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National Geographic
16-04-2025
- Science
- National Geographic
How to see the northern lights—and why they're showing up more recently
The northern lights, or aurora borealis, hang above the fishing village of Reine on Norway's Lofoten archipelago. The best places to see this ethereal display are in "auroral zones" that are close to Earth's poles—but sometimes you can see them from even farther north and south. Photograph by Rieger Bertrand, Getty Images The aurora borealis and aurora australis have dazzled us in the night sky for centuries. Here's what causes them—and where the best places are to catch a glimpse. No matter how many times you see them, the northern lights, or aurora borealis—and their Southern Hemisphere equivalent, the aurora australis—are an ethereal, breathtaking sight. Dancing silently in Earth's upper atmosphere, they form iridescent sheets of green and red (or sometimes blue and purple) light. And this week, across the northern United States—and even parts of the Midwest—they're expected to put on a rare show. On April 12 and 13, a pair of coronal mass ejections (CMEs) erupted from the surface of the sun; as a result, when their electrically charged particles hit Earth's atmosphere this week, states as far south as Iowa may be treated to vivid displays of northern lights. As many as 18 states—from Alaska and Montana to New England and New York—may experience colorful displays. The phenomenon is expected to peak on April 16 before tapering off the next day. Although the lights may be visible all night, the best viewing times are expected to be between 10 p.m. and 2 a.m. local time wherever you're skygazing. However, this won't be the last opportunity for viewers in these areas to see northern lights over the next several months, as the sun is in the middle of a "solar maximum," the peak of an 11-year cycle in which storm activity on its surface waxes and wanes. Common in polar and sub-polar regions, auroras can sometimes be seen at lower latitudes, including recent dazzling displays as far south as Florida. If you live in the contiguous United States, but it seems like you've been able to see auroras far more often than you normally would—well, you're right. Here's why. What are auroras, or the northern and southern lights? Italian astronomer Galileo Galilei, coined the term aurora in 1619 after the Roman goddess of dawn—mistakenly believing it to be the reflection of sunlight off the atmosphere. In fact, both northern and southern lights are caused by the interaction of gases in Earth's atmosphere with the solar wind: a stream of electrically charged particles, called ions, that shoot out from the sun in all directions. (Staring at the sun: an interactive look at our dynamic home star.) When the solar wind reaches Earth, it slams into the planet's magnetic field, producing currents of charged particles that flow toward the poles. Some of the ions become trapped in a layer of the atmosphere called the ionosphere, where they collide with gas atoms—primarily oxygen and nitrogen—and "excite" them with extra energy. This energy then gets released as particles of light, or photons. Why are auroras different colors? An aurora's colors signify where in the atmosphere, and with which gases, all of this is happening. For example, it takes almost two minutes for an excited oxygen atom to emit a red photon, and if one atom collides with another during that time, the process may be interrupted or terminated. So, when we see red auroras, they are most likely at the highest levels of the ionosphere, approximately 150 miles (240 kilometers) high, where there are fewer oxygen atoms to interfere with one another. (Why is the sky blue? Learn about it with your kids.) The aurora borealis lights up the night sky behind Iceland's iconic Kirkjufell volcano. Auroras are caused when charged particles from the sun collide with gases in Earth's atmosphere. The color signifies the layer of Earth's atmosphere where these interactions are happening. Photograph by Babak Tafreshi, Nat Geo Image Collection In contrast, green photons are discharged in less than a second, so are more common in moderately dense parts of the atmosphere, 60 to 150 miles (100 to 240 kilometers) above Earth's surface. In the very thick lower atmosphere, less than 60 miles (100 kilometers) above the planet's surface, we see a purplish mixture of red and blue lights—the signature colors of molecular nitrogen. Where can you see auroras? Auroras have been observed on every planet in the solar system except Mercury—even, as with Venus and Mars, when the magnetic field is very weak or nonexistent. They have even been detected on a huge 'rogue planet' 20 light years away. And astronauts have taken spectacular photographs and video of Earth's auroras from the International Space Station. For the more earthbound among us, the best places to see auroras are in the 'auroral zone,' between about 60 and 75 degrees latitude, both north and south. You're even likelier to see an aurora if you're in a smaller band of Earth between 65 and 70 degrees latitude. The broader band includes locations like Anchorage, Alaska and Yellowknife, Canada, while the smaller zone includes Fairbanks, Alaska and Tromso, Norway. (Here's the best place to see northern lights in the lower 48 states—and how to visit it.) You also need somewhere where the skies are dark and clear and far from light pollution. In the Southern Hemisphere, that generally means Antarctica, Tasmania, or southern New Zealand in fall or winter. North of the Equator it includes locales such as the areas around Fairbanks, Alaska; Churchill, Manitoba; and the Lapland area of northern Sweden and Finland, among many others. When do auroras occur—and are they happening more often? One good way to predict a strong aurora night is to count forward 27 days from the most recent one; auroras are strongly associated with sunspot activity, and as it takes 27 days for the sun to rotate on its axis, that's how long it will take an aurora-producing sunspot to show up again. Some years see more auroras than others. Sunspot activity fluctuates on an 11-year cycle; the most recent upward trend began in 2019 and is peaking this year. A tent is pitched underneath the northern lights at Gates of the Arctic, the northernmost national park in the United States. This region of Alaska is among the best places on Earth for viewing auroras. Photograph by Katie Orlinsky, Nat Geo Image Collection Greater sunspot activity is also why there are sometimes aurora displays in parts of the world that otherwise rarely see them. This rise in activity creates a greater likelihood of large solar storms, which can shoot electromagnetic radiation and particles toward Earth; when they hit our atmosphere, they flood it with so many particles that the auroral zone expands far beyond its usual limits. This effect was most recently in evidence in early 2023, as solar storms resulted in auroras being visible as far south as Arizona and England. In addition to causing dazzling displays, however, these solar storms can also impact power grids and GPS systems. (Solar storms may throw off whale navigation too.) Even the most active of sunspot cycles, however, will find it hard to match the largest solar storm on record, however. On September 1, 1859, astronomers had been watching a growing number of sunspots develop on our star's surface when a solar flare sped toward Earth, creating vivid aurora displays as far south as Cuba and as far north as Santiago, Chile. Having never seen them before, some observers believed the bright lights presaged the end of the world, or that 'it appeared as if there was a colossal fire on earth which reflected its flames on the heavens.'
The Independent
08-04-2025
- Science
- The Independent
Saturn has 128 more moons than astronomers previously thought
Earlier this week, Saturn gained a whopping 128 new official moons, as the International Astronomical Union recognised discoveries from a team of astronomers led by Edward Ashton at the Academia Sinica in Taiwan. The sixth planet from the Sun now has a grand total of 274 moons, the most of any planet in the Solar System. The discovery has raised a lot of questions. How do you spot moons, and why hadn't anybody seen these ones already? Doesn't Jupiter have the most moons? What are they going to call all these moons? Are there more out there? And what exactly makes something a moon, anyway? These new discoveries cement Saturn's place as the winner of the Solar System's moon competition, with more confirmed moons than all of the other planets combined. But it hasn't always been this way. Jupiter's four largest moons – Io, Europa, Ganymede and Callisto – were the first ever discovered orbiting another planet. They were spotted by Galileo Galilei more than 400 years ago, in 1610. Saturn's first known moon, Titan, was discovered by Dutch astronomer Christiaan Huygens 45 years later. The new batch of 128 moons was discovered by stacking images from the Canada France Hawaii telescope. Some of Saturn's other moons were discovered by space voyages, and some during what are called 'ring-plane crossings'. When the Voyager 1 spacecraft passed by Saturn, it took images that were used to discover the moon Atlas. The Cassini Mission later discovered seven new Saturnian moons. A ring-crossing is where Saturn's rings seem to disappear from our point of view here on Earth. This is when Saturn is at just the right angle so we're looking at the rings exactly side-on (that is, when we can only see the edge of the rings). Titan was discovered during a ring-plane crossing, and so were 12 other moons. Saturn's rings will be edge-on twice in 2025, in March and November. From 2019 to 2023, Jupiter and Saturn were fighting for first place in the moon race. In 2019, Saturn surpassed Jupiter with the discovery of 20 new moons. This took the count to 82 for Saturn and 79 for Jupiter. Just a few years later, in February 2023, Jupiter took the lead with 12 new moons, beating Saturn's 83 moons at the time. Only a short time later, still in 2023, the same astronomers who discovered the recent 128 moons discovered 62 moons orbiting Saturn. This placed the ringed planet firmly in the lead. Elsewhere in the Solar System, Earth has one moon, Mars has two, Jupiter has 95, Uranus has 28 and Neptune has 16, for a total of 142 moons. We only need to discover ten more moons around Saturn to give it double the number of all the other planets combined. The newly discovered moons are all small. Each one is only a few kilometres across. If something that small can be a moon, what really counts as a moon? NASA tells us 'naturally formed bodies that orbit planets are called moons', but even asteroids can have moons. We crashed a spacecraft into an asteroid's moon in 2022. Earth has had a few mini-moons, some only a couple of metres in size. The line of what is and isn't a moon is a bit hazy. Moons orbiting planets in the Solar System can be either 'regular' or 'irregular'. The new moons are all irregular. Regular moons are formed around a planet at the same time as the planet itself forms. Irregular moons are thought to be small planets (planetesimals) that are captured by a planet as it finishes forming. They are then broken into pieces by collisions. Regular moons tend to orbit their planets in nice, circular orbits around the equator. Irregular moons typically orbit in big ovals further away from planets, and at a range of angles. Saturn has 24 regular moons and 250 irregular moons. Studying these moons can tell us about how moons form, and reveal clues about how the Solar System formed and evolved. Saturn's rings are made of small chunks of ice and rock. Astronomers think they formed out of pieces of comets, asteroids and moons that were torn apart by Saturn's gravity. So for Saturn in particular, irregular moons can tell us more about the formation of its beautiful rings. Names of astronomical objects are governed by the International Astronomical Union (IAU). Originally, all moons in the Solar System were given names from Greco-Roman mythology. But the large number of moons, particularly of Saturn and Jupiter, means the IAU has expanded to giants and gods from other mythology. And it's all about the details. If binary moons are discovered, they are required to be given names of twins or siblings. Saturn's first seven moons were given numbers instead of names. In 1847, John Herschel named them after the Greek Titans. After they ran out of titans and Greek mythological giants, they expanded the naming system to include Inuit and Gallic gods and Norse giants. Discoverers get to suggest names for moons, and the names they suggest are given priority by the IAU. In the past, there have been competitions to name new moons of Jupiter and Saturn. With 128 new moons for Saturn, it might take a while to come up with names that follow the IAU rules. Maybe we'll even see the addition of different mythologies. We'll have to wait and see. Until then, each moon has a name made of a string of numbers and letters, such as 'S/2020 S 27'. Without a solid definition of what a moon is, it's hard to say when (or if) we will ever finish finding them. Everyone agrees we shouldn't call every single chunk of rock in Saturn's rings a moon, but exactly where to draw the line isn't clear. That said, there is probably a limit to the number of moon-like objects astronomers are likely to want to add to the list. Edward Ashton, who led the discovery of the new moons, doesn't think we'll be finding too many new moons until our technology improves.
Yahoo
24-03-2025
- Science
- Yahoo
‘Planetary sleight of hand': Kentucky set to see Saturn's rings disappear
KENTUCKY (FOX 56) — On the heels of the worm moon turning to blood, stargazers in Kentucky are set to see the heaven's next magic trick. At 12:04 p.m. on Sunday, Earth officially passed through the sixth planet's 'ring plane.' Pedestrian in critical condition after crash on Alexandria Drive Missing person search operation underway in London 'Planetary sleight of hand': Kentucky set to see Saturn's rings disappear Due to a transition in Saturn's planetary axis, Earth's ability to perceive Saturn's vibrant rings will be in 'perfect alignment' with Earth, causing them to be nearly invisible, according to At 12:04 p.m. on Sunday, Earth officially passed through the sixth planet's 'ring plane.' 'The rings engage in sort of a planetary 'sleight of hand,' where, when viewed from the edge, the rings seem to disappear (think of a sheet of paper—it looks large when viewed from above, but as you tilt it, it gets thinner and thinner),' explained Dr. Amy Simon, Senior Scientist for Planetary Atmospheres Research in the Solar System Exploration Division at the NASA Goddard Space Flight Center. Read more of the latest Kentucky news In the 1600s, Galileo Galilei described the faraway world as having 'ears.' Once the rings vanish from sight, the planet with ears will look like 'a pale yellow sphere' through telescopes. claims that only the most powerful of telescopes might be able to see the subtle line of Saturn's rings. The rings stretch around 170,000 miles long but are only about 30 feet thick, according to The rings will come back into full view in November as Earth and Saturn will shift positions, and lucky skywatchers may even be able to catch a glimpse of its many moons. The Weather Authority is calling for a mix of clouds across the central Kentucky sky when Saturn is at its brightest Monday evening. Celestial enthusiasts will want to jump at the chance to witness the solar system's next magic trick. Copyright 2025 Nexstar Media, Inc. All rights reserved. This material may not be published, broadcast, rewritten, or redistributed.
The Independent
23-03-2025
- Science
- The Independent
Astronomers stunned to find Saturn has 128 more moons in rare discovery
Earlier this week, Saturn gained a whopping 128 new official moons, as the International Astronomical Union recognised discoveries from a team of astronomers led by Edward Ashton at the Academia Sinica in Taiwan. The sixth planet from the Sun now has a grand total of 274 moons, the most of any planet in the Solar System. The discovery has raised a lot of questions. How do you spot moons, and why hadn't anybody seen these ones already? Doesn't Jupiter have the most moons? What are they going to call all these moons? Are there more out there? And what exactly makes something a moon, anyway? These new discoveries cement Saturn's place as the winner of the Solar System's moon competition, with more confirmed moons than all of the other planets combined. But it hasn't always been this way. Jupiter's four largest moons – Io, Europa, Ganymede and Callisto – were the first ever discovered orbiting another planet. They were spotted by Galileo Galilei more than 400 years ago, in 1610. Saturn's first known moon, Titan, was discovered by Dutch astronomer Christiaan Huygens 45 years later. The new batch of 128 moons was discovered by stacking images from the Canada France Hawaii telescope. Some of Saturn's other moons were discovered by space voyages, and some during what are called 'ring-plane crossings'. When the Voyager 1 spacecraft passed by Saturn, it took images that were used to discover the moon Atlas. The Cassini Mission later discovered seven new Saturnian moons. A ring-crossing is where Saturn's rings seem to disappear from our point of view here on Earth. This is when Saturn is at just the right angle so we're looking at the rings exactly side-on (that is, when we can only see the edge of the rings). Titan was discovered during a ring-plane crossing, and so were 12 other moons. Saturn's rings will be edge-on twice in 2025, in March and November. From 2019 to 2023, Jupiter and Saturn were fighting for first place in the moon race. In 2019, Saturn surpassed Jupiter with the discovery of 20 new moons. This took the count to 82 for Saturn and 79 for Jupiter. Just a few years later, in February 2023, Jupiter took the lead with 12 new moons, beating Saturn's 83 moons at the time. Only a short time later, still in 2023, the same astronomers who discovered the recent 128 moons discovered 62 moons orbiting Saturn. This placed the ringed planet firmly in the lead. Elsewhere in the Solar System, Earth has one moon, Mars has two, Jupiter has 95, Uranus has 28 and Neptune has 16, for a total of 142 moons. We only need to discover ten more moons around Saturn to give it double the number of all the other planets combined. The newly discovered moons are all small. Each one is only a few kilometres across. If something that small can be a moon, what really counts as a moon? NASA tells us 'naturally formed bodies that orbit planets are called moons', but even asteroids can have moons. We crashed a spacecraft into an asteroid's moon in 2022. Earth has had a few mini-moons, some only a couple of metres in size. The line of what is and isn't a moon is a bit hazy. Moons orbiting planets in the Solar System can be either 'regular' or 'irregular'. The new moons are all irregular. Regular moons are formed around a planet at the same time as the planet itself forms. Irregular moons are thought to be small planets (planetesimals) that are captured by a planet as it finishes forming. They are then broken into pieces by collisions. Regular moons tend to orbit their planets in nice, circular orbits around the equator. Irregular moons typically orbit in big ovals further away from planets, and at a range of angles. Saturn has 24 regular moons and 250 irregular moons. Studying these moons can tell us about how moons form, and reveal clues about how the Solar System formed and evolved. Saturn's rings are made of small chunks of ice and rock. Astronomers think they formed out of pieces of comets, asteroids and moons that were torn apart by Saturn's gravity. So for Saturn in particular, irregular moons can tell us more about the formation of its beautiful rings. Names of astronomical objects are governed by the International Astronomical Union (IAU). Originally, all moons in the Solar System were given names from Greco-Roman mythology. But the large number of moons, particularly of Saturn and Jupiter, means the IAU has expanded to giants and gods from other mythology. And it's all about the details. If binary moons are discovered, they are required to be given names of twins or siblings. Saturn's first seven moons were given numbers instead of names. In 1847, John Herschel named them after the Greek Titans. After they ran out of titans and Greek mythological giants, they expanded the naming system to include Inuit and Gallic gods and Norse giants. Discoverers get to suggest names for moons, and the names they suggest are given priority by the IAU. In the past, there have been competitions to name new moons of Jupiter and Saturn. With 128 new moons for Saturn, it might take a while to come up with names that follow the IAU rules. Maybe we'll even see the addition of different mythologies. We'll have to wait and see. Until then, each moon has a name made of a string of numbers and letters, such as 'S/2020 S 27'. Without a solid definition of what a moon is, it's hard to say when (or if) we will ever finish finding them. Everyone agrees we shouldn't call every single chunk of rock in Saturn's rings a moon, but exactly where to draw the line isn't clear. That said, there is probably a limit to the number of moon-like objects astronomers are likely to want to add to the list. Edward Ashton, who led the discovery of the new moons, doesn't think we'll be finding too many new moons until our technology improves.
The Independent
14-03-2025
- Science
- The Independent
Astronomers find Saturn has 128 more moons in rare discovery
Earlier this week, Saturn gained a whopping 128 new official moons, as the International Astronomical Union recognised discoveries from a team of astronomers led by Edward Ashton at the Academia Sinica in Taiwan. The sixth planet from the Sun now has a grand total of 274 moons, the most of any planet in the Solar System. The discovery has raised a lot of questions. How do you spot moons, and why hadn't anybody seen these ones already? Doesn't Jupiter have the most moons? What are they going to call all these moons? Are there more out there? And what exactly makes something a moon, anyway? These new discoveries cement Saturn's place as the winner of the Solar System's moon competition, with more confirmed moons than all of the other planets combined. But it hasn't always been this way. Jupiter's four largest moons – Io, Europa, Ganymede and Callisto – were the first ever discovered orbiting another planet. They were spotted by Galileo Galilei more than 400 years ago, in 1610. Saturn's first known moon, Titan, was discovered by Dutch astronomer Christiaan Huygens 45 years later. The new batch of 128 moons was discovered by stacking images from the Canada France Hawaii telescope. Some of Saturn's other moons were discovered by space voyages, and some during what are called 'ring-plane crossings'. When the Voyager 1 spacecraft passed by Saturn, it took images that were used to discover the moon Atlas. The Cassini Mission later discovered seven new Saturnian moons. A ring-crossing is where Saturn's rings seem to disappear from our point of view here on Earth. This is when Saturn is at just the right angle so we're looking at the rings exactly side-on (that is, when we can only see the edge of the rings). Titan was discovered during a ring-plane crossing, and so were 12 other moons. Saturn's rings will be edge-on twice in 2025, in March and November. From 2019 to 2023, Jupiter and Saturn were fighting for first place in the moon race. In 2019, Saturn surpassed Jupiter with the discovery of 20 new moons. This took the count to 82 for Saturn and 79 for Jupiter. Just a few years later, in February 2023, Jupiter took the lead with 12 new moons, beating Saturn's 83 moons at the time. Only a short time later, still in 2023, the same astronomers who discovered the recent 128 moons discovered 62 moons orbiting Saturn. This placed the ringed planet firmly in the lead. Elsewhere in the Solar System, Earth has one moon, Mars has two, Jupiter has 95, Uranus has 28 and Neptune has 16, for a total of 142 moons. We only need to discover ten more moons around Saturn to give it double the number of all the other planets combined. The newly discovered moons are all small. Each one is only a few kilometres across. If something that small can be a moon, what really counts as a moon? NASA tells us 'naturally formed bodies that orbit planets are called moons', but even asteroids can have moons. We crashed a spacecraft into an asteroid's moon in 2022. Earth has had a few mini-moons, some only a couple of metres in size. The line of what is and isn't a moon is a bit hazy. Moons orbiting planets in the Solar System can be either 'regular' or 'irregular'. The new moons are all irregular. Regular moons are formed around a planet at the same time as the planet itself forms. Irregular moons are thought to be small planets (planetesimals) that are captured by a planet as it finishes forming. They are then broken into pieces by collisions. Regular moons tend to orbit their planets in nice, circular orbits around the equator. Irregular moons typically orbit in big ovals further away from planets, and at a range of angles. Saturn has 24 regular moons and 250 irregular moons. Studying these moons can tell us about how moons form, and reveal clues about how the Solar System formed and evolved. Saturn's rings are made of small chunks of ice and rock. Astronomers think they formed out of pieces of comets, asteroids and moons that were torn apart by Saturn's gravity. So for Saturn in particular, irregular moons can tell us more about the formation of its beautiful rings. Names of astronomical objects are governed by the International Astronomical Union (IAU). Originally, all moons in the Solar System were given names from Greco-Roman mythology. But the large number of moons, particularly of Saturn and Jupiter, means the IAU has expanded to giants and gods from other mythology. And it's all about the details. If binary moons are discovered, they are required to be given names of twins or siblings. Saturn's first seven moons were given numbers instead of names. In 1847, John Herschel named them after the Greek Titans. After they ran out of titans and Greek mythological giants, they expanded the naming system to include Inuit and Gallic gods and Norse giants. Discoverers get to suggest names for moons, and the names they suggest are given priority by the IAU. In the past, there have been competitions to name new moons of Jupiter and Saturn. With 128 new moons for Saturn, it might take a while to come up with names that follow the IAU rules. Maybe we'll even see the addition of different mythologies. We'll have to wait and see. Until then, each moon has a name made of a string of numbers and letters, such as 'S/2020 S 27'. Without a solid definition of what a moon is, it's hard to say when (or if) we will ever finish finding them. Everyone agrees we shouldn't call every single chunk of rock in Saturn's rings a moon, but exactly where to draw the line isn't clear. That said, there is probably a limit to the number of moon-like objects astronomers are likely to want to add to the list. Edward Ashton, who led the discovery of the new moons, doesn't think we'll be finding too many new moons until our technology improves.
