Magnetic - Blog Posts

Neutron Stars Are Even Weirder Than We Thought

Let’s face it, it’s hard for rapidly-spinning, crushed cores of dead stars NOT to be weird. But we’re only beginning to understand how truly bizarre these objects — called neutron stars — are.

Neutron stars are the collapsed remains of massive stars that exploded as supernovae. In each explosion, the outer layers of the star are ejected into their surroundings. At the same time, the core collapses, smooshing more than the mass of our Sun into a sphere about as big as the island of Manhattan.

Our Neutron star Interior Composition Explorer (NICER) telescope on the International Space Station is working to discover the nature of neutron stars by studying a specific type, called pulsars. Some recent results from NICER are showing that we might have to update how we think about pulsars!

Here are some things we think we know about neutron stars:

Pulsars are rapidly spinning neutron stars ✔︎

Pulsars get their name because they emit beams of light that we see as flashes. Those beams sweep in and out of our view as the star rotates, like the rays from a lighthouse.

Pulsars can spin ludicrously fast. The fastest known pulsar spins 43,000 times every minute. That’s as fast as blender blades! Our Sun is a bit of a slowpoke compared to that — it takes about a month to spin around once.

The beams come from the poles of their strong magnetic fields ✔︎

Pulsars also have magnetic fields, like the Earth and Sun. But like everything else with pulsars, theirs are super-strength. The magnetic field on a typical pulsar is billions to trillions of times stronger than Earth’s!

Near the magnetic poles, the pulsar’s powerful magnetic field rips charged particles from its surface. Some of these particles follow the magnetic field. They then return to strike the pulsar, heating the surface and causing some of the sweeping beams we see.

The beams come from two hot spots… ❌❓✔︎ 🤷🏽

Think of the Earth’s magnetic field — there are two poles, the North Pole and the South Pole. That’s standard for a magnetic field.

On a pulsar, the spinning magnetic field attracts charged particles to the two poles. That means there should be two hot spots, one at the pulsar’s north magnetic pole and the other at its south magnetic pole.

This is where things start to get weird. Two groups mapped a pulsar, known as J0030, using NICER data. One group found that there were two hot spots, as we might have expected. The other group, though, found that their model worked a little better with three (3!) hot spots. Not two.

… that are circular … ❌❓✔︎ 🤷🏽

The particles that cause the hot spots follow the magnetic field lines to the surface. This means they are concentrated at each of the magnetic poles. We expect the magnetic field to appear nearly the same in any direction when viewed from one of the poles. Such symmetry would produce circular hot spots.

In mapping J0030, one group found that one of the hot spots was circular, as expected. But the second spot may be a crescent. The second team found its three spots worked best as ovals.

… and lie directly across from each other on the pulsar ❌❓✔︎ 🤷🏽

Think back to Earth’s magnetic field again. The two poles are on opposite sides of the Earth from each other. When astronomers first modeled pulsar magnetic fields, they made them similar to Earth’s. That is, the magnetic poles would lie at opposite sides of the pulsar.

Since the hot spots happen where the magnetic poles cross the surface of the pulsar, we would expect the beams of light to come from opposite sides of the pulsar.

But, when those groups mapped J0030, they found another surprising characteristic of the spots. All of the hot spots appear in the southern half of the pulsar, whether there were two or three of them.

This also means that the pulsar’s magnetic field is more complicated than our initial models!

J0030 is the first pulsar where we’ve mapped details of the heated regions on its surface. Will others have similarly bizarre-looking hotspots? Will they bring even more surprises? We’ll have to stay tuned to NICER find out!

And check out the video below for more about how this measurement was done.

Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com.

Farewell to the Van Allen Probes

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 nasa.gov/vanallen.

Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com

Space Radiation: Hazard of Stealth

A human journey to Mars, at first glance, offers an inexhaustible amount of complexities. To bring a mission to the Red Planet from fiction to fact, our Human Research Program has organized hazards astronauts will encounter on a continual basis into five classifications.

The first hazard of a human mission to Mars is also the most difficult to visualize because, well, space radiation is invisible to the human eye. Radiation is not only stealthy, but considered one of the most menacing of the five hazards.

Above Earth’s natural protection, radiation exposure increases cancer risk, damages the central nervous system, can alter cognitive function, reduce motor function and prompt behavioral changes. To learn what can happen above low-Earth orbit, we study how radiation affects biological samples using a ground-based research laboratory.

Exploration to the Moon and Mars will expose astronauts to five known hazards of spaceflight, including radiation. To learn more, and find out what our Human Research Program is doing to protect humans in space, check out the "Hazards of Human Spaceflight" website or check out this week’s episode of “Houston We Have a Podcast,” in which our host Gary Jordan further dives into the threat of radiation with Zarana Patel, a radiation lead scientist at the Johnson Space Center.

Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com.

Our Spacecraft Have Discovered a New Magnetic Process in Space

Just as gravity is one key to how things move on Earth, a process called magnetic reconnection is key to how electrically-charged particles speed through space. Now, our Magnetospheric Multiscale mission, or MMS, has discovered magnetic reconnection – a process by which magnetic field lines explosively reconfigure – occurring in a new and surprising way near Earth.

Invisible to the eye, a vast network of magnetic energy and particles surround our planet — a dynamic system that influences our satellites and technology. The more we understand the way those particles move, the more we can protect our spacecraft and astronauts both near Earth and as we explore deeper into the solar system.

Earth’s magnetic field creates a protective bubble that shields us from highly energetic particles that stream in both from the Sun and interstellar space. As this solar wind bathes our planet, Earth’s magnetic field lines get stretched. Like elastic bands, they eventually release energy by snapping and flinging particles in their path to supersonic speeds.

That burst of energy is generated by magnetic reconnection. It’s pervasive throughout the universe — it happens on the Sun, in the space near Earth and even near black holes.

Scientists have observed this phenomenon many times in Earth’s vast magnetic environment, the magnetosphere. Now, a new study of data from our MMS mission caught the process occurring in a new and unexpected region of near-Earth space. For the first time, magnetic reconnection was seen in the magnetosheath — the boundary between our magnetosphere and the solar wind that flows throughout the solar system and one of the most turbulent regions in near-Earth space.

The four identical MMS spacecraft — flying through this region in a tight pyramid formation — saw the event in 3D. The arrows in the data visualization below show the hundreds of observations MMS took to measure the changes in particle motion and the magnetic field.

The data show that this event is unlike the magnetic reconnection we’ve observed before. If we think of these magnetic field lines as elastic bands, the ones in this region are much smaller and stretchier than elsewhere in near-Earth space — meaning that this process accelerates particles 40 times faster than typical magnetic reconnection near Earth. In short, MMS spotted a completely new magnetic process that is much faster than what we’ve seen before.

What’s more, this observation holds clues to what’s happening at smaller spatial scales, where turbulence takes over the process of mixing and accelerating particles. Turbulence in space moves in random ways and creates vortices, much like when you mix milk into coffee. The process by which turbulence energizes particles in space is still a big area of research, and linking this new discovery to turbulence research may give insights into how magnetic energy powers particle jets in space.

Keep up with the latest discoveries from the MMS mission: @NASASun on Twitter and Facebook.com/NASASunScience.

Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com. 

A magnetic power struggle of galactic proportions - new research highlights the role of the Sun’s magnetic landscape in the development of solar eruptions that can trigger space weather events around Earth.

Using data from our Solar Dynamics Observatory, scientists examined an October 2014 Jupiter-sized sunspot group, an area of complex magnetic fields, often the site of solar activity. This was the biggest group in the past two solar cycles and a highly active region. Though conditions seemed ripe for an eruption, the region never produced a major coronal mass ejection (CME) - a massive, bubble-shaped eruption of solar material and magnetic field - on its journey across the Sun. It did, however, emit a powerful X-class flare, the most intense class of flares. What determines, the scientists wondered, whether a flare is associated with a CME?

The scientists found that a magnetic cage physically prevented a CME from erupting that day. Just hours before the flare, the sunspot’s natural rotation contorted the magnetic rope and it grew increasingly twisted and unstable, like a tightly coiled rubber band.

Credits: Tahar Amari et al./Center for Theoretical Physics/École Polytechnique/NASA Goddard/Joy Ng

Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com.

Our sun is dynamic and ever-changing. On Friday, July 14, a solar flare and a coronal mass ejection erupted from the same, large active region. The coils arcing over this active region are particles spiraling along magnetic field lines.

Solar flares are explosions on the sun that send energy, light and high-speed particles into space. Such flares are often associated with solar magnetic storms known as coronal mass ejections. While these are the most common solar events, the sun can also emit streams of very fast protons – known as solar energetic particle (SEP) events – and disturbances in the solar wind known as corotating interaction regions (CIRs).

Learn more HERE.

Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com

Diving into New Magnetic Territory with the MMS Mission

Our Magnetospheric Multiscale Mission, or MMS, is on a journey to study a new region of space.  

On May 4, 2017, after three months of precisely coordinated maneuvers, MMS reached its new orbit to begin studying the magnetic environment on the ever-rotating nighttime side of Earth.

The space around Earth is not as empty as it looks. It’s packed with high energy electrons and ions that zoom along magnetic field lines and surf along waves created by electric and magnetic fields.  

MMS studies how these particles move in order to understand a process known as magnetic reconnection, which occurs when magnetic fields explosively collide and re-align.

After launch, MMS started exploring the magnetic environment on the side of Earth closest to the sun. Now, MMS has been boosted into a new orbit that tops out twice as high as before, at over 98,000 miles above Earth’s surface.

The new orbit will allow the spacecraft to study magnetic reconnection on the night side of Earth, where the process is thought to cause the northern and southern lights and energize particles that fill the radiation belts, a doughnut-shaped region of trapped particles surrounding Earth.  

MMS uses four separate but identical spacecraft, which fly in a tight pyramid formation known as a tetrahedron. This allows MMS to map the magnetic environment in three dimensions.

MMS made many discoveries during its first two years in space, and its new orbit will open the door to even more. The information scientists get from MMS will help us better understand our space environment, which helps in planning future missions to explore even further beyond our planet. Learn more about MMS at nasa.gov/mms.

Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com

Exploring the Invisible: Magnetic Reconnection

People always say that space is a vacuum. That’s true – space is about a thousand times emptier than even the best laboratory vacuums on Earth. Even so, space contains lots of stuff we can’t see. We study this invisible space stuff because we need to understand it to safely send technology and astronauts into space.

The stuff that fills space is mostly plasma, which is gas where particles have separated into positive ions and negative electrons, creating a sea of electrically-charged particles. This plasma also contains something else – magnetic fields.

The particles in space can reach very high speeds, creating radiation. One of the main engines that drives that acceleration to high speeds is called magnetic reconnection. But what is magnetic reconnection?

Magnetic reconnection happens when two oppositely-aligned magnetic fields pinch together and explosively realign. As the lines snap into their new configuration – as in the animation below – the sudden change sends electrons and ions flying at incredible speeds.

Magnetic reconnection releases energy. We can't see the energy itself, but we can see the results: It can set off solar explosions – such as solar flares and coronal mass ejections – or disturbances near Earth that cause auroras.

In March 2015, we launched the four Magnetospheric Multiscale, or MMS, spacecraft on a mission to study magnetic reconnection. Magnetic reconnection only happens in a vacuum with ionized gas. These conditions are vanishingly rare on Earth, so we went to space to study this explosive process.

Because MMS has four separate – but essentially identical – spacecraft, it can watch magnetic reconnection in three dimensions.

The below animation shows what MMS sees – the magnetic fields are magenta, positive ions are purple, and electrons are yellow. The arrows show which the direction the fields and particles are moving.

Like how a research plane flies through a hurricane, MMS flew directly through a magnetic reconnection event in October 2015.

In the data visualization below, you can see the magnetic reconnection happening as the yellow arrows (which represent electrons) explode in all directions. You’ll notice that the magnetic field (represented by magenta arrows) changes direction after the magnetic reconnection, showing that the magnetic field has reconfigured.

Magnetic reconnection transfers energy into Earth’s atmosphere – but it’s not inherently dangerous. Sometimes, the changes in Earth’s magnetic field caused by magnetic reconnection can create electric currents that put a strain on power systems. However, the energy released is more often channeled into auroras, the multicolored lights that most often appear near the North and South Poles.

As the MMS mission continues the four spacecraft can be moved closer together or farther apart, letting us measure magnetic reconnection on all different scales. Each set of observations contributes to explaining different aspects of this invisible phenomenon of magnetic reconnection. Together, the information will help scientists better map out our space environment — crucial information as we journey ever farther beyond our home planet.

Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com