#sun science

Remember the big solar storm in May? Scientists have just discovered that, in addition to creating spellbinding auroras, the storm also made a new temporary ring of charged, high-energy particles encircling Earth.

Earth is typically surrounded two of these giant, donut-shaped rings of particles called the Van Allen Belts. But during especially large solar storms, a temporary third Belt can form sandwiched between the two permanent ones.

The new Belt, which was discovered by NASA’s Colorado Inner Radiation Belt Experiment (CIRBE) CubeSat, could last months to years. Scientists are studying the data to better understand the Belt and how long it might stick around. Stay tuned for their findings!

For the first time in history, a spacecraft has touched the Sun. Our Parker Solar Probe flew right through the Sun’s atmosphere, the corona. (That’s the part of the Sun that we can see during a total solar eclipse.)

This marks one great step for Parker Solar Probe and one giant leap for solar science! Landing on the Moon helped scientists better understand how it was formed. Now, touching the Sun will help scientists understand our star and how it influences worlds across the solar system.

Unlike Earth, the Sun doesn’t have a solid surface (it’s a giant ball of seething, boiling gases). But the Sun does have a superheated atmosphere. Heat and pressure push solar material away from the Sun. Eventually, some of that material escapes the pull of the Sun’s gravity and magnetism and becomes the solar wind, which gusts through the entire solar system.

But where exactly does the Sun’s atmosphere end and the solar wind begin? We’ve never known for sure. Until now!

In April 2021, Parker Solar Probe swooped near the Sun. It passed through a massive plume of solar material in the corona. This was like flying into the eye of a hurricane. That flow of solar stuff — usually a powerful stream of particles — hit the brakes and went into slow-motion.

For the first time, Parker Solar Probe found itself in a place where the Sun’s magnetism and gravity were strong enough to stop solar material from escaping. That told scientists Parker Solar Probe had passed the boundary: On one side, space filled with solar wind, on the other, the Sun’s atmosphere.

Parker Solar Probe’s proximity to the Sun has led to another big discovery: the origin of switchbacks, zig-zag-shaped magnetic kinks in the solar wind.

These bizarre shapes were first observed in the 1990s. Then, in 2019, Parker Solar Probe revealed they were much more common than scientists first realized. But they still had questions, like where the switchbacks come from and how the Sun makes them.

Recently, Parker Solar Probe dug up two important clues. First, switchbacks tend to have lots of helium, which scientists know comes from the solar surface. And they come in patches.

Those patches lined up just right with magnetic funnels that appear on the Sun’s surface. Matching these clues up like puzzle pieces, scientists realized switchbacks must come from near the surface of the Sun.

Figuring out where switchbacks come from and how they form will help scientists understand how the Sun produces the solar wind. And that could clue us into one of the Sun’s biggest mysteries: why the Sun’s atmosphere is much, much hotter than the surface below.

Parker Solar Probe will fly closer and closer to the Sun. Who knows what else we’ll discover?

NASA Sun Science Stamps issued by U.S. Postal Service

To start off the summer, the U.S. Postal Service issued a set of stamps showcasing views of the Sun from our Solar Dynamics Observatory!

Since its launch in 2010, the Solar Dynamics Observatory (or SDO) has kept up a near-constant watch on the Sun from its vantage point in orbit around Earth. SDO watches the Sun in more than 10 different types of light, including some that are absorbed by Earth’s atmosphere so can only be seen from space. These different types of light allow scientists to study different parts of the Sun – from its surface to its atmosphere – and better understand the solar activity that can affect our technology on Earth and in space.

The new set of stamps features 10 images from SDO. Most of these images are in extreme ultraviolet light, which is invisible to human eyes.

Let’s explore the science behind some of the stamps!

Coronal hole (May 2016)

The dark area capping the northern polar region of the Sun is a coronal hole, a magnetically open area on the Sun from which high-speed solar wind escapes into space. Such high-speed solar wind streams can spark magnificent auroral displays on Earth when they collide with our planet’s magnetic field.

Solar flare (August 2011)

The bright flash on the Sun’s upper right is a powerful solar flare. Solar flares are bursts of light and energy that can disturb the part of Earth’s atmosphere where GPS and radio signals travel.

Active Sun (October 2014)

This view highlights the many active regions dotting the Sun’s surface. Active regions are areas of intense and complex magnetic fields on the Sun – linked to sunspots – that are prone to erupting with solar flares or explosions of material called coronal mass ejections.

Plasma blast (August 2012)

These images show a burst of material from the Sun, called a coronal mass ejection. These eruptions of magnetized solar material can create space weather effects on Earth when they collide with our planet’s magnetosphere, or magnetic environment – including aurora, satellite disruptions, and, when extreme, even power outages.

Coronal loops (July 2012)

These images show evolving coronal loops across the limb and disk of the Sun. Just days after these images were taken, the Sun unleashed a powerful solar flare.

Coronal loops are often found over sunspots and active regions, which are areas of intense and complex magnetic fields on the Sun.

Sunspots (October 2014)

This view in visible light – the type of light we can see – shows a cluster of sunspots near the center of the Sun. Sunspots appear dark because they are relatively cool compared to surrounding material, a consequence of the way their extremely dense magnetic field prevents heated material from rising to the solar surface.

For more Sun science, follow NASA Sun on Twitter, on Facebook, or on the web.

On June 10, people in parts of the northern hemisphere will have the chance to witness a solar eclipse.

Watch the full visualization of the eclipse.

The June 10 eclipse is an annular solar eclipse, meaning that the Sun will never be completely covered by the Moon. The Moon’s orbit around the Earth is not a perfect circle, so throughout each month, the Moon’s distance from Earth varies. During an annular eclipse, the Moon is far enough away from Earth that the Moon appears smaller than the Sun in the sky. Since the Moon does not block the entire view of the Sun, it will look like a dark disk on top of a larger, bright disk. This creates what looks like a ring of fire around the Moon.

People in the narrow path of annularity — which, for this eclipse, cuts through Canada, Greenland, and northern Russia — will see the ring of fire effect as the Moon passes across the Sun.

Credit: Dale Cruikshank

Outside this path of annularity, many people in the northern hemisphere have a chance to see a partial solar eclipse. The partial eclipse will fall on parts of the eastern United States, as well as northern Alaska. Some locations will only see a very small piece of the Sun covered, while locations closer to the path of annularity can see the Moon cover most of the Sun.

To learn which times the eclipse may be visible in certain areas, you can click anywhere on the map here. (Note that the maximum obscuration and maximum eclipse timing noted on this map may occur before sunrise in many locations.)

This solar eclipse is a pair with the total lunar eclipse that happened on May 26.

Both solar and lunar eclipses happen when the Sun, Moon, and Earth line up in the same plane — a lunar eclipse happens when Earth is in the middle and casts its shadow on the Moon, and a solar eclipse happens when the Moon is in the middle and casts its shadow on Earth. The Moon’s orbit is tilted, so it’s usually too high or too low for this alignment to work out.

The May 26 lunar eclipse was a supermoon lunar eclipse, meaning that the full moon happened while the Moon was near its closest point to Earth, making the Moon appear larger in the sky. The solar eclipse happens at the opposite point of the Moon’s orbit, during the new moon — and in this case, the new moon happens near the Moon’s farthest point from Earth, making the Moon appear smaller and resulting in an annular (rather than total) solar eclipse.

How to watch the eclipse

From anywhere: Watch the eclipse online with us! Weather permitting, we’ll be sharing live telescope views of the partial eclipse courtesy of Luc Boulard of the Royal Astronomical Society of Canada Sudbury Centre. Tune in starting at 5 a.m. EDT on June 10 at nasa.gov/live.

From the path of the annular or partial eclipse: Be sure to take safety precuations if you plan to watch in person!

It is never safe to look directly at the Sun's rays, even if the Sun is partly or mostly obscured, like during a partial or annular eclipse — doing so can severely harm your eyes. If you’re planning to watch the eclipse on June 10, you should use solar viewing glasses or an indirect viewing method at all points during the eclipse if you want to face the Sun. Solar viewing glasses, sometimes called eclipse glasses, are NOT regular sunglasses; regular sunglasses are not safe for viewing the Sun.

If you don’t have solar viewing or eclipse glasses, you can use an alternate indirect method like a pinhole projector. Pinhole projectors shouldn’t be used to look at the Sun; instead, they’re an easy way to project an image of the Sun onto a surface. Read more about how to create a pinhole projector.

This is a sunrise eclipse in the contiguous U.S. At locations in the lower 48 states that can see the partial eclipse, the show starts before sunrise, when the Sun is still below the horizon. That means the best chance to see the eclipse in these locations will be during and shortly after sunrise, when the Sun is very low in the sky. In northern Alaska, the eclipse happens in the very early hours of June 10 when the Sun is low on the horizon.

Bottom line: If you’re trying to watch the eclipse in the contiguous U.S., look for a location with a clear view of the horizon to the northeast, and plan to watch starting at sunrise with your solar filter or indirect viewer.

The next two eclipses in the continental U.S. are in 2023 and 2024. The annular solar eclipse of Oct. 14, 2023, will cut from Oregon to Texas, and the total solar eclipse of April 8, 2024, will pass from Texas to Maine. Keep up with the latest on eclipses and eclipse science at nasa.gov/eclipse.

A quarter-century ago, the Solar and Heliospheric Observatory (SOHO) launched to space. Its 25 years of data have changed the way we think about the Sun — illuminating everything from the Sun’s inner workings to the constant changes in its outermost atmosphere.

SOHO — a joint mission of the European Space Agency and NASA — carries 12 instruments to study different aspects of the Sun. One of the gamechangers was SOHO’s coronagraph, a type of instrument that uses a solid disk to block out the bright face of the Sun and reveal the relatively faint outer atmosphere, the corona. With SOHO’s coronagraph, scientists could image giant eruptions of solar material and magnetic fields, called coronal mass ejections, or CMEs. SOHO’s images revealed shape and structure of CMEs in breathtaking detail.

These solar storms can impact robotic spacecraft in their path, or — when intense and aimed at Earth — threaten astronauts on spacewalks and even disrupt power grids on the ground. SOHO is particularly useful in viewing Earth-bound storms, called halo CMEs — so called because when a CME barrels toward us on Earth, it appears circular, surrounding the Sun, much like watching a balloon inflate by looking down on it.

Before SOHO, the scientific community debated whether or not it was even possible to witness a CME coming straight toward us. Today, SOHO images are the backbone of space weather prediction models, regularly used in forecasting the impacts of space weather events traveling toward Earth.

Beyond the day-to-day monitoring of space weather, SOHO has been able to provide insight about our dynamic Sun on longer timescales as well. With 25 years under its belt, SOHO has observed a full magnetic cycle — when the Sun’s magnetic poles switch places and then flip back again, a process that takes about 22 years in total. This trove of data has led to revolutions in solar science: from revelations about the behavior of the solar core to new insight into space weather events that explode from the Sun and travel throughout the solar system.

Data from SOHO, sonified by the Stanford Experimental Physics Lab, captures the Sun’s natural vibrations and provides scientists with a concrete representation of its dynamic movements.

The legacy of SOHO’s instruments — such as the extreme ultraviolet imager, the first of its kind to fly in orbit — also paved the way for the next generation of NASA solar satellites, like the Solar Dynamics Observatory and STEREO. Even with these newer instruments now in orbit, SOHO’s data remains an invaluable part of solar science, producing nearly 200 scientific papers every year.

Relatively early in its mission, SOHO had a brush with catastrophe. During a routine calibration procedure in June 1998, the operations team lost contact with the spacecraft. With the help of a radio telescope in Arecibo, the team eventually located SOHO and brought it back online by November of that year. But luck only held out so long: Complications from the near loss emerged just weeks later, when all three gyroscopes — which help the spacecraft point in the right direction — failed. The spacecraft was no longer stabilized. Undaunted, the team’s software engineers developed a new program that would stabilize the spacecraft without the gyroscopes. SOHO resumed normal operations in February 1999, becoming the first spacecraft of its kind to function without gyroscopes.

SOHO’s coronagraph have also helped the Sun-studying mission become the greatest comet finder of all time. The mission’s data has revealed more than 4,000 comets to date, many of which were found by citizen scientists. SOHO’s online data during the early days of the mission made it possible for anyone to carefully scrutinize a image and potentially spot a comet heading toward the Sun. Amateur astronomers from across the globe joined the hunt and began sending their findings to the SOHO team. To ease the burden on their inboxes, the team created the SOHO Sungrazer Project, where citizen scientists could share their findings.

Keep up with the latest SOHO findings at nasa.gov/soho, and follow along with @NASASun on Twitter and facebook.com/NASASunScience.

Scientists just announced that our Sun is in a new cycle.

Solar activity has been relatively low over the past few years, and now that scientists have confirmed solar minimum was in December 2019, a new solar cycle is underway — meaning that we expect to see solar activity start to ramp up over the next several years.

The Sun goes through natural cycles, in which the star swings from relatively calm to stormy. At its most active — called solar maximum — the Sun is freckled with sunspots, and its magnetic poles reverse. At solar maximum, the Sun’s magnetic field, which drives solar activity, is taut and tangled. During solar minimum, sunspots are few and far between, and the Sun’s magnetic field is ordered and relaxed.

Understanding the Sun’s behavior is an important part of life in our solar system. The Sun's violent outbursts can disturb the satellites and communications signals traveling around Earth, or one day, Artemis astronauts exploring distant worlds. Scientists study the solar cycle so we can better predict solar activity.

Measuring the solar cycle

Surveying sunspots is the most basic of ways we study how solar activity rises and falls over time, and it’s the basis of many efforts to track the solar cycle. Around the world, observers conduct daily sunspot censuses. They draw the Sun at the same time each day, using the same tools for consistency. Together, their observations make up the international sunspot number, a complex task run by the World Data Center for the Sunspot Index and Long-term Solar Observations, at the Royal Observatory of Belgium in Brussels, which tracks sunspots and pinpoints the highs and lows of the solar cycle. Some 80 stations around the world contribute their data.

Credit: USET data/image, Royal Observatory of Belgium, Brussels

Other indicators besides sunspots can signal when the Sun is reaching its low. In previous cycles, scientists have noticed the strength of the Sun’s magnetic field near the poles at solar minimum hints at the intensity of the next maximum. When the poles are weak, the next peak is weak, and vice versa.

Another signal comes from outside the solar system. Cosmic rays are high-energy particle fragments, the rubble from exploded stars in distant galaxies that shoot into our solar system with astounding energy. During solar maximum, the Sun’s strong magnetic field envelops our solar system in a magnetic cocoon that is difficult for cosmic rays to infiltrate. In off-peak years, the number of cosmic rays in the solar system climbs as more and more make it past the quiet Sun. By tracking cosmic rays both in space and on the ground, scientists have yet another measure of the Sun’s cycle.

Since 1989, an international panel of experts—sponsored by NASA and NOAA—meets each decade to make their prediction for the next solar cycle. The prediction includes the sunspot number, a measure of how strong a cycle will be, and the cycle’s expected start and peak. This new solar cycle is forecast to be about the same strength as the solar cycle that just ended — both fairly weak. The new solar cycle is expected to peak in July 2025.

Learn more about the Sun’s cycle and how it affects our solar system at nasa.gov/sunearth.