How Do We Learn About A Planet’s Atmosphere?

The Moon Just Photobombed NASA’s Solar Dynamics Observatory

On May 25, 2017, the moon photobombed one of our sun-watching satellites by passing directly between the satellite and the sun.

The Solar Dynamics Observatory, or SDO, orbits Earth and watches the sun nearly 24/7 — except when another body, like the moon, gets in the way. These lunar photobombs are called transits, the generic term for when any celestial body passes in front of another.

Transits are one way we detect distant worlds. When a planet in another star system passes in front of its host star, it blocks some of the star’s light so the star appears slightly dimmer. By monitoring changes in a star’s light over time, scientists can deduce the presence of a planet, and even determine what its atmosphere is like. This method has been used to discover thousands of planets, including the TRAPPIST-1 planets.

SDO sees lunar transits about twice a year, and this one lasted about an hour with the moon covering about 89 percent of the sun at the peak of its journey across the sun’s face.

When they’re seen from Earth, we call lunar transits by another name: eclipses.

Solar eclipses are just a special kind of transit where the moon blocks all or part of our view of the sun. Since SDO’s view of the sun was only partially blocked, it saw a partial eclipse. Later this year, on Aug. 21, a total eclipse will be observable from the ground: The moon will completely block the sun’s face in some parts of the US, creating a total solar eclipse on a 70-mile-wide stretch of land, called the path of totality, that runs from Oregon to South Carolina.

Throughout the rest of North America — and even in parts of South America, Africa, Europe and Asia — the moon will partially obscure the sun, creating a partial eclipse. SDO will also witness this partial eclipse.

Total solar eclipses are incredible, cosmic coincidences: The sun is about 400 times wider than the moon, but it also happens to be 400 times farther away, so the sun and moon appear to be the same size in our sky. This allows the moon to completely block the sun when they line up just right.

Within the path of totality, the moon completely obscures the sun’s bright face, revealing the comparatively faint corona — the sun’s pearly-white outer atmosphere.

It’s essential to observe eye safety during an eclipse. You must use proper eclipse glasses or an indirect viewing method when any part of the sun’s surface is exposed, whether during the partial phases of an eclipse, or just on a regular day. If you’re in the path of totality, you may look at  the eclipse ONLY during the brief moments of totality.

A total solar eclipse is one of nature’s most awe-inspiring sights, so make your plans now for August 21! You’ll also be able to see the eclipse cross the country that day through the eyes of NASA – including views of the partial eclipse from SDO – on NASA TV and at nasa.gov.

Learn more about the August eclipse — including where, when, and how to safely see it — at eclipse2017.nasa.gov and follow along on Twitter @NASASun.

Let Us See Jupiter Through Your Eyes

Our Juno spacecraft will fly over Jupiter’s Great Red Spot on July 10 at 10:06 p.m. EDT. This will be humanity’s first up-close and personal view of the gas giant’s iconic 10,000-mile-wide storm, which has been monitored since 1830 and possibly existing for more than 350 years.

The data collection of the Great Red Spot is part of Juno’s sixth science flyby over Jupiter’s mysterious cloud tops. Perijove (the point at which an orbit comes closest to Jupiter’s center) will be July 10 at 9:55 p.m. EDT. 

At the time of perijove, Juno will be about 2,200 miles above the planet’s cloud tops. Eleven minutes and 33 seconds later…Juno will have covered another 24,713 miles and will be directly above the coiling crimson cloud tops of the Great Red Spot. The spacecraft will pass about 5,600 miles above its clouds. 

When will we see images from this flyby?

During the flyby, all eight of the spacecraft’s instruments will be turned on, as well as its imager, JunoCam. Because the spacecraft will be collecting data with its Microwave Radiometer (MWR), which measures radio waves from Jupiter’s deep atmosphere, we cannot downlink information during the pass. The MWR can tell us how much water there is and how material is moving far below the cloud tops.

During the pass, all data will be stored on-board…with a downlink planned afterwards. Once the downlink begins, engineering data from the spacecraft’s instruments will come to Earth first, followed by images from JunoCam.

The unprocessed, raw images will be located HERE, on approximately July 14. Follow @NASAJuno on Twitter for updates.

Did you know you can download and process these raw images?

We invite the public to act as a virtual imaging team…participating in key steps of the process, from identifying features of interest to sharing the finished images online. After JunoCam data arrives on Earth, members of the public can process the images to create color pictures. The public also helps determine which points on the planet will be photographed. Learn more about voting on JunoCam’s next target HERE.

JunoCam has four filters: red, green, blue and near-infrared. We get red, green and blue strips on one spacecraft rotation (the spacecraft rotation rate is 2 revolutions per minute) and the near-infrared strips on the second rotation. To get the final image product, the strips must be stitched together and the colors lined up.

Anything from cropping to color enhancing to collaging is fair game. Be creative!

Submit your images to Juno_outreach@jpl.nasa.gov to be featured on the Mission Juno website!

Check out some of these citizen-scientist processed images from previous Juno orbits: 

Credit: Sean Doran (More)

Credit: Amelia Carolina (More)

Credit: Michael Ranger (More)

Credit: Jason Major (More)

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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. 

What Did Astronaut Scott Kelly Do After a #YearInSpace?

Astronaut Scott Kelly just returned from his One-Year Mission aboard the International Space Station. After spending 340 days on orbit, you can imagine that he started to miss a few Earthly activities. Here are a few things he did after his return home:

Watched a Sunset

While on the International Space Station for his One-Year Mission, astronaut Scott Kelly saw 16 sunrises/sunsets each day...so he definitely didn’t miss out on the beauty. That said, watching a sunset while on Earth is something that he had to wait to see. Tweet available HERE. 

Ate Fresh Food

After spending a year on the International Space Station, eating precooked food, anyone would be excited to dig into a REAL salad. Astronaut Scott Kelly was no exception, and posted about his first salad on Earth after his one-year mission. Learn more about what astronauts eat while in space HERE. Tweet available HERE.

Jumped into a Pool

Water is a precious resource in space. Unfortunately, that means that there isn’t a pool on the space station. Luckily, astronaut Scott Kelly was able to jump into some water after his return to Earth. Tweet/video available HERE.

Sat at a Dinner Table

While living on the International Space Station, crew members regularly enjoy their meals together, but do so while floating in microgravity. The comfort of pulling up a chair to the dinner table is something they can only experience once they’re back home on Earth. Tweet available HERE.

Enjoyed the Weather

When crew members live on the space station they can’t just step outside for a stroll. The only time they go outside the orbiting laboratory is during a spacewalk. Even then, they are confined inside a bulky spacesuit. Experiencing the cool breeze or drops of rain are Earthly luxuries. Tweet available HERE.

Stopped by the Doctor’s Office

The One-Year Mission doesn’t stop now that astronaut Scott Kelly is back on Earth. Follow-up exams and tests will help scientists understand the impacts of microgravity on the human body during long-duration spaceflight. This research will help us on our journey to Mars. Tweet available HERE. 

Visited the Denist

When you spend a year in space, you’ll probably need to catch up on certain things when you return to Earth. Astronaut Scott Kelly made sure to include a visit to the dentist on his “return home checklist”. Tweet available HERE.

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The Lives, Times, and Deaths of Stars

Who among us doesn’t covertly read tabloid headlines when we pass them by? But if you’re really looking for a dramatic story, you might want to redirect your attention from Hollywood’s stars to the real thing. From birth to death, these burning spheres of gas experience some of the most extreme conditions our cosmos has to offer.

All stars are born in clouds of dust and gas like the Pillars of Creation in the Eagle Nebula pictured below. In these stellar nurseries, clumps of gas form, pulling in more and more mass as time passes. As they grow, these clumps start to spin and heat up. Once they get heavy and hot enough (like, 27 million degrees Fahrenheit or 15 million degrees Celsius), nuclear fusion starts in their cores. This process occurs when protons, the nuclei of hydrogen atoms, squish together to form helium nuclei. This releases a lot of energy, which heats the star and pushes against the force of its gravity. A star is born.

Credit: NASA, ESA and the Hubble Heritage Team (STScI/AURA)

From then on, stars’ life cycles depend on how much mass they have. Scientists typically divide them into two broad categories: low-mass and high-mass stars. (Technically, there’s an intermediate-mass category, but we’ll stick with these two to keep it straightforward!)

Low-mass stars

A low-mass star has a mass eight times the Sun's or less and can burn steadily for billions of years. As it reaches the end of its life, its core runs out of hydrogen to convert into helium. Because the energy produced by fusion is the only force fighting gravity’s tendency to pull matter together, the core starts to collapse. But squeezing the core also increases its temperature and pressure, so much so that its helium starts to fuse into carbon, which also releases energy. The core rebounds a little, but the star’s atmosphere expands a lot, eventually turning into a red giant star and destroying any nearby planets. (Don’t worry, though, this is several billion years away for our Sun!)

Red giants become unstable and begin pulsating, periodically inflating and ejecting some of their atmospheres. Eventually, all of the star’s outer layers blow away, creating an expanding cloud of dust and gas misleadingly called a planetary nebula. (There are no planets involved.)

Credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA)

All that’s left of the star is its core, now called a white dwarf, a roughly Earth-sized stellar cinder that gradually cools over billions of years. If you could scoop up a teaspoon of its material, it would weigh more than a pickup truck. (Scientists recently found a potential planet closely orbiting a white dwarf. It somehow managed to survive the star’s chaotic, destructive history!)

High-mass stars

A high-mass star has a mass eight times the Sun’s or more and may only live for millions of years. (Rigel, a blue supergiant in the constellation Orion, pictured below, is 18 times the Sun’s mass.)

Credit: Rogelio Bernal Andreo

A high-mass star starts out doing the same things as a low-mass star, but it doesn’t stop at fusing helium into carbon. When the core runs out of helium, it shrinks, heats up, and starts converting its carbon into neon, which releases energy. Later, the core fuses the neon it produced into oxygen. Then, as the neon runs out, the core converts oxygen into silicon. Finally, this silicon fuses into iron. These processes produce energy that keeps the core from collapsing, but each new fuel buys it less and less time. By the point silicon fuses into iron, the star runs out of fuel in a matter of days. The next step would be fusing iron into some heavier element, but doing requires energy instead of releasing it.  

The star’s iron core collapses until forces between the nuclei push the brakes, and then it rebounds back to its original size. This change creates a shock wave that travels through the star’s outer layers. The result is a huge explosion called a supernova.

What’s left behind depends on the star’s initial mass. Remember, a high-mass star is anything with a mass more than eight times the Sun’s — which is a huge range! A star on the lower end of this spectrum leaves behind a city-size, superdense neutron star. (Some of these weird objects can spin faster than blender blades and have powerful magnetic fields. A teaspoon of their material would weigh as much as a mountain.)

At even higher masses, the star’s core turns into a black hole, one of the most bizarre cosmic objects out there. Black holes have such strong gravity that light can’t escape them. If you tried to get a teaspoon of material to weigh, you wouldn’t get it back once it crossed the event horizon — unless it could travel faster than the speed of light, and we don’t know of anything that can! (We’re a long way from visiting a black hole, but if you ever find yourself near one, there are some important safety considerations you should keep in mind.)

The explosion also leaves behind a cloud of debris called a supernova remnant. These and planetary nebulae from low-mass stars are the sources of many of the elements we find on Earth. Their dust and gas will one day become a part of other stars, starting the whole process over again.

That’s a very brief summary of the lives, times, and deaths of stars. (Remember, there’s that whole intermediate-mass category we glossed over!) To keep up with the most recent stellar news, follow NASA Universe on Twitter and Facebook.

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Zoom to the Moon! Astronauts will blast off to the Moon in the Orion spacecraft with NASA’s Space Launch System, the world’s most powerful rocket ever built. Help #AstronautSnoopy launch into deep space, farther than any human or bird has ever gone before. https://www.nasa.gov/feature/peanuts-toys-and-books-commemorate-50th-anniversary-of-apollo/

What Scientists Are Learning from the Eclipse

While millions of people in North America headed outside to watch the eclipse on Aug. 21, 2017, hundreds of scientists got out telescopes, set up instruments, and prepared balloon launches – all so they could study the Sun and its complicated influence on Earth.

Total solar eclipses happen about once every 18 months somewhere in the world, but the August eclipse was rare because of its long path over land. The total eclipse lasted more than 90 minutes over land, from when it first reached Oregon to when it left the U.S. in South Carolina.

This meant that scientists could collect more data from land than during most eclipses, giving us new insight into our world and the star that powers it.

A moment in the Sun’s atmosphere

During a total solar eclipse, the Sun’s outer atmosphere, the corona, is visible from Earth. It’s normally too dim to see next to the Sun’s bright face, but, during an eclipse, the Moon blocks out the Sun, revealing the corona.

Image Credit: Peter Aniol, Miloslav Druckmüller and Shadia Habbal

Though we can study parts of the corona with instruments that create artificial eclipses, some of the innermost regions of the corona are only visible during total solar eclipses. Solar scientists think this part of the corona may hold the secrets to some of our most fundamental questions about the Sun: Like how the solar wind – the constant flow of magnetized material that streams out from the Sun and fills the solar system – is accelerated, and why the corona is so much hotter than the Sun’s surface below.  

Depending on where you were, someone watching the total solar eclipse on Aug. 21 might have been able to see the Moon completely obscuring the Sun for up to two minutes and 42 seconds. One scientist wanted to stretch that even further – so he used a pair of our WB-57 jets to chase the path of the Moon’s shadow, giving their telescopes an uninterrupted view of the solar corona for just over seven and half minutes.

These telescopes were originally designed to help monitor space shuttle launches, and the eclipse campaign was their first airborne astronomy project!

These scientists weren’t the only ones who had the idea to stretch out their view of the eclipse: The Citizen CATE project (short for Continental-America Telescopic Eclipse) did something similar, but with the help of hundreds of citizen scientists. 

Citizen CATE included 68 identical small telescopes spread out across the path of totality, operated by citizen and student scientists. As the Moon’s shadow left one telescope, it reached the next one in the lineup, giving scientists a longer look at the way the corona changes throughout the eclipse.

After accounting for clouds, Citizen CATE telescopes were able to collect 82 minutes of images, out of the 93 total minutes that the eclipse was over the US. Their images will help scientists study the dynamics of the inner corona, including fast solar wind flows near the Sun’s north and south poles.

The magnetized solar wind can interact with Earth’s magnetic field, causing auroras, interfering with satellites, and – in extreme cases – even straining our power systems, and all these measurements will help us better understand how the Sun sends this material speeding out into space.

Exploring the Sun-Earth connection

Scientists also used the eclipse as a natural laboratory to explore the Sun’s complicated influence on Earth.

High in Earth’s upper atmosphere, above the ozone layer, the Sun’s intense radiation creates a layer of electrified particles called the ionosphere. This region of the atmosphere reacts to changes from both Earth below and space above. Such changes in the lower atmosphere or space weather can manifest as disruptions in the ionosphere that can interfere with communication and navigation signals.

One group of scientists used the eclipse to test computer models of the ionosphere’s effects on these communications signals. They predicted that radio signals would travel farther during the eclipse because of a drop in the number of energized particles. Their eclipse day data – collected by scientists spread out across the US and by thousands of amateur radio operators – proved that prediction right.

In another experiment, scientists used the Eclipse Ballooning Project to investigate the eclipse’s effects lower in the atmosphere. The project incorporated weather balloon flights from a dozen locations to form a picture of how Earth’s lower atmosphere – the part we interact with and which directly affects our weather – reacted to the eclipse. They found that the planetary boundary layer, the lowest part of Earth’s atmosphere, actually moved closer to Earth during the eclipse, dropped down nearly to its nighttime altitude.

A handful of these balloons also flew cards containing harmless bacteria to explore the potential for contamination of other planets with Earth-born life. Earth’s stratosphere is similar to the surface of Mars, except in one main way: the amount of sunlight. But during the eclipse, the level of sunlight dropped to something closer to what you’d expect to see on Mars, making this the perfect testbed to explore whether Earth microbes could hitch a ride to the Red Planet and survive. Scientists are working through the data collected, hoping to build up better information to help robotic and human explorers alike avoid carrying bacterial hitchhikers to Mars.

Image: The small metal card used to transport bacteria.

Finally, our EPIC instrument aboard NOAA’s DSCOVR satellite provided awe-inspiring views of the eclipse, but it’s also helping scientists understand Earth’s energy balance. Earth’s energy system is in a constant dance to maintain a balance between incoming radiation from the Sun and outgoing radiation from Earth to space, which scientists call the Earth’s energy budget. The role of clouds, both thick and thin, is important in their effect on energy balance.

Like a giant cloud, the Moon during the total solar eclipse cast a large shadow across a swath of the United States. Scientists know the dimensions and light-blocking properties of the Moon, so they used ground- and space-based instruments to learn how this large shadow affects the amount of sunlight reaching Earth’s surface, especially around the edges of the shadow. Measurements from EPIC show a 10% drop in light reflected from Earth during the eclipse (compared to about 1% on a normal day). That number will help scientists model how clouds radiate the Sun’s energy – which drives our planet’s ocean currents, seasons, weather and climate – away from our planet.

For even more eclipse science updates, stay tuned to nasa.gov/eclipse.

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Do you guys (everyone at mission control) have inside jokes?

What is the best about being mission control?

As someone who's about to go to college to hopefully be astronaut if everything goes to plan. What is some good advice you wish someone told you?

What dose it feel like being inside a space suit?

The suit weighs about 300 pounds. We are made neutrally buoyant in the pool, but over time we can become negatively buoyant. The suit can feel heavy, even the bearings can become stiff, so it can be difficult to operate in the suit. With practice and the help of a great spacewalk team, we can make a spacewalk look seamless.

Vice President Mike Pence visited our Kennedy Space Center in Florida today. While there, he delivered remarks to the workforce and toured our complex to see progress toward sending humans deeper into space, and eventually to Mars. He also had the opportunity to see our work with commercial companies to launch humans from U.S. soil to the International Space Station.