa in 1845. Since then, there have been dino discoveries in about 10 countries, including South Africa, Tanzania, Niger, Zimbabwe and Morocco. For instance, the fossilized bones of Ledumahadi mafube, which lived 200 million years ago, came from South Africa.
But compared to other parts of the world, there have not been many dinosaur discoveries in Africa. Lead author Paul Barrett of the Natural History Museum in London commented:
The main reason for the underrepresentation of African dinosaur fossils is ‘undersampling.’ Put simply, there have been fewer people looking for and unearthing dinosaurs in comparison with other regions of the world.
However, finding this new species gives scientists hope that more discoveries await them. Barrett said:
Over the last six years, many new fossil sites have been recorded in Zimbabwe, yielding a diverse array of prehistoric animals, including the first sub-Saharan mainland African phytosaurs (ancient crocodile-like reptiles), metoposaurid amphibians (giant armored amphibians), lungfish and other reptile remains.
Chapelle added:
Based on where it sits on the dinosaur family tree, Musanwka sanyantiensis is the first dinosaur of its kind from Zimbabwe. It, therefore, highlights the potential of the region for further paleontological discoveries.
A team of scientists from Zimbabwe, South Africa and the UK is seen working at the Lake Kariba shoreline, near the discovery site of Musankwa sanyatiensis. Image via Lara Sciscio/ EurekaAlert.
Bottom line: Scientists have unearthed a new dinosaur species near Lake Kariba in Zimbabwe. It was a plant-eater that lived around 210 million years ago.
Artist’s depiction of the new dinosaur species Musankwa sanyatiensis (left), with a metoposaur (right). Image via Atashni Moopen/ EurekaAlert.
A new dinosaur from Zimbabwe
Scientists said on May 30, 2024, they’ve discovered a new dinosaur species from fossils found near Lake Kariba in Zimbabwe, Africa. The new species – Musankwa sanyatiensis – is the 4th dinosaur species discovery in the country. It was a plant-eater that lived around 210 million years ago.
The dinosaur’s genus name, “Musankwa,” was the name of the houseboat scientists used during their expeditions to the research site. Moreover, in the Tonga dialect, it means “boy close to marriage.” In addition, its species name “sanyatiensis” alludes to the Sanyati River that flows into Lake Kariba.
The researchers published their peer-reviewed findings in the journal Acta Palaeontologica Polonica on May 30, 2024.
Identifying a new species from leg bones
In 2018, scientists found the fossils embedded in sandy siltstone on the shoreline of Lake Kariba in Zimbabwe. The rocks that held those fossils dated to the late Triassic period, about 210 million years ago.
They recovered a hind leg that included thigh, shin and ankle bones. Those bones alone were enough to identify it as a sauropodomorpha. These Triassic sauropodomorpha were plant-eaters with long necks that walked on their hind legs.
The leg bones of Musankwa sanyatiensis. This photograph shows them on the shoreline of Lake Kariba in Zimbabwe, the site of their discovery. Image via Paul Barrett/ EurekaAlert.
This new species likely weighed about 850 lbs (386 kg), about the size of a medium-sized horse. Also, scientists think it was one of the larger dinosaurs of that era. It was closely related to other late Triassic sauropodomorpha found in South Africa and Argentina.
Moreover, its fossilized hind leg had features researchers had not seen in other sauropodomorpha. As a result, scientists were able to identify it as a new species. Co-author Kimberley Chapelle of Stony Brook University said:
Despite the limited fossil material, these bones possess unique features that distinguish them from those of other dinosaurs living at the same time.
Dinosaurs in Africa
The first dinosaur discovery from the continent of Africa was in South Africa in 1845. Since then, there have been dino discoveries in about 10 countries, including South Africa, Tanzania, Niger, Zimbabwe and Morocco. For instance, the fossilized bones of Ledumahadi mafube, which lived 200 million years ago, came from South Africa.
But compared to other parts of the world, there have not been many dinosaur discoveries in Africa. Lead author Paul Barrett of the Natural History Museum in London commented:
The main reason for the underrepresentation of African dinosaur fossils is ‘undersampling.’ Put simply, there have been fewer people looking for and unearthing dinosaurs in comparison with other regions of the world.
However, finding this new species gives scientists hope that more discoveries await them. Barrett said:
Over the last six years, many new fossil sites have been recorded in Zimbabwe, yielding a diverse array of prehistoric animals, including the first sub-Saharan mainland African phytosaurs (ancient crocodile-like reptiles), metoposaurid amphibians (giant armored amphibians), lungfish and other reptile remains.
Chapelle added:
Based on where it sits on the dinosaur family tree, Musanwka sanyantiensis is the first dinosaur of its kind from Zimbabwe. It, therefore, highlights the potential of the region for further paleontological discoveries.
A team of scientists from Zimbabwe, South Africa and the UK is seen working at the Lake Kariba shoreline, near the discovery site of Musankwa sanyatiensis. Image via Lara Sciscio/ EurekaAlert.
Bottom line: Scientists have unearthed a new dinosaur species near Lake Kariba in Zimbabwe. It was a plant-eater that lived around 210 million years ago.
View at EarthSky Community Photos. | The bright star in this montage of time-exposure photos is Polaris, the North Star. Perhaps you’ve heard it stays still in the northern sky, while the other stars circle around it? That’s almost true, but not quite. Marcella Giulia Pace in Modica, Sicily, Italy, contributed this photo. She made a comparison of Polaris trails in late 2022 and throughout 2023. As you can see, Polaris does move in a tiny circle around celestial north. Beautiful work, Marcella! Thank you. Read more about this photo here.
The North Star, aka Polaris
The North Star, also known as Polaris, appears to stay fixed in our northern sky. It marks the location of the sky’s north pole, or the north celestial pole, the point around which the whole northern sky – full of stars – turns. That’s why you can always use Polaris to find the direction north.
Even though the North Star doesn’t appear to move, it does move. The North Star is a symbol for constancy. But, a video of it overnight, reveals that it makes its own little circle around the sky’s north pole every day. That’s because the North Star is offset a little – by about 0.65 degrees – from celestial north. So, Polaris makes a circle that’s 1.3 degrees in diameter each day. When it’s closest to the celestial pole in about 100 years, at a distance of only 0.45 degrees, it’ll make a daily circle of only 0.90 degrees.
Where does this movement – or in Polaris’ case, lack of movement – come from? It comes from Earth’s spin. Earth spins under the sky once a day, and our spin causes the sun in the daytime – and the stars at night – to rise in the east and set in the west. But the North Star is a special case. Because it lies almost exactly above Earth’s northern axis, it’s like the hub of a wheel. It doesn’t rise or set. Instead, it appears to stay put in the northern sky.
View at EarthSky Community Photos. | Radu Anghel in Motoseni, Romania, offered this larger image of star trails around the sky’s north pole in August 2023. In this image, Polaris is the brightest star near the pole. Radu wrote: “A bright Perseid meteor and a Polaris star trail from August 13, 2023.” Thank you, Radu!
How high in your sky?
The North Star not only points toward the north, but its height in the northern sky also matches your latitude on earth. If you are sailing the Caribbean at 16° north latitude, the north star will be about 16° high in your sky. If you are sailing around Nova Scotia, at 44° north latitude, then the North Star will be about 44° high in your northern sky. Each degree north or south equals 69 miles (111 km), so traveling 690 miles north or south will change your latitude, and the North Star’s elevation, by 10 degrees.
The 26,000-year precession cycle causes the north celestial pole to move counterclockwise relative to the background stars. Whichever star is closest to the north celestial pole is called the North Star. Image via Wikimedia Commons (CC BY-SA 2.5).
Taking turns as the North Star
A motion of Earth called precession causes our axis to trace out an imaginary circle on the celestial sphere every 26,000 years. Thousands of years ago, when the pyramids were rising from the sands of ancient Egypt, the North Star was an inconspicuous star called Thuban in the constellation Draco the Dragon. Twelve thousand years from now, the blue-white star Vega in the constellation Lyra the Harp will be a much brighter North Star than our current Polaris.
Polaris could be a name for any North Star. Our current Polaris used to be called Phoenice. It is the 49th brightest star in the sky. It is not known for its brightness, but for its unique position in the sky.
Proper motion
By the way, Polaris – like all stars – has more than one kind of motion. The stars we see in our night sky are all members of our Milky Way galaxy. All of these stars are moving through space, but they’re so far away we can’t easily see them move relative to each other. That’s why the stars appear fixed relative to each other. And it’s why, for the most part, we see the same constellations as our ancestors.
But over time, this movement, called proper motion rearranges the patterns of stars we see in our sky. For Polaris, that movement is small, about 46 arcseconds in 1,000 years. That is about 1/40th of the diameter of the full moon as seen from the earth. So when you’re talking about stars moving or staying fixed, remember … they are all moving through the vastness of space. It’s just the relatively short time of a human lifespan that prevents us from seeing this grand motion.
Bottom line: The North Star is a symbol for constancy. But a video of it overnight reveals that it makes its own little circle around the sky’s north pole every day.
View at EarthSky Community Photos. | The bright star in this montage of time-exposure photos is Polaris, the North Star. Perhaps you’ve heard it stays still in the northern sky, while the other stars circle around it? That’s almost true, but not quite. Marcella Giulia Pace in Modica, Sicily, Italy, contributed this photo. She made a comparison of Polaris trails in late 2022 and throughout 2023. As you can see, Polaris does move in a tiny circle around celestial north. Beautiful work, Marcella! Thank you. Read more about this photo here.
The North Star, aka Polaris
The North Star, also known as Polaris, appears to stay fixed in our northern sky. It marks the location of the sky’s north pole, or the north celestial pole, the point around which the whole northern sky – full of stars – turns. That’s why you can always use Polaris to find the direction north.
Even though the North Star doesn’t appear to move, it does move. The North Star is a symbol for constancy. But, a video of it overnight, reveals that it makes its own little circle around the sky’s north pole every day. That’s because the North Star is offset a little – by about 0.65 degrees – from celestial north. So, Polaris makes a circle that’s 1.3 degrees in diameter each day. When it’s closest to the celestial pole in about 100 years, at a distance of only 0.45 degrees, it’ll make a daily circle of only 0.90 degrees.
Where does this movement – or in Polaris’ case, lack of movement – come from? It comes from Earth’s spin. Earth spins under the sky once a day, and our spin causes the sun in the daytime – and the stars at night – to rise in the east and set in the west. But the North Star is a special case. Because it lies almost exactly above Earth’s northern axis, it’s like the hub of a wheel. It doesn’t rise or set. Instead, it appears to stay put in the northern sky.
View at EarthSky Community Photos. | Radu Anghel in Motoseni, Romania, offered this larger image of star trails around the sky’s north pole in August 2023. In this image, Polaris is the brightest star near the pole. Radu wrote: “A bright Perseid meteor and a Polaris star trail from August 13, 2023.” Thank you, Radu!
How high in your sky?
The North Star not only points toward the north, but its height in the northern sky also matches your latitude on earth. If you are sailing the Caribbean at 16° north latitude, the north star will be about 16° high in your sky. If you are sailing around Nova Scotia, at 44° north latitude, then the North Star will be about 44° high in your northern sky. Each degree north or south equals 69 miles (111 km), so traveling 690 miles north or south will change your latitude, and the North Star’s elevation, by 10 degrees.
The 26,000-year precession cycle causes the north celestial pole to move counterclockwise relative to the background stars. Whichever star is closest to the north celestial pole is called the North Star. Image via Wikimedia Commons (CC BY-SA 2.5).
Taking turns as the North Star
A motion of Earth called precession causes our axis to trace out an imaginary circle on the celestial sphere every 26,000 years. Thousands of years ago, when the pyramids were rising from the sands of ancient Egypt, the North Star was an inconspicuous star called Thuban in the constellation Draco the Dragon. Twelve thousand years from now, the blue-white star Vega in the constellation Lyra the Harp will be a much brighter North Star than our current Polaris.
Polaris could be a name for any North Star. Our current Polaris used to be called Phoenice. It is the 49th brightest star in the sky. It is not known for its brightness, but for its unique position in the sky.
Proper motion
By the way, Polaris – like all stars – has more than one kind of motion. The stars we see in our night sky are all members of our Milky Way galaxy. All of these stars are moving through space, but they’re so far away we can’t easily see them move relative to each other. That’s why the stars appear fixed relative to each other. And it’s why, for the most part, we see the same constellations as our ancestors.
But over time, this movement, called proper motion rearranges the patterns of stars we see in our sky. For Polaris, that movement is small, about 46 arcseconds in 1,000 years. That is about 1/40th of the diameter of the full moon as seen from the earth. So when you’re talking about stars moving or staying fixed, remember … they are all moving through the vastness of space. It’s just the relatively short time of a human lifespan that prevents us from seeing this grand motion.
Bottom line: The North Star is a symbol for constancy. But a video of it overnight reveals that it makes its own little circle around the sky’s north pole every day.
Watch the video above to learn more about the most distant galaxy discovered so far.
NASA published this original article on May 30, 2024. Edits by EarthSky.
Most distant galaxy yet known
Over the last two years, astronomers have been using NASA’s James Webb Space Telescope (also called Webb or JWST) to explore what they call the Cosmic Dawn. It’s the first few hundred million years after the Big Bang, when the first stars and galaxies were born. Looking far out into space and far back in time with Webb, astronomers are using these galaxies to obtain vital insights into the ways in which the gas, stars and black holes were changing when the universe was very young. On May 30, 20224, these astronomers announced the most distant galaxy known so far.
These astronomers from around the globe used Webb to observe galaxies as part of the JWST Advanced Deep Extragalactic Survey (JADES) program. Using Webb’s Near-Infrared Spectrograph (NIRSpec), they obtained a spectrum of a record-breaking galaxy observed only 290 million years after the Big Bang. This corresponds to a redshift of about 14.
Redshift is a measurement of how much the expansion of the universe stretches a galaxy’s light. NASA invited Stefano Carniani from Scuola Normale Superiore in Pisa, Italy, and Kevin Hainline from the University of Arizona in Tucson, Arizona, to tell us more about how Webb found this source and what its unique properties tell us about galaxy formation.
Keep reading to learn what they said.
The Near Infrared Camera (NIRCam) on the Webb space telescope took this infrared image for the JWST Advanced Deep Extragalactic Survey, or JADES, program. The NIRCam data helped determine which galaxies to study further with spectroscopic observations. One such galaxy, JADES-GS-z14-0 (shown in the pullout), had a redshift of 14.32 (+0.08/-0.20). That measurement makes it the current record-holder for the most distant known galaxy. This galaxy existed less than 300 million years after the Big Bang. Image via NASA/ ESA/ CSA/ STScI/ Brant Robertson (UC Santa Cruz)/ Ben Johnson (CfA)/ Sandro Tacchella (Cambridge)/ Phill Cargile (CfA).
Finding the high redshift galaxy
Carniani and Hainline said:
Engineers designed the instruments on Webb to find and understand the earliest galaxies. And in the first year of observations as part of the JWST Advanced Deep Extragalactic Survey (JADES), we found many hundreds of candidate galaxies from the first 650 million years after the Big Bang.
In early 2023, we discovered a galaxy in our data that had strong evidence of being above a redshift of 14, which was very exciting. But there were some properties of the source that made us wary. The source was surprisingly bright, which we wouldn’t expect for such a distant galaxy. And it was very close to another galaxy such that the two appeared to be part of one larger object.
We observed the source again in October 2023 as part of the JADES Origins Field. New imaging data obtained with Webb’s narrower Near-Infrared Camera (NIRCam) filters pointed even more toward the high-redshift hypothesis. We knew we needed a spectrum, as whatever we would learn would be of immense scientific importance, either as a new milestone in Webb’s investigation of the early universe or as a confounding oddball of a middle-aged galaxy.
New most distant galaxy record
Carniani and Hainline continued:
In January 2024, NIRSpec observed this galaxy, JADES-GS-z14-0, for almost 10 hours. And when astronomers first processed the spectrum, there was unambiguous evidence that the galaxy was indeed at a redshift of 14.32. This shattered the previous most-distant galaxy record (z = 13.2 of JADES-GS-z13-0).
Seeing this spectrum was incredibly exciting for the whole team, given the mystery surrounding the source. This discovery was not just a new distance record for our team; the most important aspect of JADES-GS-z14-0 was that at this distance, we know that this galaxy must be intrinsically very luminous. From the images, the source is more than 1,600 light-years across. So that proves the light we see comes mostly from young stars and not from emission near a growing supermassive black hole. This much starlight implies the galaxy is several hundreds of millions of times the mass of the sun!
This raises the question: How can nature make such a bright, massive and large galaxy in less than 300 million years?
Most distant galaxy is surprisingly bright
Carniani and Hainline also said:
The data reveal other important aspects of this astonishing galaxy. We see the color of the galaxy is not as blue as it could be, indicating some of the light is reddened by dust, even at these very early times.
JADES researcher Jake Helton of Steward Observatory and the University of Arizona also identified that JADES-GS-z14-0 was detected at longer wavelengths with Webb’s Mid-Infrared Instrument (MIRI). And that’s a remarkable achievement considering its distance. The MIRI observation covers wavelengths of light emitted in the visible-light range, which are redshifted out of reach for Webb’s near-infrared instruments.
Jake’s analysis indicates the brightness of the source implied by the MIRI observation is above what would be extrapolated from the measurements by the other Webb instruments. And so it indicates the presence of strong ionized gas emission in the galaxy in the form of bright emission lines from hydrogen and oxygen. The presence of oxygen so early in the life of this galaxy is a surprise. It suggests multiple generations of very massive stars had already lived their lives before we observed the galaxy.
Scientists used Webb’s Near-Infrared Spectrograph (NIRSpec) to obtain a spectrum of the distant galaxy JADES-GS-z14-0. This helped them accurately measure its redshift and determine its age. The location of a critical wavelength known as the Lyman-alpha break can determine the redshift. This galaxy dates back to less than 300 million years after the Big Bang. Image via NASA/ ESA/ CSA/ Joseph Olmsted (STScI) and Science via S. Carniani (Scuola Normale Superiore)/ JADES Collaboration.
Distant, luminous galaxy will be one of many
Carniani and Hainline noted:
All these observations, together, tell us that JADES-GS-z14-0 is not like the types of galaxies that have been predicted by theoretical models and computer simulations to exist in the very early universe. Given the observed brightness of the source, we can forecast how it might grow over cosmic time. And so far we have not found any suitable analogs from the hundreds of other galaxies we’ve observed at high redshift in our survey.
Given the relatively small region of the sky that we searched to find JADES-GS-z14-0, its discovery has profound implications for the predicted number of bright galaxies we see in the early universe, as discussed in another concurrent JADES study (Robertson et al., recently accepted). It is likely that astronomers will find many such luminous galaxies, possibly at even earlier times, over the next decade with Webb. We’re thrilled to see the extraordinary diversity of galaxies that existed at Cosmic Dawn!
Stefano Carniani (left) of Scuola Normale Superiore in Pisa, Italy, and Kevin Hainline (right) of the University of Arizona wrote about the new record-holder for most distant galaxy. Images via X.
This post highlights data from Webb science in progress, which has not yet been through the peer-review process.
Bottom line: Astronomers using the Webb space telescope have discovered the most distant galaxy yet known. It existed 290 million years after the Big Bang.
Watch the video above to learn more about the most distant galaxy discovered so far.
NASA published this original article on May 30, 2024. Edits by EarthSky.
Most distant galaxy yet known
Over the last two years, astronomers have been using NASA’s James Webb Space Telescope (also called Webb or JWST) to explore what they call the Cosmic Dawn. It’s the first few hundred million years after the Big Bang, when the first stars and galaxies were born. Looking far out into space and far back in time with Webb, astronomers are using these galaxies to obtain vital insights into the ways in which the gas, stars and black holes were changing when the universe was very young. On May 30, 20224, these astronomers announced the most distant galaxy known so far.
These astronomers from around the globe used Webb to observe galaxies as part of the JWST Advanced Deep Extragalactic Survey (JADES) program. Using Webb’s Near-Infrared Spectrograph (NIRSpec), they obtained a spectrum of a record-breaking galaxy observed only 290 million years after the Big Bang. This corresponds to a redshift of about 14.
Redshift is a measurement of how much the expansion of the universe stretches a galaxy’s light. NASA invited Stefano Carniani from Scuola Normale Superiore in Pisa, Italy, and Kevin Hainline from the University of Arizona in Tucson, Arizona, to tell us more about how Webb found this source and what its unique properties tell us about galaxy formation.
Keep reading to learn what they said.
The Near Infrared Camera (NIRCam) on the Webb space telescope took this infrared image for the JWST Advanced Deep Extragalactic Survey, or JADES, program. The NIRCam data helped determine which galaxies to study further with spectroscopic observations. One such galaxy, JADES-GS-z14-0 (shown in the pullout), had a redshift of 14.32 (+0.08/-0.20). That measurement makes it the current record-holder for the most distant known galaxy. This galaxy existed less than 300 million years after the Big Bang. Image via NASA/ ESA/ CSA/ STScI/ Brant Robertson (UC Santa Cruz)/ Ben Johnson (CfA)/ Sandro Tacchella (Cambridge)/ Phill Cargile (CfA).
Finding the high redshift galaxy
Carniani and Hainline said:
Engineers designed the instruments on Webb to find and understand the earliest galaxies. And in the first year of observations as part of the JWST Advanced Deep Extragalactic Survey (JADES), we found many hundreds of candidate galaxies from the first 650 million years after the Big Bang.
In early 2023, we discovered a galaxy in our data that had strong evidence of being above a redshift of 14, which was very exciting. But there were some properties of the source that made us wary. The source was surprisingly bright, which we wouldn’t expect for such a distant galaxy. And it was very close to another galaxy such that the two appeared to be part of one larger object.
We observed the source again in October 2023 as part of the JADES Origins Field. New imaging data obtained with Webb’s narrower Near-Infrared Camera (NIRCam) filters pointed even more toward the high-redshift hypothesis. We knew we needed a spectrum, as whatever we would learn would be of immense scientific importance, either as a new milestone in Webb’s investigation of the early universe or as a confounding oddball of a middle-aged galaxy.
New most distant galaxy record
Carniani and Hainline continued:
In January 2024, NIRSpec observed this galaxy, JADES-GS-z14-0, for almost 10 hours. And when astronomers first processed the spectrum, there was unambiguous evidence that the galaxy was indeed at a redshift of 14.32. This shattered the previous most-distant galaxy record (z = 13.2 of JADES-GS-z13-0).
Seeing this spectrum was incredibly exciting for the whole team, given the mystery surrounding the source. This discovery was not just a new distance record for our team; the most important aspect of JADES-GS-z14-0 was that at this distance, we know that this galaxy must be intrinsically very luminous. From the images, the source is more than 1,600 light-years across. So that proves the light we see comes mostly from young stars and not from emission near a growing supermassive black hole. This much starlight implies the galaxy is several hundreds of millions of times the mass of the sun!
This raises the question: How can nature make such a bright, massive and large galaxy in less than 300 million years?
Most distant galaxy is surprisingly bright
Carniani and Hainline also said:
The data reveal other important aspects of this astonishing galaxy. We see the color of the galaxy is not as blue as it could be, indicating some of the light is reddened by dust, even at these very early times.
JADES researcher Jake Helton of Steward Observatory and the University of Arizona also identified that JADES-GS-z14-0 was detected at longer wavelengths with Webb’s Mid-Infrared Instrument (MIRI). And that’s a remarkable achievement considering its distance. The MIRI observation covers wavelengths of light emitted in the visible-light range, which are redshifted out of reach for Webb’s near-infrared instruments.
Jake’s analysis indicates the brightness of the source implied by the MIRI observation is above what would be extrapolated from the measurements by the other Webb instruments. And so it indicates the presence of strong ionized gas emission in the galaxy in the form of bright emission lines from hydrogen and oxygen. The presence of oxygen so early in the life of this galaxy is a surprise. It suggests multiple generations of very massive stars had already lived their lives before we observed the galaxy.
Scientists used Webb’s Near-Infrared Spectrograph (NIRSpec) to obtain a spectrum of the distant galaxy JADES-GS-z14-0. This helped them accurately measure its redshift and determine its age. The location of a critical wavelength known as the Lyman-alpha break can determine the redshift. This galaxy dates back to less than 300 million years after the Big Bang. Image via NASA/ ESA/ CSA/ Joseph Olmsted (STScI) and Science via S. Carniani (Scuola Normale Superiore)/ JADES Collaboration.
Distant, luminous galaxy will be one of many
Carniani and Hainline noted:
All these observations, together, tell us that JADES-GS-z14-0 is not like the types of galaxies that have been predicted by theoretical models and computer simulations to exist in the very early universe. Given the observed brightness of the source, we can forecast how it might grow over cosmic time. And so far we have not found any suitable analogs from the hundreds of other galaxies we’ve observed at high redshift in our survey.
Given the relatively small region of the sky that we searched to find JADES-GS-z14-0, its discovery has profound implications for the predicted number of bright galaxies we see in the early universe, as discussed in another concurrent JADES study (Robertson et al., recently accepted). It is likely that astronomers will find many such luminous galaxies, possibly at even earlier times, over the next decade with Webb. We’re thrilled to see the extraordinary diversity of galaxies that existed at Cosmic Dawn!
Stefano Carniani (left) of Scuola Normale Superiore in Pisa, Italy, and Kevin Hainline (right) of the University of Arizona wrote about the new record-holder for most distant galaxy. Images via X.
This post highlights data from Webb science in progress, which has not yet been through the peer-review process.
Bottom line: Astronomers using the Webb space telescope have discovered the most distant galaxy yet known. It existed 290 million years after the Big Bang.
The Arietids are an active shower, but they’re visible mostly in daytime. Watch for them in the sunrise direction in the dark hour before dawn from May 29 to June 17. You’ll be looking for meteors that shoot up from the horizon. The radiant point is below the constellation Aries. Chart by John Jardine Goss.
June 2024 daytime meteor shower … the Arietids
Most meteor showers are easy to observe. Just find a dark sky, and look up! But what about meteor showers that happen in the daytime, when the sun is up? The Arietids are sometimes said to be the most active daytime meteor shower. In 2024, their predicted** peak will be around the morning of June 4. You might catch some Arietids around that morning in the dark hour before dawn.
When to watch: Watch from May 29 to June 17. There’s a predicted** peak for the mornings around June 4, 2024. Watch for them in the sunrise direction in the dark hour before dawn breaks. Nearest moon phase: In 2024, a new moon occurs at 12:38 UTC on June 6. So the mornings around the peak will be completely moon-free. Radiant: The shower’s radiant point – the point in the sky from which the meteors appear to radiate – is in the constellation Aries. You’ll find this constellation in the east before sunrise. Duration of shower: May 29 to June 17. Expected meteors at peak: This is tricky for daytime meteor showers because once the sun comes up, you won’t be able to see them. But the Arietids have a strong zenithal hourly rate (ZHR)! Meteor counts with radar and radio echoes have indicated a rate of 60 meteors per hour, and perhaps as high as 200 meteors per hour. Note: The Arietids are sometimes said to be the most active daytime meteor shower.
The Arietids shower’s radiant point – the point in the sky from which the meteors appear to radiate – is only 30 degrees from the sun. This 30-degree angle – the angle between the sun and the meteor radiant as seen from Earth – is the shower’s elongation.
How to observe the Arietids
So – although most Arietid meteors fly in daylight – you might catch an Arietid in the last dark hour before dawn, any time during the first and second weeks of June.
The trick is to catch them in the narrow window after the radiant rises (or when it is about to rise), but before the visible breaking of dawn. The radiant rises just before the beginning of astronomical twilight – the darkest twilight stage – which is defined as the period of time when the center of the sun is 12 degrees below the horizon to 18 degrees below the horizon. You probably won’t even notice any illumination in the sky during astronomical twilight.
Face east and watch for meteors moving away from the radiant. The meteors will be moving out in all directions from the radiant. Therefore, many will never breach your horizon. But some meteors will move upward in your eastern predawn sky.
How many meteors will you see?
A shower’s zenithal hourly rate (ZHR) is the number of meteors you’ll see in one hour when the radiant is directly overhead and you can see stars as faint as magnitude 6.5.
For daytime meteor showers, we have a couple of problems here. When a daytime meteor shower’s radiant is overhead, it’s daytime. And so you can’t see stars down to magnitude 6.5. But when it’s nighttime and seeing faint stars becomes possible, a daytime meteor shower’s radiant is below your horizon.
So we never have ideal conditions for seeing the Arietids. But they have an awesome ZHR! Meteor counts with radar and radio echoes have indicated a rate of 60 meteors per hour, and perhaps as high as 200 meteors per hour.
How many will you see on the morning of June 7, or the several mornings around then? Meteor shower peaks often vary between experts. At the website of the American Meteor Society (AMS), in his Meteor Outlook for June 1 to 7, 2024, Robert Lunsford wrote last year:
Current rates are expected to be less than 1 no matter your location.
But who knows? You might see more! And it’d be fun to see any meteors from this (mostly) daytime shower.
Also, Robert Lunsford points out:
You can keep track of the activity of [daytime] meteor showers, as well as those beyond the limits of visual observing, by visiting the NASA Meteor Shower Portal available at: https://meteorshowers.seti.org/ You can move the sky globe to see different areas of the sky. Colored dots indicate shower meteors while white dots indicate sporadic (random) activity. The large orange disk indicates the position of the sun, so little activity will be seen in that area of the sky.
Arietids history and parent comet
The Arietids have a fascinating history. Astronomers at the Jodrell Bank Radio Telescope in England first noticed them in 1947. Here’s a paper that discusses this daytime meteor shower, plus three other showers. Scientists made the discovery with radar echoes and confirmed them, in some cases, with photographs.
For many years, no one knew the parent comet for the Arietids. Then, in May 1986, this author, Don Machholz, discovered a comet that became known as 96P/Machholz. This comet might be directly involved with this meteor shower, or the shower’s source might be a part of the Machholz Complex. The Machholz Complex is a combination of two comet groups, eight meteor showers and at least one asteroid all associated with Comet 96P/Machholz.
If you see an Arietid meteor in 2024, let us know!
Bottom line: The Arietids are mostly a daytime meteor shower, but the radiant rises in the last dark hour before dawn. The Arietids peak around the morning of June 4, 2024. The moon will not interfere. Face east, and watch for meteors shooting up from the horizon.
**Predicted peak times and dates for meteor showers are from the American Meteor Society. Note that meteor shower peak times can vary.
The Arietids are an active shower, but they’re visible mostly in daytime. Watch for them in the sunrise direction in the dark hour before dawn from May 29 to June 17. You’ll be looking for meteors that shoot up from the horizon. The radiant point is below the constellation Aries. Chart by John Jardine Goss.
June 2024 daytime meteor shower … the Arietids
Most meteor showers are easy to observe. Just find a dark sky, and look up! But what about meteor showers that happen in the daytime, when the sun is up? The Arietids are sometimes said to be the most active daytime meteor shower. In 2024, their predicted** peak will be around the morning of June 4. You might catch some Arietids around that morning in the dark hour before dawn.
When to watch: Watch from May 29 to June 17. There’s a predicted** peak for the mornings around June 4, 2024. Watch for them in the sunrise direction in the dark hour before dawn breaks. Nearest moon phase: In 2024, a new moon occurs at 12:38 UTC on June 6. So the mornings around the peak will be completely moon-free. Radiant: The shower’s radiant point – the point in the sky from which the meteors appear to radiate – is in the constellation Aries. You’ll find this constellation in the east before sunrise. Duration of shower: May 29 to June 17. Expected meteors at peak: This is tricky for daytime meteor showers because once the sun comes up, you won’t be able to see them. But the Arietids have a strong zenithal hourly rate (ZHR)! Meteor counts with radar and radio echoes have indicated a rate of 60 meteors per hour, and perhaps as high as 200 meteors per hour. Note: The Arietids are sometimes said to be the most active daytime meteor shower.
The Arietids shower’s radiant point – the point in the sky from which the meteors appear to radiate – is only 30 degrees from the sun. This 30-degree angle – the angle between the sun and the meteor radiant as seen from Earth – is the shower’s elongation.
How to observe the Arietids
So – although most Arietid meteors fly in daylight – you might catch an Arietid in the last dark hour before dawn, any time during the first and second weeks of June.
The trick is to catch them in the narrow window after the radiant rises (or when it is about to rise), but before the visible breaking of dawn. The radiant rises just before the beginning of astronomical twilight – the darkest twilight stage – which is defined as the period of time when the center of the sun is 12 degrees below the horizon to 18 degrees below the horizon. You probably won’t even notice any illumination in the sky during astronomical twilight.
Face east and watch for meteors moving away from the radiant. The meteors will be moving out in all directions from the radiant. Therefore, many will never breach your horizon. But some meteors will move upward in your eastern predawn sky.
How many meteors will you see?
A shower’s zenithal hourly rate (ZHR) is the number of meteors you’ll see in one hour when the radiant is directly overhead and you can see stars as faint as magnitude 6.5.
For daytime meteor showers, we have a couple of problems here. When a daytime meteor shower’s radiant is overhead, it’s daytime. And so you can’t see stars down to magnitude 6.5. But when it’s nighttime and seeing faint stars becomes possible, a daytime meteor shower’s radiant is below your horizon.
So we never have ideal conditions for seeing the Arietids. But they have an awesome ZHR! Meteor counts with radar and radio echoes have indicated a rate of 60 meteors per hour, and perhaps as high as 200 meteors per hour.
How many will you see on the morning of June 7, or the several mornings around then? Meteor shower peaks often vary between experts. At the website of the American Meteor Society (AMS), in his Meteor Outlook for June 1 to 7, 2024, Robert Lunsford wrote last year:
Current rates are expected to be less than 1 no matter your location.
But who knows? You might see more! And it’d be fun to see any meteors from this (mostly) daytime shower.
Also, Robert Lunsford points out:
You can keep track of the activity of [daytime] meteor showers, as well as those beyond the limits of visual observing, by visiting the NASA Meteor Shower Portal available at: https://meteorshowers.seti.org/ You can move the sky globe to see different areas of the sky. Colored dots indicate shower meteors while white dots indicate sporadic (random) activity. The large orange disk indicates the position of the sun, so little activity will be seen in that area of the sky.
Arietids history and parent comet
The Arietids have a fascinating history. Astronomers at the Jodrell Bank Radio Telescope in England first noticed them in 1947. Here’s a paper that discusses this daytime meteor shower, plus three other showers. Scientists made the discovery with radar echoes and confirmed them, in some cases, with photographs.
For many years, no one knew the parent comet for the Arietids. Then, in May 1986, this author, Don Machholz, discovered a comet that became known as 96P/Machholz. This comet might be directly involved with this meteor shower, or the shower’s source might be a part of the Machholz Complex. The Machholz Complex is a combination of two comet groups, eight meteor showers and at least one asteroid all associated with Comet 96P/Machholz.
If you see an Arietid meteor in 2024, let us know!
Bottom line: The Arietids are mostly a daytime meteor shower, but the radiant rises in the last dark hour before dawn. The Arietids peak around the morning of June 4, 2024. The moon will not interfere. Face east, and watch for meteors shooting up from the horizon.
**Predicted peak times and dates for meteor showers are from the American Meteor Society. Note that meteor shower peak times can vary.
The Lucy mission took this image a few minutes after closest approach on November 1, 2023. We clearly see the asteroid’s double moon, Selam, on the right, as 2 smaller bodies stuck together. The asteroid Dinkinesh is on the left. Image via NASA/ SwRI/ Johns Hopkins APL/ NOIRLab.
A new study of asteroid Dinkinesh and its moon Selam, led by researchers at Southwest Research Institute, shows a complex geological history for both bodies.
Data from NASA’s Lucy mission, which passed by Dinkinesh in November 2023, show ejected material from the larger asteroid likely formed its satellite, the dual-lobed Selam.
Lucy will be visiting at least nine more asteroids during its mission, including eight Trojan asteroids near Jupiter.
Asteroid Dinkinesh and its lobed moon, Selam
When the NASA spacecraft Lucy visited the asteroid Dinkinesh in the main asteroid belt in November 2023, it made quite a discovery. It found Dinkinesh had a small companion moon, which researchers named Selam. A few days after that discovery, more images from Lucy showed Selam wasn’t just a single satellite but two fused together. A team led by researchers at Southwest Research Institute (SwRI) in Boulder, Colorado, recently studied data sent back by Lucy. They said on May 30, 2024, that new research shows how the asteroid’s double moon points to a complex history of all three mini-worlds.
The researchers published their findings in a new peer-reviewed paper in Nature on May 29, 2024.
Asteroid’s double moon
Scientists say Selam likely formed when material on Dinkinesh shifted, which created a trough on the asteroid and ejected material into space. Some material fell back on Dinkinesh and formed a ridge. Then, some of the other ejected material coalesced to form Selam. Astronomers aren’t quite sure how the satellite arrived at its current form of two lobes stuck together, or what scientists call a contact binary. But these closer looks at the ridged asteroid Dinkinesh and binary Selam suggest they have a lot of internal strength. Lead author Hal Levison at SwRI said:
This flyby showed us Dinkinesh has some strength and allowed us to do a little ‘archaeology’ to see how this tiny asteroid evolved. When it broke apart, a disk of material formed, some of which rained back onto the surface, creating the ridge.
Levison also said:
To understand the history of planets like Earth, we need to understand how objects behave when they hit each other, which is affected by the strength of the planetary materials. We think the planets formed as zillions of objects orbiting the sun, like asteroids, ran into each other. Whether objects break apart when they hit or stick together has a lot to do with their strength and internal structure.
So just how the material from Dinkinesh formed the lobed moonlet is still uncertain. As astrophysicist Kevin Walsh at SwRI explained:
We see ridges around asteroids’ equators regularly among near-Earth asteroids, but seeing one up close, around an asteroid with a satellite, helps to unravel some of the possible histories of these binary asteroids.
Asteroid’s double moon delivers data and delights
The Lucy flyby provided data and unexpected delights. Simone Marchi, Lucy deputy principal investigator and second author of the paper, said:
The Lucy science team started gathering data about Dinkinesh using telescopes in January 2023, when it was added to our list of targets. Thanks to the telescopic data, we thought we had quite a good picture of what Dinkinesh would look like, and we were thrilled to make so many unexpected discoveries.
NASA’s Lucy spacecraft captured this view of asteroid Dinkinesh and its smaller moon Selam on November 1, 2023. Here, the little moon looks like 1 small body. But later images would show it to be 2, attached together. Image via NASA/ SwRI/ Johns Hopkins APL/ NOIRLab.
More asteroids for Lucy
Lucy’s mission is far from over. There are nine more asteroids the spacecraft will explore over the next several years. Currently, it’s heading back toward Earth. It will use Earth’s gravity in December 2024 to slingshot out toward its next encounters. Its next target? Asteroid Donaldjohanson in 2025.
After that, it will head for its primary target, the Trojan asteroids. The Trojans share the same orbit as Jupiter, in swarms both ahead of and behind the planet. In 2027, Lucy will fly past no less than eight Trojan asteroids, in both swarms. Will Lucy find any more asteroids with moons? Or even double moons? Stay tuned!
When Lucy flew past Dininesh on November 1, 2023, it found some surprises. The larger asteroid has a small moon. And the moon is a pair of 2 smaller bodies fused together. Image via NASA’s Goddard Space Flight Center/ YouTube.
Bottom line: A new study of asteroid Dinkinesh and its moon, Selam, shows a complex history. Data from the Lucy mission provided a deeper insight of Dinkinesh and the asteroid’s double moon.
The Lucy mission took this image a few minutes after closest approach on November 1, 2023. We clearly see the asteroid’s double moon, Selam, on the right, as 2 smaller bodies stuck together. The asteroid Dinkinesh is on the left. Image via NASA/ SwRI/ Johns Hopkins APL/ NOIRLab.
A new study of asteroid Dinkinesh and its moon Selam, led by researchers at Southwest Research Institute, shows a complex geological history for both bodies.
Data from NASA’s Lucy mission, which passed by Dinkinesh in November 2023, show ejected material from the larger asteroid likely formed its satellite, the dual-lobed Selam.
Lucy will be visiting at least nine more asteroids during its mission, including eight Trojan asteroids near Jupiter.
Asteroid Dinkinesh and its lobed moon, Selam
When the NASA spacecraft Lucy visited the asteroid Dinkinesh in the main asteroid belt in November 2023, it made quite a discovery. It found Dinkinesh had a small companion moon, which researchers named Selam. A few days after that discovery, more images from Lucy showed Selam wasn’t just a single satellite but two fused together. A team led by researchers at Southwest Research Institute (SwRI) in Boulder, Colorado, recently studied data sent back by Lucy. They said on May 30, 2024, that new research shows how the asteroid’s double moon points to a complex history of all three mini-worlds.
The researchers published their findings in a new peer-reviewed paper in Nature on May 29, 2024.
Asteroid’s double moon
Scientists say Selam likely formed when material on Dinkinesh shifted, which created a trough on the asteroid and ejected material into space. Some material fell back on Dinkinesh and formed a ridge. Then, some of the other ejected material coalesced to form Selam. Astronomers aren’t quite sure how the satellite arrived at its current form of two lobes stuck together, or what scientists call a contact binary. But these closer looks at the ridged asteroid Dinkinesh and binary Selam suggest they have a lot of internal strength. Lead author Hal Levison at SwRI said:
This flyby showed us Dinkinesh has some strength and allowed us to do a little ‘archaeology’ to see how this tiny asteroid evolved. When it broke apart, a disk of material formed, some of which rained back onto the surface, creating the ridge.
Levison also said:
To understand the history of planets like Earth, we need to understand how objects behave when they hit each other, which is affected by the strength of the planetary materials. We think the planets formed as zillions of objects orbiting the sun, like asteroids, ran into each other. Whether objects break apart when they hit or stick together has a lot to do with their strength and internal structure.
So just how the material from Dinkinesh formed the lobed moonlet is still uncertain. As astrophysicist Kevin Walsh at SwRI explained:
We see ridges around asteroids’ equators regularly among near-Earth asteroids, but seeing one up close, around an asteroid with a satellite, helps to unravel some of the possible histories of these binary asteroids.
Asteroid’s double moon delivers data and delights
The Lucy flyby provided data and unexpected delights. Simone Marchi, Lucy deputy principal investigator and second author of the paper, said:
The Lucy science team started gathering data about Dinkinesh using telescopes in January 2023, when it was added to our list of targets. Thanks to the telescopic data, we thought we had quite a good picture of what Dinkinesh would look like, and we were thrilled to make so many unexpected discoveries.
NASA’s Lucy spacecraft captured this view of asteroid Dinkinesh and its smaller moon Selam on November 1, 2023. Here, the little moon looks like 1 small body. But later images would show it to be 2, attached together. Image via NASA/ SwRI/ Johns Hopkins APL/ NOIRLab.
More asteroids for Lucy
Lucy’s mission is far from over. There are nine more asteroids the spacecraft will explore over the next several years. Currently, it’s heading back toward Earth. It will use Earth’s gravity in December 2024 to slingshot out toward its next encounters. Its next target? Asteroid Donaldjohanson in 2025.
After that, it will head for its primary target, the Trojan asteroids. The Trojans share the same orbit as Jupiter, in swarms both ahead of and behind the planet. In 2027, Lucy will fly past no less than eight Trojan asteroids, in both swarms. Will Lucy find any more asteroids with moons? Or even double moons? Stay tuned!
When Lucy flew past Dininesh on November 1, 2023, it found some surprises. The larger asteroid has a small moon. And the moon is a pair of 2 smaller bodies fused together. Image via NASA’s Goddard Space Flight Center/ YouTube.
Bottom line: A new study of asteroid Dinkinesh and its moon, Selam, shows a complex history. Data from the Lucy mission provided a deeper insight of Dinkinesh and the asteroid’s double moon.
