Today on our solar tour, we’re exploring the magnetosphere – the last stop before heading into space! Earth’s magnetosphere is created by our planet’s molten core and protects us from the solar wind, the constant stream of radiation and charged particles coming from the Sun!
We’re not alone (magnetically speaking)
Earth isn’t the only object in our solar system with a magnetosphere! This protective shield may be essential for the development of conditions friendly to life, so finding magnetospheres around other planets is a big step toward determining if they could support life.
In this story, learn how not all magnetospheres are created equal.
Earth has a magnetosphere – and so does our Sun!
Before becoming a Delta State University professor and director of the Wiley Planetarium, solar scientist Maria Weber studied how magnetism makes its way to the Sun’s surface by connecting what we see on the surface to what’s happening below. This could help scientists predict solar storms, protecting people and technology on Earth and in space.
Early this morning, there was a total solar eclipse across Antarctica!
During a total solar eclipse, the Moon blocks out the Sun, creating the illusion of night during the day and a breathtaking sight in our sky.
Join NASA Edge at 1:30 p.m. EST on NASA TV to see the eclipse and learn more: https://go.nasa.gov/3nTvrOA
Learning from eclipses
Eclipses have played a major role in scientific discoveries, from the Sun’s structure to the element helium. The corona – the Sun’s outer atmosphere – normally can’t be seen because of the bright solar surface, but during an eclipse, the corona emerges, offering unique science opportunities.
The corona up close
What we can see from the Sun’s corona during an eclipse can teach us a lot about our star. Imagine what we’d learn if we actually touched the corona? NASA has sent Parker Solar Probe to the Sun to do just that. 🛰
Eclipsing right along…
While today’s eclipse may be over, you still have opportunities to watch eclipses in person! An annular solar eclipse will cross the U.S. in 2023, and a total solar eclipse will cross the U.S. in 2024. For now, see what’s next in our #SolarTour by joining in tomorrow.
Our solar tour begins on Earth. From here, one star shines brighter than all the rest. It’s the closest star and the center of our solar system: our Sun. Earth is in the Goldilocks zone, just the right distance from the Sun to be habitable.
A mission to touch the Sun
We can answer some questions about the Sun from 93 million miles away on Earth, but to learn more, we knew we’d have to venture to our nearest star. In 2018, NASA launched Parker Solar Probe, our mission to touch the Sun.
Why won’t it melt?
Flying close to the Sun is risky business (just ask Icarus), but engineers were up to the task. Check out this video to learn how they built a spacecraft that won’t melt, even when it’s heated to temperatures up to 2500° F. Hint: don’t use wax!
Now, we’re heading south to catch a special event where day becomes night and the Moon is the star of the show. Can you guess what we’ll see?
The Sun has an immense influence in space. It shapes and impacts our entire solar system in ways that we are still trying to understand.
To help unravel some of the Sun’s biggest mysteries, NASA launched Parker Solar Probe in 2018 to study the Sun up close. This year, the mission has big news!
Follow along on our Solar Tour: Starting tomorrow, Dec. 3, we will begin our 12-day journey from Earth to the Sun. Each day, we’ll make pit stops to learn how our Sun influences different places across the solar system. The grand tour will end with Parker Solar Probe’s big announcement on Dec. 14 at our final destination!
By Miles Hatfield NASA’s Goddard Space Flight Center
New results from NASA satellite data show that space weather – the changing conditions in space driven by the Sun – can heat up Earth’s hottest and highest atmospheric layer.
The findings, published in July in Geophysical Research Letters, used data from NASA’s Global Observations of the Limb and Disk, or GOLD mission. Launched in 2018 aboard the SES-14 communications satellite, GOLD looks down on Earth’s upper atmosphere from what’s known as geosynchronous orbit, effectively “hovering” over the western hemisphere as Earth turns. GOLD’s unique position gives it a stable view of one entire face of the globe – called the disk – where it scans the temperature of Earth’s upper atmosphere every 30 minutes.
“We found results that were not previously possible because of the kind of data that we get from GOLD,” said Fazlul Laskar, who led the research. Dr. Laskar is a research associate at the Laboratory for Atmospheric and Space Physics at the University of Colorado, Boulder.
From its perch some 22,000 miles (35,400 kilometers) above us, GOLD looks down on the thermosphere, a region of Earth’s atmosphere between about 53 and 373 miles (85 and 600 kilometers) high. The thermosphere is home to the aurora, the International Space Station, and the highest temperatures in Earth’s atmosphere, up to 2,700 °F (1,500 °C). It reaches such incredible temperatures by absorbing the Sun’s high-energy X-rays and extreme ultraviolet rays, heating the thermosphere and stopping these types of light from making it to the ground.
But the new findings point to some heating not driven by sunlight, but instead by the solar wind – the particles and magnetic fields continuously escaping the Sun.
The solar wind is always blowing, but stronger gusts can disturb Earth’s magnetic field, inducing so-called geomagnetic activity. Laskar and his collaborators compared days with more geomagnetic activity to days with less, and found an increase of over 160 °F (90 °C) in thermospheric temperatures. Magnetic disturbances, driven by the Sun, were heating up Earth’s hottest atmospheric layer.
Some amount of heating was expected near Earth’s poles, where a weak point in our magnetic field allows some solar wind to pour into our upper atmosphere. But GOLD’s data showed temperature increases across the whole globe – even near the equator, far from any incoming solar wind.
Laskar and colleagues suggest it has to do with changing circulation patterns. There’s a swirling of air high above us — a global circulation that pushes air from the equator up to the poles and back around at lower altitudes. As the solar wind pours into the thermosphere near the poles, the added energy can alter this circulation pattern, driving winds and atmospheric compression that can raise temperatures even far away.
Changing circulation might also underlie another surprise finding. GOLD’s data showed the amount of heat added depended on the time of day. The team discovered a stronger effect in the morning hours compared to that in the afternoon. They suspect that geomagnetic activity might especially strengthen the circulation during the night and early morning hours, though this explanation awaits confirmation in further studies.
Laskar was most impressed with the subtlety of the changes they could detect in GOLD’s data.
“We used to believe that only prominent geomagnetic events could change the thermosphere,” Laskar said. “We are now seeing that even minor activity can have an impact.”
With its steady stream of temperature measurements, GOLD is painting a picture of an upper atmosphere much more sensitive to the magnetic conditions around Earth than previously thought.
NASA’s SunRISE mission — short for the Sun Radio Interferometer Space Experiment — passed a mission review on Sept. 8, 2021, moving the mission into its next phase.
“SunRISE will detect and study eruptions of radio waves from the Sun that often precede major solar events containing high energy particle radiation,” said Justin Kasper, SunRISE principal investigator at the University of Michigan in Ann Arbor. “Knowing when and how solar storms produce intense radiation will help us better prepare and protect our astronauts and technology.”
The review, Key Decision Point C, evaluated the mission’s preliminary design and project plan to achieve launch by its target launch readiness date. With the successful review, SunRISE now moves into Phase C, which includes the final design of the mission and fabrication of the spacecraft and instruments. The six spacecraft will then go through final assembly and testing before their launch readiness date of April 2024.
Consisting of six miniature solar-powered spacecraft known as CubeSats, the SunRISE constellation will operate together as one large telescope — forming the first space-based imaging low radio frequency interferometer — to create 3D maps pinpointing how giant bursts of energetic particles originate from the Sun and evolve as they expand outward into space. The mission will also map, for the first time, how the Sun’s magnetic field extends into interplanetary space — a key factor that drives where and how storms move throughout the solar system. Data from SunRISE will be collected and transmitted to Earth via NASA’s Deep Space Network. The six CubeSats will span roughly six miles across and fly slightly above geosynchronous orbit at 22,000 miles from Earth’s surface.
“The unique formation of the CubeSats gives us a detailed view of the Sun that will help us figure out how high energy particle radiation is initiated and accelerated near the Sun and how it affects interplanetary space,” said Joseph Lazio, SunRISE project scientist at NASA’s Jet Propulsion Laboratory. “Studying the radio waves that precede solar particle storms could potentially help us create an early warning system.”
SunRISE is a Mission of Opportunity under the Heliophysics Division of NASA’s Explorers Program Office. Missions of Opportunity are part of the Explorers Program, which is the oldest continuous NASA program designed to provide frequent, low-cost access to space using principal investigator-led space science investigations relevant to the Science Mission Directorate’s (SMD) astrophysics and heliophysics programs. The program is managed by NASA’s Goddard Space Flight Center in Greenbelt, Maryland, for SMD, which conducts a wide variety of research and scientific exploration programs for Earth studies, space weather, the solar system and universe.
SunRISE will be built by the Space Dynamics Laboratory at Utah State University and be a hosted payload on a commercial spacecraft provided by Maxar of Westminster, Colorado. Once in orbit, the host spacecraft will deploy the six SunRISE spacecraft, place the CubeSats into their orbits, and then continue its prime mission. SunRISE will launch no earlier than April 2024 and no later than September 2025 depending on the schedule of the commercial host spacecraft.
SunRISE is led by the University of Michigan in Ann Arbor and managed by NASA’s Jet Propulsion Laboratory in Southern California.
By Joy Ng NASA’s Goddard Space Flight Center, Greenbelt, Md.
From its vantage point in geostationary orbit, NASA’s GOLD mission – short for Global-scale Observations of the Limb and Disk – has given scientists a new view of dynamics in Earth’s upper atmosphere. Together, three research papers show different ways the upper atmosphere changes unexpectedly, even during relatively mild conditions that aren’t typically thought to trigger such events.
GOLD studies both neutral particles and those that have electric charge – collectively called the ionosphere – which, unlike neutral particles, are guided by electric and magnetic fields. At night, the ionosphere typically features twin bands of dense charged particles. But GOLD’s data revealed previously unseen structures in the nighttime ionosphere’s electrons, described in research published in the Journal of Geophysical Research: Space Physics on Aug. 24, 2020.
While comparing GOLD’s data to maps created with ground-based sensors, scientists spotted a third dense pocket of electrons, in addition to the typical two electron bands near the magnetic equator. Reviewing GOLD data from throughout the mission, they found that the peak appeared several times in October and November of multiple years, suggesting that it might be a seasonal feature.
Though scientists don’t know what exactly creates this extra pocket of dense electrons, it appeared during a period of relatively mild space weather conditions. This was a surprise to scientists, given that big, unpredictable changes in the ionosphere are usually tied to higher levels of space weather activity.
GOLD also saw large drops in the upper atmosphere’s oxygen-to-nitrogen ratio – a measurement typically linked to the electron changes that can cause GPS and radio signal disturbances.
This event was notable to scientists not for what happened, but when: The dips that GOLD saw happened during a relatively calm period in terms of space weather, even though scientists have long associated these events with intense space weather storms. The research was published on Sept. 9, 2020, in Geophysical Research Letters.
During a geomagnetic storm – space weather conditions that disturb Earth’s magnetosphere on a global scale – gases in the upper atmosphere at high latitudes can become heated. As a result, nitrogen-rich air from lower altitudes begins to rise and flow towards the poles. This also creates a wind towards the equator that carries this nitrogen-rich air down towards lower latitudes. Higher nitrogen in the upper atmosphere is linked to drops in electron density in the ionosphere, changing its electrical properties and potentially interfering with signals passing through the region. GOLD observed this effect several times during relatively calm space weather conditions during the day – outside of the disturbed conditions when scientists would normally expect this to happen.
These changes during seemingly calm conditions may point to a space weather system that’s more complicated than previously thought, responding to mild space environment conditions in bigger ways.
“The situation is more complex – the ionosphere is more structured and dynamic than we could have seen before,” said Dr. Sarah Jones, mission scientist for GOLD at NASA’s Goddard Space Flight Center in Greenbelt, Maryland.
Indeed, GOLD’s observations of changing atmospheric composition are already informing scientists’ computer models of these processes. A paper published in Geophysical Research Letters on May 20, 2021, uses GOLD’s data as a reference to show how changes near the poles can influence the ionosphere’s conditions in the mid-latitudes, even during periods of calm space weather activity. GOLD’s broad, two-dimensional view was critical to the finding.
“When you look in two dimensions, a lot of things that look mysterious from one data point become very clear,” said Dr. Alan Burns, a researcher at the High Altitude Observatory in Boulder, Colorado, who worked on the studies.
By Sarah Frazier NASA’s Goddard Space Flight Center, Greenbelt, Md.
By Mara Johnson-Groh NASA’s Goddard Space Flight Center
Plasma – a fourth state of matter after solid, liquid, and gas where particles have split into charged ions and electrons – is the most common form of matter in the universe. It’s somewhat rare on Earth, but it makes up 99% of the matter in the visible universe. Despite its prevalence, scientists haven’t been able to observationally verify a foundational theory describing how plasma moves in response to electric and magnetic forces. Until now.
With its ultraprecise measurements, NASA’s Magnetospheric Multiscale mission – MMS – has finally measured plasma’s movement on the small scales necessary to see if plasma collectively interacts with electromagnetic fields in the way the fundamental theory predicts, which is described mathematically by the so-called Vlasov equation.
Since the beginning of plasma physics research nearly 100 years ago, the Vlasov equation has often been assumed to be valid for many kinds of plasmas in space. But now the new MMS results, which were published in the journal Nature Physics on July 5, 2021, have allowed scientists to finally see the fundamental plasma variations described in the theory for the first time in nature.
Measuring the basic interactions of space plasmas with electric and magnetic fields helps scientists better understand different mechanisms that fuel energetic space weather events, from auroras to plasma ejections off the Sun, which can interfere with satellites and communications on Earth.
A Century of Plasma Physics Progress
The basic theory of plasma motion originated out of a fundamental theory for gases from the nineteenth century. In the 1890s, an Austrian physicist by the name Ludwig Boltzmann came up with a way to describe the microscopic movement of gases and fluids using statistics. It’s known as the Boltzmann equation, and it’s still taught in physics courses today.
In the 1930s, this work was extended to describe plasmas by Anatoly Vlasov, a Russian physicist. His work specifically described collisionless plasmas, which exist at such high temperatures and low densities that individual plasma particles almost never collide.
Collisionless plasma environments are common in space and can be found in the Sun’s outer atmosphere, solar wind, and in various regions throughout Earth’s magnetic environment, called the magnetosphere.
Unlike ordinary gases, plasmas are electrically charged, as they’re made of positively and negatively charged particles – namely atomic nuclei and their separated electrons. This makes plasmas behave very differently than gases since they are sensitive to electromagnetic forces, which influence their movements. Whereas individual particles in a gas constantly bounce off each other as they erratically travel along, collisionless plasma particles rarely interact and are instead controlled solely by electric and magnetic forces. Vlasov’s equation describes the interplay between plasma particles and electromagnetic fields in these unique collisionless plasma systems – and it has formed the foundation for many ideas about plasmas in the years since.
“The Vlasov equation governs all collisionless plasma phenomena that we know of,” said Jason Shuster, lead author on the new study, Assistant Research Scientist at the University of Maryland in College Park, and MMS scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland.
Nevertheless, the terms in the Vlasov equation have never been directly measured because the observation requires seven different types of measurements to be made simultaneously at very small scales in a diffuse plasma – something which is only possible in space.
“In smaller experiments in labs we can’t probe the plasma without disturbing it,” said Barbara Giles, co-author on the new study, Project Scientist for MMS and research scientist at NASA’s Goddard Space Flight Center. “Only in space can we fully immerse instruments within the same phenomenon and accurately test these theories without disturbing the system.”
The MMS Tetrahedron
In 2015, the launch of the four MMS spacecraft changed the way physicists could study plasma in space. Flying in a tetrahedral – or pyramid-shaped – formation with high-resolution instruments, MMS can take measurements far beyond the capabilities of previous spacecraft missions. In their record-breaking tight flying formation, the four MMS spacecraft also fly close enough to measure small-scale properties of plasma, which enabled them to detect variations in terms of the Vlasov equation for the first time.
“With MMS, we can actually probe those minute details at higher resolution than ever before,” Shuster said.
To measure terms in the Vlasov equation, MMS used 64 particle spectrometers – instruments which measure particle energies and charges. The unprecedented spectrometers can simultaneously record multiple types of measurements in position, velocity, and time needed to resolve terms in Vlasov equation. Since each of the four spinning MMS spacecraft has 16 spectrometers sampling particles around its entire circumference, MMS is uniquely able to take these measurements at incredibly high speeds – every 0.03 seconds, which is nearly 100 times faster than previous missions.
“MMS takes advantage of the natural laboratory provided by Earth’s magnetic environment in outer space,” Shuster said. “In the lab, it is very difficult to create a vacuum with a pressure and density low enough to measure the types of electron-scale structures that we’re able to probe with MMS.”
Improving Global Predictions
Now that MMS has observationally confirmed fundamental predictions of the Vlasov equation, this data can be used to better understand phenomena in plasma environments in near-Earth space.
For example, applying small-scale knowledge of plasma to the global-scale magnetosphere can help scientists better understand different mechanisms that fuel energetic space weather events – such as magnetic reconnection, an explosive event unique to plasma that occurs when magnetic field lines sharply reverse direction.
Additionally, just as high- and low-pressure systems create winds and storms on Earth, electric currents and plasma flows drive weather systems in space. Fast moving jets of energetic plasma, such as those scientists observed in this study with MMS, can sustain strong electric currents and pressure gradients which drive space weather phenomena throughout Earth’s magnetic environment.
Having direct observations of the terms in the Vlasov equation provides scientists with a deeper understanding of these basic plasma motions, which enables them to predict the triggers of these fundamental plasma processes more accurately.
“The measurements of terms in the Vlasov equation provide information we can use to constrain and increase the accuracy of our global space weather models, which currently rely on large-scale approximations,” Shuster said. “These discoveries improve our ability to predict space weather operating close to home in Earth’s magnetosphere and deepen our overall understanding of plasmas existing throughout the universe.”