A new study shows that some 4 billion years ago, a giant asteroid slammed into Jupiter’s moon, Ganymede, shifting its axis. Ganymede is the largest of Jupiter’s moons and the largest moon in our solar system. Image via Hirata Naoyuki (CC BY)/ Kobe University.
Jupiter’s moon slammed and tipped by ancient asteroid
Some 4 billion years ago, a behemoth asteroid – perhaps 20 times larger than Earth’s dinosaur-killer – slammed into Jupiter’s moon Ganymede. The incredible impact would have sent ejecta flying outward, creating concentric circles of debris around the impact site. On September 3, 2024, Kobe University said the impact caused Ganymede to shift on its axis as a result.
The scientists published their results in the peer-reviewed journal Scientific Reports on September 3, 2024.
Furrows on Ganymede
In images of Ganymede, you can see long lines called furrows covering much of one side of the moon (see image below). These ancient markings are partly covered by craters from more recent impact events. Previously, scientists in the ’80s determined that these furrows were the concentric rings of ejecta pointing back to the site of a major impact. Hirata Naoyuki, the lead author of the new study, said:
The Jupiter moons Io, Europa, Ganymede and Callisto all have interesting individual characteristics. But the one that caught my attention was these furrows on Ganymede. We know that this feature was created by an asteroid impact about 4 billion years ago. But we were unsure how big this impact was and what effect it had on the moon.
Ganymede, the largest moon of Jupiter and the largest in our solar system, was hit by an asteroid (near the red cross) some 4 billion years ago. It left behind furrows on the planets surface, which appear as parallel lines in the inset at right. Image via Hirata Naoyuki (CC BY)/ Kobe University.
Jupiter’s moon Ganymede and the new discovery
Ganymede is our solar system’s largest moon. In fact, it’s even larger than the planet Mercury. And beneath Ganymede’s icy surface lies an ocean of liquid water. Also, if we lived on Jupiter, we would only ever see one side of Ganymede, just like we do with Earth’s moon. That’s because both satellites are tidally locked to their planets.
While examining the furrows on Ganymede, Hirata noticed the impact site is on the opposite side of the moon from Jupiter. This reminded him of a discovery that New Horizons made at Pluto. On Pluto, a huge basin named Sputnik Planitia is likely the result of a giant impact that tilted Pluto’s axis. The press release said:
Drawing from similarities with an impact event on Pluto that caused the dwarf planet’s rotational axis to shift and that we learned about through the New Horizons space probe, this implied that Ganymede, too, had undergone such a reorientation.
Hirata’s many simulations of impact events on moons and asteroids helped him calculate an impact that would have put this reorientation into motion.
The giant impact
Hirata calculated the asteroid would have had to be around 195 miles (300 km) in diameter. And it would have created an initial crater between 875 to 1,000 miles (1,400 to 1,600 km) in diameter. (That’s before the ejecta settles back in.) This is the size of impact that would be necessary to change the mass distribution to shift the moon’s rotational axis to where it is now. Hirata said:
I want to understand the origin and evolution of Ganymede and other Jupiter moons. The giant impact must have had a significant impact on the early evolution of Ganymede, but the thermal and structural effects of the impact on the interior of Ganymede have not yet been investigated at all. I believe that further research applying the internal evolution of ice moons could be carried out next.
In the top image, we see the distribution of furrows in the hemisphere that always faces away from Jupiter. At bottom is a cylindrical projection map of Ganymede. Gray regions represent younger terrain without furrows. The furrows (green lines) are only on old terrain (black). Image via Hirata Naoyuki (CC BY)/ Kobe University.
JUICE on route to Jupiter
ESA’s JUICE space mission is currently speeding toward Jupiter and its moons. A decade from now, we may know more about Ganymede and better understand what happened during its giant impact some 4 billion years ago.
Bottom line: About 4 billion years ago, a huge asteroid – 20 times larger than Earth’s dinosaur-killer – struck Ganymede and tilted the moon’s orientation.
A new study shows that some 4 billion years ago, a giant asteroid slammed into Jupiter’s moon, Ganymede, shifting its axis. Ganymede is the largest of Jupiter’s moons and the largest moon in our solar system. Image via Hirata Naoyuki (CC BY)/ Kobe University.
Jupiter’s moon slammed and tipped by ancient asteroid
Some 4 billion years ago, a behemoth asteroid – perhaps 20 times larger than Earth’s dinosaur-killer – slammed into Jupiter’s moon Ganymede. The incredible impact would have sent ejecta flying outward, creating concentric circles of debris around the impact site. On September 3, 2024, Kobe University said the impact caused Ganymede to shift on its axis as a result.
The scientists published their results in the peer-reviewed journal Scientific Reports on September 3, 2024.
Furrows on Ganymede
In images of Ganymede, you can see long lines called furrows covering much of one side of the moon (see image below). These ancient markings are partly covered by craters from more recent impact events. Previously, scientists in the ’80s determined that these furrows were the concentric rings of ejecta pointing back to the site of a major impact. Hirata Naoyuki, the lead author of the new study, said:
The Jupiter moons Io, Europa, Ganymede and Callisto all have interesting individual characteristics. But the one that caught my attention was these furrows on Ganymede. We know that this feature was created by an asteroid impact about 4 billion years ago. But we were unsure how big this impact was and what effect it had on the moon.
Ganymede, the largest moon of Jupiter and the largest in our solar system, was hit by an asteroid (near the red cross) some 4 billion years ago. It left behind furrows on the planets surface, which appear as parallel lines in the inset at right. Image via Hirata Naoyuki (CC BY)/ Kobe University.
Jupiter’s moon Ganymede and the new discovery
Ganymede is our solar system’s largest moon. In fact, it’s even larger than the planet Mercury. And beneath Ganymede’s icy surface lies an ocean of liquid water. Also, if we lived on Jupiter, we would only ever see one side of Ganymede, just like we do with Earth’s moon. That’s because both satellites are tidally locked to their planets.
While examining the furrows on Ganymede, Hirata noticed the impact site is on the opposite side of the moon from Jupiter. This reminded him of a discovery that New Horizons made at Pluto. On Pluto, a huge basin named Sputnik Planitia is likely the result of a giant impact that tilted Pluto’s axis. The press release said:
Drawing from similarities with an impact event on Pluto that caused the dwarf planet’s rotational axis to shift and that we learned about through the New Horizons space probe, this implied that Ganymede, too, had undergone such a reorientation.
Hirata’s many simulations of impact events on moons and asteroids helped him calculate an impact that would have put this reorientation into motion.
The giant impact
Hirata calculated the asteroid would have had to be around 195 miles (300 km) in diameter. And it would have created an initial crater between 875 to 1,000 miles (1,400 to 1,600 km) in diameter. (That’s before the ejecta settles back in.) This is the size of impact that would be necessary to change the mass distribution to shift the moon’s rotational axis to where it is now. Hirata said:
I want to understand the origin and evolution of Ganymede and other Jupiter moons. The giant impact must have had a significant impact on the early evolution of Ganymede, but the thermal and structural effects of the impact on the interior of Ganymede have not yet been investigated at all. I believe that further research applying the internal evolution of ice moons could be carried out next.
In the top image, we see the distribution of furrows in the hemisphere that always faces away from Jupiter. At bottom is a cylindrical projection map of Ganymede. Gray regions represent younger terrain without furrows. The furrows (green lines) are only on old terrain (black). Image via Hirata Naoyuki (CC BY)/ Kobe University.
JUICE on route to Jupiter
ESA’s JUICE space mission is currently speeding toward Jupiter and its moons. A decade from now, we may know more about Ganymede and better understand what happened during its giant impact some 4 billion years ago.
Bottom line: About 4 billion years ago, a huge asteroid – 20 times larger than Earth’s dinosaur-killer – struck Ganymede and tilted the moon’s orientation.
Note: The large spiral Triangulum galaxy is slightly more distant at 2.7 million light-years. Like the Andromeda galaxy, it’s a member of our Local Group of galaxies. And it’s sometimes visible to the eye also. But it’s turned face-on to us, and so has a low surface brightness. Unlike the Andromeda galaxy, it’s more challenging to see.
Astronomers sometimes call the Andromeda galaxy by the name Messier 31, or M31. It was the 31st on a famous list of fuzzy sky objects compiled by the French astronomer Charles Messier (1730-1817). His catalog listed “objects to avoid” when comet-hunting. Nowadays, amateur astronomers seek out these objects with their telescopes and binoculars. They’re some of most beautiful deep-sky objects known.
Most Messier objects are star clusters or gas clouds in our Milky Way galaxy. But the Andromeda galaxy is a whole separate galaxy, even bigger than our Milky Way. In a dark sky, you can see that it’s big on the sky as well, a smudge of distant light larger than a full moon.
Some images of M31 from our EarthSky community
View at EarthSky Community Photos. | Jeremy Likness in Newport, Oregon, captured this telescopic view of the Andromeda galaxy on July 9, 2024. Jeremy wrote: “It’s a galaxy so near it could be interacting with our stars. It’s so big and bright that you can photograph it with an ordinary camera. The Andromeda galaxy, named for the constellation it hangs out in, is located just off the edge of the distinct ‘W’ of Cassiopeia. I used a hydrogen-alpha filter to find the red emissions hanging out in the limbs of this barred spiral galaxy that is our neighbor.” Thank you, Jeremy!View at EarthSky Community Photos. | Steven Bellavia in Mattituck, New York, assembled this impressive composite of the Andromeda galaxy on January 27, 2024. Steven wrote: “I decided to take my last 2 years of data on M31, the Andromeda galaxy, and put it all together. The star-forming regions appear as small red ‘knots’ in and beyond the spiral arms, and the collections of young, hot blue stars appear as blue regions. The Andromeda Galaxy is a barred spiral galaxy and the nearest major galaxy to the Milky Way. It’s about 2.5 million light-years from Earth.” Thank you, Steven!
When to look for it
From mid-northern latitudes, you can see Andromeda – M31 – for at least part of every night, all year long. But most people see the galaxy first around August or September, when it’s high enough in the sky to be seen from evening until daybreak.
In early September, begin looking for the galaxy in mid-evening, about midway between your local nightfall and midnight.
In late September and early October, the Andromeda galaxy shines in your eastern sky at nightfall, swings high overhead in the middle of the night, and stands rather high in the west at the onset of morning dawn.
Winter evenings are also good for viewing the Andromeda galaxy.
If you are far from city lights, and you’re stargazing during a moonless night during the late summer, or on any autumn or winter evening, it’s possible that you’ll simply notice the galaxy there in your night sky. But if you don’t manage to easily see it, you can star-hop to find the galaxy in one of two ways. The easiest way is to use the constellation Cassiopeia the Queen. You can also use the Great Square of Pegasus.
Use Cassiopeia to find the Andromeda galaxy
Here’s the technique most people use to find the Andromeda galaxy. Just be sure you’re looking in a dark sky. Look northward for the M – or W – shaped constellation Cassiopeia the Queen. Now locate the star Schedar in Cassiopeia. It’s the constellation’s brightest star, and it points to the Andromeda galaxy.
The constellation Cassiopeia is easy to find. Look generally northward on the sky’s dome for a pattern of stars shaped like the letter M or W. If you can recognize the North Star, Polaris – and if you know how to find the Big Dipper – be aware that the Big Dipper and Cassiopeia move around Polaris like the hands of a clock, always opposite each other.
Once you’ve found Cassiopeia, look for its star Schedar. In the illustration above, see how Schedar points to the Andromeda galaxy?
Or use the Great Square to find M31
Here’s another way to find the Andromeda galaxy. The constellation Andromeda can be seen as 2 streams of stars extending from one side of the Great Square of Pegasus. See the star Alpheratz? It joins Pegasus to Andromeda. Now notice the star Mirach, then Mu Andromedae. An imaginary line drawn through Mirach to Mu points to the Andromeda galaxy.
You can also star-hop to the Andromeda galaxy, using the Great Square of Pegasus. It’s a longer route. But, in many ways, it’s more beautiful.
You’ll be hopping to the Andromeda galaxy from the Great Square of Pegasus. In autumn, the Great Square of Pegasus looks like a great big baseball diamond in the eastern sky. Envision the bottom star of the Square’s four stars as home plate, then draw an imaginary line from the “1st base” star though the “3rd base” star to locate two streamers of stars flying away from the Great Square. These stars belong to the constellation Andromeda the Princess.
On each streamer, go two stars north (left) of the third base star, locating the stars Mirach and Mu Andromedae. Draw a line from Mirach through Mu Andromedae, going twice the Mirach/Mu Andromedae distance. You’ve just landed on the Andromeda galaxy, which looks like a smudge of light to the unaided eye.
If you can’t see the Andromeda galaxy with the eye alone, by all means use binoculars.
History of our knowledge of the Andromeda galaxy
The Great Andromeda Nebula, photographed in the year 1900. At this point, astronomers couldn’t discern individual stars in the galaxy. Many thought this object was a cloud of gas within our Milky Way, a place where new stars were forming. Image via Wikimedia Commons (public domain).
At one time, the Andromeda galaxy was called the Great Andromeda Nebula. Astronomers thought this patch of light was composed of glowing gases, or was perhaps a solar system in the process of formation.
It wasn’t until the 20th century that astronomers were able to resolve the Andromeda spiral nebula into individual stars. This discovery lead to a controversy about whether the Andromeda spiral nebula and other spiral nebulae lie within or outside the Milky Way.
In the 1920s Edwin Hubble finally put the matter to rest, when he used Cepheid variable stars within the Andromeda galaxy to determine that it is indeed an “island universe” residing beyond the bounds of our Milky Way galaxy.
The Andromeda and Milky Way galaxies reign as the two most massive and dominant galaxies within the Local Group of galaxies. The Andromeda galaxy is the largest galaxy of the Local Group, which, in addition to the Milky Way, also contains the Triangulum galaxy and about 50 other smaller galaxies.
Both the Milky Way and the Andromeda galaxies lay claim to about a dozen satellite galaxies. Both are some 100,000 light-years across, containing enough mass to make billions of stars.
Astronomers have discovered that our Local Group is on the outskirts of a giant cluster of several thousand galaxies, which astronomers call the Virgo Cluster.
We also know of an irregular supercluster of galaxies, which contains the Virgo Cluster, which in turn contains our Local Group, which in turn contains our Milky Way galaxy and the nearby Andromeda galaxy. At least 100 galaxy groups and clusters are located within this Virgo Supercluster. Its diameter is thought to be about 110 million light-years.
And the Virgo Supercluster is thought to be one of millions of superclusters in the observable universe.
Will the Andromeda galaxy collide with the Milky Way?
One of our readers wrote:
I’ve heard that the Andromeda galaxy will someday collide with our galaxy! Is that still a definite possibility?
A definite possibility describes much of what we know – or think we know – about the universe. As for the Andromeda galaxy and its future collision with our Milky Way: the first attempt to measure the radial velocity of this galaxy (its motion forward or back, along our line of sight) was made in 1912. After that, astronomers believed for some decades that the galaxy was approaching at nearly 200 miles per second (320 km/s), but later astronomers disagreed.
Then in May 2012, NASA astronomers announced they can now predict the time of this collision of titanic galaxies with certainty. Remember, though, that the Andromeda galaxy is 2.2 million light-years away, with a single light-year being almost 6 trillion miles (10 trillion km). So although it does appear that this galaxy is approaching our Milky Way galaxy … it’s nothing to lose sleep over. When will they collide? According to NASA astronomers in 2012, it’ll be four billion years from now.
However, in March 2022, the peer-reviewedAstrophysical Journal published new research revealing that the collision between our galaxies is already underway. Or at least our galactic halos – which consist of gas, dust and stray stars – may already be touching.
What happens when galaxies collide? They don’t exactly crash into each other. Because there’s so much more space than stars even in a galaxy, colliding galaxies pass through each other, like ghosts.
This image represents Earth’s night sky in 3.75 billion years. The Andromeda galaxy (left) will fill our field of view then, astronomers say, as it heads toward a collision with our Milky Way galaxy. Image via NASA/ ESA/ Z. Levay and R. van der Marel, STScI/ T. Hallas/ A. Mellinger.
The Andromeda galaxy (M31) is located at the coordinates RA: 0h 42.7m; Dec: 41o 16′ north.
Bottom line: At 2.5 million light-years, the great Andromeda galaxy (Messier 31) rates as the most distant object you can see with the unaided eye.
Note: The large spiral Triangulum galaxy is slightly more distant at 2.7 million light-years. Like the Andromeda galaxy, it’s a member of our Local Group of galaxies. And it’s sometimes visible to the eye also. But it’s turned face-on to us, and so has a low surface brightness. Unlike the Andromeda galaxy, it’s more challenging to see.
Astronomers sometimes call the Andromeda galaxy by the name Messier 31, or M31. It was the 31st on a famous list of fuzzy sky objects compiled by the French astronomer Charles Messier (1730-1817). His catalog listed “objects to avoid” when comet-hunting. Nowadays, amateur astronomers seek out these objects with their telescopes and binoculars. They’re some of most beautiful deep-sky objects known.
Most Messier objects are star clusters or gas clouds in our Milky Way galaxy. But the Andromeda galaxy is a whole separate galaxy, even bigger than our Milky Way. In a dark sky, you can see that it’s big on the sky as well, a smudge of distant light larger than a full moon.
Some images of M31 from our EarthSky community
View at EarthSky Community Photos. | Jeremy Likness in Newport, Oregon, captured this telescopic view of the Andromeda galaxy on July 9, 2024. Jeremy wrote: “It’s a galaxy so near it could be interacting with our stars. It’s so big and bright that you can photograph it with an ordinary camera. The Andromeda galaxy, named for the constellation it hangs out in, is located just off the edge of the distinct ‘W’ of Cassiopeia. I used a hydrogen-alpha filter to find the red emissions hanging out in the limbs of this barred spiral galaxy that is our neighbor.” Thank you, Jeremy!View at EarthSky Community Photos. | Steven Bellavia in Mattituck, New York, assembled this impressive composite of the Andromeda galaxy on January 27, 2024. Steven wrote: “I decided to take my last 2 years of data on M31, the Andromeda galaxy, and put it all together. The star-forming regions appear as small red ‘knots’ in and beyond the spiral arms, and the collections of young, hot blue stars appear as blue regions. The Andromeda Galaxy is a barred spiral galaxy and the nearest major galaxy to the Milky Way. It’s about 2.5 million light-years from Earth.” Thank you, Steven!
When to look for it
From mid-northern latitudes, you can see Andromeda – M31 – for at least part of every night, all year long. But most people see the galaxy first around August or September, when it’s high enough in the sky to be seen from evening until daybreak.
In early September, begin looking for the galaxy in mid-evening, about midway between your local nightfall and midnight.
In late September and early October, the Andromeda galaxy shines in your eastern sky at nightfall, swings high overhead in the middle of the night, and stands rather high in the west at the onset of morning dawn.
Winter evenings are also good for viewing the Andromeda galaxy.
If you are far from city lights, and you’re stargazing during a moonless night during the late summer, or on any autumn or winter evening, it’s possible that you’ll simply notice the galaxy there in your night sky. But if you don’t manage to easily see it, you can star-hop to find the galaxy in one of two ways. The easiest way is to use the constellation Cassiopeia the Queen. You can also use the Great Square of Pegasus.
Use Cassiopeia to find the Andromeda galaxy
Here’s the technique most people use to find the Andromeda galaxy. Just be sure you’re looking in a dark sky. Look northward for the M – or W – shaped constellation Cassiopeia the Queen. Now locate the star Schedar in Cassiopeia. It’s the constellation’s brightest star, and it points to the Andromeda galaxy.
The constellation Cassiopeia is easy to find. Look generally northward on the sky’s dome for a pattern of stars shaped like the letter M or W. If you can recognize the North Star, Polaris – and if you know how to find the Big Dipper – be aware that the Big Dipper and Cassiopeia move around Polaris like the hands of a clock, always opposite each other.
Once you’ve found Cassiopeia, look for its star Schedar. In the illustration above, see how Schedar points to the Andromeda galaxy?
Or use the Great Square to find M31
Here’s another way to find the Andromeda galaxy. The constellation Andromeda can be seen as 2 streams of stars extending from one side of the Great Square of Pegasus. See the star Alpheratz? It joins Pegasus to Andromeda. Now notice the star Mirach, then Mu Andromedae. An imaginary line drawn through Mirach to Mu points to the Andromeda galaxy.
You can also star-hop to the Andromeda galaxy, using the Great Square of Pegasus. It’s a longer route. But, in many ways, it’s more beautiful.
You’ll be hopping to the Andromeda galaxy from the Great Square of Pegasus. In autumn, the Great Square of Pegasus looks like a great big baseball diamond in the eastern sky. Envision the bottom star of the Square’s four stars as home plate, then draw an imaginary line from the “1st base” star though the “3rd base” star to locate two streamers of stars flying away from the Great Square. These stars belong to the constellation Andromeda the Princess.
On each streamer, go two stars north (left) of the third base star, locating the stars Mirach and Mu Andromedae. Draw a line from Mirach through Mu Andromedae, going twice the Mirach/Mu Andromedae distance. You’ve just landed on the Andromeda galaxy, which looks like a smudge of light to the unaided eye.
If you can’t see the Andromeda galaxy with the eye alone, by all means use binoculars.
History of our knowledge of the Andromeda galaxy
The Great Andromeda Nebula, photographed in the year 1900. At this point, astronomers couldn’t discern individual stars in the galaxy. Many thought this object was a cloud of gas within our Milky Way, a place where new stars were forming. Image via Wikimedia Commons (public domain).
At one time, the Andromeda galaxy was called the Great Andromeda Nebula. Astronomers thought this patch of light was composed of glowing gases, or was perhaps a solar system in the process of formation.
It wasn’t until the 20th century that astronomers were able to resolve the Andromeda spiral nebula into individual stars. This discovery lead to a controversy about whether the Andromeda spiral nebula and other spiral nebulae lie within or outside the Milky Way.
In the 1920s Edwin Hubble finally put the matter to rest, when he used Cepheid variable stars within the Andromeda galaxy to determine that it is indeed an “island universe” residing beyond the bounds of our Milky Way galaxy.
The Andromeda and Milky Way galaxies reign as the two most massive and dominant galaxies within the Local Group of galaxies. The Andromeda galaxy is the largest galaxy of the Local Group, which, in addition to the Milky Way, also contains the Triangulum galaxy and about 50 other smaller galaxies.
Both the Milky Way and the Andromeda galaxies lay claim to about a dozen satellite galaxies. Both are some 100,000 light-years across, containing enough mass to make billions of stars.
Astronomers have discovered that our Local Group is on the outskirts of a giant cluster of several thousand galaxies, which astronomers call the Virgo Cluster.
We also know of an irregular supercluster of galaxies, which contains the Virgo Cluster, which in turn contains our Local Group, which in turn contains our Milky Way galaxy and the nearby Andromeda galaxy. At least 100 galaxy groups and clusters are located within this Virgo Supercluster. Its diameter is thought to be about 110 million light-years.
And the Virgo Supercluster is thought to be one of millions of superclusters in the observable universe.
Will the Andromeda galaxy collide with the Milky Way?
One of our readers wrote:
I’ve heard that the Andromeda galaxy will someday collide with our galaxy! Is that still a definite possibility?
A definite possibility describes much of what we know – or think we know – about the universe. As for the Andromeda galaxy and its future collision with our Milky Way: the first attempt to measure the radial velocity of this galaxy (its motion forward or back, along our line of sight) was made in 1912. After that, astronomers believed for some decades that the galaxy was approaching at nearly 200 miles per second (320 km/s), but later astronomers disagreed.
Then in May 2012, NASA astronomers announced they can now predict the time of this collision of titanic galaxies with certainty. Remember, though, that the Andromeda galaxy is 2.2 million light-years away, with a single light-year being almost 6 trillion miles (10 trillion km). So although it does appear that this galaxy is approaching our Milky Way galaxy … it’s nothing to lose sleep over. When will they collide? According to NASA astronomers in 2012, it’ll be four billion years from now.
However, in March 2022, the peer-reviewedAstrophysical Journal published new research revealing that the collision between our galaxies is already underway. Or at least our galactic halos – which consist of gas, dust and stray stars – may already be touching.
What happens when galaxies collide? They don’t exactly crash into each other. Because there’s so much more space than stars even in a galaxy, colliding galaxies pass through each other, like ghosts.
This image represents Earth’s night sky in 3.75 billion years. The Andromeda galaxy (left) will fill our field of view then, astronomers say, as it heads toward a collision with our Milky Way galaxy. Image via NASA/ ESA/ Z. Levay and R. van der Marel, STScI/ T. Hallas/ A. Mellinger.
The Andromeda galaxy (M31) is located at the coordinates RA: 0h 42.7m; Dec: 41o 16′ north.
Bottom line: At 2.5 million light-years, the great Andromeda galaxy (Messier 31) rates as the most distant object you can see with the unaided eye.
View larger. | Near-Earth Objects (NEOs) are asteroids that could potentially hit us at some point, or at least come very close, as in this artist’s illustration. Astronomers search for them, and track them. Today (September 4, 2024) – just hours ago – an astronomer in Arizona discovered a small asteroid that will strike Earth’s atmosphere later today. Image via urikyo33/ Pixabay.
Small asteroid to hit us
Heads up! A small asteroid – approximately 1 meter (3 feet) wide – will strike Earth’s atmosphere today (September 4, 2024) over the Philippines around 16:46 UTC according to the European Space Agency. That’s after midnight tonight in the Philippines. And it’s 11:46 a.m. CDT on Wednesday, September 4, for us in North America. The asteroid is expected to burn up in Earth’s atmosphere above the area of Luzon. It’s expected to create a bright fireball for anyone watching! If you’re in the Philippines, go outside and look around 12:46 a.m. PHST on Thursday, September 5.
This is only the 9th time we’ve spotted an asteroid before it’s struck us. And it was Jacqueline Fazekas at the Catalina Sky Survey in Arizona who discovered this asteroid just hours ago. Jacqueline discovered the object about eight hours before its predicted impact. The asteroid has been given the provisional designation CAQTDL2.
A small asteroid, just discovered hours ago, will strike Earth’s atmosphere above the Philippines around 16:46 UTC on September 4. Image via ESA.
?UPDATE: We expect the ~1 m asteroid discovered this morning to strike Earth's atmosphere over the Philippines near Luzon Island at 16:46 UTC today.
However the nearby tropical storm Yagi/Enteng will make fireball observations difficult.
Here’s the good news! We’re getting better at spotting asteroids before they hit us. Here was a discovery that caused a stir in March 2022 before it hit hours later. And here’s another example from earlier this year.
This detection is actually great news! This is only the ninth time that humankind has discovered an asteroid before it impacts us and is a sign of our improving planetary defence capabilities.
View larger. | Near-Earth Objects (NEOs) are asteroids that could potentially hit us at some point, or at least come very close, as in this artist’s illustration. Astronomers search for them, and track them. Today (September 4, 2024) – just hours ago – an astronomer in Arizona discovered a small asteroid that will strike Earth’s atmosphere later today. Image via urikyo33/ Pixabay.
Small asteroid to hit us
Heads up! A small asteroid – approximately 1 meter (3 feet) wide – will strike Earth’s atmosphere today (September 4, 2024) over the Philippines around 16:46 UTC according to the European Space Agency. That’s after midnight tonight in the Philippines. And it’s 11:46 a.m. CDT on Wednesday, September 4, for us in North America. The asteroid is expected to burn up in Earth’s atmosphere above the area of Luzon. It’s expected to create a bright fireball for anyone watching! If you’re in the Philippines, go outside and look around 12:46 a.m. PHST on Thursday, September 5.
This is only the 9th time we’ve spotted an asteroid before it’s struck us. And it was Jacqueline Fazekas at the Catalina Sky Survey in Arizona who discovered this asteroid just hours ago. Jacqueline discovered the object about eight hours before its predicted impact. The asteroid has been given the provisional designation CAQTDL2.
A small asteroid, just discovered hours ago, will strike Earth’s atmosphere above the Philippines around 16:46 UTC on September 4. Image via ESA.
?UPDATE: We expect the ~1 m asteroid discovered this morning to strike Earth's atmosphere over the Philippines near Luzon Island at 16:46 UTC today.
However the nearby tropical storm Yagi/Enteng will make fireball observations difficult.
Here’s the good news! We’re getting better at spotting asteroids before they hit us. Here was a discovery that caused a stir in March 2022 before it hit hours later. And here’s another example from earlier this year.
This detection is actually great news! This is only the ninth time that humankind has discovered an asteroid before it impacts us and is a sign of our improving planetary defence capabilities.
An artist’s depiction of a sea cow being attacked by a crocodile, with a shark swimming nearby. Image via Jaime Bran Sarmiento/ Taylor and Francis Group.
Fossils of a prehistoric sea cow reveal it was attacked by a crocodile and later scavenged by sharks around 11.6 to 23 million years ago in what is now modern-day Venezuela.
The sea cow’s bones show bite marks from both a crocodile and sharks, indicating a rare instance of multiple predators feeding on the same prey.
These fossils provide a detailed snapshot of ancient food chains, highlighting the sea cow’s role in the ecosystem during the Miocene.
Ancient sea cow attack preserved in fossils
Fossils of an extinct sea cow – a marine mammal related to manatees – have captured a predatory event that happened millions of years ago. Tooth marks left on the animal’s bones reveal it may have been attacked by a crocodile. Furthermore, a tooth and more bone bite marks indicate sharks then scavenged the remains of the sea cow. Scientists revealed this glimpse of the ancient food chain on August 29, 2024. The attack occurred during the Miocene Epoch, 11.6 to 23 million years ago, in what is now modern-day Venezuela.
The scientists published their peer-reviewed results in the Journal of Vertebrate Paleontology on August 28, 2024.
Sea cow fossils show significant bone bite marks
Scientists occasionally find evidence of predation and scavenging of marine mammals on fossils. For example, there are fossilized bones of seals, walruses, and whales showing teeth marks from predators such as sharks.
This new finding, however, is remarkable because it’s a rare case in the fossil record of multiple predators feeding on a single prey.
Scientists studying the sea cow fossils – a partial skull, some back vertebrae and ribs – found bite marks from a crocodile and sharks all over the bones. They used that evidence to try to reconstruct what happened to the sea cow many millions of years ago. There were deep tooth impacts on the sea cow’s snout, suggesting the crocodile grabbed the snout to try to suffocate the sea cow. Additional markings suggest the crocodile may have then dragged the sea cow before tearing into it.
Furthermore, a tiger shark’s tooth was found near the sea cow’s neck. There were even more markings on the skeleton indicating that sharks had bitten into the carcass, scavenging what was left of it.
An illustration of the sea cow’s skeleton, with pink shading to show areas of recovered fossilized bones. Image via Benites-Palomino et al./ Journal of Vertebrate Paleontology (CC BY 4.0).
Valuable insights into an ancient food chain
The food chain, the scientists observed, was very much like it is in the wild today. The paper’s lead author, Aldo Benites Palomino of the University of Zurich, said:
Today, often when we observe a predator in the wild, we find the carcass of prey which demonstrates its function as a food source for other animals too, but fossil records of this are rarer.
We have been unsure as to which animals would serve this purpose as a food source for multiple predators. Our previous research has identified sperm whales scavenged by several shark species, and this new research highlights the importance of sea cows within the food chain.
A remarkable discovery in Venezuela
The fossils were near the city of Coro in northwestern Venezuela. Marcelo R. Sanchez Villagra, also with the University of Zurich, talked about the discovery:
We first learned about the site through word of mouth from a local farmer who had noticed some unusual ‘rocks.’ Intrigued, we decided to investigate.
Initially, we were unfamiliar with the site’s geology, and the first fossils we unearthed were parts of skulls. It took us some time to determine what they were: sea cow remains, which are quite peculiar in appearance.
By consulting geological maps and examining the sediments at the new locality, we were able to determine the age of the rocks in which the fossils were found.
Excavating the partial skeleton required several visits to the site. We managed to unearth much of the vertebral column, and since these are relatively large animals, we had to remove a significant amount of sediment.
The region is known for evidence of predation on aquatic mammals, and one factor that enabled us to observe such evidence was the excellent preservation of the fossil’s cortical layer [hard outer layer], which is attributed to the fine sediments in which it was embedded.
After locating the fossil site, our team organized a paleontological rescue operation, employing extraction techniques with full casing protection.
The operation took about seven hours, with a team of five people working on the fossil. The subsequent preparation took several months, especially the meticulous work of preparing and restoring the cranial elements.
Bite marks from the crocodile on sea cow bones
In the skull, in the area corresponding to the sea cow’s snout, the scientists found shallow round punctures. The shape of those marks indicate they came from the teeth of a crocodile. (See images labeled “A” and “B” below.)
The next type of bite marks they saw were punctures with a dragging effect. This showed the crocodile bit deeply into the sea cow, tearing violently into it. (See the image labeled “C” below.)
These images, taken from the paper, show the bites inflicted by the crocodile. The first image shows a puncture in the sea cow’s skull, and the second image, labeled “B”, shows a closeup of it. You can see the deep tearing bite marks from the crocodile in the image labeled “C.” Image via Benites-Palomino et al./ Journal of Vertebrate Paleontology (CC BY 4.0).
Bite marks from sharks
There was a third category of bite marks, long narrow grooves with a triangular-shaped cross section. These came from the teeth of sharks. They showed how the sharks bit into the bone and dragged their teeth as they tore out flesh from the sea cow. Scientists could not identify the shark species based on teeth marks alone. But, luckily, one of those sharks left a tooth near the sea cow’s neck. It was a tiger shark (Galeocerdo aduncus).
The images labeled “E” and “F” show shark bite marks on the sea cow’s ribs. The image labeled “G” is a tiger shark tooth found near the sea cow’s neck. Image via Benites-Palomino et al./ Journal of Vertebrate Paleontology (CC BY 4.0).
Bottom line: The fossil remains of a sea cow from the Miocene Period reveal bite marks that suggest it was attacked by a crocodile and subsequently scavenged by sharks.
An artist’s depiction of a sea cow being attacked by a crocodile, with a shark swimming nearby. Image via Jaime Bran Sarmiento/ Taylor and Francis Group.
Fossils of a prehistoric sea cow reveal it was attacked by a crocodile and later scavenged by sharks around 11.6 to 23 million years ago in what is now modern-day Venezuela.
The sea cow’s bones show bite marks from both a crocodile and sharks, indicating a rare instance of multiple predators feeding on the same prey.
These fossils provide a detailed snapshot of ancient food chains, highlighting the sea cow’s role in the ecosystem during the Miocene.
Ancient sea cow attack preserved in fossils
Fossils of an extinct sea cow – a marine mammal related to manatees – have captured a predatory event that happened millions of years ago. Tooth marks left on the animal’s bones reveal it may have been attacked by a crocodile. Furthermore, a tooth and more bone bite marks indicate sharks then scavenged the remains of the sea cow. Scientists revealed this glimpse of the ancient food chain on August 29, 2024. The attack occurred during the Miocene Epoch, 11.6 to 23 million years ago, in what is now modern-day Venezuela.
The scientists published their peer-reviewed results in the Journal of Vertebrate Paleontology on August 28, 2024.
Sea cow fossils show significant bone bite marks
Scientists occasionally find evidence of predation and scavenging of marine mammals on fossils. For example, there are fossilized bones of seals, walruses, and whales showing teeth marks from predators such as sharks.
This new finding, however, is remarkable because it’s a rare case in the fossil record of multiple predators feeding on a single prey.
Scientists studying the sea cow fossils – a partial skull, some back vertebrae and ribs – found bite marks from a crocodile and sharks all over the bones. They used that evidence to try to reconstruct what happened to the sea cow many millions of years ago. There were deep tooth impacts on the sea cow’s snout, suggesting the crocodile grabbed the snout to try to suffocate the sea cow. Additional markings suggest the crocodile may have then dragged the sea cow before tearing into it.
Furthermore, a tiger shark’s tooth was found near the sea cow’s neck. There were even more markings on the skeleton indicating that sharks had bitten into the carcass, scavenging what was left of it.
An illustration of the sea cow’s skeleton, with pink shading to show areas of recovered fossilized bones. Image via Benites-Palomino et al./ Journal of Vertebrate Paleontology (CC BY 4.0).
Valuable insights into an ancient food chain
The food chain, the scientists observed, was very much like it is in the wild today. The paper’s lead author, Aldo Benites Palomino of the University of Zurich, said:
Today, often when we observe a predator in the wild, we find the carcass of prey which demonstrates its function as a food source for other animals too, but fossil records of this are rarer.
We have been unsure as to which animals would serve this purpose as a food source for multiple predators. Our previous research has identified sperm whales scavenged by several shark species, and this new research highlights the importance of sea cows within the food chain.
A remarkable discovery in Venezuela
The fossils were near the city of Coro in northwestern Venezuela. Marcelo R. Sanchez Villagra, also with the University of Zurich, talked about the discovery:
We first learned about the site through word of mouth from a local farmer who had noticed some unusual ‘rocks.’ Intrigued, we decided to investigate.
Initially, we were unfamiliar with the site’s geology, and the first fossils we unearthed were parts of skulls. It took us some time to determine what they were: sea cow remains, which are quite peculiar in appearance.
By consulting geological maps and examining the sediments at the new locality, we were able to determine the age of the rocks in which the fossils were found.
Excavating the partial skeleton required several visits to the site. We managed to unearth much of the vertebral column, and since these are relatively large animals, we had to remove a significant amount of sediment.
The region is known for evidence of predation on aquatic mammals, and one factor that enabled us to observe such evidence was the excellent preservation of the fossil’s cortical layer [hard outer layer], which is attributed to the fine sediments in which it was embedded.
After locating the fossil site, our team organized a paleontological rescue operation, employing extraction techniques with full casing protection.
The operation took about seven hours, with a team of five people working on the fossil. The subsequent preparation took several months, especially the meticulous work of preparing and restoring the cranial elements.
Bite marks from the crocodile on sea cow bones
In the skull, in the area corresponding to the sea cow’s snout, the scientists found shallow round punctures. The shape of those marks indicate they came from the teeth of a crocodile. (See images labeled “A” and “B” below.)
The next type of bite marks they saw were punctures with a dragging effect. This showed the crocodile bit deeply into the sea cow, tearing violently into it. (See the image labeled “C” below.)
These images, taken from the paper, show the bites inflicted by the crocodile. The first image shows a puncture in the sea cow’s skull, and the second image, labeled “B”, shows a closeup of it. You can see the deep tearing bite marks from the crocodile in the image labeled “C.” Image via Benites-Palomino et al./ Journal of Vertebrate Paleontology (CC BY 4.0).
Bite marks from sharks
There was a third category of bite marks, long narrow grooves with a triangular-shaped cross section. These came from the teeth of sharks. They showed how the sharks bit into the bone and dragged their teeth as they tore out flesh from the sea cow. Scientists could not identify the shark species based on teeth marks alone. But, luckily, one of those sharks left a tooth near the sea cow’s neck. It was a tiger shark (Galeocerdo aduncus).
The images labeled “E” and “F” show shark bite marks on the sea cow’s ribs. The image labeled “G” is a tiger shark tooth found near the sea cow’s neck. Image via Benites-Palomino et al./ Journal of Vertebrate Paleontology (CC BY 4.0).
Bottom line: The fossil remains of a sea cow from the Miocene Period reveal bite marks that suggest it was attacked by a crocodile and subsequently scavenged by sharks.
On August 7, 2024, a landslide in Alaska sent rocks and debris into the Pederson Lagoon in Kenai Fjords National Park. The landslide triggered a tsunami about 56 feet (17 meters) high, according to the National Park Service. With global warming, tsunamis like this are becoming more common. Image via USGS/ NASA Earth Observatory.
Landslide-triggered tsunamis more common with global warming
Earth is warming at a rapid rate due to human activities that drive greenhouse gases into the atmosphere. And as glaciers and permafrost are melting, these destabilizing forces are driving more landslides. Some of those landslides, in turn, enter bodies of water, displacing them and triggering giant waves known as tsunamis. These landslide-triggered tsunamis are also called megatsunamis. And, because of climate change, they’re becoming more common.
A group of researchers led by Angela Carrillo-Ponce of GFZ German Research Centre for Geoscience in Potsdam, Germany, published a new paper on August 8, 2024. The paper appeared in the peer-reviewed journal The Seismic Record. The authors wrote:
The effects of global warming and changes in permafrost are likely to further reduce slope stability and increase the incidence of landslides and tsunamis. The occurrence and propagation of tsunamis, especially in fjord locations, are considered to be one of the most devastating of all natural disasters.
September 16, 2023, Greenland megatsunami
The authors studied the September 16, 2023, megatsunami that created a unique seismic signal in remote eastern Greenland. The waves from this tsunami were more than 650 feet (200 meters) tall at their highest. And they averaged 200 feet (60 meters) along a 6-mile (10-km) stretch of the fjord. In fact, the megatsunami was so powerful that the waves sloshed back and forth between the shores of Dickson Fjord for a week.
Carrillo-Ponce said:
The fact that the signal of a rockslide-triggered sloshing wave in a remote area of Greenland can be observed worldwide and for over a week is exciting.
Because it was a remote area, the only reported damage was to a military installation on Ella Island, which was closed and unmanned for winter.
Carrillo-Ponce said:
The analysis of the seismic signal can give us some answers regarding the processes involved and may even lead to improved monitoring of similar events in the future.
And the press release added:
The findings will help researchers as they study the impacts of landslides in Greenland and similar regions around the world where global warming and the loss of permafrost are making rocky slopes and glaciers increasingly unstable.
The Dickson Fjord in Greenland was the site of a megatsunami on September 16, 2023. At top, the yellow star marks the location of the landslide that triggered the tsunami. The bottom map shows a closer view of Dickson Fjord. Image via TSR (2024) Carrillo-Ponce et al./ Seismological Society of America.
Tsunami in Alaska in August 2024
Retreating glaciers expose rocky cliffs that are vulnerable to landslides. In southern Alaska in August, the addition of heavy rainfall helped trigger a landslide in Kenai Fjords National Park that then generated a tsunami. Some 2 million cubic meters of rocks and debris came rushing down into the Pederson Lagoon, propogating a 56-foot (17-m) tsunami. NASA Earth Observatory reported:
The wave damaged trees and flattened vegetation between the upper and lower portions of the Pedersen Lagoon. According to local reports, it also damaged a lodge’s boardwalk on the eastern side of the lower lagoon.
This is the before image from the Pederson Lagoon in Kenai Fjords National Park, Alaska, from July 27, 2024. Image via NASA Earth Observatory.This is the after image from the landslide-triggered tsunami on August 7, 2024. This image is from August 20, 2024. Image via NASA Earth Observatory.
Risk of tsunamis
The landmass that caused the landslide and tsunami in Alaska is an area scientists had already identified as a potential problem. They had been planning to do fieldwork there before the event occurred. In fact, they just missed out on beforehand observations. National Park Service (NPS) Alaska Regional Geologist Chad Hults told KTUU in Anchorage:
We had a flight for measuring the tidewater glaciers the week prior, but we had a technical issue that kept us from continuing the operation that day, so we weren’t able to capture it before the landslide released.
Hults said the National Park Service and USGS are looking at more areas in Alaska that could have landslide-triggered tsunamis:
There are some unstable slopes that we’ve identified that are above glaciers that are retreating, and they could potentially release and land on the glacier and then flow down the glacier before they hit the water.
People in these regions where the slopes are becoming unstable should take the landscape into account when deciding where to camp or boat. Hults said:
Southern Alaska has very steep slopes that could be potentially unstable, and recognizing that hazard exists is important for your making your decisions.
Bottom line: Landslide-triggered tsunamis due to melting glaciers and permafrost are becoming more common with global warming.
On August 7, 2024, a landslide in Alaska sent rocks and debris into the Pederson Lagoon in Kenai Fjords National Park. The landslide triggered a tsunami about 56 feet (17 meters) high, according to the National Park Service. With global warming, tsunamis like this are becoming more common. Image via USGS/ NASA Earth Observatory.
Landslide-triggered tsunamis more common with global warming
Earth is warming at a rapid rate due to human activities that drive greenhouse gases into the atmosphere. And as glaciers and permafrost are melting, these destabilizing forces are driving more landslides. Some of those landslides, in turn, enter bodies of water, displacing them and triggering giant waves known as tsunamis. These landslide-triggered tsunamis are also called megatsunamis. And, because of climate change, they’re becoming more common.
A group of researchers led by Angela Carrillo-Ponce of GFZ German Research Centre for Geoscience in Potsdam, Germany, published a new paper on August 8, 2024. The paper appeared in the peer-reviewed journal The Seismic Record. The authors wrote:
The effects of global warming and changes in permafrost are likely to further reduce slope stability and increase the incidence of landslides and tsunamis. The occurrence and propagation of tsunamis, especially in fjord locations, are considered to be one of the most devastating of all natural disasters.
September 16, 2023, Greenland megatsunami
The authors studied the September 16, 2023, megatsunami that created a unique seismic signal in remote eastern Greenland. The waves from this tsunami were more than 650 feet (200 meters) tall at their highest. And they averaged 200 feet (60 meters) along a 6-mile (10-km) stretch of the fjord. In fact, the megatsunami was so powerful that the waves sloshed back and forth between the shores of Dickson Fjord for a week.
Carrillo-Ponce said:
The fact that the signal of a rockslide-triggered sloshing wave in a remote area of Greenland can be observed worldwide and for over a week is exciting.
Because it was a remote area, the only reported damage was to a military installation on Ella Island, which was closed and unmanned for winter.
Carrillo-Ponce said:
The analysis of the seismic signal can give us some answers regarding the processes involved and may even lead to improved monitoring of similar events in the future.
And the press release added:
The findings will help researchers as they study the impacts of landslides in Greenland and similar regions around the world where global warming and the loss of permafrost are making rocky slopes and glaciers increasingly unstable.
The Dickson Fjord in Greenland was the site of a megatsunami on September 16, 2023. At top, the yellow star marks the location of the landslide that triggered the tsunami. The bottom map shows a closer view of Dickson Fjord. Image via TSR (2024) Carrillo-Ponce et al./ Seismological Society of America.
Tsunami in Alaska in August 2024
Retreating glaciers expose rocky cliffs that are vulnerable to landslides. In southern Alaska in August, the addition of heavy rainfall helped trigger a landslide in Kenai Fjords National Park that then generated a tsunami. Some 2 million cubic meters of rocks and debris came rushing down into the Pederson Lagoon, propogating a 56-foot (17-m) tsunami. NASA Earth Observatory reported:
The wave damaged trees and flattened vegetation between the upper and lower portions of the Pedersen Lagoon. According to local reports, it also damaged a lodge’s boardwalk on the eastern side of the lower lagoon.
This is the before image from the Pederson Lagoon in Kenai Fjords National Park, Alaska, from July 27, 2024. Image via NASA Earth Observatory.This is the after image from the landslide-triggered tsunami on August 7, 2024. This image is from August 20, 2024. Image via NASA Earth Observatory.
Risk of tsunamis
The landmass that caused the landslide and tsunami in Alaska is an area scientists had already identified as a potential problem. They had been planning to do fieldwork there before the event occurred. In fact, they just missed out on beforehand observations. National Park Service (NPS) Alaska Regional Geologist Chad Hults told KTUU in Anchorage:
We had a flight for measuring the tidewater glaciers the week prior, but we had a technical issue that kept us from continuing the operation that day, so we weren’t able to capture it before the landslide released.
Hults said the National Park Service and USGS are looking at more areas in Alaska that could have landslide-triggered tsunamis:
There are some unstable slopes that we’ve identified that are above glaciers that are retreating, and they could potentially release and land on the glacier and then flow down the glacier before they hit the water.
People in these regions where the slopes are becoming unstable should take the landscape into account when deciding where to camp or boat. Hults said:
Southern Alaska has very steep slopes that could be potentially unstable, and recognizing that hazard exists is important for your making your decisions.
Bottom line: Landslide-triggered tsunamis due to melting glaciers and permafrost are becoming more common with global warming.
The September birthstone is sapphire. Although it’s traditionally thought of as blue, it comes in many colors such as this pink sapphire ring. Image via Charles Sharp/ Wikipedia.
September birthstone
September’s birthstone, the sapphire, is a relative of July’s birthstone, the ruby. That’s because both are forms of the mineral corundum, a crystalline form of aluminum oxide. But red corundum is ruby. And all other gem-quality forms of corundum are sapphires.
All corundum, including sapphire, has a hardness of 9 on the Mohs scale. In fact, sapphires are second in hardness only to diamonds.
Of course, probably the best-known color of sapphire is blue. Image via gemrockauctions.com. Used with permission.
Typically, sapphires appear as blue stones. They range from very pale blue to deep indigo. As a matter of fact, the exact shade depends on how much titanium and iron lies within the crystal structure. By the way, the most valued shade of blue is the medium-deep cornflower blue. However, sapphires also occur in other natural colors and tints – colorless, gray, yellow, pale pink, orange, green, violet and brown – called fancy sapphires. Different kinds of impurities within the crystal cause the various gemstone colors. For example, yellow sapphires get their color from ferric iron, and colorless gems have no contaminants.
It’s time for #MineralMonday! #DYK? Not all sapphires are blue. Exhibiting a spectacular range of colors, sapphire is a gem variety of the mineral corundum. Beyond blue, sapphires range from colorless to orange to green to violet, but not red—red corundum is ruby!? #NewYorkRockspic.twitter.com/hjLvvN2bNc
Primarily, the biggest source of sapphires world-wide is Australia, especially New South Wales and Queensland. They are found in alluvial deposits of weathered basalt. Australian sapphires typically are blue stones with a dark and inky appearance. On the other hand, Kashmir, in India, used to be a well-known source of the cornflower-blue stones. And in the United States, a major source is the Yogo Gulch Mine in Montana. It mostly yields small stones for industrial use.
Sapphire lore about the September birthstone
The word sapphire has its roots in ancient languages: from the Latin sapphirus (meaning blue) and from the Greek word sappheiros for the island of Sappherine in the Arabian Sea. That was the source for sapphire in ancient Grecian times, in its turn from the Arabic safir. Ancient Persians called sapphire the “Celestial Stone.” It was the gem of Apollo, Greek God of prophecy. Worshipers visiting his shrine in Delphi to seek his help wore sapphires. Ancient Etruscans used sapphires as far back as the 7th century B.C.
Besides being the September birthstone, the sapphire represented the purity of the soul. Before and during the Middle Ages, priests wore it as protection from impure thoughts and temptations of the flesh. Medieval kings of Europe valued these stones for rings and brooches, believing that it protected them from harm and envy. Warriors presented their young wives with sapphire necklaces so they would remain faithful. A common belief was that the stone’s color would darken if worn by an adulterer or adulteress, or by an unworthy person.
Some believed sapphires protected people from snakes. People believed that by placing poisonous reptiles and spiders in a jar containing the stone, the creatures would immediately die. The French of the 13th century believed that sapphire transformed stupidity to wisdom, and irritability to good temper.
Some famous sapphires
It's arguably the world's most famous engagement ring. Princess Diana's and now Kate Middleton's Sapphire ring. pic.twitter.com/hsDdzPHZo4
One of the most famous sapphires rests on the Imperial State Crown worn by Queen Victoria in 1838. It resides in the British Crown Jewels in the Tower of London. In fact, this gem once belonged to Edward the Confessor. He wore the stone on a ring during his coronation in 1042, and thus called it St. Edward’s Sapphire.
The Logan Sapphire Brooch, the second largest sapphire known (at 422.99 carats), is on display at the National Museum of Natural History in Washington, D.C. Image via Andrew Bossi/ Wikipedia.
Bottom line: The September birthstone is the sapphire. It is generally known as a blue gemstone, but it comes in many colors.
Find out about the birthstones for the other months of the year:
The September birthstone is sapphire. Although it’s traditionally thought of as blue, it comes in many colors such as this pink sapphire ring. Image via Charles Sharp/ Wikipedia.
September birthstone
September’s birthstone, the sapphire, is a relative of July’s birthstone, the ruby. That’s because both are forms of the mineral corundum, a crystalline form of aluminum oxide. But red corundum is ruby. And all other gem-quality forms of corundum are sapphires.
All corundum, including sapphire, has a hardness of 9 on the Mohs scale. In fact, sapphires are second in hardness only to diamonds.
Of course, probably the best-known color of sapphire is blue. Image via gemrockauctions.com. Used with permission.
Typically, sapphires appear as blue stones. They range from very pale blue to deep indigo. As a matter of fact, the exact shade depends on how much titanium and iron lies within the crystal structure. By the way, the most valued shade of blue is the medium-deep cornflower blue. However, sapphires also occur in other natural colors and tints – colorless, gray, yellow, pale pink, orange, green, violet and brown – called fancy sapphires. Different kinds of impurities within the crystal cause the various gemstone colors. For example, yellow sapphires get their color from ferric iron, and colorless gems have no contaminants.
It’s time for #MineralMonday! #DYK? Not all sapphires are blue. Exhibiting a spectacular range of colors, sapphire is a gem variety of the mineral corundum. Beyond blue, sapphires range from colorless to orange to green to violet, but not red—red corundum is ruby!? #NewYorkRockspic.twitter.com/hjLvvN2bNc
Primarily, the biggest source of sapphires world-wide is Australia, especially New South Wales and Queensland. They are found in alluvial deposits of weathered basalt. Australian sapphires typically are blue stones with a dark and inky appearance. On the other hand, Kashmir, in India, used to be a well-known source of the cornflower-blue stones. And in the United States, a major source is the Yogo Gulch Mine in Montana. It mostly yields small stones for industrial use.
Sapphire lore about the September birthstone
The word sapphire has its roots in ancient languages: from the Latin sapphirus (meaning blue) and from the Greek word sappheiros for the island of Sappherine in the Arabian Sea. That was the source for sapphire in ancient Grecian times, in its turn from the Arabic safir. Ancient Persians called sapphire the “Celestial Stone.” It was the gem of Apollo, Greek God of prophecy. Worshipers visiting his shrine in Delphi to seek his help wore sapphires. Ancient Etruscans used sapphires as far back as the 7th century B.C.
Besides being the September birthstone, the sapphire represented the purity of the soul. Before and during the Middle Ages, priests wore it as protection from impure thoughts and temptations of the flesh. Medieval kings of Europe valued these stones for rings and brooches, believing that it protected them from harm and envy. Warriors presented their young wives with sapphire necklaces so they would remain faithful. A common belief was that the stone’s color would darken if worn by an adulterer or adulteress, or by an unworthy person.
Some believed sapphires protected people from snakes. People believed that by placing poisonous reptiles and spiders in a jar containing the stone, the creatures would immediately die. The French of the 13th century believed that sapphire transformed stupidity to wisdom, and irritability to good temper.
Some famous sapphires
It's arguably the world's most famous engagement ring. Princess Diana's and now Kate Middleton's Sapphire ring. pic.twitter.com/hsDdzPHZo4
One of the most famous sapphires rests on the Imperial State Crown worn by Queen Victoria in 1838. It resides in the British Crown Jewels in the Tower of London. In fact, this gem once belonged to Edward the Confessor. He wore the stone on a ring during his coronation in 1042, and thus called it St. Edward’s Sapphire.
The Logan Sapphire Brooch, the second largest sapphire known (at 422.99 carats), is on display at the National Museum of Natural History in Washington, D.C. Image via Andrew Bossi/ Wikipedia.
Bottom line: The September birthstone is the sapphire. It is generally known as a blue gemstone, but it comes in many colors.
Find out about the birthstones for the other months of the year:
View larger. | The European Space Agency’s Mars Express spacecraft captured this new image of Mars on July 13, 2024. And Andrea Luck processed it. The dark object hovering above Mars (center top of this image) is its larger moon, Phobos. And the dark orange protrusion near the limb (edge) – in about the 4 o’clock position – is our solar system’s largest volcano, Olympus Mons. Plus, look closely at the Martian limb itself in this new Mars image. You can see wisps of Mars’ thin atmosphere against the darkness of space. Image via ESA/ Andrea Luck/ CC BY.
New Mars image shows stunning detail
ESA’s Mars Express spacecraft has been observing the red planet for more than two decades. One of the craft’s newest images – captured on July 13, 2024, and processed by Andrea Luck – shows an impressive array of Martian features. In it, we can see the lumpy satellite that is the Mars moon Phobos, the massive volcano Olympus Mons on Mars’ surface, and a thin wisp of high-altitude clouds in Mars’s atmosphere along the planet’s limb, or edge.
Phobos and Mars’ other moon, Deimos, were likely once asteroids that the red planet drew in with its gravity. Phobos is the larger of the two moons, and it’s circling ever-closer to Mars. One day some 50 million years from now, it will either crash into the planet or get shredded into a ring.
Olympus Mons is the largest volcano in our solar system. But it hasn’t erupted for about 25 million years. Still, scientists consider it the youngest of the large volcanoes on Mars. The giant volcano is about the size of Poland.
And the red planet’s atmosphere is quite thin, showing up with some high-altitude clouds looking like a pale wisp against the blackness of space. In fact, Olympus Mons is taller than the atmosphere is thick. As Lowell Observatory has reported:
Mars’ atmosphere is so thin that the volcano’s peak actually pokes out above it, meaning that if one were to hike to the summit of Olympus Mons, they would hike into space.
Another image looking down at Mars
If you love images of Mars, then check out this one below from the Mars Reconnaissance Orbiter. This image, from September 24, 2021, captures a 3rd mission to Mars, the Perseverance rover, exploring the red planet’s surface.
1) Open this image up
2) Zoom in to find the small, bright, bluey–white object
View larger. | The European Space Agency’s Mars Express spacecraft captured this new image of Mars on July 13, 2024. And Andrea Luck processed it. The dark object hovering above Mars (center top of this image) is its larger moon, Phobos. And the dark orange protrusion near the limb (edge) – in about the 4 o’clock position – is our solar system’s largest volcano, Olympus Mons. Plus, look closely at the Martian limb itself in this new Mars image. You can see wisps of Mars’ thin atmosphere against the darkness of space. Image via ESA/ Andrea Luck/ CC BY.
New Mars image shows stunning detail
ESA’s Mars Express spacecraft has been observing the red planet for more than two decades. One of the craft’s newest images – captured on July 13, 2024, and processed by Andrea Luck – shows an impressive array of Martian features. In it, we can see the lumpy satellite that is the Mars moon Phobos, the massive volcano Olympus Mons on Mars’ surface, and a thin wisp of high-altitude clouds in Mars’s atmosphere along the planet’s limb, or edge.
Phobos and Mars’ other moon, Deimos, were likely once asteroids that the red planet drew in with its gravity. Phobos is the larger of the two moons, and it’s circling ever-closer to Mars. One day some 50 million years from now, it will either crash into the planet or get shredded into a ring.
Olympus Mons is the largest volcano in our solar system. But it hasn’t erupted for about 25 million years. Still, scientists consider it the youngest of the large volcanoes on Mars. The giant volcano is about the size of Poland.
And the red planet’s atmosphere is quite thin, showing up with some high-altitude clouds looking like a pale wisp against the blackness of space. In fact, Olympus Mons is taller than the atmosphere is thick. As Lowell Observatory has reported:
Mars’ atmosphere is so thin that the volcano’s peak actually pokes out above it, meaning that if one were to hike to the summit of Olympus Mons, they would hike into space.
Another image looking down at Mars
If you love images of Mars, then check out this one below from the Mars Reconnaissance Orbiter. This image, from September 24, 2021, captures a 3rd mission to Mars, the Perseverance rover, exploring the red planet’s surface.
1) Open this image up
2) Zoom in to find the small, bright, bluey–white object
