Tag Archives: aurora

Physicists find definite proof of how auroras are born

Auroras are produced by electrons accelerated by powerful electromagnetic waves called Alfven waves. Credit: Austin Montelius, University of Iowa.

Those closer to the North or South poles are privileged to witness some of nature’s most dazzling ‘fireworks’. These spectacular light shows, known as the aurora borealis in the northern hemisphere and aurora australis in the southern hemisphere, are produced when Earth’s sheltering magnetic field interacts with certain kinds of solar storms. Now, scientists at the University of Iowa have reported exactly how auroras are created, performing experiments whose results perfectly match the theory.

Electrons ‘surfing’ on waves of electric fields

Writing in the journal Nature Communications, the physicists explain that the brilliant auroras are generated by powerful electromagnetic waves known as Alfven waves. These waves accelerate a small population of electrons towards Earth’s magnetic field, similar to how a surfer catches a wave and is continually accelerated as the surfer moves along with the wave.

But it’s not like scientists have been in the dark so far. For decades, scientists have designed models that describe the physical mechanisms by which energized particles emanating from the sun interact with Earth’s magnetic field and collide with oxygen and nitrogen molecules in the upper molecules. These excited molecules respond by emitting light in various colorful hues, lighting the night’s sky.

Yet although these models have been validated by some observations, such as measurements of Alfven waves taken by spacecraft that traveled above auroras, some limitations inherent to these spacecraft and rocket measurements had prevented a definite confirmation of the theory.

These challenges were overcome by the physicists at the University of Iowa through a series of experiments conducted at the Large Plasma Device lab located at UCLA’s Basic Plasma Science Facility.

The setup was rather challenging, requiring precise measurement of a very small population of electrons, numbering less than one in a thousand of the electrons in the plasma itself, traveling down the chamber of the Large Plasma Device at nearly the same speed as the Alfven waves.

Using a combination of numerical simulations and mathematical modeling on the results of the experiments, the researchers confirmed the theory that electrons “surf” on the wave of an electric field. This phenomenon is formally known as Landau damping, after Russian physicist Lev Landau who first proposed it in 1946.

“The idea that these waves can energize the electrons that create the aurora goes back more than four decades, but this is the first time we’ve been able to confirm definitively that it works,” says Craig Kletzing, professor in the Department of Physics and Astronomy at Iowa and a study co-author. “These experiments let us make the key measurements that show that the space measurements and theory do, indeed, explain a major way in which the aurora are created.”

Auroras have always fascinated people with their beauty. But the science behind them is certainly no less intriguing. Who knows what secrets they might have to share in the future. 

Surprisingly enough, comets can generate auroras too — in ultraviolet light

A team at the Southwest Research Institute (SwRI) has spotted the first comet we’ve ever seen to create an aurora in the ultraviolet spectrum.

Comet 67P. Image Courtesy of ESA/Rosetta/NAVCAM.

On Earth, auroras (or ‘polar lights’) are created when charged particles from the Sun hit those in our planet’s atmosphere. They form at the poles because that’s where the Earth’s magnetic field is weakest, allowing such particles to reach the atmosphere.

The discovery of a similar phenomena on a comet, bodies that lack our planet’s magnetic field, has researchers understandably excited.

A space first

“Charged particles from the Sun streaming towards the comet in the solar wind interact with the gas surrounding the comet’s icy, dusty nucleus and create the auroras,” said SwRI Vice President Dr. Jim Burch, in charge of the Ion and Electron Sensor (IES) instrument on board of the craft, in a statement.

“The IES instrument detected the electrons that caused the aurora.”

The IES is installed aboard the European Space Agency’s Rosetta spacecraft, which was launched back in 2004 and whose mission ended in 2016. Together with Philae, its lander module, Rosetta was the first of our probes to fly alongside a frozen comet (67P/Churyumov–Gerasimenko) as it hurdled towards the Sun, observing how it behaved along the way.

Now, data from Rosetta has revealed ultraviolet auroras around 67P, the first ever seen on a comet. These auroras are produced by charged particles interacting with the ‘coma’, the bubble of gas that is created from and encases the comet. This interaction excites the gases enough to make them glow in ultraviolet (UV) light.

Dr. Joel Parker, a member of SwRI who handled data from the Alice far-ultraviolet (FUV) spectrograph on Rosetta, recounts that at first, the team believed they were seeing 67P’s ‘dayglow’, a well-documented phenomenon created by this bubble of gas interacting with photons (light). But they soon realized that this wasn’t the case.

“We were amazed to discover that the UV emissions are aurora, driven not by photons, but by electrons in the solar wind that break apart water and other molecules in the coma and have been accelerated in the comet’s nearby environment,” he explains.”The resulting excited atoms make this distinctive light.”

The findings show that its possible for auroras to form around comets, despite their lack of a magnetic envelope. The techniques developed by the team to integrate data from several devices and discover these auroras can serve us to find similar phenomena on other comets in the future.

The findings will been published in the journal Nature Astronomy.

Mars gets auroras almost every day — it’s just that we can’t see them

We’ve all heard of the majestic North Lights which sometimes sweep Earth’s atmosphere in a dazzling light show. But did you know Mars has auroras, too? Scientists first learned about them in 2016. Now, a new study suggests that Martian auroras are not at all rare as previously thought. In fact, they sometimes occur nearly on a daily basis. Unlike their Earthen counterparts, however, you’d need some ultraviolet goggles to see the Martian aurora.

MAVEN images of the Martian atmosphere under normal conditions (left) and with an aurora (middle and right). (Credit: Embry-Riddle Aeronautical University/LASP, CU Boulder)

Auroras are nature’s own dynamic light show. These are created by charged particles from the Sun traveling along Earth’s magnetic field lines and exciting our atmosphere. The interaction causes electrons and protons to ionize different compounds in the atmosphere, causing the sky to light up in red and green tints. In the North, these displays are called aurora borealis (or the northern lights), named after the Roman goddess of dawn, Aurora, and the Greek name for the north wind, Boreas.

The physical interaction that produces the lights was first demonstrated by Norwegian physicist Kristian Birkeland almost a century ago when he produced his own auroras in the lab. In his world-famous experiment, he demonstrated how the lights form around magnetic spheres inside a small vacuum chamber. A modern-day version of this experiment is called the Planeterrella, whose inner workings are explained in this great video produced by the University of Leicester, embedded below.

In 2016, NASA’s MAVEN spacecraft observed auroras on Mars for the first time. Unlike Earthen auroras, the Martian variety is triggered exclusively by protons and occurs during the day. What’s more, the lights are emitted only in the ultraviolet spectrum, meaning you can’t see them with the naked eye — but MAVEN’s instruments sure can.

“At first, we believed that these events were rather rare because we weren’t looking at the right times and places,” said Mike Chaffin, who is a planetary scientist at the University of Colorado Boulder. “But after a closer look, we found that proton aurora are occurring far more often in dayside southern summer observations than we initially expected.”

Martian auroras are formed when the solar wind strikes Mars’ thin atmosphere, stripping away electrons from hydrogen atoms, which are now basically just protons. These protons collide with the planet’s hydrogen corona — an envelope of hydrogen gas surrounding the red planet, which is linked to water loss on Martian surface — stealing electrons, becoming a whole atom again. In the process, the hydrogen atom slams into the Martian atmosphere, colliding with other gas molecules and emitting ultraviolet light.

“Perhaps one day, when interplanetary travel becomes commonplace, travelers arriving at Mars during southern summer will have front-row seats to observe Martian proton aurora majestically dancing across the dayside of the planet (while wearing ultraviolet-sensitive goggles, of course). These travelers will witness firsthand the final stages of Mars losing the remainder of its water to space,” said Andréa Hughes of Embry-Riddle Aeronautical University in Daytona Beach.

In their new study, Chaffin and colleagues found proton aurora on Mars occur far more often in the dayside southern summer than initially expected. Measurements suggest that proton aurora occurs in about 14% of dayside observations, increasing to nearly 80% of observations when considering only dayside southern summer observations.

Because auroras and water loss on Mars are linked due to the hydrogen cycle, scientists are very interested in studying this phenomenon. Mars is closest to the Sun during its southern summer, and this sudden influx of solar wind could explain the new observations.

Seasonal differences in Mars’ proton aurora. During the planet’s northern summer (left), it receives less sunlight and experiences fewer dust storms, leading to decreased aurora. During the southern summer, in contrast, the planet gets a lot more light, and aurora abound. (Credit: Embry-Riddle Aeronautical University/LASP, CU Boulder)

“All the conditions necessary to create Martian proton aurora (e.g., solar wind protons, an extended hydrogen atmosphere, and the absence of a global dipole magnetic field) are more commonly available at Mars than those needed to create other types of aurora,” said Hughes. “Also, the connection between MAVEN’s observations of increased atmospheric escape and increases in proton aurora frequency and intensity means that proton aurora can actually be used as a proxy for what’s happening in the hydrogen corona surrounding Mars, and therefore, a proxy for times of increased atmospheric escape and water loss.” 

The findings appeared in the Journal of Geophysical Research, Space Physics and were presented during this week’s American Geophysical Union meeting.

Credit: Wikimedia Commons.

Auroras act like speed bumps for satellites, dragging them down towards Earth

Credit: Wikimedia Commons.

Credit: Wikimedia Commons.

Auroras are some of the most dazzling light shows in the world but for the aerospace industry, they can be a real nuisance that could cost billions in damages. According to recent research, northern and southern lights cause satellites to slow down, which brings them closer to Earth. And if the satellites don’t have any more fuel left to boost them back to their intended orbits, they will eventually fall into Earth’s atmosphere.

For decades, scientists have been aware that when the sun’s activity is high, orbiting satellites tend to slow down. Auroras are caused by charged particles like electrons that interact with molecules from a planet’s atmosphere or magnetosphere. Scientists suspected that the charged particles also loft pockets of air high enough for satellites to interact with them. The drag caused by the air molecules would then slow the satellites, pulling them closer to Earth. Now, a recent mission has confirmed that this theory is probably true.

In 2015, scientists launched the Rocket Experiment for Neutral Upwelling 2 (RENU2) straight into the northern lights in order to understand how solar activity alters the atmosphere. The mission focused on Poleward Moving Auroral Forms (PMAFs), a type of fainter auroras which appear as dancing clouds on dark nights in high latitudes. The reason why PMAFs are o particular interest in this kind of research is that they form higher in the atmosphere and are less energetic than the more common and spectacular auroras. PMAFs dance at about 150 to 250 miles above the surface while most auroras typically form at an altitude of only 60 miles.

Researchers at the University of New Hampshire who led the project found that although PMAFs are weaker than most forms of auroras, their energy was still high enough to heat air pockets, causing them to drift upwards. As an analogy, the researchers likened the phenomenon to bubbles rising in a lava lamp. The study also found that the PMAF’s activity isn’t uniform but rather acts in narrow wisps that collectively affect areas larger than ten miles across. PMAFs also ebb and flow, changing their structure within minutes.

In the future, this kind of information will help engineers design safer satellites that can remain operational in orbit for longer.

The results appeared in the journal Geophysical Research Letters

Credit: Catalin Tapardel‎, Alberta Aurora Chasers.

STEVE, the ‘ribbon aurora’, is actually a new kind of celestial phenomenon

Credit: Catalin Tapardel‎, Alberta Aurora Chasers.

Credit: Catalin Tapardel‎, Alberta Aurora Chasers.

In 2016, odd ribbons of purple and white light were brought to the attention of scientists, who classed it as a new type of aurora. In reality, the beautiful beam of light (called STEVE) may be far more interesting, after physicists concluded in a new study that it may actually be an entirely new celestial phenomenon.

Aurora chasers and star enthusiasts have been sighting STEVE for decades but it was only recently that scientists were called in to make sense of it. Initially, physicists classed STEVE as a ‘proton arc’ — another rare type of aurora, which isn’t caused by electrons hitting Earth’s magnetic field but by more massive proton outbursts following a solar flare. Later, with the help of NASA –which sent a swarm of satellites right through a STEVE event — scientists found that accelerated and heated charged particles may have been interacting with a particular part of the Earth’s magnetic field in the ionosphere.

The data suggested that STEVE is a “subauroral ion drift.”

Researchers at the University of Calgary in Canada weren’t convinced, though. STEVE shines in thin ribbons of purple, rather than in red, green, or yellow curtains, as is the case of typical auroras. This suggested that the light show is cut of a different cloth from an aurora. Another clue was that STEVE is only visible a few times per year while auroras are visible every night if viewing conditions are right.

The researchers decided to focus on a STEVE event in March 2008, which was recorded using both ground-based cameras designed to track auroras but also NOAA’s Polar Orbiting Environmental Satellite 17, which was directly overhead at the time. The analysis showed that STEVE’s light isn’t produced by particles raining down into the ionosphere, as typically happens with the aurora. This means that STEVE is an entirely new phenomenon distinct from typical auroras.

“Our main conclusion is that STEVE is not an aurora,” said Bea Gallardo-Lacourt, a space physicist at the University of Calgary in Canada and lead author of the new study.

“So right now, we know very little about it. And that’s the cool thing, because this has been known by photographers for decades. But for the scientists, it’s completely unknown.”

Credit: Dave Markel Photography.

The new kind of optical phenomenon is called “skyglow”, the authors wrote in the journal Geophysical Research Letters. In the future, the researchers plan to determine whether streams of fast ions and hot electrons in the ionosphere are creating STEVE’s light, or if the  is produced higher up in the atmosphere. In the process, scientists will gain a better understanding of the upper atmosphere and the light-generating processes in the sky.

“This is really interesting because we haven’t figured it out and when you get a new problem, it’s always exciting,” said Joe Borovsky, a space physicist at the Space Science Institute in Los Alamos, New Mexico who was not connected to the new study. “It’s like you think you know everything and it turns out you don’t.”

What’s up with Steve: A new kind of aurora demystified by scientists

Few things compare to the dazzling light show performed by nature’s northern and southern lights — but they’re not alone. It was only in the past few years that a new type of aurora was found. Thanks to the watchful eye of citizen scientists and photographers, we can now add to programme an exquisite short-lived shimmering purple ribbon of plasma called Steve. Meanwhile, scientists have had time to carefully study the phenomenon in an attempt to learn what makes it tick.

The Aurora Named STEVE

A band of dedicated Canadian aurora chasers was among the first who took pictures of Steve. The aurora feature was first posted on the Facebook group Alberta Aurora Chasers in 2016 and, initially, most thought they were looking at a ‘proton arc’ — another rare type of aurora, which isn’t caused by electrons hitting Earth’s magnetic field but by more massive protons following a solar flare.

Eric Donovan from the University of Calgary was one of the first scientists who probed Steve, a 25 to 30 kilometer (15 to 18 miles) wide arc that aligns east-west and can extend over hundreds of miles. He recognized that this wasn’t a proton arc for a number of reasons, including the fact that a proton aurora is hardly visible.

Meet Steve. Image: Dave Markel Photography.

Donovan called some colleagues, and soon enough people like Elizabeth MacDonald, a space physicist at NASA Goddard Space Flight Center in Greenbelt, Maryland, sent ESA’s Swarm magnetic field mission through Steve. Swarm is a constellation of satellites tasked with studying Earth’s magnetic field. The instruments recorded accelerated and heated charged particles coming from the sun, which physicists found that they interact with a particular part of the Earth’s magnetic field in the ionosphere. So, rather than a proton arc, Macdonald and colleagues associate Steve with a so-called “subauroral ion drift,” they wrote in a new paper published in Science Advances on Wednesday. This occurs 60 degrees above the equator, where the global electric and magnetic fields align, making ions and electrons fly rapidly from east to west.

These rather rare auroras last only an hour and must coincide with space weather, specifically an ejection of charged particles from the sun. And instead of red, green, or yellow auroras shaped in mesmerizing curtains, Steve forms a ribbon across the sky that looks purplish in color. Sometimes, as some lucky photographers found, Steve also features small green picket fence-like arcs.

Most recently, Steve has been sighted in Scotland, from near Oban in Argyll and Gairloch in Wester Ross. Other places where Steve has been spotted so far include the UK, Canada, Alaska, northern US states, and New Zealand.

Credit: Catalin Tapardel‎, Alberta Aurora Chasers.

To legitimize Steve in academia, the researchers also found a clever backronym for Steve: Strong Thermal Emission Velocity Enhancement. Originally, the people who first discovered the new aurora called it Steve in honor of the children’s movie Over the Hedge, in which a character arbitrarily conjures up the name Steve to describe an object he’s not sure about.

NASA is now calling on citizen scientists and photographers to help research Steve by reporting any sightings to the Aurorasaurus project. If you live in the right latitude, this might be your chance to make a huge contribution to science.

“Because this is a new way of observing a phenomenon linked to space, it provides a new way to study it,” Vassilis Angelopoulos, a space physicist at UCLA not involved in the study, told National Geographic. “Citizen scientists can also be involved in triangulating them and determining their altitudes.

Northern Lights.

Solar storm expected to bring northern lights to the U.S. tonight

There’s more bad weather forecasted for today, but this is the kind that we’ll all be thankful for — a minor solar storm will hit our planet on Wednesday, March 14. The event could amp up Earth’s auroras, making them visible from the northernmost parts of the U.S.

Northern Lights.

Image credits Svetlana Nesterova.

“Northern tier” states, such as Michigan or Maine, could be in for a treat as amped-up auroras (northern lights) could dance across the sky tonight, a product of a solar storm inbound towards Earth. The same storm could also induce some fluctuations in weaker power grids, and should only have a minor effect on our satellites, according to an alert issued from the Space Weather Prediction Center (SWPC), part of the National Oceanic and Atmospheric Administration (NOAA), in Boulder, Colorado.

Researchers at the SWPC predict that the storm originates from a coronal hole in the sun, a region of lower energy and with a weaker magnetic field in the Sun’s outer layer. The particular conditions in this area allow high-speed, charged particles to shoot out into space, eventually finding their way to Earth. The storm will be a G1 class — making it a relatively minor event — and should last from Wednesday to Thursday, March 15.

Light it up

Auroras (known as ‘borealis’ over the North Pole and ‘australis’ over the South Pole) form from the interaction of these particles with the Earth’s magnetic field. Because they are charged, they are directly affected by the magnetic field when trying to pass through; similarly to how a pane of glass would ‘interact’ with you, should you try to pass through it.

We don’t fully understand the mechanisms behind aurora formation, but, in broad lines, the pretty colors are the result of ionization in the upper atmosphere. This, in turn, is produced by successive collisions of high-speed charged particles with atoms in the Earth’s upper atmosphere, causing them to shed electrons and protons (to ionize). Auroras can form on other planets with an atmosphere, through a similar process.

Particularly strong solar storms can trigger geomagnetic storms. Depending on its intensity, this could mean radio blackouts, fluctuations in power grids, maybe even with satellites in orbit.

Auroras or polar lights typically form near the (magnetic) poles, where the geomagnetic field is thinnest, and these charged particles can force their way through. Events such as solar storms widen the area on which auroras form because they put out more charged particles than usual — the deluge compresses Earth’s magnetic field, so some particles can push through at lower latitudes. In 1989, for example, a similar event made auroras form all the way down to Texas.

So fingers crossed, and you might get to enjoy one superb light show later today — nature’s treat.

Credit: NASA/Goddard/University of Colorado.

Powerful solar storm sparks the brightest Auroras on Mars we’ve recorded

Credit: NASA/Goddard/University of Colorado.

Credit: NASA/Goddard/University of Colorado.

Between Sep. 12 and 13, the thin Martian atmosphere became 25 times brighter than usual, after an extremely powerful solar storm struck the planet. The event, which was recorded by NASA’s Maven spacecraft orbiting the red planet, triggered a global ultraviolet aurora but also doubled the amount of radiation that reached the planet’s surface.

“NASA’s distributed set of science missions is in the right place to detect activity on the Sun and examine the effects of such solar events at Mars as never possible before,” said MAVEN Program Scientist Elsayed Talaat, program scientist at NASA Headquarters, Washington, for NASA’s Mars Atmosphere and Volatile Evolution, or MAVEN, mission.

The solar storm lit up Mars like a light bulb

Even though this should be a quiet period in the Sun’s 11-year sunspot and storm-activity cycle, the coronal mass ejection (CME) which triggered the Martian aurora over the weekend was extremely powerful. A CME is a burst of charged particles, mostly electrons and protons, emanating from twisted magnetic field structures, or “flux ropes”, present on sun’s corona. These solar storms can vary in strength wildly and are known to impact Earth’s magnetosphere, being responsible for geomagnetic storms and the mesmerizing auroras. This month’s event was powerful and broad enough, for instance, to be detected on Earth despite the fact that the sunspots from which the CME gushed were on the opposite side of the Sun than we were facing.

“The current solar cycle has been an odd one, with less activity than usual during the peak, and now we have this large event as we’re approaching solar minimum,” said Sonal Jain of the University of Colorado Boulder’s Laboratory for Atmospheric and Space Physics, who is a member of MAVEN’s Imaging Ultraviolet Spectrograph instrument team.

“When a solar storm hits the Martian atmosphere, it can trigger auroras that light up the whole planet in ultraviolet light. The recent one lit up Mars like a light bulb. An aurora on Mars can envelope the entire planet because Mars has no strong magnetic field like Earth’s to concentrate the aurora near polar regions. The energetic particles from the Sun also can be absorbed by the upper atmosphere, increasing its temperature and causing it to swell up.”

This weekend’s CME doubled radiation levels on Mars’ surface. Credit: NASA/JPL-Caltech/Univ. of Colorado/SwRI-Boulder/UC Berkeley

While Maven was busy studying the pretty ultraviolet lights in Mars’ atmosphere, below on the surface NASA’s Curiosity rover picked up the radiation levels. Here on Earth, we’re protected from the sun’s bursts of plasma by the magnetosphere that shrouds our planet, blocking most radiation. Mars lost its magnetic fields ages ago, though, and it’s thus far more vulnerable to solar mood swings. In only one day, the radiation levels on the red planet‘s surface spiked more than double anything previously measured by the Curiosity rover’s Radiation Assessment Detector, or RAD, since the mission started in 2012.

“This is exactly the type of event both missions were designed to study, and it’s the biggest we’ve seen on the surface so far,” said RAD Principal Investigator Don Hassler of the Southwest Research Institute’s Boulder, Colorado, office. “It will improve our understanding of how such solar events affect the Martian environment, from the top of the atmosphere all the way down to the surface.”

However, the extreme radiation exposure raises new troubling concerns as to the habitability of Mars, one of the main fields of study for the Curiosity mission — that’s speaking about a planet with alarmingly high radiation levels hitting its surface already. On average, Mars sees 22 millirads per day, which works out to 8000 millirads (8 rads) per year. For comparison, human beings in developed nations are exposed to 0.62 rads per year. Studies suggest that the human body could withstand a dose of up to 200 rads without permanent damage. However, prolonged exposure to the kinds of levels detected on Mars significantly increases the risk of acute radiation sickness, increased risk of cancer, genetic damage, and even death.

“If you were outdoors on a Mars walk and learned that an event like this was imminent, you would definitely want to take shelter, just as you would if you were on a space walk outside the International Space Station,” Hassler said. “To protect our astronauts on Mars in the future, we need to continue to provide this type of space weather monitoring there.”

NASA, and likely SpaceX too which has a stated goal of building a martian colony numbering one million inhabitants, will have to bear these intense radiation fluctuations in mind when designing their habitats.

The story and science behind a new type of aurora called ‘Steve’

A new natural phenomenon was discovered on social media, of all places. The ribbon of purple and green light is unlike any other aurora feature documented thus far but one thing’s for sure — it’s very beautiful, an impression shared by hundreds of thousands of people on Facebook. And like most things left to devices of the internet’s hive mind, the natural phenomenon was named ‘Steve’. Meanwhile, scientists working with the ESA kept an eye out for more ‘Steves’ and found these strange arcs are far more common than we thought.

steve-arc

Meet Steve. Image: Dave Markel Photography.

Credit: Catalin Tapardel‎, Alberta Aurora Chasers.

Credit: Catalin Tapardel‎, Alberta Aurora Chasers.

Citizen science in action!

The aurora feature was first posted on the Facebook group Alberta Aurora Chasers last year. Initially, most users thought they were looking at a ‘proton arc’, which is a rare type of aurora which isn’t caused by electrons hitting Earth’s magnetic field but by more massive protons following an energetic event on the Sun. Eric Donovan from the University of Calgary was one of the first scientists who saw Steve, the 25 to 30 kilometer (15 to 18 miles) wide arc that aligns east-west and can extend over hundreds of miles. He recognized that this wasn’t a proton arc for a number of reasons, including the fact that a proton aurora is hardly visible.

Prof. Donovan spoke to colleagues and eventually managed to get ESA’s Swarm magnetic field mission — a  constellation of satellites tasked with studying Earth’s magnetic field — to study more of Steve’s shows. It didn’t take too long before the satellites flew straight through a Steve and learned new things about it. 

“The temperature 300 km above Earth’s surface jumped by 3000°C and the data revealed a 25 km-wide ribbon of gas flowing westwards at about 6 km/s compared to a speed of about 10 m/s either side of the ribbon. “It turns out that Steve is actually remarkably common, but we hadn’t noticed it before. It’s thanks to ground-based observations, satellites, today’s explosion of access to data and an army of citizen scientists joining forces to document it.

Steve was named in honor of the children’s movie Over the Hedge, in which a character arbitrarily conjures up the name Steve to describe an object he’s not sure about, Gizmodo reported.

Users on the Facebook group debated what the new phenomenon should be called. They stuck with 'Steve'. Credit: Facebook Screenshot.

Users on the Facebook group Alberta Aurora Chasers debated what the new phenomenon should be called. They stuck with ‘Steve’. Credit: Facebook Screenshot.

It’s important to understand, Donovan notes, that in 1997 or just two decades ago, studying Steve would have been nearly impossible. It would have taken $200 million to $300 million to track down Steve and could have taken ten years. Thanks to ESA and NASA’s constellation of new observational satellites equipped with modern tools, but also thanks to citizens scientists who know how to use social media to share and advance knowledge, it was possible to close the loop on Steve in a matter of weeks. That’s really remarkable!

“It’s thanks to ground-based observations, satellites, today’s explosion of access to data and an army of citizen scientists joining forces to document it,” Donovan said.

Donovan said that he and colleagues are currently working on a paper that is studying the conditions under which Steve can form. The draft is still a work in progress so he didn’t want to share any more details other than ‘you’ll soon learn more’.

 

This is an artist interpretation of what aurorae may look like close to magnetic anomalies on Mars. Credits: NASA/JPL-Caltech/MSSS and CSW/DB

On Mars, auroras are blue and visible to the naked eye. Here’s a simulation

Mars has auroras too, and in addition to the red and green Northern Lights here on Earth, they also come in blue. According to NASA, these should be visible to the naked eye for a Martian astronaut if he were to look to the sky from one of the two poles.

This is an artist interpretation of what aurorae may look like close to magnetic anomalies on Mars. Credits: NASA/JPL-Caltech/MSSS and CSW/DB

This is an artist interpretation of what aurorae may look like close to magnetic anomalies on Mars.
Credits: NASA/JPL-Caltech/MSSS and CSW/DB

Auroras are nature’s own dynamic light show. These are created by charged particles from the Sun travelling along the Earth’s magnetic field lines and exciting our atmosphere. In the North these displays are called  aurora borealis (or the northern lights), named after the Roman goddess of dawn, Aurora, and the Greek name for the north wind, Boreas, by Galileo in 1619. The physical interaction that produces the lights was first demonstrated by Norwegian physicist Kristian Birkeland almost a century ago when he produced his own auraras. In his world famous experiment, he demonstrated how the lights form around magnetic spheres inside a small vacuum chamber. A modern day version of this experiment is called the  Planeterrella, whose inner workings are explained in this great video produced by University of Leicester.

Using the same polar light simulator, researchers at NASA produced the Northern Lights equivalent in a Mars environment. First, they changed the magnets to be more akin to the Martian planet. While Planeterrella uses a vacuum pump to simulate the thin atmosphere where the charged particles interact with the magnetic field lines, it does not pump out all of the air, leaving a fraction behind. In this case, more CO2 was pumped to represent the Martian atmosphere. Now, I know what you’re thinking: Mars doesn’t have a magnetic field! Well, that’s not entirely true. According to NASA, there are still “local spots of increased magnetic fields, called crustal magnetic anomalies, [..] concentrated in the southern hemisphere, where aurorae are predicted to occur.”

The Planeterella sphere simulates a magnetized planet with an atmosphere of CO2 and bombarded by the solar wind. Blue aurorae develop according to its magnetic field configuration. Credits: D. Bernard/IPAG — CNRS

The Planeterella sphere simulates a magnetized planet with an atmosphere of CO2 and bombarded by the solar wind. Blue aurorae develop according to its magnetic field configuration.
Credits: D. Bernard/IPAG — CNRS

When the Planeterrella was turned on under this setup, the so-called Martian Auroras (excitation of atomic oxygen) were mostly blue, but also green and red (excitation of atomic oxygen).

Scientists first suspected auroras might appear in the Martain sky based on date from the SPICAM imaging instrument on the European Space Agency’s Mars Express. Later on, in April, the Maven mission confirmed this hypothesis when the probe spotted an aurora  at low altitudes in the northern hemisphere, even though these should be most prominent in the southern hemisphere.

Study shows auroras also occur outside our solar system

Researchers from Leicester University have shown that auroras (similar to Earth’s aurora borealis) occur on other bodies outside our solar system.

Aurora borealis

Northern Lights

Aurora borealis is a natural light display occuring in high latitude areas (both north and south), caused by the collision of energetic charged particles with atoms in the high altitude atmosphere. Here’s what happens: emissions of photons in the Earth’s upper atmosphere, above 80 km (50 mi), from ionized nitrogen atoms regaining an electron; oxygen and nitrogen atoms return from an excited state to ground state. Then, the solar wind kicks in and collides with them, with the particles being funneled down and accelerated along the Earth’s magnetic field lines, creating the dazzling light shows we see from below.

In our solar system, this phenomena has been observed on several planets, most notably on Jupiter, where they are brightest – about 100 times brighter than those on Earth. However, no auroras have been observed beyond Neptune.

Artistic representation of an aurora on Jupiter

Artistic representation of an aurora on Jupiter

Outside the solar system

A new study conducted by University of Leicester lecturer Dr Jonathan Nichols concluded that phenomena extremely similar to Jupiter auroras could be responsible for radio emissions detected from a number of objects outside our solar system. What’s interesting is that these emissions are powerful enough to be detected across interstellar distances, and could potentially be a great tool to observe new objects outside our solar system.

It was indeed believed that auroras occur practically everywhere in the Universe, but so far, this study published in the Astrophysical Journal is the first to actually show that it happens outside our solar system. The conclusion is that radio emissions from a number of ultracool dwarfs may also be caused by auroras, much stronger than even those on Jupiter. Dr Nichols, a Lecturer and Research Fellow in the University of Leicester’s Department of Physics and Astronomy, explained:

“We have recently shown that beefed-up versions of the auroral processes on Jupiter are able to account for the radio emissions observed from certain “ultracool dwarfs” – bodies which comprise the very lowest mass stars – and “brown dwarfs” – ‘failed stars’ which lie in between planets and stars in terms of mass. “These results strongly suggest that auroras do occur on bodies outside our solar system, and the auroral radio emissions are powerful enough – one hundred thousand times brighter than Jupiter’s – to be detectable across interstellar distances.”

Studies of these auroras could provide valuable information about the length of the planet’s day, the strength of its magnetic field, how the planet interacts with its parent star and even whether it has any moons.

Via Leicester University and Wikipedia. Scientific source here.

Astronomers luckily spot Aurora on Uranus

When Voyager 2 made its flyby near the planet of Uranus, astronomers got their first direct glimpse of what an aurora might look on the cold planet. However, such lights have never been observed from Earth – that is, until last year, when a team of scientists used careful planning and the Hubble Telescope to observe the lovely phenomena.

The international team will publish their discoveries in Geophysical Research Letters; wanting to catch auroras is a tricky deal, and one which requires a lot of careful planning, because they are caused by the interaction between charged particles from the sun and a planet’s magnetic field – something which doesn’t happen quite every day. The team first had to wait for a particular arrangement of planets which ensured that the solar wind from the Sun has a direct, open path to Uranus. Then, they had to wait until the sun let loose a burst of charged particles, which happened in September, last year.

After this happened, they calculated how much the solar wind would take to reach Uranus, which was November, then booked time on the Hubble during that exact same period. Their calculations proved correct, and they were able to witness the fascinating phenomena.

But observing the aurora on Uranus isn’t as simple as directing a telescope at the planet. Uranus not only spins nearly on its side, the planet also has an off-kilter magnetic field. By observing how the magnetic field of Uranus functions with something we understand as well as aurora, the researchers hoped to learn much more about the magnetosphere of planets.

“We have ideas of how things work on Earth and places like Jupiter and Saturn, but I don’t believe you really know how things work until you test them on a very different system.”, said Laurent Lamy, the lead researcher on the team, quote by the American Geophysical Union.

Via AGU