On March 26th, the ESA’s Solar Orbiter made its closest approach to the Sun so far. It ventured inside Mercury’s orbit and was about one-third the distance from Earth to the Sun. It was hot but worth it.
The Solar Orbiter’s primary mission is to understand the connection between the Sun and its heliosphere, and new images from the close approach are helping build that understanding.
In the search for “potentially-habitable” extrasolar planets, one of the main things scientists look at is stellar activity. Whereas stars like our own, a G-type (G2V) yellow dwarf, are considered stable over time, other classes are variable and prone to flare-ups – particularly M-type red dwarf stars. Even if a star has multiple planets orbiting within its habitable zone (HZ), the tendency to periodically flare could render these planets completely uninhabitable.
According to a new study, stars like our own may not be as stable as previously thought. While observing EK Draconis, a G1.5V yellow dwarf located 110.71 light-years away, an international team of astronomers witnessed a massive coronal mass ejection that dwarfed anything we’ve ever seen in our Solar System. These observations suggest that these ejections can worsen over time, which could be a dire warning for life here on Earth.
There’s an old adage that says there is ‘nothing new under the Sun…’ but that doesn’t apply when it comes to solar eclipse science.
Beyond just providing an awesome celestial spectacle, astronomers have often taken advantage of the brief moments afforded by solar totality to explore the Sun and its environs. To this end, total solar eclipses have historically offered chances to carry out scientific experiments in the past, and continue to do so today.
“A great fire appeared in the sky to the North, and lasted three nights,” wrote a Portuguese scribe in early March, 1582. Across the globe in feudal Japan, observers in Kyoto noted the same fiery red display in their skies too. Similar accounts of strange nighttime lights were recorded in Leipzig, Germany; Yecheon, South Korea; and a dozen other cities across Europe and East Asia.
It was a stunning event. While people living at high latitudes were well aware of auroras in 1582, most people living closer to the equator were not. The solar storm that year was unlike anything in living memory, and it was so strong it brought the aurora to latitudes as low as 28 degrees (in line with Florida, Egypt, and southern Japan). People this close to the equator had no frame of reference for such dazzling nighttime displays, and many took it as a religious portent.
The Sun is not exactly placid, though it appears pretty peaceful in the quick glances we can steal with our naked eyes. In reality though, the Sun is a dynamic, chaotic body, spraying out solar wind and radiation and erupting in great sheets of plasma. Living in a technological society next to all that is a challenge.
For the first time ever, astronomers have witnessed a coronal mass ejection (CME) on a star other than our very own Sun. The star, named HR 9024 (and also known as OU Andromeda,) is about 455 light years away, in the constellation Andromeda. It’s an active, variable star with a strong magnetic field, which astronomers say may cause CMEs.
If you’ve read enough of our articles, you know I’ve got an uneasy alliance with the Sun. Sure, it provides the energy we need for all life on Earth. But, it’s a great big ongoing thermonuclear reaction, and it’s right there! As soon as we get fusion, Sun, in like, 30 years or so, I tell you, we’ll be the ones laughing.
But to be honest, we still have so many questions about the Sun. For starters, we don’t fully understand the solar wind blasting out of the Sun. This constant wind of charged particles is constantly blowing out into space, but sometimes it’s stronger, and sometimes it’s weaker.
What are the factors that contribute to the solar wind? And as you know, these charged particles are not healthy for the human body, or for our precious electronics. In fact, the Sun occasionally releases enormous blasts that can damage our satellites and electrical grids.
How can we predict the intensity so that we can be better prepared for dangerous solar storms? Especially the Carrington-class events that might take down huge portions of our modern society.
Perhaps the biggest mystery with the Sun is the temperature of its corona. The surface of the Sun is hot, like 5,500 degrees Celsius. But if you rise up into the atmosphere of the Sun, into its corona, the temperature jumps beyond a million degrees.
The list of mysteries is long. And to start understanding what’s going on, we’ll need to get much much closer to the Sun.
Good news, NASA has a new mission in the works to do just that.
The mission is called the Parker Solar Probe. Actually, last week, it was called the Solar Probe Plus, but then NASA renamed it, and that reminded me to do a video on it.
It’s pretty normal for NASA to rename their spacecraft, usually after a dead astronomer/space scientist, like Kepler, Chandra, etc. This time, though, they renamed it for a legendary solar astronomer Eugene Parker, who developed much of our modern thinking on the Sun’s solar wind. Parker just turned 90 and this is the first time NASA has named it after someone living.
Anyway, back to the spacecraft.
The mission is due to launch in early August 2018 on a Delta IV Heavy, so we’re still more than a year away at this point. When it does, it’ll carry the spacecraft on a very unusual trajectory through the inner Solar System.
The problem is that the Sun is actually a very difficult place to reach. In fact, it’s the hardest place to get to in the entire Solar System.
Remember that the Earth is traveling around the Sun at a velocity of 30 km/s. That’s almost three times the velocity it takes to get into orbit. That’s a lot of velocity.
In order to be able to get anywhere near the Sun, the probe needs to shed velocity. And in order to do this, it’s going to use gravitational slingshots with Venus. We’ve talked about gravitational slingshots in the past, and how you can use them to speed up a spacecraft, but you can actually do the reverse.
The Parker Solar Probe will fall down into Venus’ gravity well, and give orbital velocity to Venus. This will put it on a new trajectory which takes it closer to the Sun. It’ll do a total of 7 flybys in 7 years, each of which will tweak its trajectory and shed some of that orbital momentum.
You know, trying to explain orbital maneuvering is tough. I highly recommend that you try out Kerbal Space Program. I’ve learned more about orbital mechanics by playing that game for a few months than I have in almost 2 decades of space journalism. Go ahead, try to get to the Sun, I challenge you.
Anyway, with each Venus flyby, the Parker Solar Probe will get closer and closer to the Sun, well within the orbit of Mercury. Far closer than any spacecraft has ever gotten to the Sun. At its closest point, it’ll only be 5.9 million kilometers from the Sun. Just for comparison, the Earth orbits at an average distance of about 150 million kilometers. That’s close.
And over the course of its entire mission, the spacecraft is expected to make a total of 24 complete orbits of the Sun, analyzing that plasma ball from every angle.
The orbit is also highly elliptical, which means that it’s going really really fast at its closest point. Almost 725,000 km/h.
In order to withstand the intense temperatures of being this close to the Sun, NASA has engineered the Parker Solar Probe to shed heat. It’s equipped with an 11.5 cm-thick shield made of carbon-composite. For that short time it spends really close to the Sun, the spacecraft will keep the shield up, blocking that heat from reaching the rest of its instruments.
And it’s going to get hot. We’re talking about more than 1,300 degrees Celsius, which is about 475 times as much energy as a spacecraft receives here on Earth. In the outer Solar System, the problem is that there just isn’t enough energy to power solar panels. But where Parker is going, there’s just too much energy.
Now we’ve talked about the engineering difficulties of getting a spacecraft this close to the Sun, let’s talk about the science.
The biggest question astronomers are looking to solve is, how does the corona get so hot. The surface is 5,500 Celsius. As you get farther away from the Sun, you’d expect the temperature to go down. And it certainly does once you get as far as the orbit of the Earth.
But the Sun’s corona, or its outer atmosphere, extends millions of kilometers into space. You can see it during a solar eclipse as this faint glow around the Sun. Instead of dropping, the temperature rises to more than a million degrees.
What could be causing this? There are a couple of ideas. Plasma waves pushed off the Sun could bunch up and release their heat into the corona. You could also get the crisscrossing of magnetic field lines that create mini-flares within the corona, heating it up.
The second great mystery is the solar wind, the stream of charged protons and electrons coming from the Sun. Instead of a constant blowing wind, it can go faster or slower. And when the speed changes, the contents of the wind change too.
There’s the slow wind, that goes a mere 1.1 million km/h and seems to emanate from the Sun’s equatorial regions. And then the fast wind, which seems to be coming out of coronal holes, cooler parts in the Sun’s corona, and can be going at 2.7 million km/h.
Why does the solar wind speed change? Why does its consistency change?
The Parker Solar Probe is equipped with four major instruments, each of which will gather data from the Sun and its environment.
The FIELDS experiment will measure the electric and magnetic fields and waves around the Sun. We know that much of the Sun’s behavior is driven by the complex interaction between charged plasma in the Sun. In fact, many physicists agree that magnetohydrodynamics is easily one of the most complicated fields you can get into.
Integrated Science Investigation of the Sun, or ISOIS (which I suspect needs a renaming) will measure the charged particles streaming off the Sun, during regular solar activity and during dangerous solar storms. Can we get any warning before these events occur, giving astronauts more time to protect themselves?
Wide-field Imager for Solar PRobe or WISPR is its telescope and camera. It’s going to be taking close up, high resolution images of the Sun and its corona that will blow our collective minds… I hope. I mean, if it’s just a bunch of interesting data and no pretty pictures, it’s going to be hard to make cool videos showcasing the results of the mission. You hear me NASA, we want pictures and videos. And science, sure.
And then the Solar Wind Electrons Alphas and Protons Investigation, or SWEAP, will measure type, velocity, temperature and density of particles around the Sun, to help us understand the environment around it.
One interesting side note, the spacecraft will be carrying a tiny chip on board with photos of Eugene Parker and a copy of his original 1958 paper explaining the Sun’s solar wind.
I know we’re still more than a year away from liftoff, and several years away before the science data starts pouring in. But you’ll be hearing more and more about this mission shortly, and I’m pretty excited about what it’s going to accomplish. So stay tuned, and once the science comes in, I’m sure you’ll hear plenty more about it.
Coronal Mass Ejections (aka. solar flares) are a seriously hazardous thing. Whenever the Sun emits a burst of these charged particles, it can play havoc with electrical systems, aircraft and satellites here on Earth. Worse yet is the harm it can inflict on astronauts stationed aboard the ISS, who do not have the protection of Earth’s atmosphere. As such, it is obvious why scientists want to be able to predict these events better.
For this reason, the Smithsonian Astrophysical Observatory and the Charles Stark Draper Laboratory – a Cambridge, Massachusetts-based non-profit engineering organization – are working to develop specialized sensors for NASA’s proposed solar spacecraft. Launching in 2018, this spacecraft will fly into the Sun atmosphere and “touch” the face of the Sun to learn more about its behavior.
This spacecraft – known as the Solar Probe Plus (SPP) – is currently being designed and built by the Johns Hopkins University Applied Physics Laboratory. Once it is launched, the SPP will use seven Venus flybys over nearly seven years to gradually shrink its orbit around the Sun. During this time, it will conduct 24 flybys of the Sun and pass into the Sun’s upper atmosphere (corona), passing within 6.4 million km (4 million mi) of its surface.
At this distance, it will have traveled 37.6 million km (23.36 million mi) closer to the Sun than any spacecraft in history. At the same time, it will set a new record for the fastest moving object ever built by human beings – traveling at speeds of up to 200 km/sec (124.27 mi/s). And last but not least, it will be exposed to heat and radiation that no spacecraft has ever faced, which will include temperatures in excess of 1371 °C (2500 °F).
As Seamus Tuohy, the Director of the Space Systems Program Office at Draper, said in a CfA press release:
“Such a mission would require a spacecraft and instrumentation capable of withstanding extremes of radiation, high velocity travel and the harsh solar condition—and that is the kind of program deeply familiar to Draper and the Smithsonian Astrophysical Observatory.”
In addition to being an historic first, this probe will provide new data on solar activity and help scientists develop ways of forecasting major space-weather events – which impact life on Earth. This is especially important in an age when people are increasingly reliant on technology that can be negatively impacted by solar flares – ranging from aircraft and satellites to appliances and electrical devices.
According to a recent study by the National Academy of Sciences, it is estimated that a huge solar event today could cause two trillion dollars in damage in the US alone – and places like the eastern seaboard would be without power for up to a year. Without electricity to provide heating, utilities, light, and air-conditioning, the death toll from such an event would be significant.
As such, developing advanced warning systems that could reliably predict when a coronal mass ejection is coming is not just a matter of preventing damage, but saving lives. As Justin C. Kasper, the principal investigator at the Smithsonian Astrophysical Observatory and a professor in space science at the University of Michigan, said:
“[I]n addition to answering fundamental science questions, the intent is to better understand the risks space weather poses to the modern communication, aviation and energy systems we all rely on. Many of the systems we in the modern world rely on—our telecommunications, GPS, satellites and power grids—could be disrupted for an extended period of time if a large solar storm were to happen today. Solar Probe Plus will help us predict and manage the impact of space weather on society.”
To this end, the SPP has three major scientific objectives. First, it will seek to trace the flow of energy that heats and accelerates the solar corona and solar wind. Second, its investigators will attempt to determine the structure and dynamics of plasma and magnetic fields as the source of solar wind. And last, it will explore the mechanisms that accelerate and transport energetic particles – specifically electrons, protons, and helium ions.
To do this, the SPP will be equipped with an advanced suite of instruments. One of the most important of these is the one built by the Smithsonian Astrophysical Observatory with technical support from Draper. Known as the Faraday Cup – and named after famous electromagnetic scientists Michael Faraday – this device will be operated by SAO and the University of Michigan in Ann Arbor.
Designed to withstand interference from electromagnetic radiation, the Farady Cup will measure the velocity and direction of the Sun’s charged particles, and will be only two positioned outside of the SPP’s protective sun shield – another crucial component. Measuring 11.43 cm (4.5 inches) thick, this carbon composition shield will ensure that the probe can withstand the extreme conditions as it conducts its many flybys through the Sun’s corona.
Naturally, the mission presents several challenges, not the least of which will be capturing data while operating within an extreme environment, and while traveling at extreme speeds. But the payoff is sure to be worth it. For years, astronomers have studied the Sun, but never from inside the Sun’s atmosphere.
By flying through the birthplace of the highest-energy solar particles, the SPP is set to advance our understanding of the Sun and the origin and evolution of the solar wind. This knowledge could not only help us avoid a natural catastrophe here on Earth, but help advance our long-term goal of exploring (and even colonizing) the Solar System.
Isn’t modern society great? With all this technology surrounding us in all directions. It’s like a cocoon of sweet, fluffy silicon. There are chips in my fitness tracker, my bluetooth headset, mobile phone, car keys and that’s just on my body.
At all times in the Cain household, there dozens of internet devices connected to my wifi router. I’m not sure how we got to the point, but there’s one thing I know for sure, more is better. If I could use two smartphones at the same time, I totally would.
And I’m sure you agree, that without all this technology, life would be a pale shadow of its current glory. Without these devices, we’d have to actually interact with each other. Maybe enjoy the beauty of nature, or something boring like that.
It turns out, that terrible burning orb in the sky, the Sun, is fully willing and capable of bricking our precious technology. It’s done so in the past, and it’s likely to take a swipe at us in the future.
I’m talking about solar storms, of course, tremendous blasts of particles and radiation from the Sun which can interact with the Earth’s magnetosphere and overwhelm anything with a wire.
In fact, we got a sneak preview of this back in 1859, when a massive solar storm engulfed the Earth and ruined our old timey technology. It was known as the Carrington Event.
Follow your imagination back to Thursday, September 1st, 1859. This was squarely in the middle of the Victorian age.
And not the awesome, fictional Steampunk Victorian age where spectacled gentleman and ladies of adventure plied the skies in their steam-powered brass dirigibles.
No, it was the regular crappy Victorian age of cholera and child labor. Technology was making huge leaps and bounds, however, and the first telegraph lines and electrical grids were getting laid down.
Imagine a really primitive version of today’s electrical grid and internet.
On that fateful morning, the British astronomer Richard Carrington turned his solar telescope to the Sun, and was amazed at the huge sunspot complex staring back at him. So impressed that he drew this picture of it.
While he was observing the sunspot, Carrington noticed it flash brightly, right in his telescope, becoming a large kidney-shaped bright white flare.
Carrington realized he was seeing unprecedented activity on the surface of the Sun. Within a minute, the activity died down and faded away.
And then about 5 minutes later. Aurora activity erupted across the entire planet. We’re not talking about those rare Northern Lights enjoyed by the Alaskans, Canadians and Northern Europeans in the audience. We’re talking about everyone, everywhere on Earth. Even in the tropics.
In fact, the brilliant auroras were so bright you could read a book to them.
The beautiful night time auroras was just one effect from the monster solar flare. The other impact was that telegraph lines and electrical grids were overwhelmed by the electricity pushed through their wires. Operators got electrical shocks from their telegraph machines, and the telegraph paper lit on fire.
What happened? The most powerful solar flare ever observed is what happened.
A solar flare occurs because the Sun’s magnetic field lines can get tangled up in the solar atmosphere. In a moment, the magnetic fields reorganize themselves, and a huge wave of particles and radiation is released.
Flares happen in three stages. First, you get the precursor stage, with a blast of soft X-ray radiation. This is followed by the impulsive stage, where protons and electrons are accelerated off the surface of the Sun. And finally, the decay stage, with another burp of X-rays as the flare dies down.
These stages can happen in just a few seconds or drag out over an hour.
Remember those particles hurled off into space? They take several hours or a few days to reach Earth and interact with our planet’s protective magnetosphere, and then we get to see beautiful auroras in the sky.
This geomagnetic storm causes the Earth’s magnetosphere to jiggle around, which drives charges through wires back and forth, burning out circuits, killing satellites, overloading electrical grids.
Back in 1859, this wasn’t a huge deal, when our quaint technology hadn’t progressed beyond the occasional telegraph tower.
Today, our entire civilization depends on wires. There are wires in the hundreds of satellites flying overhead that we depend on for communications and navigation. Our homes and businesses are connected by an enormous electrical grid. Airplanes, cars, smartphones, this camera I’m using.
Everything is electronic, or controlled by electronics.
Think it can’t happen? We got a sneak preview back in March, 1989 when a much smaller geomagnetic storm crashed into the Earth. People as far south as Florida and Cuba could see auroras in the sky, while North America’s entire interconnected electrical grid groaned under the strain.
The Canadian province of Quebec’s electrical grid wasn’t able to handle the load and went entirely offline. For 12 hours, in the freezing Quebec winter, almost the entire province was without power. I’m telling you, that place gets cold, so this was really bad timing.
Satellites went offline, including NASA’s TDRS-1 communication satellite, which suffered 250 separate glitches during the storm.
And on July 23, 2012, a Carrington-class solar superstorm blasted off the Sun, and off into space. Fortunately, it missed the Earth, and we were spared the mayhem.
If a solar storm of that magnitude did strike the Earth, the cleanup might cost $2 trillion, according to a study by the National Academy of Sciences.
It’s been 160 years since the Carrington Event, and according to ice core samples, this was the most powerful solar flare over the last 500 years or so. Solar astronomers estimate solar storms like this happen twice a millennium, which means we’re not likely to experience another one in our lifetimes.
But if we do, it’ll cause worldwide destruction of technology and anyone reliant on it. You might want to have a contingency plan with some topic starters when you can’t access the internet for a few days. Locate nearby interesting nature spots to explore and enjoy while you wait for our technological civilization to be rebuilt.
Have you ever seen an aurora in your lifetime? Give me the details of your experience in the comments.
The Northern Lights have fascinated human beings for millennia. In fact, their existence has informed the mythology of many cultures, including the Inuit, Northern Cree, and ancient Norse. They were also a source of intense fascination for the ancient Greeks and Romans, and were seen as a sign from God by medieval Europeans.
Thanks to the birth of modern astronomy, we now know what causes both the Aurora Borealis and its southern sibling – Aurora Australis. Nevertheless, they remain the subject of intense fascination, scientific research, and are a major tourist draw. For those who live north of 60° latitude, this fantastic light show is also a regular occurrence.
Aurora Borealis (and Australis) is caused by interactions between energetic particles from the Sun and the Earth’s magnetic field. The invisible field lines of Earth’s magnetoshere travel from the Earth’s northern magnetic pole to its southern magnetic pole. When charged particles reach the magnetic field, they are deflected, creating a “bow shock” (so-named because of its apparent shape) around Earth.
However, Earth’s magnetic field is weaker at the poles, and some particles are therefore able to enter the Earth’s atmosphere and collide with gas particles in these regions. These collisions emit light that we perceive as wavy and dancing, and are generally a pale, yellowish-green in color.
The variations in color are due to the type of gas particles that are colliding. The common yellowish-green is produced by oxygen molecules located about 100 km (60 miles) above the Earth, whereas high-altitude oxygen – at heights of up to 320 km (200 miles) – produce all-red auroras. Meanwhile, interactions between charged particles and nitrogen will produces blue or purplish-red auroras.
The visibility of the northern (and southern) lights depends on a lot of factors, much like any other type of meteorological activity. Though they are generally visible in the far northern and southern regions of the globe, there have been instances in the past where the lights were visible as close to the equator as Mexico.
In places like Alaska, Norther Canada, Norway and Siberia, the northern lights are often seen every night of the week in the winter. Though they occur year-round, they are only visible when it is rather dark out. Hence why they are more discernible during the months where the nights are longer.
Because they depend on the solar wind, auroras are more plentiful during peak periods of activity in the Solar Cycle. This cycle takes places every 11 years, and is marked by the increase and decrease of sunspots on the sun’s surface. The greatest number of sunspots in any given solar cycle is designated as a “Solar Maximum“, whereas the lowest number is a “Solar Minimum.”
A Solar Maximum also accords with bright regions appearing in the Sun’s corona, which are rooted in the lower sunspots. Scientists track these active regions since they are often the origin of eruptions on the Sun, such as solar flares or coronal mass ejections.
The most recent solar minimum occurred in 2008. As of January 2010, the Sun’s surface began to increase in activity, which began with the release of a lower-intensity M-class flare. The Sun continued to get more active, culminating in a Solar Maximum by the summer of 2013.
Locations for Viewing:
The ideal places to view the Northern Lights are naturally located in geographical regions north of 60° latitude. These include northern Canada, Greenland, Iceland, Scandinavia, Alaska, and Northern Russia. Many organizations maintain websites dedicated to tracking optimal viewing conditions.
For instance, the Geophysical Institute of the University of Alaska Fairbanks maintains the Aurora Forecast. This site is regularly updated to let residents know when auroral activity is high, and how far south it will extend. Typically, residents who live in central or northern Alaska (from Fairbanks to Barrow) have a better chance than those living in the south (Anchorage to Juneau).
In Northern Canada, auroras are often spotted from the Yukon, the Northwest Territories, Nunavut, and Northern Quebec. However, they are sometimes seen from locations like Dawson Creek, BC; Fort McMurry, Alberta; northern Saskatchewan and the town of Moose Factory by James Bay, Ontario. For information, check out Canadian Geographic Magazine’s “Northern Lights Across Canada“.
The National Oceanic and Atmospheric Agency also provides 30 minute forecasts on auroras through their Space Weather Prediction Center. And then there’s Aurora Alert, an Android App that allows you to get regular updates on when and where an aurora will be visible in your region.
Understanding the scientific cause of auroras has not made them any less awe-inspiring or wondrous. Every year, countless people venture to locations where they can be seen. And for those serving aboard the ISS, they got the best seat in the house!
Speaking of which, be sure to check out this stunning NASA video which shows the Northern Lights being viewed from the ISS:
For more information, visit the THEMIS website – a NASA mission that is currently studying space weather in great detail. The Space Weather Center has information on the solar wind and how it causes aurorae.