How Did You Get To Where You Are Now? And Di You Always Know That This Is Where You Wanted To End Up?

Everything You Need to Know About the Aug. 21 Eclipse

On Aug. 21, all of North America will experience a solar eclipse.

If skies are clear, eclipse-watchers will be able to see a partial solar eclipse over several hours, and some people – within the narrow path of totality – will see a total solar eclipse for a few moments.

How to Watch

It’s never safe to look at the Sun, and an eclipse is no exception. During a partial eclipse (or on any regular day) you must use special solar filters or an indirect viewing method to watch the Sun.

If you have solar viewing glasses, check to make sure they’re safe and undamaged before using them to look at the Sun. Make sure you put them on before looking up at the Sun, and look away before removing them. Eclipse glasses can be used over your regular eyeglasses, but they should never be used when looking through telescopes, binoculars, camera viewfinders, or any other optical device.

If you don’t have eclipse glasses, you can still watch the eclipse indirectly! You can make a pinhole projector out of a box, or use any other object with tiny holes – like a piece of cardstock with a hole, or your outstretched, interlaced fingers – to project an image of the partially eclipsed Sun onto the ground.

Of course, if it’s cloudy (or you’d just rather stay inside), you can watch the whole thing online with us at nasa.gov/eclipselive. Tune in starting at noon ET.

If you’re in the path of totality, there will be a few brief moments when it is safe to look directly at the eclipse. Only once the Moon has completely covered the Sun and there is no light shining through is it safe to look at the eclipse. Make sure you put your eclipse glasses back on or return to indirect viewing before the first flash of sunlight appears around the Moon’s edge.

Why do eclipses happen?

A solar eclipse happens when the Moon passes directly between the Sun and Earth, casting its shadow down on Earth’s surface. The path of totality – where the Moon completely covers the Sun – is traced out by the Moon’s inner shadow, the umbra. People within the Moon’s outer shadow, the penumbra, can see a partial eclipse.

The Moon’s orbit around Earth is tilted by about five degrees, meaning that its shadow usually doesn’t fall on Earth. Only when the Moon lines up exactly between the Sun and Earth do we see an eclipse.

Though the Sun is about 400 times wider than the Moon, it is also about 400 times farther away, making their apparent sizes match up almost exactly. This is what allows the Moon to block out the Sun’s bright face, while revealing the comparatively faint, pearly-white corona.

The Science of Eclipses

Eclipses are a beautiful sight to see, and they’re also helpful for our scientists, so we’re funding eleven ground-based science investigations to learn more about the Sun and Earth.

Total solar eclipses reveal the innermost regions of the Sun’s atmosphere, the corona. Though it’s thought to house the processes that kick-start much of the space weather that can influence Earth, as well as heating the whole corona to extraordinarily high temperatures, we can’t study this region at any other time. This is because coronagraphs – the instruments we use to study the Sun’s atmosphere by creating artificial eclipses – must cover up much of the corona, as well as the Sun’s face in order to produce clear images.

Eclipses also give us the chance to study Earth’s atmosphere under uncommon conditions: the sudden loss of solar radiation from within the Moon’s shadow. We’ll be studying the responses of both Earth’s ionosphere – the region of charged particles in the upper atmosphere – and the lower atmosphere.

Learn all about the Aug. 21 eclipse at eclipse2017.nasa.gov, and follow @NASASun on Twitter and NASA Sun Science on Facebook for more. Watch the eclipse through the eyes of NASA at nasa.gov/eclipselive starting at 12 PM ET on Aug. 21. 

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What Are the Bright Spots on Ceres?

Dwarf planet Ceres has more than 130 bright areas, and most of them are associated with impact craters. Now, Ceres has revealed some of its well-kept secrets in two new studies in the journal Nature, thanks to data from our Dawn spacecraft.

Two studies have been looking into the mystery behind these bright areas. One study identifies this bright material as a kind of salt, while the other study suggests the detection of ammonia-rich clays. 

Study authors write that the bright material is consistent with a type of magnesium sulfate called hexahydrite. A different type of magnesium sulfate is familiar on Earth as Epsom salt.

Researchers, using images from Dawn’s framing camera, suggest that these salt-rich areas were left behind when water-ice sublimated in the past. Impacts from asteroids would have unearthed the mixture of ice and salt.

An image of Occator Crater (below) shows the brightest material on Ceres. Occator itself is 60 miles in diameter, and its central pit, covered by this bright material, measures about 6 miles wide. With its sharp rim and walls, it appears to be among the youngest features on the dwarf planet.

In the second nature study, members of the Dawn science team examined the composition of Ceres and found evidence for ammonia-rich clays. Why is this important?

Well, ammonia ice by itself would evaporate on Ceres today, because it is too warm. However, ammonia molecules could be stable if present in combination with other minerals. This raises the possibility that Ceres did not originate in the main asteroid belt between Mars and Jupiter, where it currently resides. But instead, might have formed in the outer solar system! Another idea is that Ceres formed close to its present position, incorporating materials that drifted in from the outer solar system, near the orbit of Neptune, where nitrogen ices are thermally stable.

As of this week, our Dawn spacecraft has reached its final orbital altitude at Ceres (about 240 miles from the surface). In mid-December, it will begin taking observations from this orbit, so be sure to check back for details!

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@saraxmix: What is it that makes you go back up there once you're home?

Solar System 10 Things to Know: Planetary Atmospheres

Every time you take a breath of fresh air, it’s easy to forget you can safely do so because of Earth’s atmosphere. Life on Earth could not exist without that protective cover that keeps us warm, allows us to breathe and protects us from harmful radiation—among other things.

What makes Earth’s atmosphere special, and how do other planets’ atmospheres compare? Here are 10 tidbits:

1. On Earth, we live in the troposphere, the closest atmospheric layer to Earth’s surface. “Tropos” means “change,” and the name reflects our constantly changing weather and mixture of gases. 

It’s 5 to 9 miles (8 to 14 kilometers) thick, depending on where you are on Earth, and it’s the densest layer of atmosphere. When we breathe, we’re taking in an air mixture of about 78 percent nitrogen, 21 percent oxygen and 1 percent argon, water vapor and carbon dioxide. More on Earth’s atmosphere›

2. Mars has a very thin atmosphere, nearly all carbon dioxide. Because of the Red Planet’s low atmospheric pressure, and with little methane or water vapor to reinforce the weak greenhouse effect (warming that results when the atmosphere traps heat radiating from the planet toward space), Mars’ surface remains quite cold, the average surface temperature being about -82 degrees Fahrenheit (minus 63 degrees Celsius). More on the greenhouse effect›

3. Venus’ atmosphere, like Mars’, is nearly all carbon dioxide. However, Venus has about 154,000 times more carbon dioxide in its atmosphere than Earth (and about 19,000 times more than Mars does), producing a runaway greenhouse effect and a surface temperature hot enough to melt lead. A runaway greenhouse effect is when a planet’s atmosphere and surface temperature keep increasing until the surface gets so hot that its oceans boil away. More on the greenhouse effect›

4. Jupiter likely has three distinct cloud layers (composed of ammonia, ammonium hydrosulfide and water) in its "skies" that, taken together, span an altitude range of about 44 miles (71 kilometers). The planet's fast rotation—spinning once every 10 hours—creates strong jet streams, separating its clouds into dark belts and bright zones wrapping around the circumference of the planet. More on Jupiter›

5. Saturn’s atmosphere—where our Cassini spacecraft ended its 13 extraordinary years of exploration of the planet—has a few unusual features. Its winds are among the fastest in the solar system, reaching speeds of 1,118 miles (1,800 kilometers) per hour. Saturn may be the only planet in our solar system with a warm polar vortex (a mass of swirling atmospheric gas around the pole) at both the North and South poles. Also, the vortices have “eye-wall clouds,” making them hurricane-like systems like those on Earth.

Another uniquely striking feature is a hexagon-shaped jet streamencircling the North Pole. In addition, about every 20 to 30 Earth years, Saturn hosts a megastorm (a great storm that can last many months). More on Saturn›

6. Uranus gets its signature blue-green color from the cold methane gas in its atmosphere and a lack of high clouds. The planet’s minimum troposphere temperature is 49 Kelvin (minus 224.2 degrees Celsius), making it even colder than Neptune in some places. Its winds move backward at the equator, blowing against the planet’s rotation. Closer to the poles, winds shift forward and flow with the planet’s rotation. More on Uranus›

7. Neptune is the windiest planet in our solar system. Despite its great distance and low energy input from the Sun, wind speeds at Neptune surpass 1,200 miles per hour (2,000 kilometers per hour), making them three times stronger than Jupiter’s and nine times stronger than Earth’s. Even Earth's most powerful winds hit only about 250 miles per hour (400 kilometers per hour). Also, Neptune’s atmosphere is blue for the very same reasons as Uranus’ atmosphere. More on Neptune›

8. WASP-39b, a hot, bloated, Saturn-like exoplanet (planet outside of our solar system) some 700 light-years away, apparently has a lot of water in its atmosphere. In fact, scientists estimate that it has about three times as much water as Saturn does. More on this exoplanet›

9. A weather forecast on “hot Jupiters”—blistering, Jupiter-like exoplanets that orbit very close to their stars—might mention cloudy nights and sunny days, with highs of 2,400 degrees Fahrenheit (about 1,300 degrees Celsius, or 1,600 Kelvin). Their cloud composition depends on their temperature, and studies suggest that the clouds are unevenly distributed. More on these exoplanets›

10. 55 Cancri e, a “super Earth” exoplanet (a planet outside of our solar system with a diameter between Earth’s and Neptune’s) that may be covered in lava, likely has an atmosphere containing nitrogen, water and even oxygen–molecules found in our atmosphere–but with much higher temperatures throughout. Orbiting so close to its host star, the planet could not maintain liquid water and likely would not be able to support life. More on this exoplanet›

Read the full version of this week’s Solar System 10 Things to Know HERE.

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Solar System: Things to Know This Week

Earlier this month, Mars was at opposition, which is the point in their orbits when Mars, Earth and the sun all line up, making for good conditions to view the Red Planet from Earth.

Now, it’s Saturn’s turn. The ringed planet will be at opposition on June 3, and this week is a great time to see it — both in the sky as well as up close, thanks to our spacecraft. Here are a few things to know about Saturn exploration this week:

1. Group Portrait

Thanks to their current orbital positions, our sun-observing spacecraft STEREO-A was recently able to capture the sun, Saturn, Mars and Earth in one image. Take a closer look HERE. Discover more about the STEREO mission HERE.

2. Likable, Lick-able Saturn

Saturn’s handsome visage is featured among the new stamps that the US Postal Service is releasing this week to highlight our adventures in planetary exploration.

3. Do You Even Know Saturn?

Yes, yes, it’s the one with the rings. But did you know Saturn has winds that can exceed 1000 miles per hour? Or that its magnetic field is hundreds of times as powerful as the Earth’s? Or that its day is just 10 hours long? How well do you really know the sixth planet?

4. Picking Up Signals

One thing you many not know about the planet is that it’s loud, at least if you listen to its radio signals. When our robotic Cassini spacecraft first approached Saturn, it detected the powerful fields that surround it. Engineers turned those signals into beautiful, eerie sounds. Listen to them HERE.

5.  Not All Who Wander Are Lost

The Cassini mission’s explorations of the Saturn system are very much ongoing. In the next few days, the spacecraft will be touring many locations, including the giant moon Titan, Saturn’s turbulent clouds, the tiny moon Albiorix and more! Get the full itinerary HERE.

Want to learn more? Read our full list of the 10 things to know this week about the solar system HERE.

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New Sun Science Stamps from the U.S. Postal Service

To start off the summer, the U.S. Postal Service issued a set of stamps showcasing views of the Sun from our Solar Dynamics Observatory!

Since its launch in 2010, the Solar Dynamics Observatory (or SDO) has kept up a near-constant watch on the Sun from its vantage point in orbit around Earth. SDO watches the Sun in more than 10 different types of light, including some that are absorbed by Earth’s atmosphere so can only be seen from space. These different types of light allow scientists to study different parts of the Sun – from its surface to its atmosphere – and better understand the solar activity that can affect our technology on Earth and in space.

The new set of stamps features 10 images from SDO. Most of these images are in extreme ultraviolet light, which is invisible to human eyes.

Let’s explore the science behind some of the stamps!

Coronal hole (May 2016)

The dark area capping the northern polar region of the Sun is a coronal hole, a magnetically open area on the Sun from which high-speed solar wind escapes into space. Such high-speed solar wind streams can spark magnificent auroral displays on Earth when they collide with our planet’s magnetic field.

Solar flare (August 2011)

The bright flash on the Sun’s upper right is a powerful solar flare. Solar flares are bursts of light and energy that can disturb the part of Earth’s atmosphere where GPS and radio signals travel.

Active Sun (October 2014)

This view highlights the many active regions dotting the Sun’s surface. Active regions are areas of intense and complex magnetic fields on the Sun – linked to sunspots – that are prone to erupting with solar flares or explosions of material called coronal mass ejections.

Plasma blast (August 2012)

These images show a burst of material from the Sun, called a coronal mass ejection. These eruptions of magnetized solar material can create space weather effects on Earth when they collide with our planet’s magnetosphere, or magnetic environment – including aurora, satellite disruptions, and, when extreme, even power outages.

Coronal loops (July 2012)

These images show evolving coronal loops across the limb and disk of the Sun. Just days after these images were taken, the Sun unleashed a powerful solar flare.

Coronal loops are often found over sunspots and active regions, which are areas of intense and complex magnetic fields on the Sun.

Sunspots (October 2014)

This view in visible light – the type of light we can see – shows a cluster of sunspots near the center of the Sun. Sunspots appear dark because they are relatively cool compared to surrounding material, a consequence of the way their extremely dense magnetic field prevents heated material from rising to the solar surface.

For more Sun science, follow NASA Sun on Twitter, on Facebook, or on the web.

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How will Cygnus Spacecraft Dock to Space Station?

Orbital ATK’s Cygnus CRS-6 spacecraft launched to the International Space Station on March 22. 

Cygnus will carry almost 7,500 pounds of science and research, crew supplies and vehicle hardware to the orbiting laboratory.

After launch in Florida, the spacecraft will arrive to the station on Saturday, March 26. Upon arrival, NASA astronaut and Expedition 46 Commander Tim Kopra will capture Cygnus at about 6:40 a.m. using the space station's Canadarm2 robotic arm to take hold of the spacecraft. Astronaut Tim Peake of ESA (European Space Agency) will support Kopra in a backup position. 

Installation (when Cygnus is connected to space station) is expected to begin at 9:25 a.m. NASA TV coverage for installation resumes at 9:15 a.m.

After the Cygnus spacecraft is berthed (connected) to the space station, the contents will be emptied and brought inside for use. Any trash that is on the space station, can be put inside the empty Cygnus before it is undocked from station and sent to burn up in Earth’s atmosphere.

Watch Capture

You can watch the capture of Orbital ATK’s Cygnus spacecraft online. Stream live coverage starting at 5:30 a.m. EDT on Saturday, March 26. Capture is scheduled for 6:40 a.m. 

Tune in again at 9:15 a.m. to watch #Cygnus installation to the station. 

Watch online: nasa.gov/nasatv

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How can citizens become more involved and informed about Earth sciences and developments? Are there mailing lists or accounts you suggest following?

Website: https://science.nasa.gov/citizenscience

NASA’s Satellite Data Help Save Lives

For the first time, measurements from our Earth-observing satellites are being used to help combat a potential outbreak of life-threatening cholera. Humanitarian teams in Yemen are targeting areas identified by a NASA-supported project that precisely forecasts high-risk regions based on environmental conditions observed from space.

Cholera is caused by consuming food or water contaminated with a bacterium called Vibrio cholerae.

The disease affects millions of people every year and can be deadly. It remains a major threat to global health, especially in developing countries, such as Yemen, where access to clean water is limited.

To calculate the likelihood of an outbreak, scientists run a computer model that takes satellite observations of things like rain and temperatures and combines them with information on local sanitation and clean water infrastructure. In 2017, the model achieved 92 percent accuracy in predicting the regions where cholera was most likely to occur and spread in Yemen. An outbreak that year in Yemen was the world's worst, with more than 1.1 million suspected cases and more than 2,300 deaths, according to the World Health Organization.

International humanitarian organizations took notice. In January 2018, Fergus McBean, a humanitarian adviser with the U.K.'s Department for International Development, read about the NASA-funded team's 2017 results and contacted them with an ambitious challenge: to create and implement a cholera forecasting system for Yemen, in only four months.

“It was a race against the start of rainy season,” McBean said.

The U.S. researchers began working with U.K. Aid, the U.K. Met Office, and UNICEF on the innovative approach to use the model to inform cholera risk reduction in Yemen.

In March, one month ahead of the rainy season, the U.K. international development office began using the model’s forecasts. Early results show the science team’s model predictions, coupled with Met Office weather forecasts, are helping UNICEF and other aid groups target their response to where support is needed most.

Photo Credit: UNICEF

“By joining up international expertise with those working on the ground, we have for the very first time used these sophisticated predictions to help save lives and prevent needless suffering,” said Charlotte Watts, chief scientist for United Kingdom’s Department for International Development.

Read more: go.nasa.gov/2MxKyw4

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5 of Your Fermi Gamma-ray Space Telescope Questions Answered

The Fermi Gamma-ray Space Telescope is a satellite in low-Earth orbit that detects gamma rays from exotic objects like black holes, neutron stars and fast-moving jets of hot gas. For 11 years Fermi has seen some of the highest-energy bursts of light in the universe and is helping scientists understand where gamma rays come from.

Confused? Don’t be! We get a ton of questions about Fermi and figured we'd take a moment to answer a few of them here.

1. Who was this Fermi guy?

The Fermi telescope was named after Enrico Fermi in recognition of his work on how the tiny particles in space become accelerated by cosmic objects, which is crucial to understanding many of the objects that his namesake satellite studies.

Enrico Fermi was an Italian physicist and Nobel Prize winner (in 1938) who immigrated to the United States to be a professor of physics at Columbia University, later moving to the University of Chicago.

Original image courtesy Argonne National Laboratory

Over the course of his career, Fermi was involved in many scientific endeavors, including the Manhattan Project, quantum theory and nuclear and particle physics. He even engineered the first-ever atomic reactor in an abandoned squash court (squash is the older, English kind of racquetball) at the University of Chicago.

There are a number of other things named after Fermi, too: Fermilab, the Enrico Fermi Nuclear Generating Station, the Enrico Fermi Institute and more. (He’s kind of a big deal in the physics world.)

Fermi even had something to say about aliens! One day at lunch with his buddies, he wondered if extraterrestrial life existed outside our solar system, and if it did, why haven't we seen it yet? His short conversation with friends sparked decades of research into this idea and has become known as the Fermi Paradox — given the vastness of the universe, there is a high probability that alien civilizations exist out there, so they should have visited us by now.  

2. So, does the Fermi telescope look for extraterrestrial life?

No. Although both are named after Enrico Fermi, the Fermi telescope and the Fermi Paradox have nothing to do with one another.

Fermi does not look for aliens, extraterrestrial life or anything of the sort! If aliens were to come our way, Fermi would be no help in identifying them, and they might just slip right under Fermi’s nose. Unless, of course, those alien spacecraft were powered by processes that left behind traces of gamma rays.

Fermi detects gamma rays, the highest-energy form of light, which are often produced by events so far away the light can take billions of years to reach Earth. The satellite sees pulsars, active galaxies powered by supermassive black holes and the remnants of exploding stars. These are not your everyday stars, but the heavyweights of the universe. 

3. Does the telescope shoot gamma rays?

No. Fermi DETECTS gamma rays using its two instruments, the Large Area Telescope (LAT) and the Gamma-ray Burst Monitor (GBM).

The LAT sees about one-fifth of the sky at a time and records gamma rays that are millions of times more energetic than visible light. The GBM detects lower-energy emissions, which has helped it identify more than 2,000 gamma-ray bursts – energetic explosions in galaxies extremely far away.

The highest-energy gamma ray from a gamma-ray burst was detected by Fermi’s LAT, and traveled 3.8 billion light-years to reach us from the constellation Leo.

4. Will gamma rays turn me into a superhero?

Nope. In movies and comic books, the hero has a tragic backstory and a brush with death, only to rise out of some radioactive accident stronger and more powerful than before. In reality, that much radiation would be lethal.

In fact, as a form of radiation, gamma rays are dangerous for living cells. If you were hit with a huge amount of gamma radiation, it could be deadly — it certainly wouldn’t be the beginning of your superhero career.

5. That sounds bad…does that mean if a gamma-ray burst hit Earth, it would wipe out the planet and destroy us all?

Thankfully, our lovely planet has an amazing protector from gamma radiation: an atmosphere. That is why the Fermi telescope is in orbit; it’s easier to detect gamma rays in space!

Gamma-ray bursts are so far away that they pose no threat to Earth. Fermi sees gamma-ray bursts because the flash of gamma rays they release briefly outshines their entire home galaxies, and can sometimes outshine everything in the gamma-ray sky.

If a habitable planet were too close to one of these explosions, it is possible that the jet emerging from the explosion could wipe out all life on that planet. However, the probability is extremely low that a gamma-ray burst would happen close enough to Earth to cause harm. These events tend to occur in very distant galaxies, so we’re well out of reach.

We hope that this has helped to clear up a few misconceptions about the Fermi Gamma-ray Space Telescope. It’s a fantastic satellite, studying the craziest extragalactic events and looking for clues to unravel the mysteries of our universe!

Now that you know the basics, you probably want to learn more! Follow the Fermi Gamma-ray Space Telescope on Twitter (@NASAFermi) or Facebook (@nasafermi), and check out more awesome stuff on our Fermi webpage.

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