Category: sun


In August 2018, our Parker Solar Probe mission launched to space, soon becoming the closest-ever spacecraft from the Sun. Now, scientists have announced their first discoveries from this exploration of our star!

The Sun may look calm to us here on Earth, but it’s an active star, unleashing powerful bursts of light, deluges of particles moving near the speed of light and billion-ton clouds of magnetized material. All of this activity can affect our technology here on Earth and in space.

Parker Solar Probe’s main science goals are to understand the physics that drive this activity — and its up-close look has given us a brand-new perspective. Here are a few highlights from what we’ve learned so far.

1. Surprising events in the solar wind

The Sun releases a continual outflow of magnetized material called the solar wind, which shapes space weather near Earth. Observed near Earth, the solar wind is a relatively uniform flow of plasma, with occasional turbulent tumbles. Closer to the solar wind’s source, Parker Solar Probe saw a much different picture: a complicated, active system. 

One type of event in particular drew the eye of the science teams: flips in the direction of the magnetic field, which flows out from the Sun, embedded in the solar wind. These reversals — dubbed “switchbacks” — last anywhere from a few seconds to several minutes as they flow over Parker Solar Probe. During a switchback, the magnetic field whips back on itself until it is pointed almost directly back at the Sun.


The exact source of the switchbacks isn’t yet understood, but Parker Solar Probe’s measurements have allowed scientists to narrow down the possibilities — and observations from the mission’s 21 remaining solar flybys should help scientists better understand these events. 

2. Seeing tiny particle events

The Sun can accelerate tiny electrons and ions into storms of energetic particles that rocket through the solar system at nearly the speed of light. These particles carry a lot of energy, so they can damage spacecraft electronics and even endanger astronauts, especially those in deep space, outside the protection of Earth’s magnetic field — and the short warning time for such particles makes them difficult to avoid.


Energetic particles from the Sun impact a detector on ESA & NASA’s SOHO satellite.

Parker Solar Probe’s energetic particle instruments have measured several never-before-seen events so small that all trace of them is lost before they reach Earth. These instruments have also measured a rare type of particle burst with a particularly high number of heavier elements — suggesting that both types of events may be more common than scientists previously thought.

3. Rotation of the solar wind

Near Earth, we see the solar wind flowing almost straight out from the Sun in all directions. But the Sun rotates as it releases the solar wind, and before it breaks free, the wind spins along in sync with the Sun’s surface. For the first time, Parker was able to observe the solar wind while it was still rotating – starting more than 20 million miles from the Sun.


The strength of the circulation was stronger than many scientists had predicted, but it also transitioned more quickly than predicted to an outward flow, which helps mask the effects of that fast rotation from the vantage point where we usually see them from, near Earth, about 93 million miles away. Understanding this transition point in the solar wind is key to helping us understand how the Sun sheds energy, with implications for the lifecycles of stars and the formation of protoplanetary disks.

4. Hints of a dust-free zone

Parker also saw the first direct evidence of dust starting to thin out near the Sun – an effect that has been theorized for nearly a century, but has been impossible to measure until now. Space is awash in dust, the cosmic crumbs of collisions that formed planets, asteroids, comets and other celestial bodies billions of years ago. Scientists have long suspected that, close to the Sun, this dust would be heated to high temperatures by powerful sunlight, turning it into a gas and creating a dust-free region around the Sun.


For the first time, Parker’s imagers saw the cosmic dust begin to thin out a little over 7 million miles from the Sun. This decrease in dust continues steadily to the current limits of Parker Solar Probe’s instruments, measurements at a little over 4 million miles from the Sun. At that rate of thinning, scientists expect to see a truly dust-free zone starting a little more than 2-3 million miles from the Sun — meaning the spacecraft could observe the dust-free zone as early as 2020, when its sixth flyby of the Sun will carry it closer to our star than ever before.

These are just a few of Parker Solar Probe’s first discoveries, and there’s plenty more science to come throughout the mission! For the latest on our Sun, follow @NASASun on Twitter and NASA Sun Science on Facebook.

Watch Mercury Transit the Sun on Nov. 11

On Nov. 11, Earthlings will be treated to a rare cosmic event — a Mercury transit.


For about five and a half hours on Monday, Nov. 11 — from about 7:35 a.m. EST to 1:04 p.m. EST — Mercury will be visible from Earth as a tiny black dot crawling across the face of the Sun. This is a transit and it happens when Mercury lines up just right between the Sun and Earth.

Mercury transits happen about 13 times a century. Though it takes Mercury only about 88 days to zip around the Sun, its orbit is tilted, so it’s relatively rare for the Sun, Mercury and Earth to line up perfectly. The next Mercury transit isn’t until 2032 — and in the U.S., the next opportunity to catch a Mercury transit is in 2049!

How to watch

Our Solar Dynamics Observatory satellite, or SDO, will provide near-real time views of the transit. SDO keeps a constant eye on the Sun from its position in orbit around Earth to monitor and study the Sun’s changes, putting it in the front row for many eclipses and transits.

Visit to tune in!


Our Solar Dynamics Observatory also saw Mercury transit the Sun in 2016.

If you’re thinking of watching the transit from the ground, keep in mind that it is never safe to look directly at the Sun. Even with solar viewing glasses, Mercury is too small to be easily seen with the unaided eye. Your local astronomy club may have an opportunity to see the transit using specialized, properly-filtered solar telescopes — but remember that you cannot use a regular telescope or binoculars in conjunction with solar viewing glasses.

Transits in other star systems

Transiting planets outside our solar system are a key part of how we look for exoplanets.

Our Transiting Exoplanet Survey Satellite, or TESS, is NASA’s latest planet-hunter, observing the sky for new worlds in our cosmic neighborhood. TESS searches for these exoplanets, planets orbiting other stars, by using its four cameras to scan nearly the whole sky one section at a time. It monitors the brightness of stars for periodic dips caused by planets transiting those stars.


This is similar to Mercury’s transit across the Sun, but light-years away in other solar systems! So far, TESS has discovered 29 confirmed exoplanets using transits — with over 1,000 more candidates being studied by scientists!


Discover more transit and eclipse science at, and tune in on Monday, Nov. 11, at

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A quiet, starry night sky might not seem like a very spooky spectacle, but space can be a creepy place! Monsters lurk in the shadowy depths of the universe, sometimes hidden in plain sight. Many of them are invisible to our eyes, so we have to use special telescopes to see them. Read on to discover some of these strange cosmic beasts, but beware — sometimes fact is scarier than fiction.

Monster Black Holes ⚫


You know those nightmares where no matter how fast you try to run you never seem to get anywhere? Black holes are a sinister possible version of that dream — especially because they’re real! If you get too close to a black hole, there is no possibility of escape.

Just last year our Fermi Gamma-ray Space Telescope traced an otherworldly ghost particle back to one of these monster black holes, providing additional insight into the many signals we’re picking up from some of the most feared creatures in the cosmic deep.

But it gets worse. Our Hubble Space Telescope revealed that these things are hidden in the hearts of nearly every galaxy in the universe. That means supermassive black holes lurk in the shadows of the night sky in every direction you look!

A Hazy Specter 👻


This fiendish specter lives in the center of the Milky Way, haunting our galaxy’s supermassive black hole. But it’s not as scary as it looks! Our SOFIA observatory captured streamlines tracing a magnetic field that appears to be luring most of the material quietly into orbit around the black hole. In other galaxies, magnetic fields seem to be feeding material into hungry black holes — beware! Magnetic fields might be the answer to why some black holes are starving while others are feasting.

Bats in the Belfry 🦇


The universe has bats in the attic! Hubble spotted the shadow of a giant cosmic bat in the Serpens Nebula. Newborn stars like the one at the center of the bat, called HBC 672, are surrounded by disks of material, which are hard to study directly. The shadows they cast, like the bat, can clue scientists in on things like the disk’s size and density. Our solar system formed from the same type of disk of material, but we can only see the end result of planet building here — we want to learn more about the process!

Jack-o-lantern Sun 🎃


A jack-o-lantern in space?! Our Solar Dynamics Observatory watches the Sun at all times, keeping a close eye on space weather. In October 2014, the observatory captured a chilling image of the Sun with a Halloweenish face!

Skull Comet 💀

On Halloween a few years ago, an eerie-looking object known as 2015 TB145 sped across the night sky. Scientists observing it with our Infrared Telescope Facility determined that it was most likely a dead comet. It’s important to study objects like comets and asteroids because they’re dangerous if they cross Earth’s path — just ask the dinosaurs!

Halloween Treat 🍬


Trick-or-treat! Add a piece of glowing cosmic candy to your Halloween haul, courtesy of Hubble! This image shows the Saturn Nebula, formed from the outer layers ejected by a dying star, destined to be recycled into later generations of stars and planets. Our Sun will experience a similar fate in around five billion years.

Witch’s Broom Nebula 🧹


Massive stars are in for a more fiery fate, as the Witch’s Broom Nebula shows. Hubble’s close-up look reveals wisps of gas — shrapnel leftover from a supernova explosion. Astronomers believe that a couple of supernovae occur each century in galaxies like our own Milky Way.

Zombie Stars 🧟


Supernovae usually herald the death of a star, but on a few occasions astronomers have found “zombie stars” left behind after unusually weak supernovae. Our Nuclear Spectroscopic Telescope Array (NuSTAR) has even spotted a mysterious glow of high-energy X-rays that could be the “howls” of dead stars as they feed on their neighbors.

Intergalactic Ghost Towns 🏚️


The universe is brimming with galaxies, but it’s also speckled with some enormous empty pockets of space, too. These giant ghost towns, called voids, may be some of the largest things in the cosmos, and since the universe is expanding, galaxies are racing even farther away from each other all the time! Be grateful for your place in space — the shadowy patches of the universe are dreadful lonely scenes.

Mysterious Invisible Force 🕵️‍♀️


Some forces are a lot spookier than floorboards creaking or a door slamming shut unexpectedly when you’re home alone. Dark energy is a mysterious antigravity pressure that our Wide Field Infrared Survey Telescope (WFIRST) is going to help us understand. All we know so far is that it’s present everywhere in the cosmos (even in the room with you as you read this) and it controls the fate of the universe, but WFIRST will study hundreds of millions of galaxies to figure out just what dark energy is up to.

Want to learn some fun ways to celebrate Halloween in (NASA) style? Check out this link!

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After seven years of studying the radiation around Earth, the Van Allen Probes spacecraft have retired.


Originally slated for a two-year mission, these two spacecraft studied Earth’s radiation belts — giant, donut-shaped clouds of particles surrounding Earth — for nearly seven years. The mission team used the last of their propellant this year to place the spacecraft into a lower orbit that will eventually decay, allowing the Van Allen Probes to re-enter and burn up in Earth’s atmosphere.


Earth’s radiation belts exist because energized charged particles from the Sun and other sources in space become trapped in our planet’s huge magnetic field, creating vast regions around Earth that teem with radiation. This is one of the harshest environments in space — and the Van Allen Probes survived more than three times longer than planned orbiting through this intense region.

The shape, size and intensity of the radiation belts change, meaning that satellites — like those used for telecommunications and GPS — can be bombarded with a sudden influx of radiation. The Van Allen Probes shed new light on what invisible forces drive these changes — like waves of charged particles and electromagnetic fields driven by the Sun, called space weather. 


Here are a few scientific highlights from the Van Allen Probes — from the early days of the mission to earlier this year:

  • The Van Allen belts were first discovered in 1958, and for decades, scientists thought there were only two concentric belts. But, days after the Van Allen Probes launched, scientists discovered that during times of intense solar activity, a third belt can form.
  • The belts are composed of charged particles and electromagnetic fields and can be energized by different types of plasma waves. One type, called electrostatic double layers, appear as short blips of enhanced electric field. During one observing period, Probe B saw 7,000 such blips repeatedly pass over the spacecraft in a single minute!
  • During big space weather storms, which are ultimately caused by activity on the Sun, ions — electrically charged atoms or molecules — can be pushed deep into Earth’s magnetosphere. These particles carry electromagnetic currents that circle around the planet and can dramatically distort Earth’s magnetic field.
  • Across space, fluctuating electric and magnetic fields can create what are known as plasma waves. These waves intensify during space weather storms and can accelerate particles to incredible speeds. The Van Allen Probes found that one type of plasma wave known as hiss can contribute greatly to the loss of electrons from the belts.
  • The Van Allen belts are composed of electrons and ions with a range of energies. In 2015, research from the Van Allen Probes found that, unlike the outer belt, there were no electrons with energies greater than a million electron volts in the inner belt.
  • Plasma waves known as whistler chorus waves are also common in our near-Earth environment. These waves can travel parallel or at an angle to the local magnetic field. The Van Allen Probes demonstrated the two types of waves cannot be present simultaneously, resulting in greater radiation belt particle scattering in certain areas.
  • Very low frequency chorus waves, another variety of plasma waves, can pump up the energy of electrons to millions of electronvolts. During storm conditions, the Van Allen Probes found these waves can hugely increase the energy of particles in the belts in just a few hours.  
  • Scientists often use computer simulation models to understand the physics behind certain phenomena. A model simulating particles in the Van Allen belts helped scientists understand how particles can be lost, replenished and trapped by Earth’s magnetic field.
  • The Van Allen Probes observed several cases of extremely energetic ions speeding toward Earth. Research found that these ions’ acceleration was connected to their electric charge and not to their mass.
  • The Sun emits faster and slower gusts of charged particles called the solar wind. Since the Sun rotates, these gusts — the fast wind — reach Earth periodically. Changes in these gusts cause the extent of the region of cold ionized gas around Earth — the plasmasphere — to shrink. Data from the Van Allen Probes showed that such changes in the plasmasphere fluctuated at the same rate as the solar rotation — every 27 days.

Though the mission has ended, scientists will use data from the Van Allen Probes for years to come. See the latest Van Allen Probes science at

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We’re two days from launching ICON — short for Ionospheric Connection Explorer — a mission to explore the dynamic region where Earth meets space: the ionosphere.


Earth’s ionosphere stretches from 50 to 400 miles above the ground, overlapping the top of our atmosphere and the very beginning of space. The Sun cooks gases there until they lose an electron (or two or three), creating a sea of electrically charged particles. But, the ionosphere also responds to weather patterns from Earth rippling up. These changes are complex and tricky to understand.


That’s why we’re launching ICON! Changes in the ionosphere can affect astronauts, satellites and communications signals we use every day, like radio or GPS. Understanding these changes could help us eventually predict them — and better protect our technology and explorers in space.


ICON will track changes in the ionosphere by surveying airglow. It’s a natural feature of Earth’s that causes our atmosphere to constantly glow. The Sun excites gases in the upper atmosphere, so they emit light. From 360 miles above Earth, ICON will photograph airglow to measure the ionosphere’s winds, composition and temperature. ICON also carries an instrument that will capture and measure the particles directly around the spacecraft.


ICON is scheduled to launch on Oct. 9, on a Northrop Grumman Pegasus XL rocket. The night of launch, the rocket is flown up to the sky by Northrop Grumman’s L-1011 Stargazer airplane, which takes off from Cape Canaveral Air Force Station in Florida. From 40,000 feet above the open ocean, the Pegasus XL rocket drops from the plane and free-falls for about five seconds before igniting and carrying ICON into orbit.   


NASA TV coverage of the launch starts at 9:15 p.m. EDT on Oct. 9 at You can also follow along on Twitter, Facebook or at

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What do *you* think is inside a black hole? Or If they sun was a black hole what would we see in the sky? Thanks!

Say hello to the Saturn Nebula 👋

Garden-variety stars like the Sun live fairly placid lives in their galactic neighborhoods, casually churning out heat and light for billions of years. When these stars reach retirement age, however, they transform into unique and often psychedelic works of art. This Hubble Space Telescope image of the Saturn Nebula shows the result, called a planetary nebula. While it looks like a piece of wrapped cosmic candy, what we see is actually the outer layers of a dying star.

Stars are powered by nuclear fusion, but each one comes with a limited supply of fuel. When a medium-mass star exhausts its nuclear fuel, it will swell up and shrug off its outer layers until only a small, hot core remains. The leftover core, called a white dwarf, is a lot like a hot coal that glows after a barbecue — eventually it will fade out. Until then, the gaseous debris fluoresces as it expands out into the cosmos, possibly destined to be recycled into later generations of stars and planets.

Using Hubble’s observations, scientists have characterized the nebula’s composition, structure, temperature and the way it interacts with surrounding material. Studying planetary nebulas is particularly interesting since our Sun will experience a similar fate around five billion years down the road.

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Twinkle, twinkle, little star,
How I wonder what you are.
Up above the world so high,
Like a diamond in the sky. 🌟

The final stages of a star’s life allow us a glimpse into the future of our own solar system. This image from our Hubble Space Telescope shows what’s left of a star 10,000 light-years from Earth.

A star like our Sun will, at the end of its life, transform into a red giant. The core of the star will eventually collapse in on itself, ejecting the surface layers outward. After that, all that remains of the star is what we see here: glowing outer layers surrounding a white dwarf star. In just a few thousand years they will have dissipated, and all that will be left to see is the dimly glowing white dwarf. More on this image, here

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Along with the Korea Astronomy and Space Science Institute, or KASI, we’re getting ready to test a new way to see the Sun, high over the New Mexico desert.

A balloon — which looks a translucent white pumpkin, but large enough to hug a football field — will soon take flight, carrying a solar scope called BITSE. BITSE is a coronagraph, a special kind of telescope that blocks the bright face of the Sun to reveal its dimmer atmosphere, called the corona. BITSE stands for Balloon-borne Investigation of Temperature and Speed of Electrons in the corona.


Its goal? Explaining how the Sun spits out the solar wind, the stream of charged particles that blows constantly from the Sun. Scientists generally know it forms in the corona, but exactly how it does so is a mystery.

The solar wind is important because it’s the stuff that fills the space around Earth and all the other planets in our solar system. And, understanding how the solar wind works is key to predicting how solar eruptions travel. It’s a bit like a water slide: The way it flows determines how solar storms barrel through space. Sometimes, those storms crash into our planet’s magnetic field, sparking disturbances that can interfere with satellites and communications signals we use every day, like radio or GPS.


Right now, scientists and engineers are in Fort Sumner, New Mexico, preparing to fly BITSE up to the edge of the atmosphere. BITSE will take pictures of the corona, measuring the density, temperature and speed of negatively charged particles — called electrons — in the solar wind. Scientists need these three things to answer the question of how the solar wind forms.

One day, scientists hope to send an instrument like BITSE to space, where it can study the Sun day in and day out, and help us understand the powerful forces that push the solar wind out to speeds of 1 million miles per hour. BITSE’s balloon flight is an important step towards space, since it will help this team of scientists and engineers fine-tune their tech for future space-bound missions.  


Hours before sunrise, technicians from our Columbia Scientific Balloon Facility’s field site in Fort Sumner will ready the balloon for flight, partially filling the large plastic envelope with helium. The balloon is made of polyethylene — the same stuff grocery bags are made of — and is about as thick as a plastic sandwich bag, but much stronger. As the balloon rises higher into the sky, the gas in the balloon expands and the balloon grows to full size.

BITSE will float 22 miles over the desert. For at least six hours, it will drift, taking pictures of the Sun’s seething hot atmosphere. By the end of the day, it will have collected 40 feature-length movies’ worth of data.


BITSE’s journey to the sky began with an eclipse. Coronagraphs use a metal disk to mimic a total solar eclipse — but instead of the Moon sliding in between the Sun and Earth, the disk blocks the Sun’s face to reveal the dim corona. During the Aug. 21, 2017, total eclipse, our scientists tested key parts of this instrument in Madras, Oregon.


Now, the scientists are stepping out from the Moon’s shadow. A balloon will take BITSE up to the edge of the atmosphere. Balloons are a low-cost way to explore this part of the sky, allowing scientists to make better measurements and perform tests they can’t from the ground.

BITSE carries several important technologies. It’s built on one stage of lens, rather than three, like traditional coronagraphs. That means it’s designed more simply, and less likely to have a mechanical problem. And, it has a couple different sets of specialized filters that capture different kinds of light: polarized light — light waves that bob in certain directions — and specific wavelengths of light. The combination of these images provides scientists with information on the density, temperature and speed of electrons in the corona.


More than 22 miles over the ground, BITSE will fly high above birds, airplanes, weather and the blue sky itself. As the atmosphere thins out, there are less air particles to scatter light. That means at BITSE’s altitude, the sky is dimmer. These are good conditions for a coronagraph, whose goal is taking images of the dim corona. But even the upper atmosphere is brighter than space.

That’s why scientists are so eager to test BITSE on this balloon, and develop their instrument for a future space mission. The solar scope is designed to train its eyes on a slice of the corona that’s not well-studied, and key to solar wind formation. One day, a version of BITSE could do this from space, helping scientists gather new clues to the origins of the solar wind.  


At the end of BITSE’s flight, the crew at the Fort Sumner field site will send termination commands, kicking off a sequence that separates the instrument and balloon, deploys the instrument’s parachute, and punctures the balloon. An airplane circling overhead will keep watch over the balloon’s final moments, and relay BITSE’s location. At the end of its flight, far from where it started, the coronagraph will parachute to the ground. A crew will drive into the desert to recover both the balloon and BITSE at the end of the day.

For more information on how we use balloons for high-altitude science missions, visit:

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Say hello to the Butterfly Nebula 👋

It looks like our Hubble Space Telescope captured an image of a peaceful, cosmic butterfly unfurling its celestial wings, but the truth is vastly more violent. In the Butterfly Nebula, layers of gas are being ejected from a dying star. Medium-mass stars grow unstable as they run out of fuel, which leads them to blast tons of material out into space at speeds of over a million miles per hour!

Streams of intense ultraviolet radiation cause the cast-off material to glow, but eventually the nebula will fade and leave behind only a small stellar corpse called a white dwarf. Our middle-aged Sun can expect a similar fate once it runs out of fuel in about six billion years.

Planetary nebulas like this one aren’t actually related to planets; the term was coined by astronomer William Herschel, who actually discovered the Butterfly Nebula in 1826. Through his small telescope, planetary nebulas looked like glowing, planet-like orbs. While stars that generate planetary nebulas may have once had planets orbiting them, scientists expect that the fiery death throes these stars undergo will ultimately leave any planets in their vicinity completely uninhabitable.

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