Category: space

The Abyss of Time


Scotland is part of the bedrock of geology, so to speak.

In the late 18th century, Scottish farmer and scientist
James Hutton helped found the science of geology. Observing how wind and water
weathered rocks and deposited layers of soil at his farm in Berwickshire,
Hutton made a conceptual leap into a deeper and expansive view of time. After
spending decades observing the processes of erosion and sedimentation, and traveling
the Scottish countryside in search of fossils, stream cuts and interesting rock
formations, Hutton became convinced that Earth had to be much older than 6,000
years, the common belief in Western civilization at the time.

In 1788, a boat trip to Siccar Point, a rocky promontory in
Berwickshire, helped crystallize Hutton’s view. The Operational
Land Imager
 (OLI) on Landsat 8 acquired
this image of the area on June 4, 2018, top. A closer view of Siccar Point is


At Siccar Point, Hutton was confronted with the
juxtaposition of two starkly different types of rock—a gently sloping bed of
young red sandstone that was over a near vertical slab of older graywacke that
had clearly undergone intensive heating, uplift, buckling, and folding. Hutton
argued to his two companions on the boat that the only way to get the two rock
formations jammed up against one another at such an odd angle was that an
enormous amount of time must have elapsed between when they had been deposited
at the bottom of the ocean.

He was right.

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Land is Sliding, Tell Us Where!

Summer in
the northern hemisphere brings monsoon season, causing heavy
rains and flooding that trigger landslides. Next time you see a landslide in
the news, online, or in your neighborhood, submit it to our citizen science
project Landslide
to build the largest open global landslide catalog and help
us and the public learn more about when and where they occur.

Rainfall is the most common cause
of landslides.

After a storm, the soil and rock on a slope can become saturated with water and
begin to slide downwards, posing a danger to people and destroying roads,
houses and access to electricity and water supplies.


We have been monitoring rainfall from
space for

the Earth right now, the Global Precipitation Measurement (GPM)
mission is a group of 10 satellites that measure rain, snow, sleet and other
precipitation worldwide every three hours. This data tells us where and when heavy
rain is falling and if it could lead to disasters.


What can rainfall data tell us
about landslides?

using GPM data to understand where and when landslides are happening. A global
landslide model
uses information about the environment and rainfall
to anticipate where landslides are likely to happen anytime around the world
every three hours.


To improve the global
landslide model
and other landslide research, NASA is looking for
citizen scientists like you!

If you find a landslide reported online or in your neighborhood, you can provide
the event details in Landslide Reporter, our citizen
science project.


detailed reports are added into an open global landslide inventory
available at Landslide Viewer. We use
citizen science contributions along with other landslide data to check our prediction
model so we can have a better picture of how rainfall, slope steepness, forest
cover, and geology can trigger a landslide.


Because the data is open, anyone
can use the data for research or response

When you report a landslide, you improve our
collection of landslide data for everyone.

support landslide efforts worldwide by contributing to Landslide
, and you can help inform decisions that could save lives
and property today! Learn more about the project at You
can also follow the project on Twitter and Facebook.

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Isolation, Hazard of the Mind

Make sure to follow us on Tumblr for your regular dose of space: 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. (View the first hazard). Let’s dive into the second hazard:


Overcoming the second hazard, isolation and confinement, is essential for a successful mission to Mars. Behavioral issues among groups of people crammed in a small space over a long period of time, no matter how well trained they are, are inevitable. It is a topic of study and discussion currently taking place around the selection and composition of crews.


On Earth, we have the luxury of picking up our cell phones and instantly being connected with nearly everything and everyone around us. 


On a trip to Mars, astronauts will be more isolated and confined than we can imagine. 


Sleep loss, circadian desynchronization (getting out of sync), and work overload compound this issue and may lead to performance decrements or decline, adverse health outcomes, and compromised mission objectives.


To address this hazard, methods for monitoring behavioral health and adapting/refining various tools and technologies for use in the spaceflight environment are being developed to detect and treat early risk factors. Research is also being conducted in workload and performance, light therapy for circadian alignment or internal clock alignment, and team cohesion.


Exploration to the Moon and Mars will expose astronauts to five known hazards of spaceflight, including isolation and confinement. To learn more, and find out what the 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 host Gary Jordan further dives into the threat of isolation and confinement with Tom Williams, a NASA Human Factors and Behavior Performance Element Scientist at the Johnson Space Center. 


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Solar System 10 Things: Spitzer Space Telescop…

Our Spitzer Space Telescope is celebrating 15 years since its launch on August 25, 2003. This remarkable spacecraft has made discoveries its designers never even imagined, including some of the seven Earth-size planets of TRAPPIST-1. Here are some key facts about Spitzer:

1. Spitzer is one of our Great Observatories.

Our Great Observatory Program aimed to explore the universe with four large space telescopes, each specialized in viewing the universe in different wavelengths of light. The other Great Observatories are our Hubble Space Telescope, Chandra X-Ray Observatory, and Compton Gamma-Ray Observatory. By combining data from different kinds of telescopes, scientists can paint a fuller picture of our universe.

2. Spitzer operates in infrared light.

Infrared wavelengths of light, which primarily come from heat radiation, are too long to be seen with human eyes, but are important for exploring space — especially when it comes to getting information about something extremely far away. From turbulent clouds where stars are born to small asteroids close to Earth’s orbit, a wide range of phenomena can be studied in infrared light. Objects too faint or distant for optical telescopes to detect, hidden by dense clouds of space dust, can often be seen with Spitzer. In this way, Spitzer acts as an extension of human vision to explore the universe, near and far.

What’s more, Spitzer doesn’t have to contend with Earth’s atmosphere, daily temperature variations or day-night cycles, unlike ground-based telescopes. With a mirror less than 1 meter in diameter, Spitzer in space is more sensitive than even a 10-meter-diameter telescope on Earth.

3. Spitzer was the first spacecraft to fly in an Earth-trailing orbit.

Rather than circling Earth, as Hubble does, Spitzer orbits the Sun on almost the same path as Earth. But Spitzer moves slower than Earth, so the spacecraft drifts farther away from our planet each year.

This “Earth-trailing orbit” has many advantages. Being farther from Earth than a satellite, it receives less heat from our planet and enjoys a naturally cooler environment. Spitzer also benefits from a wider view of the sky by orbiting the Sun. While its field of view changes throughout the year, at any given time it can see about one-third of the sky. Our Kepler space telescope, famous for finding thousands of exoplanets – planets outside our solar system – also settled in an Earth-trailing orbit six years after Spitzer.

4. Spitzer began in a “cold mission.”

Spitzer has far outlived its initial requirement of 2.5 years. The Spitzer team calls the first 5.5 years “the cold mission” because the spacecraft’s instruments were deliberately cooled down during that time. Liquid helium coolant kept Spitzer’s instruments just a few degrees above absolute zero (which is minus 459 degrees Fahrenheit, or minus 273 degrees Celsius) in this first part of the mission.

5. The “warm mission” was still pretty cold.

Spitzer entered what was called the “warm mission” when the 360 liters of liquid helium coolant that was chilling its instruments ran out in May 2009.

At the “warm” temperature of minus 405 Fahrenheit, two of Spitzer’s instruments – the Infrared Spectrograph (IRS) and Multiband Imaging Photometer (MIPS) – stopped working. But two of the four detector arrays in the Infrared Array Camera (IRAC) persisted. These “channels” of the camera have driven Spitzer’s explorations since then.

6. Spitzer wasn’t designed to study exoplanets, but made huge strides in this area.

Exoplanet science was in its infancy in 2003 when Spitzer launched, so the mission’s first scientists and engineers had no idea it could observe planets beyond our solar system. But the telescope’s accurate star-targeting system and the ability to control unwanted changes in temperature have made it a useful tool for studying exoplanets. During the Spitzer mission, engineers have learned how to control the spacecraft’s pointing more precisely to find and characterize exoplanets, too.

Using what’s called the “transit method,” Spitzer can stare at a star and detect periodic dips in brightness that happen when a planet crosses a star’s face. In one of its most remarkable achievements, Spitzer discovered three of the TRAPPIST-1 planets and confirmed that the system has seven Earth-sized planets orbiting an ultra-cool dwarf star. Spitzer data also helped scientists determine that all seven planets are rocky, and made these the best-understood exoplanets to date.

Spitzer can also use a technique called microlensing to find planets closer to the center of our galaxy. When a star passes in front of another star, the gravity of the first star can act as a lens, making the light from the more distant star appear brighter. Scientists are using microlensing to look for a blip in that brightening, which could mean that the foreground star has a planet orbiting it. Microlensing could not have been done early in the mission when Spitzer was closer to Earth, but now that the spacecraft is farther away, it has a better chance of measuring these events.

7. Spitzer is a window into the distant past.

The spacecraft has observed and helped discover some of the most distant objects in the universe, helping scientists understand where we came from. Originally, Spitzer’s camera designers had hoped the spacecraft would detect galaxies about 12 billion light-years away. In fact, Spitzer has surpassed that, and can see even farther back in time – almost to the beginning of the universe. In collaboration with Hubble, Spitzer helped characterize the galaxy GN-z11 about 13.4 billion light-years away, whose light has been traveling since 400 million years after the big bang. It is the farthest galaxy known.

8. Spitzer discovered Saturn’s largest ring.

Everyone knows Saturn has distinctive rings, but did you know its largest ring was only discovered in 2009, thanks to Spitzer? Because this outer ring doesn’t reflect much visible light, Earth-based telescopes would have a hard time seeing it. But Spitzer saw the infrared glow from the cool dust in the ring. It begins 3.7 million miles (6 million kilometers) from Saturn and extends about 7.4 million miles (12 million kilometers) beyond that.

9. The “Beyond Phase” pushes Spitzer to new limits.

In 2016, Spitzer entered its “Beyond phase,” with a name reflecting how the spacecraft operates beyond its original scope.

As Spitzer floats away from Earth, its increasing distance presents communication challenges. Engineers must point Spitzer’s antenna at higher angles toward the Sun in order to talk to our planet, which exposes the spacecraft to more heat. At the same time, the spacecraft’s solar panels receive less sunlight because they point away from the Sun, putting more stress on the battery.

The team decided to override some autonomous safety systems so Spitzer could continue to operate in this riskier mode. But so far, the Beyond phase is going smoothly.

10. Spitzer paves the way for future infrared telescopes.

Spitzer has identified areas of further study for our upcoming James Webb Space Telescope, planned to launch in 2021. Webb will also explore the universe in infrared light, picking up where Spitzer eventually will leave off. With its enhanced ability to probe planetary atmospheres, Webb may reveal striking new details about exoplanets that Spitzer found. Distant galaxies unveiled by Spitzer together with other telescopes will also be observed in further detail by Webb. The space telescope we are planning after that, WFIRST, will also investigate long-standing mysteries by looking at infrared light. Scientists planning studies with future infrared telescopes will naturally build upon the pioneering legacy of Spitzer.

Read the web version of this week’s “Solar System: 10 Things to Know” article HERE

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Parker Solar Probe is Go for Launch

Tomorrow, Aug. 11, we’re launching a spacecraft to touch the Sun.


The first chance to launch Parker Solar Probe is 3:33 a.m. EDT on Aug. 11 from Space Launch Complex 37 at Cape Canaveral Air Force Station in Florida. Launch coverage on NASA TV starts at 3 a.m. EDT at

After launch, Parker Solar Probe begins its daring journey to the Sun’s atmosphere, or corona, going closer to the Sun than any spacecraft in history and facing brutal heat and radiation.

Though Parker Solar Probe weighs a mere 1,400 pounds — pretty light for a spacecraft — it’s launching aboard one of the world’s most powerful rockets, a United Launch Alliance Delta IV Heavy with a third stage added.


Even though you might think the Sun’s massive means things would just fall into it, it’s surprisingly difficult to actually go there.
Any object leaving Earth starts off traveling at about 67,000 miles per
hour, same as Earth — and most of that is in a sideways direction, so
you have to shed most of that sideways speed to make it to the Sun. All
that means that it takes 55 times more launch energy to go to the Sun
than it does to go to Mars. On top of its powerful launch vehicle,
Parker Solar Probe will use seven Venus gravity assists to shed sideways

Even though Parker Solar Probe will lose a lot of sideways speed, it’ll still be going incredibly fast as its orbit draws closer to the Sun throughout its seven-year mission. At its fastest, Parker Solar Probe will travel at 430,000 miles per hour — fast enough to get from Philadelphia to Washington, D.C. in one second — setting the record for the fastest spacecraft in history.


But the real challenge was to keep the spacecraft from frying once it got there.

We’ve always wanted to send a mission to the corona, but we literally haven’t had the technology that can protect a spacecraft and its instruments from its scorching heat. Only recent advances have enabled engineers to build a heat shield that will protect the spacecraft on this journey of extremes — a tricky feat that requires withstanding the Sun’s intense radiation on the front and staying cool at the back, so the spacecraft and instruments can work properly.


The 4.5-inches-thick heat shield is built like a sandwich. There’s a
thin layer of carbon material like you might find in your golf clubs or
tennis rackets, carbon foam, and then another thin piece of
carbon-carbon on the back. Even while the Sun-facing side broils at
2,500 degrees Fahrenheit, the back of the shield will remain a balmy 85
degrees — just above room temperature. There are so few particles in
this region that it’s a vacuum, so blocking the Sun’s radiation goes a
long way towards keeping the spacecraft cool.

Parker Solar Probe is also our first mission to be named after a living individual: Dr. Eugene Parker, famed solar physicist who in 1958 first predicted the existence of the solar wind.


“Solar wind” is what Dr. Parker dubbed the stream of charged particles that flows constantly from the Sun, bathing Earth and our entire solar system in the Sun’s magnetic fields. Parker Solar Probe’s flight right through the corona allows it to observe the birth of the very solar wind that Dr. Parker predicted, right as it speeds up and over the speed of sound.  


The corona is where solar material is heated to millions of degrees and where the most extreme eruptions on the Sun occur, like solar flares and coronal mass ejections, which fling particles out to space at incredible speeds near the speed of light. These explosions can also spark space weather storms near Earth that can endanger satellites and astronauts, disrupt radio communications and, at their most severe, trigger power outages.


Thanks to Parker Solar Probe’s landmark mission, solar scientists will be able to see the objects of their study up close and personal for the very first time.

Up until now, all of our studies of the corona have been remote — that is, taken from a distance, rather than at the mysterious region itself. Scientists have been very creative to glean as much as possible from their remote data, but there’s nothing like actually sending a probe to the corona to see what’s going on.


And scientists aren’t the only ones along for the adventure — Parker Solar Probe holds a microchip carrying the names of more than 1.1 million people who signed up to send their name to the Sun. This summer, these names and 1,400 pounds of science equipment begin their journey to the center of our solar system.

Three months later in November 2018, Parker Solar Probe makes its first close approach to the Sun, and in December, it will send back the data. The corona is one of the last places in the solar system where no spacecraft has visited before; each observation Parker Solar Probe makes is a potential discovery.

Stay tuned — Parker Solar Probe is about to take flight.

Keep up with the latest on the mission at or follow us on Twitter and Facebook.

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Milky Blue Water Near Prince of Wales Island

Phytoplankton are more than just nature’s watercolors: They’re
tiny ocean organisms that play a key role in Earth’s climate by removing
heat-trapping carbon dioxide from the atmosphere through photosynthesis. These
tiny organisms live in the oceans, absorbing carbon dioxide and releasing
oxygen, like plants on land. Earth’s oceans absorb about half of the carbon
dioxide in the atmosphere, which feeds phytoplankton.

This year, phytoplankton blooms popped up in the
panhandle region of Alaska and along the coast of British Columbia slightly
later in the year than the main blooms that tend to occur in May.


This image was acquired on July 21, 2018, by the Moderate Resolution Imaging Spectroradiometer (MODIS) on
our Terra satellite and shows milky blue waters near Prince of Wales Island.
The discoloration is thought to be caused by a bloom of non-toxic phytoplankton
known as coccolithophores, specifically Emiliania
, which
like warm, stratified, and low nutrient conditions.

This week, our Export Processes in the Ocean from Remote Sensing
(EXPORTS) team is shipping out into the open ocean to study these important
organisms, sailing 200 miles west from Seattle into the northeastern Pacific

Read more about the image and learn more about the EXPORTS campaign here:

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5 Reasons our Space Launch System is the Backb…

Our Space Launch
(SLS) will be the world’s most powerful rocket, engineered to carry
astronauts and cargo farther and faster than any rocket ever built. Here are
five reasons it is the backbone of bold, deep space exploration missions.


5. We’re Building This Rocket to Take Humans to the Moon and Beyond

The SLS rocket is a national asset for leading new missions to deep
space. More than 1,000 large and small
companies in 44 states
are building the rocket that will take humans to
the Moon.
Work on SLS has an economic impact of $5.7 billion and
generates 32,000 jobs. Small businesses across the U.S. supply 40 percent of
the raw materials for the rocket. An investment in SLS is an investment in
human spaceflight and in American industry and will lead to applications beyond


4. This Rocket is Built for Humans

Modern deep space systems are designed and built to keep humans safe
from launch to landing.  SLS provides the
power to safely send the Orion
and astronauts to the Moon. Orion, powered by the European
Service Module
, keeps the crew safe during the mission. Exploration
Ground Systems
at NASA’s Kennedy Space Center in Florida, safely
launches the SLS with Orion on top and recovers the astronauts and Orion after splashdown.


3. This Rocket is Engineered for a Variety of Exploration Missions

SLS is engineered for decades of human space exploration to come. SLS is
not just one rocket but a transportation
that evolves to meet the needs of a variety of missions. The
rocket can send more than 26 metric tons (57,000 pounds) to the Moon and can
evolve to send up to 45 metric tons (99,000 pounds) to the Moon. NASA has the
expertise to meet the challenges of designing and building a new, complex
rocket that evolves over time while developing our nation’s capability to
extend human existence into deep space.


2. This Rocket can Carry Crews and Cargos Farther, Faster

SLS’s versatile
enables it to carry astronauts their supplies as well as cargo
for resupply and send science missions far in the solar system. With its power
and unprecedented ability to transport heavy and large volume science payloads in
a single mission, SLS can send cargos to Mars or probes even farther out in the
solar system, such as to Jupiter’s moon Europa, faster than any other rocket
flying today. The rocket’s large cargo volume makes it possible to design
planetary probes, telescopes and other scientific instruments with fewer complex
mechanical parts.


1. This Rocket Complements International and Commercial Partners

The Space Launch System is the right rocket to enable
exploration on and around the Moon and even longer missions
from home. SLS makes it possible for astronauts to bring along supplies and
equipment needed to explore, such as pieces of the Gateway,
which will be the cornerstone of sustainable lunar exploration. SLS’s ability
to launch both people and payloads to deep space in a single mission makes
space travel safer and more efficient. With no buildings, hardware or grocery
stores on the Moon or Mars, there are plenty of opportunities for support by
other rockets. SLS and contributions by international and commercial partners
will make it possible to return to the Moon and create a springboard for exploration
of other areas in the solar system where we can discover and expand knowledge
for the benefit of humanity.


Learn more about the Space Launch System.

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Spilling the Sun’s Secrets

You might think you know the Sun: It looks quiet and unchanging. But the Sun has secrets that scientists have been trying to figure out for decades.  

One of our new missions — Parker Solar Probe — is aiming to spill the Sun’s secrets and shed new light on our neighbor in the sky.

Even though it’s 93 million miles away, the Sun is our nearest and best laboratory for understanding the inner workings of stars everywhere. We’ve been spying on the Sun with a fleet of satellites for decades, but we’ve never gotten a close-up of our nearest star.

This summer, Parker Solar Probe is launching into an orbit that will take it far closer to the Sun than any instrument has ever gone. It will fly close enough to touch the Sun, sweeping through the outer atmosphere — the corona — 4 million miles above the surface.

This unique viewpoint will do a lot more than provide gossip on the Sun. Scientists will take measurements to help us understand the Sun’s secrets — including those that can affect Earth.

Parker Solar Probe is equipped with four suites of instruments that will take detailed measurements from within the Sun’s corona, all protected by a special heat shield to keep them safe and cool in the Sun’s ferocious heat.

The corona itself is home to one of the Sun’s biggest secrets: The corona’s mysteriously high temperatures. The corona, a region of the Sun’s outer atmosphere, is hundreds of times hotter than the surface below. That’s counterintuitive, like if you got warmer the farther you walked from a campfire, but scientists don’t yet know why that’s the case.

Some think the excess heat is delivered by electromagnetic waves called Alfvén waves moving outwards from the Sun’s surface. Others think it might be due to nanoflares — bomb-like explosions that occur on the Sun’s surface, similar to the flares we can see with telescopes from Earth, but smaller and much more frequent. Either way, Parker Solar Probe’s measurements direct from this region itself should help us pin down what’s really going on.

We also want to find out what exactly accelerates the solar wind — the Sun’s constant outpouring of material that rushes out at a million miles per hour and fills the Solar System far past the orbit of Pluto. The solar wind can cause space weather when it reaches Earth — triggering things like the aurora, satellite problems, and even, in rare cases, power outages.

We know where the solar wind comes from, and that it gains its speed somewhere in the corona, but the exact mechanism of that acceleration is a mystery. By sampling particles directly at the scene of the crime, scientists hope Parker Solar Probe can help crack this case.

Parker Solar Probe should also help us uncover the secrets of some of the fastest particles from the Sun. Solar energetic particles can reach speeds of more than 50% the speed of light, and they can interfere with satellites with little warning because of how fast they move. We don’t know how they get so fast — but it’s another mystery that should be solved with Parker Solar Probe on the case.  

Parker Solar Probe launches summer 2018 on a seven-year mission to touch the Sun. Keep up with the latest on the Sun at @NASASun on Twitter, and follow along with Parker Solar Probe’s last steps to launch at

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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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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.


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