A bottlenose dolphin leaping from the ocean in Panama. Image via Christian Wittman/Shutterstock.com.
By Maria Carolina Gallego-Iradi, University of Florida and David Borchelt, University of Florida
A team of scientists in the United Kingdom and the U.S. recently reported the discovery of pathological signs of Alzheimer’s disease in dolphins, animals whose brains are similar in many ways to those of humans.
This is the first time that these signs – neurofibrillary tangles and two kinds of protein clusters called plaques – have been discovered together in marine mammals. As neuroscience researchers, we believe this discovery has added significance because of the similarities between dolphin brains and human brains.
The new finding in dolphins supports the research team’s hypothesis that two factors conspire to raise the risk of developing Alzheimer’s disease in dolphins.
Those factors are: longevity with a long post-fertility life span – that is, a species living, on average, many years after the child-bearing years are over – and insulin signaling.
Gallego-Iradi, one of the authors of the paper, began the study on the dolphins’ brains more than a decade ago on the shores of Spain. It took several more years for other researchers to establish the connection between metabolic dysfunction and insulin resistance in dolphins and humans. This recent study also did that.
Together, the insight into the similarities between dolphins and humans has led us to hypothesize that Alzheimer’s and diabetes are diseases not of old age but of a long post-fertility life span.
A disastrous disease
Alzheimer’s is a progressive brain disease that leads to memory loss and changes in cognitive ability. There is no cure, and the disease ultimately leads to death.
It is hard to overstate the burden of the disease, both on those who are diagnosed with it and their families. It is the sixth-leading cause of death in the U.S. Deaths from the disease in the U.S. rose 55 percent from 1999 to 2014.
Alzheimer’s disease has two major pathological hallmarks: The development of clusters of a protein called beta-amyloid outside the cells and tangles of another protein called tau inside the cell.
The protein clusters outside the cells are called senile plaques. The tangles inside are called neurofibrillary tangles.
We saw both of these in the brains of the deceased dolphins.
Image via University of Manchester.
The big brain theory
Dolphins belong to an order of mammals called cetaceans that have adapted to live in the water.
Although dolphins live in water and humans live on Earth, dolphins and humans are very much alike in some key ways. In the last 50-60 million years, the brains of dolphins and other cetaceans, including porpoises and whales, have hyperexpanded. So have human brains. This is a process called enchephalization.
Also, as do humans, dolphins have a highly evolved brain development and a very complex social relationship. This brain similarity with humans suggests the possibility that dolphins, as humans, have developed similar molecular machineries and pathological characteristics, including similar neurodegenerative diseases.
And, cetaceans and humans live long. This is important, as longevity is one of the most relevant factors in neurodegenerative diseases. Cetaceans have longevity ranges between 20-100 years, which is enough time to develop brain amyloid deposits.
Some aspects of Alzheimer’s pathology have been reported in a wide range of other animals. Our evolutionary relatives, such as apes and monkeys, and our pets, dogs and cats, develop one of the pathologies, the amyloid pathology. Amyloid plaques also have been described in captive wild animals such as bears.
But to see both plaques and tangles in another species is rare.
We believe this makes our findings in dolphins of both neuritic plaque and tangle pathology in dolphins all the more remarkable.
Stranded dolphins led to the first discovery
Cetaceans become stranded many times each year all over the world. This stranding generates alarm, and scientists study to understand why it happens. Some of the factors include poor water quality; animals living in very deep water who detect the shore too late; unbalance and confusion created by Earth’s magnetic field changes; contamination by heavy metals such as mercury, cadmium or zinc; or contamination by compounds such as PCBs and DDTs. Other possible causes are viruses and parasites, traumatic death, predation or fishing mutilation, or ship sonars interfering with animal echolocation.
Dolphins stranded in Spain between 2003 and 2006 led to Gallego Iradi’s findings about the Alzheimer’s pathology.
The samples represented three different species of dolphins (bottlenose, striped and Risso’s) stranded on the coasts of Spain. Their brains all had the same twisted strands and protein clusters in their brain as human patients with Alzheimer’s disease. They also had neuronal loss, strengthening the idea that dolphins and humans could have the same Alzheimer’s pathology.
Years after those findings, other scientists began to explore a possible connection between a failure in insulin signaling and Alzheimer’s.
Dr. Simon Lovestone at the University of Oxford and Dr. Frank Gunn-Moore at the University of Saint Andrews began to develop a hypothesis that this failure in insulin signaling in humans, related to post-fertility longevity, could be a cause of Alzheimer’s in humans.
And here’s another connection.
Cetaceans are uniquely prone to a prediabetes state and are one of the few animals, other than humans, with a naturally long post-fertility life span.
We postulated a linked mechanism that led us to hypothesize that animals with a long post-fertility lifespan would be at risk for both insulin resistance and Alzheimer’s. This hypothesis led us to the prediction that cetaceans and other animals with unusual longevity would be at risk for both insulin resistance and would have Alzheimers’ pathology – a prediction for which we have provided some proof in our recent article.
Maria Carolina Gallego-Iradi, Assistant Scientist, University of Florida and David Borchelt, Professor, Neuroscience, University of Florida
This article was originally published on The Conversation. Read the original article.
Bottom line: Researchers have found pathological signs of Alzheimer’s in dolphins.
A bottlenose dolphin leaping from the ocean in Panama. Image via Christian Wittman/Shutterstock.com.
By Maria Carolina Gallego-Iradi, University of Florida and David Borchelt, University of Florida
A team of scientists in the United Kingdom and the U.S. recently reported the discovery of pathological signs of Alzheimer’s disease in dolphins, animals whose brains are similar in many ways to those of humans.
This is the first time that these signs – neurofibrillary tangles and two kinds of protein clusters called plaques – have been discovered together in marine mammals. As neuroscience researchers, we believe this discovery has added significance because of the similarities between dolphin brains and human brains.
The new finding in dolphins supports the research team’s hypothesis that two factors conspire to raise the risk of developing Alzheimer’s disease in dolphins.
Those factors are: longevity with a long post-fertility life span – that is, a species living, on average, many years after the child-bearing years are over – and insulin signaling.
Gallego-Iradi, one of the authors of the paper, began the study on the dolphins’ brains more than a decade ago on the shores of Spain. It took several more years for other researchers to establish the connection between metabolic dysfunction and insulin resistance in dolphins and humans. This recent study also did that.
Together, the insight into the similarities between dolphins and humans has led us to hypothesize that Alzheimer’s and diabetes are diseases not of old age but of a long post-fertility life span.
A disastrous disease
Alzheimer’s is a progressive brain disease that leads to memory loss and changes in cognitive ability. There is no cure, and the disease ultimately leads to death.
It is hard to overstate the burden of the disease, both on those who are diagnosed with it and their families. It is the sixth-leading cause of death in the U.S. Deaths from the disease in the U.S. rose 55 percent from 1999 to 2014.
Alzheimer’s disease has two major pathological hallmarks: The development of clusters of a protein called beta-amyloid outside the cells and tangles of another protein called tau inside the cell.
The protein clusters outside the cells are called senile plaques. The tangles inside are called neurofibrillary tangles.
We saw both of these in the brains of the deceased dolphins.
Image via University of Manchester.
The big brain theory
Dolphins belong to an order of mammals called cetaceans that have adapted to live in the water.
Although dolphins live in water and humans live on Earth, dolphins and humans are very much alike in some key ways. In the last 50-60 million years, the brains of dolphins and other cetaceans, including porpoises and whales, have hyperexpanded. So have human brains. This is a process called enchephalization.
Also, as do humans, dolphins have a highly evolved brain development and a very complex social relationship. This brain similarity with humans suggests the possibility that dolphins, as humans, have developed similar molecular machineries and pathological characteristics, including similar neurodegenerative diseases.
And, cetaceans and humans live long. This is important, as longevity is one of the most relevant factors in neurodegenerative diseases. Cetaceans have longevity ranges between 20-100 years, which is enough time to develop brain amyloid deposits.
Some aspects of Alzheimer’s pathology have been reported in a wide range of other animals. Our evolutionary relatives, such as apes and monkeys, and our pets, dogs and cats, develop one of the pathologies, the amyloid pathology. Amyloid plaques also have been described in captive wild animals such as bears.
But to see both plaques and tangles in another species is rare.
We believe this makes our findings in dolphins of both neuritic plaque and tangle pathology in dolphins all the more remarkable.
Stranded dolphins led to the first discovery
Cetaceans become stranded many times each year all over the world. This stranding generates alarm, and scientists study to understand why it happens. Some of the factors include poor water quality; animals living in very deep water who detect the shore too late; unbalance and confusion created by Earth’s magnetic field changes; contamination by heavy metals such as mercury, cadmium or zinc; or contamination by compounds such as PCBs and DDTs. Other possible causes are viruses and parasites, traumatic death, predation or fishing mutilation, or ship sonars interfering with animal echolocation.
Dolphins stranded in Spain between 2003 and 2006 led to Gallego Iradi’s findings about the Alzheimer’s pathology.
The samples represented three different species of dolphins (bottlenose, striped and Risso’s) stranded on the coasts of Spain. Their brains all had the same twisted strands and protein clusters in their brain as human patients with Alzheimer’s disease. They also had neuronal loss, strengthening the idea that dolphins and humans could have the same Alzheimer’s pathology.
Years after those findings, other scientists began to explore a possible connection between a failure in insulin signaling and Alzheimer’s.
Dr. Simon Lovestone at the University of Oxford and Dr. Frank Gunn-Moore at the University of Saint Andrews began to develop a hypothesis that this failure in insulin signaling in humans, related to post-fertility longevity, could be a cause of Alzheimer’s in humans.
And here’s another connection.
Cetaceans are uniquely prone to a prediabetes state and are one of the few animals, other than humans, with a naturally long post-fertility life span.
We postulated a linked mechanism that led us to hypothesize that animals with a long post-fertility lifespan would be at risk for both insulin resistance and Alzheimer’s. This hypothesis led us to the prediction that cetaceans and other animals with unusual longevity would be at risk for both insulin resistance and would have Alzheimers’ pathology – a prediction for which we have provided some proof in our recent article.
Maria Carolina Gallego-Iradi, Assistant Scientist, University of Florida and David Borchelt, Professor, Neuroscience, University of Florida
This article was originally published on The Conversation. Read the original article.
Bottom line: Researchers have found pathological signs of Alzheimer’s in dolphins.
Triangulum galaxy – aka M33 – via the VLT Survey Telescope at European Southern Observatory’s Paranal Observatory in Chile.
Say hello to the much-photographed Triangulum galaxy – aka Messier 33 – a face-on pinwheel of swarming suns and the second-nearest spiral galaxy to our Milky Way. This galaxy is only about 2.7 million light-years away. It’s huge, with a diameter about half that of our Milky Way. But it’s turned face on to us and thus has a low surface brightness in our sky. Although theoretically visible to the unaided eye under dark skies conditions, it’s not easy to spot in binoculars or even a telescope. Follow the links below to learn more about this nearby, face-on, very beautiful spiral galaxy.
How to find the Triangulum galaxy
Science of the Triangulum galaxy
Constellation Triangulum. Notice its relationship to the constellation Andromeda and the star Mirach in Andromeda. The Andromeda galaxy is marked as M31. Via astronomy.net
Here’s the star Mirach in Andromeda again. Notice that the Triangulum galaxy (M33) is about equidistant from this star as the Andromeda galaxy (M31). In other words, once you find Mirach and the Andromeda galaxy, a line between them will point, more or less, to the Triangulum galaxy. Via ESO Public Outreach
How to find the Triangulum galaxy. Have you ever seen the Andromeda galaxy (Messier 31), closest spiral galaxy to our Milky Way? If not, try finding the Andromeda galaxy before you take on the Triangulum galaxy. Here are two ways to find the Andromeda galaxy:
Use constellation Cassiopeia to find Andromeda galaxy
Use Great Square of Pegasus to find Andromeda Galaxy
The Andromeda galaxy shines 8 to 9 times more brightly than the Triangulum galaxy, which is the most distant object that you can easily see with the unaided eye. Fortunately, the Triangulum and Andromeda galaxies are a relatively close 15 degrees apart (for reference, a fist-width at an arm length approximates 10 degrees).
Star-hop to the Andromeda galaxy to orient yourself to the Triangulum galaxy. As seen on the sky chart, the star Mirach stands about midway between the two galaxies. Once you find Mirach and the Andromeda galaxy, you can draw a line between them to point in the general direction of the Triangulum galaxy.
Now for a word of warning: even if you’re staring right at the Triangulum galaxy, it’s still possible to miss it. You won’t see the galaxy’s stars at all. Sometimes, this galaxy looks almost transparent, like a water spot on a window. The small blob in your binocular field might resemble an unwashed spot on an otherwise clean window. If you’ve never seen this deep-sky object before, it’s hard to know what to look for.
Once you finally spot the Triangulum galaxy, you may wonder how you overlooked it so many times before.
Artist’s illustration of our Local Group via Chandra X-Ray Observatory.
Science of the Triangulum galaxy. The Triangulum galaxy is located at a distance of about 2.7 million light-years from our Milky Way. It’s a spiral galaxy, whose face-on orientation has given it the nickname Pinwheel Galaxy (another face-on spiral, Messier 101, also has this nickname).
The Triangulum galaxy is the third-largest member of our Local Group of galaxies. Our Local Group consists of several dozen galaxies; our Milky Way, the Andromeda galaxy and the Triangulum galaxy are the largest members.
After the Milky Way and Andromeda galaxies, the Triangulum galaxy ranks as the third-largest Local Group member. Its diameter is about 50,000 light-years, or about one-half that of our Milky Way. It’s thought to contain some 40 billion stars, in contrast to 400 billion for the Milky Way, and a trillion (1,000 billion) stars for Andromeda.
In 2004, astronomers found evidence for a clumpy stream of hydrogen gas linking the Triangulum galaxy with the nearby Andromeda galaxy. A year later, astronomers were able to estimate the proper motion – or sideways motion on our sky’s dome – of the Triangulum galaxy for the first time. They found that this galaxy is moving towards the Andromeda galaxy. Afterwards, some astronomers suggested the Triangulum galaxy might be a satellite of the Andromeda galaxy. In other words, over a timescale so vast we haven’t yet comprehended it, the Triangulum galaxy might orbit around the Andromeda galaxy.
It’s well known that the Andromeda galaxy is moving toward our Milky Way and that a collision between the two galaxies will occur some 4 billion years from now. Meanwhile, the fate of the Triangulum Galaxy isn’t known for certain. It might someday be torn apart and absorbed by the Andromeda galaxy. It might participate in the collision between the Milky Way and Andromeda galaxies.
Two other possibilities are a collision with the Milky Way before Andromeda arrives or an ejection from the Local Group.
It’s safe to say that the fate of these great galaxies is beyond human knowledge at this time!
Enjoying EarthSky? Sign up for our free daily newsletter today!
Bottom line: The Triangulum galaxy is 2.7 million light-years away, with a diameter about half that of our Milky Way. It’s turned face-on to us and so appears faint in our sky.
Triangulum galaxy – aka M33 – via the VLT Survey Telescope at European Southern Observatory’s Paranal Observatory in Chile.
Say hello to the much-photographed Triangulum galaxy – aka Messier 33 – a face-on pinwheel of swarming suns and the second-nearest spiral galaxy to our Milky Way. This galaxy is only about 2.7 million light-years away. It’s huge, with a diameter about half that of our Milky Way. But it’s turned face on to us and thus has a low surface brightness in our sky. Although theoretically visible to the unaided eye under dark skies conditions, it’s not easy to spot in binoculars or even a telescope. Follow the links below to learn more about this nearby, face-on, very beautiful spiral galaxy.
How to find the Triangulum galaxy
Science of the Triangulum galaxy
Constellation Triangulum. Notice its relationship to the constellation Andromeda and the star Mirach in Andromeda. The Andromeda galaxy is marked as M31. Via astronomy.net
Here’s the star Mirach in Andromeda again. Notice that the Triangulum galaxy (M33) is about equidistant from this star as the Andromeda galaxy (M31). In other words, once you find Mirach and the Andromeda galaxy, a line between them will point, more or less, to the Triangulum galaxy. Via ESO Public Outreach
How to find the Triangulum galaxy. Have you ever seen the Andromeda galaxy (Messier 31), closest spiral galaxy to our Milky Way? If not, try finding the Andromeda galaxy before you take on the Triangulum galaxy. Here are two ways to find the Andromeda galaxy:
Use constellation Cassiopeia to find Andromeda galaxy
Use Great Square of Pegasus to find Andromeda Galaxy
The Andromeda galaxy shines 8 to 9 times more brightly than the Triangulum galaxy, which is the most distant object that you can easily see with the unaided eye. Fortunately, the Triangulum and Andromeda galaxies are a relatively close 15 degrees apart (for reference, a fist-width at an arm length approximates 10 degrees).
Star-hop to the Andromeda galaxy to orient yourself to the Triangulum galaxy. As seen on the sky chart, the star Mirach stands about midway between the two galaxies. Once you find Mirach and the Andromeda galaxy, you can draw a line between them to point in the general direction of the Triangulum galaxy.
Now for a word of warning: even if you’re staring right at the Triangulum galaxy, it’s still possible to miss it. You won’t see the galaxy’s stars at all. Sometimes, this galaxy looks almost transparent, like a water spot on a window. The small blob in your binocular field might resemble an unwashed spot on an otherwise clean window. If you’ve never seen this deep-sky object before, it’s hard to know what to look for.
Once you finally spot the Triangulum galaxy, you may wonder how you overlooked it so many times before.
Artist’s illustration of our Local Group via Chandra X-Ray Observatory.
Science of the Triangulum galaxy. The Triangulum galaxy is located at a distance of about 2.7 million light-years from our Milky Way. It’s a spiral galaxy, whose face-on orientation has given it the nickname Pinwheel Galaxy (another face-on spiral, Messier 101, also has this nickname).
The Triangulum galaxy is the third-largest member of our Local Group of galaxies. Our Local Group consists of several dozen galaxies; our Milky Way, the Andromeda galaxy and the Triangulum galaxy are the largest members.
After the Milky Way and Andromeda galaxies, the Triangulum galaxy ranks as the third-largest Local Group member. Its diameter is about 50,000 light-years, or about one-half that of our Milky Way. It’s thought to contain some 40 billion stars, in contrast to 400 billion for the Milky Way, and a trillion (1,000 billion) stars for Andromeda.
In 2004, astronomers found evidence for a clumpy stream of hydrogen gas linking the Triangulum galaxy with the nearby Andromeda galaxy. A year later, astronomers were able to estimate the proper motion – or sideways motion on our sky’s dome – of the Triangulum galaxy for the first time. They found that this galaxy is moving towards the Andromeda galaxy. Afterwards, some astronomers suggested the Triangulum galaxy might be a satellite of the Andromeda galaxy. In other words, over a timescale so vast we haven’t yet comprehended it, the Triangulum galaxy might orbit around the Andromeda galaxy.
It’s well known that the Andromeda galaxy is moving toward our Milky Way and that a collision between the two galaxies will occur some 4 billion years from now. Meanwhile, the fate of the Triangulum Galaxy isn’t known for certain. It might someday be torn apart and absorbed by the Andromeda galaxy. It might participate in the collision between the Milky Way and Andromeda galaxies.
Two other possibilities are a collision with the Milky Way before Andromeda arrives or an ejection from the Local Group.
It’s safe to say that the fate of these great galaxies is beyond human knowledge at this time!
Enjoying EarthSky? Sign up for our free daily newsletter today!
Bottom line: The Triangulum galaxy is 2.7 million light-years away, with a diameter about half that of our Milky Way. It’s turned face-on to us and so appears faint in our sky.
The Great Square of Pegasus consists of 4 stars of nearly equal brightness: Scheat, Alpheratz, Markab and Algenib. Illustration via AstroBob.
The Great Square of Pegasus gallops into the fall sky just after dark around the September equinox, which fell in 2017 on September 22. It consists of four stars of nearly equal brightness: Scheat, Alpheratz, Markab and Algenib. It’s a landmark of the Northern Hemisphere’s autumn sky.
To find it, first of all use the Big Dipper to star-hop to Polaris the North Star. By drawing an imaginary line from any Big Dipper handle star through Polaris, and going twice the distance, you’ll always land on the W or M-shaped constellation Cassiopeia the Queen. A line from Polaris through the star Caph of Cassiopeia faithfully escorts you to the Great Square of Pegasus.
Image via astrobob.
Great Square of Pegasus
Like the Big Dipper, the Great Square of Pegasus isn’t a constellation. Instead, it’s an asterism, or noticeable pattern on our sky’s dome.
The Great Square is used much like the Big Dipper to help you find other sky treasures, the most notable being the Andromeda Galaxy.
Use the Great Square of Pegasus to find the Andromeda galaxy. Here’s how to do it.
A great big square of nothing. Often at events where many are stargazing for the first time, one may hear:
… the Great Square has nothing in it.
But, of course, the Great Square isn’t empty. The stars in the Square are faint enough that the unaided eye can’t easily detect them. If you have binoculars or small telescopes many stars pop up within the Square.
View larger. | You often hear people say the Great Square is “empty of stars. Of course, it’s not. Charles White created this image with a Rokinon 35mm lens, f2.0 ISA1600. It’s 10 images, each a 30-second exposure (total exposure 5 minutes). Camera: Sony QX1 ILCE. Iptron Sky Tracker.
One of the most famous faint stars near the Great Square is 51 Pegasi. In 1995 astronomers announced they discovered a planet around this star. After a few months of skepticism from the astronomical community, it was confirmed the first planet outside of our solar system was discovered. Now we know that two planets orbit the star.
Some books say that 51 Pegasi can be viewed with the eye alone, but it’s a bit of a challenge. Using binoculars, look roughly halfway between Scheat and Markab. The chart below is courtesy of Professor Jim Kaler. Note that you won’t be able to see the planets. Pegasus 51 is approximately 50 light-years away from Earth.
The star 51 Pegasi in the Great Square, via Jim Kaler.
You might recall that Pegasus was a winged horse in Greek mythology. The constellation Pegasus is one of seven constellations in the sky that tells why it is not good to say that a mortal is more beautiful than the gods. This story is plastered all over the autumn night sky.
Queen Cassiopeia bragged that she (or her daughter Andromeda) was more beautiful than immortal Nereids, or sea nymphs. This angered the gods, who asked the sea-god Poseidon to take revenge. The punishment was that King Cepheus and the Queen had to sacrifice their only daughter Andromeda to Cetus the sea monster. Andromeda while chained down to a rock at sea, and about to be gobbled up by the sea monster, saw Perseus riding Pegasus the flying horse. Perseus swooped down and showed the head of the Medusa to the Cetus, the sea monster, then Cetus immediately turned to stone. Then he whacked the chains holding Andromeda and freed her.
They flew off into the sunset to live happily ever after. The mortal horse on the last day of his life was given the honor of becoming a constellation for his loyal service. The dolphin that provided comfort to Andromeda was also granted immortality in the heavens by Zeus with the Delphinus constellation.
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The Great Square of Pegasus makes up the eastern (left) half of the constellation Pegasus. Image credit: Wikimedia Commons
Bottom line: How to see the Great Square of Pegasus star pattern.
The Great Square of Pegasus consists of 4 stars of nearly equal brightness: Scheat, Alpheratz, Markab and Algenib. Illustration via AstroBob.
The Great Square of Pegasus gallops into the fall sky just after dark around the September equinox, which fell in 2017 on September 22. It consists of four stars of nearly equal brightness: Scheat, Alpheratz, Markab and Algenib. It’s a landmark of the Northern Hemisphere’s autumn sky.
To find it, first of all use the Big Dipper to star-hop to Polaris the North Star. By drawing an imaginary line from any Big Dipper handle star through Polaris, and going twice the distance, you’ll always land on the W or M-shaped constellation Cassiopeia the Queen. A line from Polaris through the star Caph of Cassiopeia faithfully escorts you to the Great Square of Pegasus.
Image via astrobob.
Great Square of Pegasus
Like the Big Dipper, the Great Square of Pegasus isn’t a constellation. Instead, it’s an asterism, or noticeable pattern on our sky’s dome.
The Great Square is used much like the Big Dipper to help you find other sky treasures, the most notable being the Andromeda Galaxy.
Use the Great Square of Pegasus to find the Andromeda galaxy. Here’s how to do it.
A great big square of nothing. Often at events where many are stargazing for the first time, one may hear:
… the Great Square has nothing in it.
But, of course, the Great Square isn’t empty. The stars in the Square are faint enough that the unaided eye can’t easily detect them. If you have binoculars or small telescopes many stars pop up within the Square.
View larger. | You often hear people say the Great Square is “empty of stars. Of course, it’s not. Charles White created this image with a Rokinon 35mm lens, f2.0 ISA1600. It’s 10 images, each a 30-second exposure (total exposure 5 minutes). Camera: Sony QX1 ILCE. Iptron Sky Tracker.
One of the most famous faint stars near the Great Square is 51 Pegasi. In 1995 astronomers announced they discovered a planet around this star. After a few months of skepticism from the astronomical community, it was confirmed the first planet outside of our solar system was discovered. Now we know that two planets orbit the star.
Some books say that 51 Pegasi can be viewed with the eye alone, but it’s a bit of a challenge. Using binoculars, look roughly halfway between Scheat and Markab. The chart below is courtesy of Professor Jim Kaler. Note that you won’t be able to see the planets. Pegasus 51 is approximately 50 light-years away from Earth.
The star 51 Pegasi in the Great Square, via Jim Kaler.
You might recall that Pegasus was a winged horse in Greek mythology. The constellation Pegasus is one of seven constellations in the sky that tells why it is not good to say that a mortal is more beautiful than the gods. This story is plastered all over the autumn night sky.
Queen Cassiopeia bragged that she (or her daughter Andromeda) was more beautiful than immortal Nereids, or sea nymphs. This angered the gods, who asked the sea-god Poseidon to take revenge. The punishment was that King Cepheus and the Queen had to sacrifice their only daughter Andromeda to Cetus the sea monster. Andromeda while chained down to a rock at sea, and about to be gobbled up by the sea monster, saw Perseus riding Pegasus the flying horse. Perseus swooped down and showed the head of the Medusa to the Cetus, the sea monster, then Cetus immediately turned to stone. Then he whacked the chains holding Andromeda and freed her.
They flew off into the sunset to live happily ever after. The mortal horse on the last day of his life was given the honor of becoming a constellation for his loyal service. The dolphin that provided comfort to Andromeda was also granted immortality in the heavens by Zeus with the Delphinus constellation.
Enjoying EarthSky so far? Sign up for our free daily newsletter today!
Donate to EarthSky: Your support means the world to us
The Great Square of Pegasus makes up the eastern (left) half of the constellation Pegasus. Image credit: Wikimedia Commons
Bottom line: How to see the Great Square of Pegasus star pattern.
View larger. | Cassini’s last, full mosaic of Saturn, via NASA/JPL-Caltech/ Space Science Institute.
After more than 13 years at Saturn, and with its fate sealed, NASA’s Cassini spacecraft bid farewell to the Saturnian system by firing the shutters of its wide-angle camera and capturing this last, full mosaic of Saturn and its rings two days before the spacecraft’s dramatic plunge into the planet’s atmosphere.
During the observation, a total of 80 wide-angle images were acquired in just over two hours. This view is constructed from 42 of those wide-angle shots, taken using the red, green and blue spectral filters, combined and mosaicked together to create a natural-color view.
Six of Saturn’s moons — Enceladus, Epimetheus, Janus, Mimas, Pandora and Prometheus — make a faint appearance in this image. (Numerous stars are also visible in the background.)
A second version of the mosaic is provided in which the planet and its rings have been brightened, with the fainter regions brightened by a greater amount. (The moons and stars have also been brightened by a factor of 15 in this version.)
The ice-covered moon Enceladus — home to a global subsurface ocean that erupts into space — can be seen at the 1 o’clock position. Directly below Enceladus, just outside the F ring (the thin, farthest ring from the planet seen in this image) lies the small moon Epimetheus. Following the F ring clock-wise from Epimetheus, the next moon seen is Janus. At about the 4:30 position and outward from the F ring is Mimas. Inward of Mimas and still at about the 4:30 position is the F-ring-disrupting moon, Pandora. Moving around to the 10 o’clock position, just inside of the F ring, is the moon Prometheus.
This view looks toward the sunlit side of the rings from about 15 degrees above the ring plane. Cassini was approximately 698,000 miles (1.1 million kilometers) from Saturn, on its final approach to the planet, when the images in this mosaic were taken. Image scale on Saturn is about 42 miles (67 kilometers) per pixel. The image scale on the moons varies from 37 to 50 miles (59 to 80 kilometers) pixel. The phase angle (the Sun-planet-spacecraft angle) is 138 degrees.
The Cassini spacecraft ended its mission on September 15, 2017.
Image and text via NASA/JPL-Caltech
View larger. | Cassini’s last, full mosaic of Saturn, via NASA/JPL-Caltech/ Space Science Institute.
After more than 13 years at Saturn, and with its fate sealed, NASA’s Cassini spacecraft bid farewell to the Saturnian system by firing the shutters of its wide-angle camera and capturing this last, full mosaic of Saturn and its rings two days before the spacecraft’s dramatic plunge into the planet’s atmosphere.
During the observation, a total of 80 wide-angle images were acquired in just over two hours. This view is constructed from 42 of those wide-angle shots, taken using the red, green and blue spectral filters, combined and mosaicked together to create a natural-color view.
Six of Saturn’s moons — Enceladus, Epimetheus, Janus, Mimas, Pandora and Prometheus — make a faint appearance in this image. (Numerous stars are also visible in the background.)
A second version of the mosaic is provided in which the planet and its rings have been brightened, with the fainter regions brightened by a greater amount. (The moons and stars have also been brightened by a factor of 15 in this version.)
The ice-covered moon Enceladus — home to a global subsurface ocean that erupts into space — can be seen at the 1 o’clock position. Directly below Enceladus, just outside the F ring (the thin, farthest ring from the planet seen in this image) lies the small moon Epimetheus. Following the F ring clock-wise from Epimetheus, the next moon seen is Janus. At about the 4:30 position and outward from the F ring is Mimas. Inward of Mimas and still at about the 4:30 position is the F-ring-disrupting moon, Pandora. Moving around to the 10 o’clock position, just inside of the F ring, is the moon Prometheus.
This view looks toward the sunlit side of the rings from about 15 degrees above the ring plane. Cassini was approximately 698,000 miles (1.1 million kilometers) from Saturn, on its final approach to the planet, when the images in this mosaic were taken. Image scale on Saturn is about 42 miles (67 kilometers) per pixel. The image scale on the moons varies from 37 to 50 miles (59 to 80 kilometers) pixel. The phase angle (the Sun-planet-spacecraft angle) is 138 degrees.
The Cassini spacecraft ended its mission on September 15, 2017.
Image and text via NASA/JPL-Caltech
Tonight – or any autumn or winter evening – if you can see the Big Dipper, use its famous pointer stars (which point to Polaris, the North Star) to find the bright golden star Capella in the constellation Auriga the Charioteer. The top two bowl stars point toward Capella, as we depict on the chart at the top of this post.
Capella is sometimes called the Goat Star. In fact, the star name Capella is the Latin word for nanny goat. Near Capella, you’ll find a tiny asterism – a noticeable pattern on the sky’s dome – consisting of three fainter stars. This little triangle of stars is called the Kids.
The phrase spring up and fall down gives you some idea of the Big Dipper’s place in the evening sky. On fall evenings for us in the Northern Hemisphere, the Big Dipper sits way down low in the northern sky.
On northern spring evenings, the Big Dipper shines high above Polaris, the North Star.
From the Southern Hemisphere: Sorry, y’all. These are northern stars and not easily visible to you … unless you come visit our part of the world!
From the far southern U.S. and similar latitudes: You won’t see the Big Dipper on these November evenings, either. From more southerly latitudes in the Northern Hemisphere, the Big Dipper is below your northern horizon on autumn evenings. Even in the northern states, it’ll be possible to miss the Big Dipper if obstructions block your view of the northern sky. However, the Big Dipper swings full circle around Polaris, the North Star, once a day. Thus, from these latitudes, the Big Dipper will appear fairly high in the northeast sky before morning dawn in November.
It’s a long jump from the Big Dipper bowl stars to Capella. Our chart at top goes all the way from northwest to northeast. That’s about one-fourth the way around the horizon.
And remember, the Big Dipper and Capella move throughout the night, and throughout the year, but – no matter when and where you see them – they are part of the “fixed” star background … and so always maintain this relationship to one another.
The bright star Capella and its constellation Auriga the Charioteer as seen in the east-northeast sky. Image via Wikimedia Commons
Bottom line: The Big Dipper’s bowl stars always point in the general direction of Capella, the northernmost first-magnitude star in all the heavens.
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Easily locate stars and constellations during any day and time with EarthSky’s Planisphere.
Tonight – or any autumn or winter evening – if you can see the Big Dipper, use its famous pointer stars (which point to Polaris, the North Star) to find the bright golden star Capella in the constellation Auriga the Charioteer. The top two bowl stars point toward Capella, as we depict on the chart at the top of this post.
Capella is sometimes called the Goat Star. In fact, the star name Capella is the Latin word for nanny goat. Near Capella, you’ll find a tiny asterism – a noticeable pattern on the sky’s dome – consisting of three fainter stars. This little triangle of stars is called the Kids.
The phrase spring up and fall down gives you some idea of the Big Dipper’s place in the evening sky. On fall evenings for us in the Northern Hemisphere, the Big Dipper sits way down low in the northern sky.
On northern spring evenings, the Big Dipper shines high above Polaris, the North Star.
From the Southern Hemisphere: Sorry, y’all. These are northern stars and not easily visible to you … unless you come visit our part of the world!
From the far southern U.S. and similar latitudes: You won’t see the Big Dipper on these November evenings, either. From more southerly latitudes in the Northern Hemisphere, the Big Dipper is below your northern horizon on autumn evenings. Even in the northern states, it’ll be possible to miss the Big Dipper if obstructions block your view of the northern sky. However, the Big Dipper swings full circle around Polaris, the North Star, once a day. Thus, from these latitudes, the Big Dipper will appear fairly high in the northeast sky before morning dawn in November.
It’s a long jump from the Big Dipper bowl stars to Capella. Our chart at top goes all the way from northwest to northeast. That’s about one-fourth the way around the horizon.
And remember, the Big Dipper and Capella move throughout the night, and throughout the year, but – no matter when and where you see them – they are part of the “fixed” star background … and so always maintain this relationship to one another.
The bright star Capella and its constellation Auriga the Charioteer as seen in the east-northeast sky. Image via Wikimedia Commons
Bottom line: The Big Dipper’s bowl stars always point in the general direction of Capella, the northernmost first-magnitude star in all the heavens.
Donate: Your support means the world to us
Enjoying EarthSky so far? Sign up for our free daily newsletter today!
Easily locate stars and constellations during any day and time with EarthSky’s Planisphere.
