These extreme UV light images from the Solar Dynamics Observatory shows the Sun at solar minimum (left, Dec. 2019) compared to the current solar maximum. Image Credit: NASA/SDO
For most of human history, the Sun appeared stable. It was a stoic stellar presence, going about its business fusing hydrogen into helium beyond our awareness and helping Earth remain habitable. But in our modern technological age, that facade fell away.
We now know that the Sun is governed by its powerful magnetic fields, and as these fields cycle through their changes, the Sun becomes more active. Right now, according to NASA, the Sun is at its solar maximum, a time of increased activity.
The Daniel K. Inouye Solar Telescope has mapped the magnetic field of the Sun's corona for the first time. The corona is the source of most space weather, and this map will help scientists better understand the corona, space weather and other stars. Image Credit: Schad et al. 2024.
If you enjoyed this summer’s display of aurora borealis, thank the Sun’s corona. The corona is the Sun’s outer layer and is the source of most space weather, including aurorae. The aurora borealis are benign light shows, but not all space weather produces such harmless displays; some of it is dangerous and destructive.
In an effort to understand space weather and the solar corona, the National Science Foundation aimed the world’s most powerful solar telescope, the Daniel K. Inouye Solar Telescope, at the corona to map its magnetic fields.
A solar flare erupts on the Sun. Credit: NASA/GSFC/SDO
On December 14th, at 12:02 PM Eastern (09:02 AM Pacific), the Sun unleashed a massive solar flare. According to the Space Weather Prediction Center, part of the National Oceanic Atmospheric Administration (NOAA), this was the strongest flare of Solar Cycle 25, which began in 2019 and will continue until 2030. What’s more, scientists at the SWPC estimate that this may be one of the most powerful solar flares recorded since 1755 when extensive recording of solar sunspot activity began.
NASA has created a video based on 133 days of observations by the Solar Dynamics Observatory. The hour-long video is a captivating look at four months of the Sun's approximately 10 billion year lifetime. Image Credit: NASA/Goddard Space Flight Center/SDO
NASA’s Goddard Space Flight Center has released an hour-long time-lapse video that shows 133 days of the Sun’s life. The video shows the Sun’s chaotic surface, where great loops of plasma arch above the star along magnetic field lines. Sometimes the looping plasma reconnects to the star, and other times it’s ejected into space, creating hazardous space weather.
Planetary formation theory has been undergoing a lot of changes recently, with an ever expanding litany of events that can potentially impact it. Everything from gravity to magnetic fields seems to impact this complex process. Now scientists want to add another confounding factor – massive solar flares thousands of times more powerful than the most powerful we have ever observed from the Sun.
This week we are pleased to welcome Dr. Meng Jin, Research Scientist at the SETI Institute, to the Weekly Space Hangout. Meng uses numerical modeling techniques to analyze Coronal Mass Ejections (CMEs) and related events [e.g., CME-Driven Shocks and Solar Energetic Particles (SEPs).]
A coronal mass ejection (CME) from the Sun on August 31, 2012, the event that caused a third ring to form in the Van Allen radiation belts. Credit: NASA
Solar storms powerful enough to wreak havoc on electronic equipment strike Earth every 25 years, according to a new study. And less powerful—yet still dangerous—storms occur every three years or so. This conclusion comes from a team of scientists from the the University of Warwick and the British Antarctic Survey.
These powerful storms can disrupt electronic equipment, including communication equipment, aviation equipment, power grids, and satellites.
This visualization depicts what a coronal mass ejection might look like like as it interacts with the interplanetary medium and magnetic forces. Credit: NASA / Steele Hill
Exactly how dangerous are solar storms? Scientists think the Carrington Event was one of the most powerful ones to ever hit Earth. They also think that storms that powerful only happen every couple centuries or so. But a new study says we can expect more storms equally as strong, and more often.
The launch of the Parker Solar Probe atop a ULA Delta IV Heavy rocket from Cape Canaveral Air Force Station on August 12th, 2018. Credit: Glenn Davis
When it comes to exploring our Solar System, there are few missions more ambitious than those that seek to study the Sun. While NASA and other space agencies have been observing the Sun for decades, the majority of these missions were conducted in orbit around Earth. To date, the closest any mission has ever come to the Sun was with the Helios 1 and 2 probes, which studied the Sun during the 1970s from inside of Mercury’s orbit at perihelion.
NASA intends to change all that with the Parker Solar Probe, the space probe that recently launched from Cape Canaveral, which will revolutionize our understanding of the Sun by entering its atmosphere (aka. the corona). Over the next seven years, the probe will use Venus’ gravity to conduct a series of slingshots that will gradually bring it closer to the Sun than any mission in the history of spaceflight!
The darker area on this image of the Sun's surface is the southern extension of the northern hemisphere polar corona. The coronal hole is a source of fast-moving streams of particles from the Sun, which can cause auroras here on Earth. Image: NASA/SDO
To the naked eye, the Sun puts out energy in a continual, steady state, unchanged through human history. (Don’t look at the sun with your naked eye!) But telescopes tuned to different parts of the electromagnetic spectrum reveal the Sun’s true nature: A shifting, dynamic ball of plasma with a turbulent life. And that dynamic, magnetic turbulence creates space weather.
Space weather is mostly invisible to us, but the part we can see is one of nature’s most stunning displays, the auroras. The aurora’s are triggered when energetic material from the Sun slams into the Earth’s magnetic field. The result is the shimmering, shifting bands of color seen at northern and southern latitudes, also known as the northern and southern lights.
This image of the northern lights over Canada was taken by a crew member on board the ISS in Sept. 2017. Image: NASA
There are two things that can cause auroras, but both start with the Sun. The first involves solar flares. Highly-active regions on the Sun’s surface produce more solar flares, which are sudden, localized increase in the Sun’s brightness. Often, but not always, a solar flare is coupled with a coronal mass ejection (CME).
A coronal mass ejection is a discharge of matter and electromagnetic radiation into space. This magnetized plasma is mostly protons and electrons. The CME ejection often just disperses into space, but not always. If it’s aimed in the direction of the Earth, chances are we get increased auroral activity.
The second cause of auroras are coronal holes on the Sun’s surface. A coronal hole is a region on the surface of the Sun that is cooler and less dense than surrounding areas. Coronal holes are the source of fast-moving streams of material from the Sun.
Whether it’s from an active region on the Sun full of solar flares, or whether it’s from a coronal hole, the result is the same. When the discharge from the Sun strikes the charged particles in our own magnetosphere with enough force, both can be forced into our upper atmosphere. As they reach the atmosphere, they give up their energy. This causes constituents in our atmosphere to emit light. Anyone who has witnessed an aurora knows just how striking that light can be. The shifting and shimmering patterns of light are mesmerizing.
The auroras occur in a region called the auroral oval, which is biased towards the night side of the Earth. This oval is expanded by stronger solar emissions. So when we watch the surface of the Sun for increased activity, we can often predict brighter auroras which will be more visible in southern latitudes, due to the expansion of the auroral oval.
This photo is of the aurora australis over New Zealand. Image: Paul Stewart, Public Domain, CC 1.0 Universal.
Something happening on the surface of the Sun in the last couple days could signal increased auroras on Earth, tonight and tomorrow (March 28th, 29th). A feature called a trans-equatorial coronal hole is facing Earth, which could mean that a strong solar wind is about to hit us. If it does, look north or south at night, depending on where your live, to see the auroras.
Of course, auroras are only one aspect of space weather. They’re like rainbows, because they’re very pretty, and they’re harmless. But space weather can be much more powerful, and can produce much greater effects than mere auroras. That’s why there’s a growing effort to be able to predict space weather by watching the Sun.
A powerful enough solar storm can produce a CME strong enough to damage things like power systems, navigation systems, communications systems, and satellites. The Carrington Event in 1859 was one such event. It produced one of the largest solar storms on record.
That storm occurred on September 1st and 2nd, 1859. It was preceded by an increase in sun spots, and the flare that accompanied the CME was observed by astronomers. The auroras caused by this storm were seen as far south as the Caribbean.
Sunspots are dark areas on the surface of the Sun that are cooler than the surrounding areas. They form where magnetic fields are particularly strong. The highly active magnetic fields near sunspots often cause solar flares. Image: NASA/SDO/AIA/HMI/Goddard Space Flight Center
The same storm today, in our modern technological world, would wreak havoc. In 2012, we almost found out exactly how damaging a storm of that magnitude could be. A pair of CMEs as powerful as the Carrington Event came barreling towards Earth, but narrowly missed us.
We’ve learned a lot about the Sun and solar storms since 1859. We now know that the Sun’s activity is cyclical. Every 11 years, the Sun goes through its cycle, from solar maximum to solar minimum. The maximum and minimum correspond to periods of maximum sunspot activity and minimum sunspot activity. The 11 year cycle goes from minimum to minimum. When the Sun’s activity is at its minimum in the cycle, most CMEs come from coronal holes.
NASA’s Solar Dynamics Observatory (SDO), and the combined ESA/NASA Solar and Heliospheric Observatory (SOHO) are space observatories tasked with studying the Sun. The SDO focuses on the Sun and its magnetic field, and how changes influence life on Earth and our technological systems. SOHO studies the structure and behavior of the solar interior, and also how the solar wind is produced.
Several different websites allow anyone to check in on the behavior of the Sun, and to see what space weather might be coming our way. The NOAA’s Space Weather Prediction Center has an array of data and visualizations to help understand what’s going on with the Sun. Scroll down to the Aurora forecast to watch a visualization of expected auroral activity.
NASA’s Space Weather site contains all kinds of news about NASA missions and discoveries around space weather. SpaceWeatherLive.com is a volunteer run site that provides real-time info on space weather. You can even sign up to receive alerts for upcoming auroras and other solar activity.
