Particles - Blog Posts

Three Ways to Travel at (Nearly) the Speed of Light

One hundred years ago, Einstein’s theory of general relativity was supported by the results of a solar eclipse experiment. Even before that, Einstein had developed the theory of special relativity — a way of understanding how light travels through space.

Particles of light — photons — travel through a vacuum at a constant pace of more than 670 million miles per hour.

All across space, from black holes to our near-Earth environment, particles are being accelerated to incredible speeds — some even reaching 99.9% the speed of light! By studying these super fast particles, we can learn more about our galactic neighborhood. 

Here are three ways particles can accelerate:

1) Electromagnetic Fields!

Electromagnetic fields are the same forces that keep magnets on your fridge! The two components — electric and magnetic fields — work together to whisk particles at super fast speeds throughout the universe. In the right conditions, electromagnetic fields can accelerate particles at near-light-speed.

We can harness electric fields to accelerate particles to similar speeds on Earth! Particle accelerators, like the Large Hadron Collider and Fermilab, use pulsed electromagnetic fields to smash together particles and produce collisions with immense amounts of energy. These experiments help scientists understand the Big Bang and how it shaped the universe!

2) Magnetic Explosions!

Magnetic fields are everywhere in space, encircling Earth and spanning the solar system. When these magnetic fields run into each other, they can become tangled. When the tension between the crossed lines becomes too great, the lines explosively snap and realign in a process known as magnetic reconnection. Scientists suspect this is one way that particles — for example, the solar wind, which is the constant stream of charged particles from the Sun — are sped up to super fast speeds.

When magnetic reconnection occurs on the side of Earth facing away from the Sun, the particles can be hurled into Earth’s upper atmosphere where they spark the auroras.

3) Wave-Particle Interactions!

Particles can be accelerated by interactions with electromagnetic waves, called wave-particle interactions. When electromagnetic waves collide, their fields can become compressed. Charged particles bounce back and forth between the waves, like a ball bouncing between two merging walls. These types of interactions are constantly occurring in near-Earth space and are responsible for damaging electronics on spacecraft and satellites in space.

Wave-particle interactions might also be responsible for accelerating some cosmic rays from outside our solar system. After a supernova explosion, a hot, dense shell of compressed gas called a blast wave is ejected away from the stellar core. Wave-particle interactions in these bubbles can launch high-energy cosmic rays at 99.6% the speed of light.

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Using All of Our Senses in Space

Today, we and the National Science Foundation (NSF) announced the detection of light and a high-energy cosmic particle that both came from near a black hole billions of trillions of miles from Earth. This discovery is a big step forward in the field of multimessenger astronomy.

But wait — what is multimessenger astronomy? And why is it a big deal?

People learn about different objects through their senses: sight, touch, taste, hearing and smell. Similarly, multimessenger astronomy allows us to study the same astronomical object or event through a variety of “messengers,” which include light of all wavelengths, cosmic ray particles, gravitational waves, and neutrinos — speedy tiny particles that weigh almost nothing and rarely interact with anything. By receiving and combining different pieces of information from these different messengers, we can learn much more about these objects and events than we would from just one.

Lights, Detector, Action!  

Much of what we know about the universe comes just from different wavelengths of light. We study the rotations of galaxies through radio waves and visible light, investigate the eating habits of black holes through X-rays and gamma rays, and peer into dusty star-forming regions through infrared light.

The Fermi Gamma-ray Space Telescope, which recently turned 10, studies the universe by detecting gamma rays — the highest-energy form of light. This allows us to investigate some of the most extreme objects in the universe.

Last fall, Fermi was involved in another multimessenger finding — the very first detection of light and gravitational waves from the same source, two merging neutron stars. In that instance, light and gravitational waves were the messengers that gave us a better understanding of the neutron stars and their explosive merger into a black hole.

Fermi has also advanced our understanding of blazars, which are galaxies with supermassive black holes at their centers. Black holes are famous for drawing material into them. But with blazars, some material near the black hole shoots outward in a pair of fast-moving jets. With blazars, one of those jets points directly at us!

Multimessenger Astronomy is Cool

Today’s announcement combines another pair of messengers. The IceCube Neutrino Observatory lies a mile under the ice in Antarctica and uses the ice itself to detect neutrinos. When IceCube caught a super-high-energy neutrino and traced its origin to a specific area of the sky, they alerted the astronomical community.

Fermi completes a scan of the entire sky about every three hours, monitoring thousands of blazars among all the bright gamma-ray sources it sees. For months it had observed a blazar producing more gamma rays than usual. Flaring is a common characteristic in blazars, so this did not attract special attention. But when the alert from IceCube came through about a neutrino coming from that same patch of sky, and the Fermi data were analyzed, this flare became a big deal!

IceCube, Fermi, and followup observations all link this neutrino to a blazar called TXS 0506+056. This event connects a neutrino to a supermassive black hole for the very first time.  

Why is this such a big deal? And why haven’t we done it before? Detecting a neutrino is hard since it doesn’t interact easily with matter and can travel unaffected great distances through the universe. Neutrinos are passing through you right now and you can’t even feel a thing!

The neat thing about this discovery — and multimessenger astronomy in general — is how much more we can learn by combining observations. This blazar/neutrino connection, for example, tells us that it was protons being accelerated by the blazar’s jet. Our study of blazars, neutrinos, and other objects and events in the universe will continue with many more exciting multimessenger discoveries to come in the future.

Want to know more? Read the story HERE.

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Meet Our ICONic New Satellite

The boundary between Earth and space is complicated and constantly changing. Unlike the rest of the atmosphere, the upper atmosphere near the edge of space has a mix of both neutral particles similar to the air we breathe, as well as electrically charged particles called ions. Changes in this region are unpredictable, but they can affect satellites and garble signals, like GPS, that pass through this region. That’s why we’re launching ICON (the Ionospheric Connection Explorer) to get our first-ever comprehensive look at our interface to space.

About 60 miles above Earth’s surface, Earth’s atmosphere gives way to space. The change is gradual: The gases of the atmosphere get steadily thinner the higher you go. On the edge of space, the Sun’s radiation cooks some of those thin gases until they lose an electron (or two or three), creating a population of electrically charged particles swarming alongside the neutral particles. These charged particles make up the ionosphere.

Because the particles of the ionosphere are electrically charged, they respond uniquely to electric and magnetic fields. Dynamic conditions in space — including shifting fields and surges of charged particles, collectively called space weather — induce shifts in the ionosphere that can have far-reaching effects. The ionosphere is where space weather manifests on Earth, and it’s inextricably connected with the neutral upper atmosphere — so distortions in one part affect the other.  

Changes in the ionosphere and upper atmosphere — including sudden shifts in composition, density, temperature, and conductivity — can affect satellites, building up electric charge that has the potential to disrupt instruments, and garble signals like those used by GPS satellites. Predicting these variances is hard, because the causes are so complex: They’re driven not only by space weather — usually a product of solar activity — but also by regular weather down near Earth’s surface.  

Differences in pressure caused by events like hurricanes, or even something as simple as a sustained wind over a mountain range, can ripple upwards until they reach this region and trigger fluctuations. Weather’s influence on the upper atmosphere was only discovered in the past ten years or so — and ICON is the first mission designed specifically to look at that interaction.

ICON carries four types of instruments to study the ionosphere and upper atmosphere. Three of them rely on taking far-away pictures of something called airglow, a faint, global glow produced by reactive compounds in the upper atmosphere. The fourth type collects and analyzes particles directly.

MIGHTI (the Michelson Interferometer for Global High-resolution Thermospheric Imaging) uses Doppler shift — the same effect that makes a siren change pitch as an ambulance passes you — to precisely track the speed and direction of upper-atmosphere winds.

FUV (the Far Ultraviolet instrument) measures airglow produced by certain types of oxygen and nitrogen molecules on Earth’s day side, as well as oxygen ions on Earth’s night side.

EUV (the Extreme Ultraviolet instrument) measures shorter wavelengths of light than FUV. Airglow measured by EUV is produced by oxygen ions on Earth’s day side, which make up the lion’s share of Earth’s daytime ionosphere.

The two identical IVMs (Ion Velocity Meters) make very precise measurements of the angle at which ionized gas enters the instruments, helping us build up a picture of how this ionized gas around the spacecraft is moving.

We’re launching ICON on June 14 Eastern Time on an Orbital ATK Pegasus XL rocket from Kwajalein Atoll in the Marshall Islands, which will deploy from Orbital’s L-1011 Stargazer aircraft. NASA TV will cover the launch — stay tuned to nasa.gov/live for updates and follow the mission on Twitter and Facebook.

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.

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A patchwork of bright, criss-crossing cloud trails was created by ships churning through the Atlantic Ocean off the coast of Portugal and Spain in this image captured by one of our Earth observing satellites. The narrow clouds known as ship tracks, form when water vapor condenses around tiny particles of pollution that ships emit.

Some of the pollution particles generated by ships (especially sulfates) are soluble in water and serve as the seeds around which cloud droplets form. Clouds infused with ship exhaust have more and smaller droplets than unpolluted clouds. Because of this, the light hitting the polluted clouds scatters in many directions, making them appear brighter and thicker than unpolluted marine clouds, which are typically seeded by larger, naturally occurring particles such as sea salt.

Learn more about this image HERE. 

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Going for GOLD

On Jan. 25, we’re going for GOLD!

We’re launching an instrument called Global-scale Observations of the Limb and Disk, GOLD for short. It’s a new mission that will study a complicated — and not yet fully understood — region of near-Earth space, called the ionosphere.

Space is not completely empty: It’s teeming with fast-moving energized particles and electric and magnetic fields that guide their motion. At the boundary between Earth’s atmosphere and space, these particles and fields — the ionosphere — co-exist with the upper reaches of the neutral atmosphere.

That makes this a complicated place. Big events in the lower atmosphere, like hurricanes or tsunamis, can create waves that travel all the way up to that interface to space, changing the wind patterns and causing disruptions.

It’s also affected by space weather. The Sun is a dynamic star, and it releases spurts of energized particles and blasts of solar material carrying electric and magnetic fields that travel out through the solar system. Depending on their direction, these bursts have the potential to disrupt space near Earth.

This combination of factors makes it hard to predict changes in the ionosphere — and that can have a big impact. Communications signals, like radio waves and signals that make our GPS systems work, travel through this region, and sudden changes can distort them or even cut them off completely.

Low-Earth orbiting satellites — including the International Space Station — also fly through the ionosphere, so understanding how it fluctuates is important for protecting these satellites and astronauts.  

GOLD is a spectrograph, an instrument that breaks light down into its component wavelengths, measuring their intensities. Breaking light up like this helps scientists see the behavior of individual chemical elements — for instance, separating the amount of oxygen versus nitrogen. GOLD sees in far ultraviolet light, a type of light that’s invisible to our eyes.

GOLD is a hosted payload. The instrument is hitching a ride aboard SES-14, a commercial communications satellite built by Airbus for SES Government Solutions, which owns and operates the satellite.

Also launching this year is the Ionospheric Connection Explorer, or ICON, which will also study the ionosphere and neutral upper atmosphere. But while GOLD will fly in geostationary orbit some 22,000 miles above the Western Hemisphere, ICON will fly just 350 miles above Earth, able to gather close up images of this region.

Together, these missions give us an unprecedented look at the ionosphere and upper atmosphere, helping us understand the very nature of how our planet interacts with space.

To learn more about this region of space and the GOLD mission, visit: nasa.gov/gold.

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