Space Launch System

What are the Universe’s Most Powerful Particle Accelerators?

Every second, every square meter of Earth’s atmosphere is pelted by thousands of high-energy particles traveling at nearly the speed of light. These zippy little assailants are called cosmic rays, and they’ve been puzzling scientists since they were first discovered in the early 1900s. One of the Fermi Gamma-ray Space Telescope’s top priority missions has been to figure out where they come from.

“Cosmic ray” is a bit of a misnomer. Makes you think they’re light, right? But they aren’t light at all! They’re particles that mostly come from outside our solar system — which means they're some of the only interstellar matter we can study — although the Sun also produces some. Cosmic rays hit our atmosphere and break down into secondary cosmic rays, most of which disperse quickly in the atmosphere, although a few do make it to Earth’s surface.

Cosmic rays aren't dangerous to those of us who spend our lives within Earth's atmosphere. But if you spend a lot of time in orbit or are thinking about traveling to Mars, you need to plan how to protect yourself from the radiation caused by cosmic rays.

Cosmic rays are subatomic particles — smaller particles that make up atoms. Most of them (99%) are nuclei of atoms like hydrogen and helium stripped of their electrons. The other 1% are lone electrons. When cosmic rays run into molecules in our atmosphere, they produce secondary cosmic rays, which include even lighter subatomic particles.

Most cosmic rays reach the same amount of energy a small particle accelerator could produce. But some zoom through the cosmos at energies 40 million times higher than particles created by the world’s most powerful man-made accelerator, the Large Hadron Collider. (Lightning is also a pretty good particle accelerator).

So where do cosmic rays come from? We should just be able to track them back to their source, right? Not exactly. Any time they run into a strong magnetic field on their way to Earth, they get deflected and bounce around like a game of cosmic pinball. So there’s no straight line to follow back to the source. Most of the cosmic rays from a single source don’t even make it to Earth for us to measure. They shoot off in a different direction while they’re pin balling.

Photo courtesy of Argonne National Laboratory

In 1949 Enrico Fermi — an Italian-American physicist, pioneer of high-energy physics and Fermi satellite namesake — suggested that cosmic rays might accelerate to their incredible speeds by ricocheting around inside the magnetic fields of interstellar gas clouds. And in 2013, the Fermi satellite showed that the expanding clouds of dust and gas produced by supernovas are a source of cosmic rays.

When a star explodes in a supernova, it produces a shock wave and rapidly expanding debris. Particles trapped by the supernova remnant magnetic field bounce around wildly.

Every now and then, they cross the shock wave and their energy ratchets up another notch. Eventually they become energetic enough to break free of the magnetic field and zip across space at nearly the speed of light — some of the fastest-traveling matter in the universe.

How can we track them back to supernovas when they don’t travel in a straight line, you ask? Very good question! We use something that does travel in a straight line — gamma rays (actual rays of light this time, on the more energetic end of the electromagnetic spectrum).

When the particles get across the shock wave, they interact with non-cosmic-ray particles in clouds of interstellar gas. Cosmic ray electrons produce gamma rays when they pass close to an atomic nucleus. Cosmic ray protons, on the other hand, produce gamma rays when they run into normal protons and produce another particle called a pion (Just hold on! We’re almost there!) which breaks down into two gamma rays.

The proton- and electron-produced gamma rays are slightly different. Fermi data taken over four years showed that most of the gamma rays coming from some supernova remnants have the energy signatures of cosmic ray protons knocking into normal protons. That means supernova remnants really are powerful particle accelerators, creating a lot of the cosmic rays that we see!

There are still other cosmic ray sources on the table — like active galactic nuclei — and Fermi continues to look for them. Learn more about what Fermi’s discovered over the last 10 years and how we’re celebrating its accomplishments.

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Before my question I would like to congratulate you on your career at Nasa, it must be amazing to work there even if you didn’t achieve your dream of being an astronaut, you can still lead missions from the ground. (Sorry if my punctuation is a bit off) as for my question, what has it been like to work at nasa all of these years and get to help with so many missions? Do you ever get nervous for the people who’s lives are in your hands? Signed ~ Phillip

Rare & Record-Breaking Black Holes

While even the most “normal” black hole seems exotic compared to the tranquil objects in our solar system, there are some record-breaking oddballs. Tag along as we look at the biggest, closest, farthest, and even “spinniest” black holes discovered in the universe … that we know of right now!

Located 700 million light-years away in the galaxy Holmberg 15A, astronomers found a black hole that is a whopping 40 billion times the mass of the Sun — setting the record for the biggest black hole found so far. On the other hand, the smallest known black hole isn’t quite so easy to pinpoint. There are several black holes with masses around five times that of our Sun. There’s even one candidate with just two and a half times the Sun’s mass, but scientists aren’t sure whether it’s the smallest known black hole or actually the heaviest known neutron star!

You may need to take a seat for this one. The black hole GRS 1915+105 will make you dizzier than an afternoon at an amusement park, as it spins over 1,000 times per second! Maybe even more bizarre than how fast this black hole is spinning is what it means for a black hole to spin at all! What we're actually measuring is how strongly the black hole drags the space-time right outside its event horizon — the point where nothing can escape. Yikes!

If you’re from Earth, the closest black hole that we know of right now, Mon X-1 in the constellation Monoceros, is about 3,000 light-years away. But never fear — that’s still really far away! The farthest known black hole is J0313-1806. The light from its surroundings took a whopping 13 billion years to get to us! And with the universe constantly expanding, that distance continues to grow.

So, we know about large (supermassive, hundreds of thousands to billions of times the Sun's mass) and small (stellar-mass, five to dozens of times the Sun's mass) black holes, but what about other sizes? Though rare, astronomers have found a couple that seem to fit in between and call them intermediate-mass black holes. As for tiny ones, primordial black holes, there is a possibility that they were around when the universe got its start — but there’s not enough evidence so far to prove that they exist!

One thing that’s on astronomers’ wishlist is to see two supermassive black holes crashing into one another. Unfortunately, that event hasn’t been detected — yet! It could be only a matter of time before one reveals itself.

Though these are the records now, in early 2021 … records are meant to be broken, so who knows what we’ll find next!

Add some of these records and rare finds to your black hole-watch list, grab your handy-dandy black hole field guide to learn even more about them — and get to searching!

Keep up with NASA Universe on Facebook and Twitter where we post regularly about black holes.

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Human Expansion Across Solar System

On this day in 1972, two NASA astronauts landed on the Moon. Now, 45 years later, we have been instructed to return to the lunar surface.

Today at the White House, President Trump signed the Space Policy Directive 1, a change in national space policy that provides for a U.S.-led program with private sector partners for a human return to the Moon, followed by missions to Mars and beyond.

Among other dignitaries on hand for the signing, were NASA astronauts Sen. Harrison “Jack” Schmitt, Buzz Aldrin, Peggy Whitson and Christina Koch.

Schmitt landed on the moon 45 years to the minute that the policy directive was signed as part of our Apollo 17 mission, and is the most recent living person to have set foot on our lunar neighbor. 

Above, at the signing ceremony instructing us to send humans back to the lunar surface, Schmitt shows First Daughter Ivanka Trump the Moon sample he collected in 1972.

The effort signed today will more effectively organize government, private industry and international efforts toward returning humans on the Moon, and will lay the foundation that will eventually enable human exploration of Mars.

To learn more, visit: https://www.nasa.gov/press-release/new-space-policy-directive-calls-for-human-expansion-across-solar-system

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NASA Spotlight: Astronaut Jonny Kim

Dr. Jonny Kim was selected by NASA to join the 2017 Astronaut Candidate Class. He reported for duty in August 2017 and having completed the initial astronaut candidate training is now eligible for mission assignments to the International Space Station, the Moon and eventually Mars. A U.S. Navy SEAL, Kim completed more than 100 combat operations. Kim was commissioned as a naval officer through an enlisted-to-officer program and earned his degree in mathematics at the University of San Diego and a doctorate of medicine at Harvard Medical School. Born and raised in Los Angeles, California to Korean-American immigrants, he enjoys spending time with his family, outdoor activities, academic and professional mentoring, strength training and lifelong learning. 

Dr. Kim took some time from his job as a NASA astronaut to answer questions about his life and career! Enjoy: 

Why did you apply to be an astronaut?

For many reasons. I think that humans are natural explorers. There is a calling in all of us to explore the unknown, push the boundaries and redefine what is possible. I’m drawn to the physical and mental challenges of space exploration and the teamwork required to complete such an objective. And finally, the opportunity to do something good for our country, for humanity, and to inspire the next generation of thinkers, leaders, explorers and scientists.

What was your favorite memory from astronaut training?

I’m a big believer that people can grow stronger bonds with each other when they succeed through shared hardship. And I think that developing relationships with one another is one of the best ways to forge successful team skills to be successful in any endeavor. With that context, I can tell you that my favorite memory from astronaut training was traversing the deep canyon slots of the Utah Canyon Lands for almost 2 weeks with my classmates. We hiked trails, climbed canyons, swam through deep, dark, cold and murky waters and forged through uncertainty, all while being together. This shared hardship was not only fun, but it helped us grow closer to one another. It’s one of the fondest memories I have when I think about my amazing classmates, and through that shared hardship, I know I can count on any one of my fellow astronauts when the going gets tough.

If you could play any song during launch, what would it be?

Don’t Stop Believin’ by Journey.

What advice would you give to your younger self?

I would tell myself to always follow your passion, never stature or money, because following a life of passion is long-term, sustainable and usually helps others. Be accountable for your mistakes and failures, and maintain the humility to learn from those mistakes and failures. And finally, I would caution myself that all worthwhile goals are difficult to obtain, but with the right attitude and hard work, you can accomplish anything.

How did your time as a Navy Seal impact your astronaut training?

Being a Naval Special Warfare Operator taught me that humans are capable of accomplishing ten times what their bodies and mind tell them. I learned there are no limits in life, and the biggest setback one can have is a poor attitude. I learned the value of strong leadership and accountability. I also learned the meaning of sacrifice, hardship, teamwork, love and compassion. All these traits helped me to develop the hard and soft skills required to be an astronaut.

How do we prepare medically for long duration missions? What tools, resources, medications do we anticipate needing, and how do we figure that out?

This is a great question and the answer is evolving. The way we answer this question is by being thoughtful and consulting the medical communities to weigh the pros and cons of every single decision we make regarding this. Mass plays an important factor, so we have to be mindful of everything we bring and how we train for it.

Who was the first person you called after being selected to be an astronaut?

It would have been my wife but she was with me when I heard the news. The first person I called was my mom.

What is one item from home that you would bring to space?

A picture of my wife and kids.

What does it mean to you to be part of the Artemis generation of astronauts?

It means that I have a duty and obligation to serve humanity’s best interests. To explore the unknown, push boundaries and redefine what’s possible. It means I have an immense opportunity to serve as an example and inspiration to our next generation of leaders and explorers. It also means there is a hard road ahead, and when the mission calls for us, we will be ready.

What are three personal items, besides photos of family and friends, that you would bring with you on your first spaceflight?

An automatic watch, because the engineering behind a timepiece is a beautiful thing. An American flag, because I proudly believe and uphold the principles and ideals our country stands for. And finally, a nice journal that I can put handwritten thoughts on.

Thank you for your time, and good luck on your first spaceflight assignment!

Follow Jonny Kim on Twitter and Instagram to keep up with his life as NASA astronaut. 

It’s not too late to APPLY to #BeAnAstronaut! Applications close TOMORROW, March 31. 

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25 Years in Space for ESA & NASA’s Sun-Watching SOHO

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.

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What's a SPOC? Isn't that a star trek character?

Our Cassini spacecraft has been traveling in space for almost 20 years, exploring Saturn, its rings and even some of its moons. This mission has revealed never-before-seen events that are changing our understanding of how planetary systems form and what conditions might lead to habitats for life.

Cassini will complete its remarkable story of exploration with an intentional plunge into Saturn’s atmosphere, ending its mission.  

Participate in our Grand Finale Events

Wednesday, Sept. 13

1 p.m. EDT – News Conference from our Jet Propulsion Laboratory with a detailed preview of final mission activities Watch HERE.

Thursday, Sept 14

4:00 - 5:00 p.m. EDT - NASA Social Live Broadcast with mission experts Watch HERE.

Friday, Sept. 15

7:00 – 8:30 a.m. EDT – Live commentary on NASA TV and online of the spacecraft’s final dive into Saturn’s atmosphere. Watch HERE.

Around 8:00 a.m. EDT – Expected time of last signal and science data from Cassini Watch HERE.

9:30 a.m. EDT – Post-mission news conference Watch HERE.

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

10 Things: How to Photograph a Meteor Shower

Taking photographs of a meteor shower can be an exercise in patience as meteors streak across the sky quickly and unannounced, but with these tips – and some good fortune – you might be rewarded with a great photo.

These tips are meant for a DSLR or mirrorless camera, but some point-and-shoot cameras with manual controls could be used as well.

1. The Photo Op: Perseids Meteors

The Perseids are dusty remnants of comet 109P/Swift-Tuttle.

Earth passes through the comet’s invisible, multi-billion mile trail of tiny debris each year around August, creating a meteor shower of so-called “shooting stars” as the particles are vaporized in our atmosphere.

Perseid meteors already are streaking across the sky. This year's shower peaks on a moonless summer night -from 4 pm on the 12th until 4 am on the 13th Eastern Daylight Time.

Read more on the Perseids ›

2. Get away from city lights and find a place with dark skies.

In this 30 second exposure, a meteor streaks across the sky in Spruce Knob, West Virginia, during the 2016 Perseids meteor shower. Credit: NASA/Bill Ingalls

Too much light and it will be hard for your eyes to see fainter meteors, plus your image will get flooded with the glow of light. Turning down the brightness of the camera’s LCD screen will help keep your eyes adjusted to the dark. The peak of the 2018 Perseid meteor shower occurs just after the new moon, meaning a thin crescent will set long before the best viewing hours, leaving hopeful sky watchers with a moonlight-free sky!

3. Use a tripod.

In this ten-second exposure, a meteor streaks across the sky above Washington, DC during the 2015 Perseids meteor shower, Credit: NASA/Joel Kowsky

Meteor photography requires long exposures, and even the steadiest of hands can’t hold a camera still enough for a clear shot. Heavier tripods help reduce shaking caused by wind and footsteps, but even a lightweight tripod will do. You can always place sandbags against the feet of the tripod to add weight and stability. If you don’t have a tripod, you might be able to prop your camera on or up against something around you, but be sure to secure your camera.

4. Use a wide-angle lens.

In this 30 second exposure taken with a circular fish-eye lens, a meteor streaks across the sky during the 2016 Perseids meteor shower as a photographer wipes moisture from the camera lens Friday, August 12, 2016 in Spruce Knob, West Virginia. Credit: NASA/Bill Ingalls

A wide-angle lens will capture more of the sky and give you a greater chance of capturing a meteor in your shot, while a zoom lens captures a smaller area of the sky. The odds of a meteor streaking past that small patch are lower.

5. Use a shutter release cable or the camera’s built-in timer.

Long exposures are not just for meteors. In this shot taken at Joshua Tree National Park, a hiker's headlamp leaves a trail of light along a twilight path. Credit: National Park Service / Hannah Schwalbe

A tripod does a great job of reducing most of the shaking your camera experiences, but even the act of pressing the shutter button can blur your extended exposure. Using the self-timer gives you several seconds for any shaking from pressing the shutter button to stop before the shutter is released. A shutter release cable (without a self-timer) eliminates the need to touch the camera at all. And if your camera has wifi capabilities, you might be able to activate the shutter from a mobile device.

6. Manually focus your lens.

In this 30 second exposure, a meteor streaks across the sky during the annual Perseids meteor shower Friday, August 12, 2016 in Spruce Knob, West Virginia. Credit: NASA/Bill Ingalls

At night, autofocus will struggle to find something on which to focus. Setting your focus to infinity will get you close, but chances are you’ll have to take some test images and do some fine tuning. With your camera on a tripod, take a test image lasting a few seconds, then use the camera’s screen to review the image. Zoom in to a star to see how sharp your focus is. If the stars look like fuzzy blobs, make tiny adjustments to the focus and take another test image.

Repeat until you are happy with the result.

If your camera has a zoomable electronic viewfinder or live view option, you might be able to zoom to a star and focus without having to take a test image.

7. Aim your camera.

The Perseids appear to radiate from the constellation Perseus, visible in the northern sky soon after sunset this time of year.

Even though we don’t know when or where a single meteor will appear, we do know the general area from which they’ll originate.

Meteor showers get their name based on the point in the sky from which they appear to radiate. In the case of the Perseids, during their peak, they appear to come from the direction of the constellation Perseus in the northern sky.

8. Calculate your exposure time.

In this 20-second exposure, a meteor lights up the sky over the top of a mountain ridge near Park City, Utah. Even though this image was captured during the annual Perseid meteor shower, this "shooting star" is probably not one of the Perseid meteors, which originate from material left behind by Comet Swift-Tuttle. Instead, it's likely one of the many bits of rock and dust that randomly fall into the atmosphere on any given night. Credit: NASA/Bill Dunford

As Earth rotates, the stars in the sky appear to move, and if your shutter is open long enough, you might capture some of that movement. If you want to avoid apparent star movement, you can follow the 500 Rule. Take 500 and divide it by the length in millimeters of your lens. The resulting number is the length of time in seconds that you can keep your shutter open before seeing star trails. For example, if you’re using a 20 mm lens, 25 seconds (500 divided by 20) is the longest you can set your exposure time before star trails start to show up in your images.

9. Experiment!

In this 30 second exposure photo, hikers find their way to the top of Spruce Knob in West Virginia to view the annual Perseids meteor shower, Friday, August 12, 2016. Credit: NASA/Bill Ingalls

Once you know the maximum exposure time, you can set your shutter priority to that length and let the camera calculate other settings for your first image. Depending on how the image turns out, you can manually adjust aperture (set it to a lower number if the image is too dark) and ISO (set it to a higher number if the image is too dark) to improve your next images. Changing only one setting at a time will give you a better understanding of how those changes affect your image.

10. Enjoy the show.

The crew of the International Space Station captured this Perseid meteor falling to Earth over China in 2011. Credit: NASA

With your camera settings adjusted, capturing that perfect photo is just a matter of time and luck. The highest rate of meteors visible per hour is in the hours after midnight and before dawn. Set up your camera next to a lounge chair or a blanket to witness the wonder of a meteor shower for yourself – and, with any luck, you’ll take home some envy-inducing shots, too!

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Will normal uv protection sunglasses work?

Unfortunately no. They do not block out enough of the sunlight so you could still burn your eyes if you were to use them to look at the Sun. The ISO 12312-2 compliant eclipse glasses are so dark you literally can’t see anything out of them unless you are looking at the Sun. You can find trusted vendors through the links at https://eclipse2017.nasa.gov/safety If you can’t get them in time, you can also make a pinhole projector  https://eclipse.aas.org/eye-safety/projection and watch the eclipse with that.