Earlier this year, while the coronavirus was just a frightening omen confined to Wuhan, NASA and the European Space Agency (ESA) launched the Solar Orbiter. The spacecraft’s primary mission is that of studying the sun in unprecedented detail. While there is still much to do, the Solar Orbiter is already providing a delicious treat — the closest image of the sun yet.
“These unprecedented pictures of the Sun are the closest we have ever obtained,” said Holly Gilbert, NASA project scientist for the mission at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “These amazing images will help scientists piece together the Sun’s atmospheric layers, which is important for understanding how it drives space weather near the Earth and throughout the solar system.”
“We didn’t expect such great results so early,” said Daniel Müller, ESA’s Solar Orbiter project scientist. “These images show that Solar Orbiter is off to an excellent start.”
‘Campfires’ on the sun
The Solar Orbit mission got off to a rocky start after the pandemic forced the mission control at the European Space Operations Center in Darmstadt, Germany to close down completely for more than a week. The lockdown coincided with the mission’s commissioning phase, a highly delicate period when all instruments on board the spacecraft have to be calibrated and extensively tested.
All but essential personnel had to work from home, but despite having to perform critical operations remotely, the space engineers were up to the task.
The spacecraft completed its commissioning just in time for its first close flyby of the sun on June 15. At that time, Solar Orbit was just 45 million miles away from the sun’s surface, and mission control snapped a picture using six imaging instruments — each of which studies a different aspect of solar activity.
For instance, the Extreme Ultraviolet Imager (EUI) recorded data that reveals solar features in unprecedented detail.
Some of these features include so-called “campfires” dotting the surface of the sun.
“The campfires we are talking about here are the little nephews of solar flares, at least a million, perhaps a billion times smaller,” said David Berghmans, an astrophysicist at the Royal Observatory of Belgium in Brussels and principal investigator of the Solar Orbit mission. “When looking at the new high-resolution EUI images, they are literally everywhere we look.”
Berghmans and colleagues aren’t sure what these campfires are or what their role is, but they have some ideas. It’s possible, the researchers say, that these features are nanoflares — mini-explosions that may help heat the sun’s outer atmosphere, known as the corona.
The corona is about 300 times hotter than the sun’s surface. If that makes absolutely no sense to you, you’re not alone. This is one of the biggest paradoxes surrounding solar activity, which scientists are still trying to figure out. The Solar Orbit mission, along with NASA’s Parker Solar Probe, is tasked with dispelling this mystery.
“So we’re eagerly awaiting our next data set,” said Frédéric Auchère, principal investigator for SPICE operations at the Institute for Space Astrophysics in Orsay, France. “The hope is to detect nanoflares for sure and to quantify their role in coronal heating.”
Besides these intriguing solar features, the spacecraft also revealed zodiacal light — a very faint light from the sun which is reflected off interplanetary dust. Normally, the bright face of the sun obscures zodiacal light, but the spacecraft’s Solar and Heliospheric Imager (SoloHi) captured a perfect zodiacal light pattern. To see it, the instrument reduced the brightness of direct light from the sun by a factor of one trillion.
Next, pictures captured by the Polar and Helioseismic Imager (PHI) shows the sun’s poles and mapped their magnetic field.
All these images and much more, including videos and raw data, are available at the ESA website.
It’s one of those things that happens so often on the internet: people get confused by the weirdest things. In this case, it started with people who (presumably) wanted to learn more about the coronavirus.
This makes sense — it’s an ongoing outbreak, it’s in the news (we’ve covered it extensively), and people want to know just how serious it is. This was highlighted by Google Trends — a website by Google that analyzes the popularity of top search queries.
The searches for coronavirus spiked.
But among those searchers, some took a weird turn. Some, apparently, were concerned that drinking Corona beer can spread the virus.
The number of searches for corona beer virus have also spiked, as shown on the relative chart from Google Trends. The searchers were most prevalent in Finland, New Zealand, and Slovenia, but also popped up in the US and Canada.
Now, as someone who enjoys the occasional pint of craft beer, I can think of many things to blame Corona for — but causing a viral outbreak is definitely not one of them.
It should be said that Google does not provide absolute numbers so we don’t really know the total number of searches, just that there was a spike. This is still a negligible number when compared to the overall coronavirus searches.
Blame the confusion on Latin
The new virus stems from a family called coronavirus — there’s a bunch of strains that can infect both humans and animals. The most famous coronavirus is probably SARS, which caused a similar outbreak in 2003.
The coronavirus gets its name from its shape, which resembles the solar corona — the aura of plasma that surrounds the Sun (and other stars). Here’s how similar the virus looks to the Sun:
The “corona” in coronavirus, and in the solar corona, comes from the Latin Corona — which means crown. The Corona in the beer comes from Spanish, which is also a Latin language — and it also means crown.
So if you though the beer can give you a virus, blame it on Latin. Oh, and if you’re still afraid of your beer, send it our way. We’ll be sure to dispose of it.
Illustration of the Parker Solar Probe. Credit: NASA.
According to Greek mythos, Daedalus was an unrivaled Athenian craftsman — the Leonardo da Vinci of his day. To his great misfortune, he angered King Minos, the ruler of the island of Crete. Desperate to flee the island, Daedalus built two pairs of wings for himself and his son Icarus, which he fixed with wax. Icarus is warned, however, that he shouldn’t fly too high lest the sun melt the wax that holds his wings. Icarus heeded his father’s advice — but only for a bit before he got cocky. Daedalus’ sonflew too high and, sure enough, his wings melted, plunging the boy into the sea where he drowned.
Fast forward to present reality and the Daedaluses of our time — NASA scientists, who are gearing up for one of the most anticipated and exciting launches of the year, that of a probe destined to ‘touch’ the sun. But unlike Icarus’ flimsy, wax-coated wings, NASA’s probe is more than well equipped to brave the sun’s corona, where temperatures can reach millions of degrees Celsius.
The Parker Solar Probe ought to launch no earlier than August 6, 2018, aboard a United Launch Alliance Delta IV Heavy that will light the sky above Cape Canaveral, Florida. Today, the mission’s scientists held a press conference detailing the probe’s science goals and the technology behind it.
“We’ve been studying the Sun for decades, and now we’re finally going to go where the action is,” said Alex Young, associate director for science in the Heliophysics Science Division at NASA’s Goddard Space Flight Center in Greenbelt, Maryland.
There’s a lot of things we don’t know about the hot ball of glowing gases at the heart of our solar system. For one, the sun is dynamic, constantly belching magnetized material outward even as far as beyond Pluto’s orbit. The intensity and frequency of these ejections wax and wane according to a nearly periodical 11-year solar cycle. For instance, at the peak of the cycle, our star grows more sunspots and spews more solar flares, which can damage satellites in Earth’s orbit and even our electricity grids.
The influence of solar activity on Earth and other worlds is known as space weather. Now, scientists are looking to understand the sun and its weather activity by sending a probe in its midst, just like weather satellites in orbit that track Earth.
This mission has been in the making for the last 60 years, ever since physicist Eugene Parker published a groundbreaking scientific paper in 1958 theorizing the existence of the solar wind.
“The Sun’s energy is always flowing past our world,” said Nicky Fox, Parker Solar Probe’s project scientist at the Johns Hopkins University Applied Physics Lab. “And even though the solar wind is invisible, we can see it encircling the poles as the aurora, which are beautiful – but reveal the enormous amount of energy and particles that cascade into our atmosphere. We don’t have a strong understanding of the mechanisms that drive that wind toward us, and that’s what we’re heading out to discover.”
To undergo its mission, Parker carries a range of instruments that can study the sun both remotely and in situ (directly) — the kind of observations that might unravel some of the sun’s most well-kept secrets.
Of course, NASA has several specific questions it wants Parker to investigate. One of them has to do with the mystery of the acceleration of solar wind — the constant ejection of magnetized material from the sun. Somewhere, somehow this solar wind is accelerated to supersonic speeds.
Parker will fly straight through the corona — the sun’s atmosphere that extends millions of kilometers into outer space. The corona is scorching hot, reaching temperatures in the range of millions of degrees Celsius. However, the sun’s surface has a temperature of only about 6,000 degrees Celsius. This makes no sense at first glance: how is it possible that the surface of the sun is much less hot than its atmosphere? Well, scientists hope that Parker might come up with an answer to this counter-intuitive conundrum.
To answer these questions and more, Parker will rely on instruments such as the FIELDS suite which will capture the scale and shape of electric and magnetic fields in the Sun’s atmosphere. Of course, there will also be an imaging instrument — because how could a probe fly this close to the sun and not take awesome pictures. Called WISPR, short for Wide-Field Imager for Parker Solar Probe, the instrument is mainly designed to image coronal mass ejections (CMEs), jets and other solar ejecta. The SWEAP suite of instruments, short for Solar Wind Electrons Alphas and Protons Investigation, will count the most abundant particles in the solar wind — electrons, protons and helium ions — and measure such properties as velocity, density, and temperature to improve our understanding of the solar wind and coronal plasma. Finally, ISʘIS suite – short for Integrated Science Investigation of the Sun, and including ʘ, the symbol for the Sun, in its acronym – measures particles across a wide range of energies in order to understand their life cycles — that is, where they came from, how they became accelerated and how they move out from the Sun through interplanetary space.
But how will Parker keep its ‘wings’ from melting? During its closest flyby, Parker will be only 6.1 million kilometers (3.8 million miles) from the sun’s surface, where temperatures can reach millions of degrees Celsius. But there’s a catch — just because the corona is that hot, that doesn’t mean that the probe will ‘feel’ that temperature due to the phenomenon of heat transfer. Simply put, some mediums conduct heat (energy) better than others.
For instance, if you stand on a bathroom’s tile floor you’ll feel cold but if you stand on a carpet your feet feel comfortably warm. However, both kinds of surfaces have the same temperature because they’ve had time to reach a thermal equilibrium — it’s just that the tile floor is a good heat conductor, which will make your feet seem cold because your body’s surface usually has a higher temperature than the ambient, whereas the carpet is a poor heat conductor and it would take you ages for your feet to match its lower temperature.
Bearing these physics in mind, we can now understand how Parker won’t get obliterated — even though the corona has a huge temperature, the sun’s outer atmosphere has a very low density and, hence, is a poor heat conductor. According to NASA, Parker’s sun-facing side will be heated to only about 1,644 degrees Kelvin (1,370 C° or 2,500 F°).
That’s still a lot, to be fair, which is why the Parker Solar Probe is equipped with a cutting-edge heat shield called the thermal protection system, or TPS. It’s a sandwich of carbon-carbon composite surrounding nearly 4.5 inches of carbon foam, which is about 97% air. Thanks to its lightweight materials, the TPS only weighs 72.5 kilograms (160 pounds) despite being nearly 2.4 meters (8 feet) in diameter. Strikingly, anything behind the shield shouldn’t heat to more than 300 Kelvin (30 C° or 85 F°)! A cooling system that runs on pressurized deionized water keep temperatures at manageable levels in the parts with Parker will be fully exposed to the sun.
The key is for the shield to be always facing the sun, but sometimes the probe will have to operate for long periods of time without being able to communicate with Earth. To solve this predicament, NASA engineers have designed a fault management system that self-corrects the probe’s course and direction facing the sun to ensure that the scientific instruments stay cool and functioning.
All in all, the Parker Solar Probe is a one-of-a-kind space mission that may not only unravel the sun’s mysteries but also those of the myriad of other stars that astronomers are eyeing.
“By studying our star, we can learn not only more about the Sun,” said Thomas Zurbuchen, the associate administrator for the Science Mission Directorate at NASA HQ. “We can also learn more about all the other stars throughout the galaxy, the universe and even life’s beginnings.”
Using images of the Sun and strong processing algorithms, scientists have observed solar winds emerging from the corona.
It’s a beautiful sight. An extreme ultraviolet light image of the Sun and its corona from NASA’s Solar Terrestrial Relations Observatory (STEREO). Credit: NASA/STEREO
Solar wind is a stream of charged particles released from the upper atmosphere of the Sun. First described as a phenomenon in 1859, it has been observed only in the 1960s. But scientists wanted to know how the solar wind looks like when it first forms, inside our star’s corona.
“This is part of the last major connection we need to make to understand how [the Sun] influences the environment around the Earth,” Craig DeForest, an astrophysicist at the Southwest Research Institute in Boulder, Colo., told Eos. DeForest is the lead author on a new paper describing the novel technique, published last week in the Astrophysical Journal.
Visualizing and understanding solar wind is not just an academic task – it can be extremely important for our modern society. The solar wind is responsible for the overall shape of Earth’s magnetosphere, interacting with it very strongly. The magnetosphere is the magnetic analog of the atmosphere. When there are changes in the wind’s speed, density, direction, and entrained magnetic field, our own planet’s magnetic field can be greatly affected. For instance, GPS satellites can be very vulnerable to this. Space weather can also knock out telecommunications, short out satellite circuitry, and damage electrical transmission lines which could cause immeasurable damage on Earth. So much of our modern technology on which we are so reliant can be threatened by solar wind.
But studying the formation of solar wind is no easy feat. The corona is very bright, and the solar wind is very faint, imposed on a background of stars and interplanetary dust. Whenever they tried to look at it before, they couldn’t realize exactly when it was forming.
So they applied an image processing algorithm, removing objects of fixed brightness (such as the stars on the background), exposing emerging features like the wind. The approach turned out to be successful, and the formation of the wind was visualized.
The new analysis already revealed some interesting things, showing that when the material travels a third of the distance to the Earth, the magnetic fields start to weaken enough for the particles to dissipate. This will help scientists to better predict the arrival and strength of the Sun’s outbursts, which, as mentioned above, can make a big difference.
One of the biggest mysteries in solar physics is how is it possible that the sun’s surface is colder than its atmosphere. At first glance, it seems that the sun’s atmosphere, called the corona, is hotter than the heat source which is preposterous given the second law of thermodynamics. So, either the sun doesn’t care of the laws of physics or something more subtle is at play.
In physics, the second law of thermodynamics says that heat flows naturally from an object at a higher temperature to an object at a lower temperature, and heat doesn’t flow in the opposite direction of its own accord. This is one of the most intuitive laws of physics, yet as the heat travels from the sun’s surface, which registers a temperature of about 5,500 degrees Celsius, to the layer a few hundred miles away from its surface (known as the sun’s corona), it rises to a temperature of 1,000,000 degrees Celsius. This is the only instance in the known universe where the thing doing the heating is actually cooler than the thing it’s heating (along with other similar stars). If it weren’t enough, it’s actually about 200 times hotter than the heat source. So, what’s going on here?
Energy carrying waves coming from inside the sun
Magnetic loop structures in the corona of the Sun. The loops highlight the Sun’s magnetic field and are visible because they support the dense, million degree gas typical of the corona. Image: NASA’s Solar Dynamic Observatory
This is known as the sun’s coronal heating problem and has been baffling scientists ever since 1939 when the huge discrepancy was first discovered. A number of explanations have been announced, but it wasn’t until recently that tantalizing evidence surfaced explaining this peculiar phenomenon.
A study published in 2012 in Nature Communications by researchers at Northumbria University found a possible mechanism that causes some stars to have a corona that is almost 200 times hotter than their photosphere (the star’s surface). The researchers used cutting-edge solar-imaging technology to observe the Sun’s chromosphere – a distinct region of the sun’s atmosphere sandwiched between the photosphere and the outer corona. Here, the researchers examined magnetohydrodynamic (MHD) waves and measured their speed and power with unprecedented detail using the dedicated solar-imaging telescope known as Rapid Oscillations in the Solar Atmosphere, or ROSA.
An estimation of the potential energy transported by these sort of waves was made, which matched those envision by researchers who first theorized that MHD waves distribute the energy generated below the star’s surface to the outer layers of the Sun’s atmosphere, thus being responsible for the heat anomaly.
Northumbria’s Dr Richard Morto said: “The Sun is our closest star and provides a unique opportunity to study the properties of stars in detail. Stars generate heat through thermonuclear reactions in their core and the temperature decreases towards the star’s surface. However, a significant number of stars have higher temperatures at the outer edges of their atmospheres than they do on their surface.
“Our observations have permitted us to estimate the amount of energy transported by the magnetic waves, and these estimates reveal that the waves’ energy meets the energy requirement for the unexplained temperature increase in the corona.”
Plasma jets may be key in explaining the coronal heating problem
Shown are jets of plasma known as spicules, which are fountains of plasma propelled upward from near the surface of the sun into the outer atmosphere. Photo: NASA
The MHD waves may not be solely responsible for heating the corona to dazzling temperatures. In 2011, a team comprised of researchers from Lockheed Martin’s Solar and Astrophysics Laboratory (LMSAL), NCAR and the University of Oslo claimed they discovered a potential source of hot gas that replenishes the corona: high energy jets of plasma that shoot from inside the photosphere (De Pontieu, B. et al. Science 331, 55-58 (2011)).
“It’s always been quite a puzzle to figure out why the sun’s atmosphere is hotter than its surface,” says Scott McIntosh, a solar physicist at the High Altitude Observatory of the National Center for Atmospheric Research (NCAR) in Boulder, Colo., who was involved in the study.
“By identifying that these jets insert heated plasma into the sun’s outer atmosphere, we can gain a much greater understanding of that region and possibly improve our knowledge of the sun’s subtle influence on the Earth’s upper atmosphere,” McIntosh says.
These plasma jets, called spicules, are “long, elongated fin features at the edge of the sun,” according to the researchers involved, and it is their motion that could explain how the sun’s atmosphere, or corona, is a few million degrees hotter than the surface. In 2007, researchers identified what they called Type II spicules, extremely fast but short-lived jets that burst upward faster than 60 miles (100 kilometers) per second.
Plasma jets up close. Photo: NASA
The researchers combined data from NASA’s recently launched Solar Dynamics Observatory and the Japanese Hinode satellite to make direct observations of these fast-moving jets of hot plasma for the first time.
“By identifying that these jets insert heated plasma into the sun’s outer atmosphere, we gain a greater knowledge of the corona and possibly improve our understanding of the sun’s subtle influence on Earth’s upper atmosphere,” said Scott McIntosh, a solar physicist at the National Center for Atmospheric Research in Boulder, Colo., who was also involved in the study.
In any case, it may be that there are more coronal heating mechanisms than the currently discovered MHD waves or plasma jets. Suffice to say, what was once an insurmountable mystery is now slowly unraveling its secrets.
From time to time, the sun projects billion-ton clouds of charged particles from its scorching surface, surrounded by a solar atmosphere scientists dub corona, into space. Sometimes, these blasts hit the Earth’s magnetic field with a high potential for wrecking havoc to satellites and communications, and in extreme cases massive electrical power surges. It’s become a sort of priority, thus, for astronomers and other scientists from around the world to study and understand how these blasts form, in order to predict and minimize the damage they might cause.
The faint oval hovering above the upper left limb of the sun in this picture is known as a coronal cavity. NASAs Solar and Terrestrial Relations Observatory (STEREO) captured this image on Aug. 9, 2007. The cavity has been the object of the study for three separate studies.
So far, NASA scientists’ best bet lies on the mysterious cavities in the sun’s outer atmosphere, or corona. Captioned above is this sort of light bulb filament shaped occurrence. The bright structure around and above that light bulb is called a streamer, while the seemingly hollow interior is called a coronal prominence cavity. It’s believed the latter, these cavities, serve as solar launch pads for the huge clouds of hurled plasma known as coronal mass ejections or CMEs.
“We don’t really know what gets these CMEs going,” Terry Kucera, of NASA’s Goddard Space Flight Center in Greenbelt, Md., said in a statement. “So we want to understand their structure before they even erupt, because then we might have a better clue about why it’s erupting and perhaps even get some advance warning on when they will erupt.”
And this is no easy task. Scientists have been studying one particular cavity as part of a series of paper studying its properties, the first two from 2010 and 2011 looked at the shape and density, respectively, and now the latest, published in Sep. 20 edition of The Astrophysical Journal, tackled temperature. By understanding these three aspects of the cavities scientists can better understand the space weather that can disrupt technologies near Earth. Especially during these rather gruesome times, as the sun comes near the end of its 11 year cycle in 2013, time at which CMEs will become more frequent and powerful.
Predicting a coronal mass ejection
Combined, the three studies have these so far to tell – the structure is similar to a croissant, while the inside is filled with a sort of magnetically charged tube, which is the prime driver for its shape. The cavity appears to be about 30 percent less dense than the material surrounding it, and its average temperatures range from 2.5 million to 3 million degrees Fahrenheit (1.4 million to 1.7 degrees Celsius), increasing with distance from the solar surface.
Concerning the latest study from the series, which discuss temperature, the scientists found that the temperature in cavities isn’t all that different form the rest of the matter in the corona, however its a lot more variable. Hopefully with enough data and scientific wisdom, the astronomers can crack down on the code and sequence of events that trigger a CME.
“Our point with all of these research projects into what might seem like side streets, is ultimately to figure out the physics of magnetic fields in the corona,” said Sarah Gibson, a solar scientist at the High Altitude Observatory at the National Center for Atmospheric Research in Boulder, Colo.
“Sometimes these cavities can be stable for days and weeks, but then suddenly erupt into a CME,” added Gibson, who is a co-author on all three studies. “We want to understand how that happens. We’re accessing so much data, so it’s an exciting time — with all these observations, our understanding is coming together to form a consistent story.”
Have you ever seen a model of the solar system? They’re just great! But most of them have one big fault – they’re not to scale. But that’s not the case with the biggest model in the world, located in Sweden, which stretches around the entire country and represents everything to scale.
The Sun is represented by the Ericsson Globe, in Stockholm, which measures 110 meters in diameter, keeping the proportions to scale if we consider both the Sun and its corona.
Mercury measures only 25 cm in diameter, and is placed 2.9 kilometers away from the ‘Sun’, in the Stockholm City Museum.
Venus (62 cm) is placed at KTH, the Royal Institute, 5.5 km from the globe. Sadly, the original Venus fell and shattered, so this is actually a replacement.
Earth lies at the Swedish Museum of Natural History (Cosmonova), 7,600 m from the Globe, and satellite pictures of our planet surround it.
There is also an elaborate model of the Moon in another room of the museum.
Mars is pretty close, in a suburb of Stockholm, at a shopping center. It measures 35 cm in diameter and is located 11.6 km from the Sun.
Jupiter is represented as a big, circular flower decoration at the Arlanda airport, some 40 km down the road. The different types of flowers represent different zones of the planet, but there are plans of building a big 3D model.
We haven’t really been able to get a picture of Saturn, so if any of you people have one, we’d be really thankful if you could share it with the rest of us. But we do know it is placed outside the old observatory of Anders Celsius, in the so-called Celsius Square, at centre of Uppsala, 73 km from the Globe
Also Uranus was vandalized and while there are plans to build it, a model isn’t currently available.
However, Neptune, measuring 2.5 meters in diameter and located 229 km away from the Globe, lies by the river Söderhamnsån in Söderhamn – known for its fishing and sailing tradition – for which Neptune is a symbol.
Also, even though it isn’t technically a planet, Pluto is still in our hearts, and it was placed with its moon Charon in Delsbo, 300 km from the Globe, near the Dellen lakes, which were formed by a meteorite impact some 90 million years ago.