Meet Fermi: Our Eyes On The Gamma-Ray Sky

All Eyes on Harvey

Our Earth-observing satellites, along with the cameras and crew of the International Space Station, are keeping a watchful eye over Hurricane Harvey as it churns in the Gulf of Mexico. When Hurricane Harvey blows ashore over coastal Texas on Friday night, it will likely be the first major hurricane to make landfall in the United States since 2005.

Above is a view of Harvey from NOAA's GOES-East satellite captured on Aug. 25 at 10:07 a.m. EDT (1407 UTC) clearly showing the storm’s eye as Harvey nears landfall in the southeastern coast of Texas. As Hurricane Harvey continued to strengthen, we analyzed the storm’s rainfall, cloud heights and cloud top temperatures. 

Above, the Global Precipitation Mission (GPM) core observatory satellite flew almost directly above intensifying Hurricane Harvey on August 24, 2017 at 6:30 p.m. EDT (2230 UTC) and we used the Microwave Imager instrument to peer through dense storm clouds to reveal the location of intense rainfall bands near the center of the hurricane. 

And from the International Space Station, cameras were pointed towards Harvey as the orbiting laboratory passed overhead 250 miles above the Earth. The video above includes views from the space station recorded on August 24, 2017 at 6:15 p.m. Eastern Time.

The National Hurricane Center expects Harvey to be a category 3 storm on the Saffir-Simpson scale—with winds higher than 111 miles (179 kilometers) per hour—when it makes landfall. It will likely produce a storm surge of 6 to 12 feet (2 to 4 meters) and drop between 15 and 25 inches (38 and 63 centimeters) of rain in some areas—enough to produce life-threatening flash floods.

For updated forecasts, visit the National Hurricane Center.  Ensure you are prepared for Hurricanes. Get tips and more at  FEMA’s Ready site. Get the latest updates from NASA satellites by visiting our Hurricane site.

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Earth Expeditions Preview

A Closer Look at Our Home Planet

Our view from space shows our planet is changing, but to really understand the details of these changes and what they mean for our future, scientists need a closer look. Over the next six months, we’re taking you on a world tour as we kick off major new field research campaigns to study regions of critical change from land, sea and air.

You can follow the Earth Expeditions on Facebook, Twitter and their Blog.

Take a look at the eight campaigns we will explore:

CORAL (Coral Reef Airborne Laboratory)

This three-year CORAL mission will use advanced airborne instruments and in-water measurements to survey a portion of the world’s coral reefs. The mission will assess the conditions of these threatened ecosystems to better understand their relation to the environment, including physical, chemical and human factors. With a new understanding of reef condition, the future of this global ecosystem can be predicted.

OMG (Oceans Melting Greenland)

Oceans Melting Greenland (OMG) mission will pave the way for improved estimates of sea level rise by addressing the question: To what extent are the oceans melting Greenland’s ice from below? This mission will observe changing water temperatures and glaciers that reach the ocean around all of Greenland from 2015 to 2020. This year, the OMG mission will fly over the periphery of Greenland to take measurements of the heights and extents of Greenland’s coastal glaciers that reach the ocean and release expendable sensors to measure the temperature and salinity of coastal waters. The OMG field campaign will gather data that will help scientists both understand how the oceans are joining with the atmosphere in melting the vast ice sheet and to predict the extent and timing of the resulting sea level rise.

NAAMES (North Atlantic Aerosols and Marine Ecosystems Study)

About half the carbon dioxide emitted into Earth’s atmosphere each year ends up in the ocean, and plankton absorb a lot of it. The NAAMES mission studies the world’s largest plankton bloom and how it gives rise to small organic particles that leave the ocean and end up in the atmosphere, ultimately influencing clouds and climate. This mission will be taking measurements from both ship and aircraft in the North Atlantic. 

KORUS-AQ (Korea U.S.-Air Quality)

Air quality is a significant environmental concern around the world. Scientists are developing new ways to untangle the different factors that contribute to poor air quality. KORUS-AQ is a joint field study between NASA and the Republic of Korea to advance the ability to monitor air pollution from space. The campaign will assess air quality across urban, rural and coastal South Korea using observations from aircraft, ground sites, ships and satellites to test air quality models and remote sensing methods. Findings from this study will help develop observing systems using models and data to improve air quality assessments for decision makers.

ABoVE (Arctic Boreal Vulnerability Experiment)

The ABoVE mission covers 2.5 million square miles of tundra, forests, permafrost and lakes in Alaska and Northwestern Canada. Scientists from the mission are using satellites and aircraft to study this formidable terrain as it changes in a warming climate. Teams of researchers will also go out into the field to gather additional data. The mission will investigate questions about the role of climate in wildfires, thawing permafrost, wildlife migration habits, insect outbreaks and more.

ATom (Atmospheric Tomography)

The ATom mission takes flight through Earth’s atmosphere to understand how short-lived greenhouse gases like ozone and methane contribute to climate change. In late July through August 2016, a suite of instruments aboard our DC-8 flying laboratory will be hopping down the Pacific Ocean from Alaska to the southern tip of South America. It will then travel north up the Atlantic to Greenland to measure more than 200 gases and particles in the air and their interactions all around the world.

ORACLES (Observations of Clouds above Aerosols and their Interactions)

Southern Africa produces almost a third of the world’s vegetative burning, which sends smoke particles up into the atmosphere, where they eventually mix with stratocumulus clouds over the southeastern Atlantic Ocean. Little is known about how these particles impact the clouds, which play a key role in both regional and global surface temperatures and precipitation. The ORACLES mission is a five-year ground and air campaign aimed at better understanding their interactions and improve on current climate models.

ACT-America (Atmospheric Carbon and Transport – America)

The ACT-America mission will conduct five airborne campaigns across three regions in the eastern United States to study the transport of atmospheric carbon. This region serves as an ideal study area for its productive biosphere, agricultural activity, gas and oil extraction and consumption, dynamic seasonally varying weather patterns and the most extensive carbon cycle and meteorological observing networks on Earth. Using space borne, airborne and ground-based measurements, this mission will enable more accurate and precise estimates for climate management and prediction by studying sources and sinks of greenhouse gases, which act as a thermal blanket for Earth.

Remember to follow the Earth Expeditions on Facebook, Twitter and their Blog.

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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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What is your advise to people who wanna be astronaut?

10 Things: Mysterious 'Oumuamua

The interstellar object 'Oumuamua perplexed scientists in October 2017 as it whipped past Earth at an unusually high speed. This mysterious visitor is the first object ever seen in our solar system that is known to have originated elsewhere.  Here are five things we know and five things we don’t know about the first confirmed interstellar object to pass through our solar system.

1. We know it’s not from around here.

 The object known as 1I/2017 U1 (and nicknamed ‘Oumuamua) was traveling too fast (196,000 mph, that’s 54 miles per second or 87.3 kilometers per second) to have originated in our solar system. Comets and asteroids from within our solar system move at a slower speed, typically an average of 12 miles per second (19 kilometers per second) . In non-technical terms, 'Oumuamua is an “interstellar vagabond.”

Artist impression of the interstellar object ‘Oumuamua. Credit: ESA/Hubble, NASA, ESO, M. Kornmesser

2. We’re not sure where it came from.

'Oumuamua entered our solar system from the rough direction of the constellation Lyra, but it’s impossible to tell where it originally came from. Thousands of years ago, when 'Oumuamua started to wander from its parent planetary system, the stars were in a different position so it’s impossible to pinpoint its point of origin. It could have been wandering the galaxy for billions of years.

3. We know it’s out of here.

'Oumuamua is headed back out of our solar system and won’t be coming back. It’s rapidly headed in the direction of the constellation Pegasus and will cross the orbit of Neptune in about four years and cover one light year’s distance in about 11,000 years.

4. We don’t really know what it looks like.

We’ve only seen it as a speck of light through a telescope (it is far away and less than half a mile in length), but its unique rotation leads us to believe that it’s elongated like a cigar, about 10 times longer than it is wide. We can’t see it anymore. Artist’s concepts are the best guesses at what it might look like.

5. We know it got a little speed boost.

A rapid response observing campaign allowed us to watch as 'Oumuamua got an unexpected boost in speed. The acceleration slightly changed its course from earlier predictions.

“This additional subtle force on ′Oumuamua likely is caused by jets of gaseous material expelled from its surface,” said Davide Farnocchia of the Center for Near Earth Object Studies (CNEOS) at NASA’s Jet Propulsion Laboratory. “This same kind of outgassing affects the motion of many comets in our solar system.”

6. We know it’s tumbling.

Unusual variations in the comet’s brightness suggest it is rotating on more than one axis.

This illustration shows ‘Oumuamua racing toward the outskirts of our solar system. As the complex rotation of the object makes it difficult to determine the exact shape, there are many models of what it could look like. Credits: NASA/ESA/STScI

7. We don’t know what it’s made of.

Comets in our solar system kick off lots of dust and gas when they get close to the Sun, but 'Oumuamua did not, which led observers to consider defining it as an asteroid.

Karen Meech, an astronomer at the University of Hawaii’s Institute of Astronomy, said small dust grains, present on the surface of most comets, may have eroded away during ′Oumuamua's long journey through interstellar space. "The more we study ′Oumuamua, the more exciting it gets." she said. It could be giving off gases that are harder to see than dust, but it’s impossible to know at this point.

8. We knew to expect it.

Just not when. The discovery of an interstellar object has been anticipated for decades. The space between the stars probably has billions and billions of asteroids and comets roaming around independently. Scientists understood that inevitably, some of these small bodies would enter our own solar system. This interstellar visit by ‘Oumuamua reinforces our models of how planetary systems form.

9. We don’t know what it’s doing now.

After January 2018, 'Oumuamua was no longer visible to telescopes, even in space. But scientists continue to analyze the data gathered during the international observing campaign and crack open more mysteries about this unique interstellar visitor.

10. We know there’s a good chance we’ll see another one...eventually.

Because ′Oumuamua is the first interstellar object ever observed in our solar system, researchers caution that it’s difficult to draw general conclusions about this newly-discovered class of celestial bodies. Observations point to the possibility that other star systems regularly eject small comet-like objects and there should be more of them drifting among the stars. Future ground- and space-based surveys could detect more of these interstellar vagabonds, providing a larger sample for scientists to analyze. Adds, Karen Meech, an astronomer at the University of Hawaii’s Institute of Astronomy: “I can hardly wait for the next interstellar object!"

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Are we alone in the universe?

There’s never been a better time to ponder this age-old question. We now know of thousands of exoplanets – planets that orbit stars elsewhere in the universe.

So just how many of these planets could support life?

Scientists from a variety of fields — including astrophysics, Earth science, heliophysics and planetary science — are working on this question. Here are a few of the strategies they’re using to learn more about the habitability of exoplanets.

Squinting at Earth

Even our best telescopic images of exoplanets are still only a few pixels in size. Just how much information can we extract from such limited data? That’s what Earth scientists have been trying to figure out.

One group of scientists has been taking high-resolution images of Earth from our Earth Polychromatic Imaging Camera and ‘degrading’ them in order to match the resolution of our pixelated exoplanet images. From there, they set about a grand process of reverse-engineering: They try to extract as much accurate information as they can from what seems — at first glance — to be a fairly uninformative image.

Credits: NOAA/NASA/DSCOVR

So far, by looking at how Earth’s brightness changes when land versus water is in view, scientists have been able to reverse-engineer Earth's albedo (the proportion of solar radiation it reflects), its obliquity (the tilt of its axis relative to its orbital plane), its rate of rotation, and even differences between the seasons. All of these factors could potentially influence a planet’s ability to support life.

Avoiding the “Venus Zone”

In life as in science, even bad examples can be instructive. When it comes to habitability, Venus is a bad example indeed: With an average surface temperature of 850 degrees Fahrenheit, an atmosphere filled with sulfuric acid, and surface pressure 90 times stronger than Earth’s, Venus is far from friendly to life as we know it.

The surface of Venus, imaged by Soviet spacecraft Venera 13 in March 1982

Since Earth and Venus are so close in size and yet so different in habitability, scientists are studying the signatures that distinguish Earth from Venus as a tool for differentiating habitable planets from their unfriendly look-alikes.

Using data from our Kepler Space Telescope, scientists are working to define the “Venus Zone,” an area where planetary insolation – the amount of light a given planet receives from its host star -- plays a key role in atmospheric erosion and greenhouse gas cycles.

Planets that appear similar to Earth, but are in the Venus Zone of their star, are, we think, unlikely to be able to support life.

Modeling Star-Planet Interactions

When you don’t know one variable in an equation, it can help to plug in a reasonable guess and see how things work out. Scientists used this process to study Proxima b, our closest exoplanet neighbor. We don’t yet know whether Proxima b, which orbits the red dwarf star Proxima Centauri four light-years away, has an atmosphere or a magnetic field like Earth’s. However, we can estimate what would happen if it did.

The scientists started by calculating the radiation emitted by Proxima Centauri based on observations from our Chandra X-ray Observatory. Given that amount of radiation, they estimated how much atmosphere Proxima b would be likely to lose due to ionospheric escape — a process in which the constant outpouring of charged stellar material strips away atmospheric gases.

With the extreme conditions likely to exist at Proxima b, the planet could lose the equivalent of Earth’s entire atmosphere in 100 million years — just a fraction of Proxima b’s 4-billion-year lifetime. Even in the best-case scenario, that much atmospheric mass escapes over 2 billion years. In other words, even if Proxima b did at one point have an atmosphere like Earth, it would likely be long gone by now.

Imagining Mars with a Different Star

We think Mars was once habitable, supporting water and an atmosphere like Earth’s. But over time, it gradually lost its atmosphere – in part because Mars, unlike Earth, doesn’t have a protective magnetic field, so Mars is exposed to much harsher radiation from the Sun's solar wind.

But as another rocky planet at the edge of our solar system’s habitable zone, Mars provides a useful model for a potentially habitable planet. Data from our Mars Atmosphere and Volatile Evolution, or MAVEN, mission is helping scientists answer the question: How would Mars have evolved if it were orbiting a different kind of star?

Scientists used computer simulations with data from MAVEN to model a Mars-like planet orbiting a hypothetical M-type red dwarf star. The habitable zone of such a star is much closer than the one around our Sun.

Being in the habitable zone that much closer to a star has repercussions. In this imaginary situation, the planet would receive about 5 to 10 times more ultraviolet radiation than the real Mars does, speeding up atmospheric escape to much higher rates and shortening the habitable period for the planet by a factor of about 5 to 20.

These results make clear just how delicate a balance needs to exist for life to flourish. But each of these methods provides a valuable new tool in the multi-faceted search for exoplanet life.  Armed with these tools, and bringing to bear a diversity of scientific perspectives, we are better positioned than ever to ask: are we alone?

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O_o  When we peer deep into space, we don't expect to find something staring back at us...

This galactic ghoul, captured by our Hubble Space Telescope, is actually a titanic head-on collision between two galaxies. Each "eye" is the bright core of a galaxy, one of which slammed into another. The outline of the face is a ring of young blue stars. Other clumps of new stars form a nose and mouth.

Although galaxy collisions are common most of them are not head-on smashups like this Arp-Madore system. Get spooked & find out what lies inside this ghostly apparition, here. 

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There’s Going to Be an Outburst!

Watch the Perseid Meteor Shower at Its Peak Tonight

The last time we had an outburst, that is a meteor shower with more meteors than usual, was in 2009. This year’s Perseid meteor shower is predicted to be just as spectacular starting tonight!

Plan to stay up late tonight or set your alarm clock for the wee morning hours to see this cosmic display of “shooting stars” light up the night sky. Known for it’s fast and bright meteors, tonight’s annual Perseid meteor shower is anticipated to be one of the best meteor viewing opportunities this year.

For stargazers experiencing cloudy or light-polluted skies, a live broadcast of the Perseid meteor shower will be available via Ustream overnight tonight and tomorrow, beginning at 10 p.m. EDT.

“Forecasters are predicting a Perseid outburst this year with double normal rates on the night of Aug. 11-12,” said Bill Cooke with NASA’s Meteoroid Environments Office in Huntsville, Alabama. “Under perfect conditions, rates could soar to 200 meteors per hour.”

Every Perseid meteor is a tiny piece of the comet Swift-Tuttle, which orbits the sun every 133 years. When Earth crosses paths with Swift-Tuttle’s debris, specks of comet-stuff hit Earth’s atmosphere and disintegrate in flashes of light. These meteors are called Perseids because they seem to fly out of the constellation Perseus.

Most years, Earth might graze the edge of Swift-Tuttle’s debris stream, where there’s less activity. Occasionally, though, Jupiter’s gravity tugs the huge network of dust trails closer, and Earth plows through closer to the middle, where there’s more material.

This is predicted be one of those years!

Learn more about the Perseids!

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I was looking at the GLOBE Observer experiments for citizens and was wondering how the eclipse affects the cloud type? Or, I guess, why is that an important thing to measure? Thank you for answering our questions!

As my dad likes to say, I went to college to take up space, so I’m not sure what happens in the atmosphere. However, I think that the atmospheric scientists are interested in the types of waves that will be set up by the temperature gradients generated by the eclipse. So as totality occurs you get a very fast temperature drop in a localized area. I believe this can set up strong winds which may affect the type of clouds and/or their shapes. This is going to be the best-observed eclipse! And one thing I’ve learned as a scientist is that you never know what you’ll find in your data so collect as much of it as possible even if you aren’t sure what you’ll find. That is sometimes when you get the most exciting results! Thanks for downloading the app and helping to collect the data! 

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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