Our Universe Is FULL Of Strange And Surprising Things.

A Wrinkle in Space-Time: The Eclipse That “Proved” Einstein Right

One hundred years ago a total solar eclipse turned an obscure scientist into a household name. You might have heard of him — his name is Albert Einstein. But how did a solar eclipse propel him to fame?

First, it would be good to know a couple things about general relativity. (Wait, don’t go! We’ll keep this to the basics!)

A decade before he finished general relativity, Einstein published his special theory of relativity, which demonstrates how space and time are interwoven as a single structure he dubbed “space-time.” General relativity extended the foundation of special relativity to include gravity. Einstein realized that gravitational fields can be understood as bends and curves in space-time that affect the motions of objects including stars, planets — and even light.

For everyday situations the centuries-old description of gravity by Isaac Newton does just fine. However, general relativity must be accounted for when we study places with strong gravity, like black holes or neutron stars, or when we need very precise measurements, like pinpointing a position on Earth to within a few feet. That makes it hard to test!

A prediction of general relativity is that light passing by an object feels a slight "tug", causing the light's path to bend slightly. The more mass the object has, the more the light will be deflected. This sets up one of the tests that Einstein suggested — measuring how starlight bends around the Sun, the strongest source of gravity in our neighborhood. Starlight that passes near the edge of the Sun on its way to Earth is deflected, altering by a small amount where those stars appear to be. How much? By about the width of a dime if you saw it at a mile and a quarter away! But how can you observe faint stars near the brilliant Sun? During a total solar eclipse!

That’s where the May 29, 1919, total solar eclipse comes in. Two teams were dispatched to locations in the path of totality — the places on Earth where the Moon will appear to completely cover the face of the Sun during an eclipse. One team went to South America and another to Africa.

On eclipse day, the sky vexed both teams, with rain in Africa and clouds in South America. The teams had only mere minutes of totality during which to take their photographs, or they would lose the opportunity until the next total solar eclipse in 1921! However, the weather cleared at both sites long enough for the teams to take images of the stars during totality.

The teams took two sets of photographs of the same patch of sky – one set during the eclipse and another set a few months before or after, when the Sun was out of the way. By comparing these two sets of photographs, researchers could see if the apparent star positions changed as predicted by Einstein. This is shown with the effect exaggerated in the image above.

A few months after the eclipse, when the teams sorted out their measurements, the results demonstrated that general relativity correctly predicted the positions of the stars. Newspapers across the globe announced that the controversial theory was proven (even though that’s not quite how science works). It was this success that propelled Einstein into the public eye.

The solar eclipse wasn’t the first test of general relativity. For more than two centuries, astronomers had known that Mercury’s orbit was a little off. Its perihelion — the point during its orbit when it is closest to the Sun — was changing faster than Newton’s laws predicted. General relativity easily explains it, though, because Mercury is so close to the Sun that its orbit is affected by the Sun’s dent in space-time, causing the discrepancy.  

In fact, we still test general relativity today under different conditions and in different situations to see whether or not it holds up. So far, it has passed every test we’ve thrown at it.

Curious to know where we need general relativity to understand objects in space? Tune into our Tumblr tomorrow to find out!

You can also read more about how our understanding of the universe has changed during the past 100 years, from Einstein's formulation of gravity through the discovery of dark energy in our Cosmic Times newspaper series.

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TESS: The Planet Hunter

So you’re thinking...who’s TESS? But, it’s more like: WHAT is TESS? 

The Transiting Exoplanet Survey Satellite (TESS) is an explorer-class planet finder that is scheduled to launch in April 2018. This mission will search the entire sky for exoplanets — planets outside our solar system that orbit sun-like stars.

In the first-ever space borne all-sky transit survey, TESS will identify planets ranging from Earth-sized to gas giants, orbiting a wide range of stellar types and orbital distances.

The main goal of this mission is to detect small planets with bright host stars in the solar neighborhood, so that we can better understand these planets and their atmospheres.

TESS will have a full time job monitoring the brightness of more than 200,000 stars during a two year mission. It will search for temporary drops in brightness caused by planetary transits. These transits occur when a planet’s orbit carries it directly in front of its parent star as viewed from Earth (cool GIF below).

TESS will provide prime targets for further, more detailed studies with the James Webb Space Telescope (JWST), as well as other large ground-based and space-based telescopes of the future.

What is the difference between TESS and our Kepler spacecraft?

TESS and Kepler address different questions: Kepler answers "how common are Earth-like planets?" while TESS answers “where are the nearest transiting rocky planets?”

What do we hope will come out of the TESS mission?

The main goal is to find rocky exoplanets with solid surfaces at the right distance from their stars for liquid water to be present on the surface. These could be the best candidates for follow-up observations, as they fall within the “habitable zone” and be at the right temperatures for liquid water on their surface.

TESS will use four cameras to study sections of the sky’s north and south hemispheres, looking for exoplanets. The cameras would cover about 90 percent of the sky by the end of the mission. This makes TESS an ideal follow-up to the Kepler mission, which searches for exoplanets in a fixed area of the sky. Because the TESS mission surveys the entire sky, TESS is expected to find exoplanets much closer to Earth, making them easier for further study.

Stay updated on this planet-hunting mission HERE.

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Voyager: The Golden Record

It’s the 1970s, and we’re about to send two spacecraft (Voyager 1 & 2) into space. These two spacecraft will eventually leave our solar system and become the most distant man-made objects…ever. How can we leave our mark on them in the case that other spacefarers find them in the distant future?

The Golden Record.

We placed an ambitious message aboard Voyager 1 and 2, a kind of time capsule, intended to communicate a story of our world to extraterrestrials. The Voyager message is carried by a phonograph record, a 12-inch gold-plated copper disk containing sounds and images selected to portray the diversity of life and culture on Earth.

The Golden Record Cover

The outward facing cover of the golden record carries instructions in case it is ever found. Detailing to its discoverers how to decipher its meaning.

In the upper left-hand corner is an easily recognized drawing of the phonograph record and the stylus carried with it. The stylus is in the correct position to play the record from the beginning. Written around it in binary arithmetic is the correct time of one rotation of the record. The drawing indicates that the record should be played from the outside in.

The information in the upper right-hand portion of the cover is designed to show how the pictures contained on the record are to be constructed from the recorded signals. The top drawing shows the typical signal that occurs at the start of the picture. The picture is made from this signal, which traces the picture as a series of vertical lines, similar to ordinary television. Immediately below shows how these lines are to be drawn vertically, with staggered “interlace” to give the correct picture rendition. Below that is a drawing of an entire picture raster, showing that there are 52 vertical lines in a complete picture.

Immediately below this is a replica of the first picture on the record to permit the recipients to verify that they are decoding the signals correctly. A circle was used in this picture to ensure that the recipients use the correct ratio of horizontal to vertical height in picture reconstruction.

The drawing in the lower left-hand corner of the cover is the pulsar map previously sent as part of the plaques on Pioneers 10 and 11. It shows the location of the solar system with respect to 14 pulsars, whose precise periods are given.

The drawing containing two circles in the lower right-hand corner is a drawing of the hydrogen atom in its two lowest states, with a connecting line and digit 1 to indicate that the time interval associated with the transition from one state to the other is to be used as the fundamental time scale, both for the time given on the cover and in the decoded pictures.

The Contents

The contents of the record were selected for NASA by a committee chaired by Carl Sagan of Cornell University and his associates. 

They assembled 115 images and a variety of natural sounds, such as those made by surf, wind and thunder, birds, whales and other animals. To this, they added musical selections from different cultures and eras, and spoken greetings from Earth-people in fifty-five languages, and printed messages from President Carter and U.N. Secretary General Waldheim.

Listen to some of the sounds of the Golden Record on our Soundcloud page:

Golden Record: Greetings to the Universe

Golden Record: Sounds of Earth

Songs from Chuck Berry’s “Johnny B. Goode,” to Beethoven’s Fifth Symphony are included on the golden record. For a complete list of songs, visit: https://voyager.jpl.nasa.gov/golden-record/whats-on-the-record/music/

The 115 images included on the record, encoded in analog form, range from mathematical definitions to humans from around the globe. See the images here: https://voyager.jpl.nasa.gov/golden-record/whats-on-the-record/images/

Making the Golden Record

Many people were instrumental in the design, development and manufacturing of the golden record. 

Blank records were provided by the Pyral S.A. of Creteil, France. CBS Records contracted the JVC Cutting Center in Boulder, CO to cut the lacquer masters which were then sent to the James G. Lee Record Processing center in Gardena, CA to cut and gold plate eight Voyager records.

The record is constructed of gold-plated copper and is 12 inches in diameter. The record’s cover is aluminum and electroplated upon it is an ultra-pure sample of the isotope uranium-238. Uranium-238 has a half-life of 4.468 billion years.

Learn more about the golden record HERE.

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Will there be a livestream to the solar eclipse on the NASA website?

Yup! We’ll have a live stream up https://eclipse2017.nasa.gov/eclipse-live-stream They I believe will also be covering events that are happening across the US. A bunch of my office mates here are going across the US to help with the coverage and to collect data! It should be incredibly exciting! 

Throwback Thursday: Apollo 11 FAQ Edition

With the help of the NASA History Office, we’ve identified some of the most frequently asked questions surrounding the first time humans walked on the surface of another world. Read on and click here to check out our previous Apollo FAQs. 

How many moon rocks did the Apollo crews bring back? What did we learn?

The six crews that landed on the Moon brought back 842 pounds (382 kilograms) of rocks, sand and dust from the lunar surface. Each time, they were transferred to Johnson Space Center’s Lunar Receiving Laboratory, a building that also housed the astronauts during their three weeks of quarantine. Today the building now houses other science divisions, but the lunar samples are preserved in the Lunar Sample Receiving Laboratory.

Built in 1979, the laboratory is the chief repository of the Apollo samples.

From these pieces of the Moon we learned that its chemical makeup is similar to that of Earth’s, with some differences. Studying the samples has yielded clues to the origins of the solar system. In March of 2019, we announced that three cases of pristine Moon samples will be unsealed for the first time in 50 years so that we can take advantage of the improved technology that exists today! 

Did you know you might not have to travel far to see a piece of the Moon up close? Visit our Find a Moon Rock page to find out where you can visit a piece of the Moon.

What did Apollo astronauts eat on their way to the Moon?

Astronaut food has come a long way since the days of Project Mercury, our first human spaceflight program that ran from 1958-1963. Back then, astronauts “enjoyed” food in cube form or squeezed out of tubes. Early astronaut food menus were designed less for flavor and more for nutritional value, but that eventually shifted as technology evolved. Astronauts today can enjoy whole foods like apples, pizza and even tacos. 

Apollo crews were the first to have hot water, making it easier to rehydrate their foods and improve its taste. They were also the first to use a “spoon bowl,” a plastic container that was somewhat like eating out of a Ziploc bag with a spoon. Here’s an example of a day’s menu for a voyage to the Moon:

Breakfast: bacon squares, strawberry cubes and an orange drink.

Lunch: beef and potatoes, applesauce and a brownie.

Dinner: salmon salad, chicken and rice, sugar cookie cubes and a pineapple grapefruit drink.

What did Michael Collins do while he orbited the Moon, alone in the Command Module?

As Neil Armstrong and Buzz Aldrin worked on the lunar surface, Command Module pilot Michael Collins orbited the Moon, alone, for the next 21.5 hours. On board he ran systems checks, made surface observations and communicated with Mission Control when there wasn’t a communications blackout. Blackouts happened every time Collins went behind the Moon. In 2009, Collins wrote this in response to a flurry of media questions about the 40th anniversary of the mission:

Q. Circling the lonely Moon by yourself, the loneliest person in the universe, weren't you lonely? A. No. Far from feeling lonely or abandoned, I feel very much a part of what is taking place on the lunar surface. I know that I would be a liar or a fool if I said that I have the best of the three Apollo 11 seats, but I can say with truth and equanimity that I am perfectly satisfied with the one I have. This venture has been structured for three men, and I consider my third to be as necessary as either of the other two.”

What will Artemis astronauts bring back when they land on the Moon?

Artemis missions to the Moon will mark humanity’s first permanent presence on another world. The first woman and the next man to explore the lunar surface will land where nobody has ever attempted to land before -- on the Moon’s south pole where there are billions of tons of water ice that can be used for oxygen and fuel. We don’t know yet what astronauts will bring back from this unexplored territory, but we do know that they will return with hope and inspiration for the next generation of explorers: the Artemis generation. Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com.

21 Years of Amazing Earth Imagery

On April 29, 1999, NASA Earth Observatory started delivering science stories and imagery to the public through the Internet. Today, we turn 21! So much has changed in the past two decades... 

One of the most notable changes is the way we view our home planet. Check out some of the beautiful imagery of our planet over the past 21 years.

2000: Pine Island Glacier

Most people will never see Pine Island Glacier in person. Located near the base of the Antarctic Peninsula—the “thumb” of the continent—the glacier lies more than 2,600 kilometers (1,600 miles) from the tip of South America. That’s shorter than a cross-country flight from New York to Los Angeles, but there are no runways on the glacier and no infrastructure. Only a handful of scientists have ever set foot on its ice.

This animation shows a wide view of Pine Island Glacier and the long-term retreat of its ice front. Images were acquired by the Moderate Resolution Imaging Spectroradiometer (MODIS) on our Terra satellite from 2000 to 2019. Notice that there are times when the front appears to stay in the same place or even advance, though the overall trend is toward retreat. Read more.

2002: The Blue Marble

In February 2002, Earth Observatory published this “blue marble” image based on the most detailed collection of true-color imagery of the entire Earth at that time. Using a collection of satellite-based observations, scientists and visualizers stitched together months of observations of the land surface, oceans, sea ice and clouds into a seamless, true-color mosaic of every square kilometer (.386 square mile) of our planet. Most of the information contained in this image came from Moderate Resolution Imaging Spectrometer (MODIS), illustrating the instrument's outstanding capacity to act as an integrated tool for observing a variety of terrestrial, oceanic and atmospheric features of the Earth. Read more.

2009: Tsauchab River Bed

The Tsauchab River is a famous landmark for the people of Namibia and tourists. Yet few people have ever seen the river flowing with water. In December 2009, an astronaut on the International Space Station caught this glimpse of the Tsauchab River bed jutting into the sea of red dunes. It ends in a series of light-colored, silty mud holes on the dry lake floor.

Like several other rivers around the Namib Desert, the Tsauchab brings sediment down from the hinterland toward the coastal lowland. This sediment is then blown from the river beds, and over tens of millions of years it has accumulated as the red dunes of the Namib Sand Sea. Read more. 

2012: Manning Island and Foxe Basin, Canada

Although it may look like a microscope’s view of a thin slice of mineral-speckled rock, this image was actually acquired in space by the Earth Observing-1 satellite in July 2012. It shows a small set of islands and a rich mixture of ice in Foxe Basin, the shallow northern reaches of Hudson Bay.

The small and diverse sizes of the ice floes indicate that they were melting. The darkest colors in the image are open water. Snow-free ice appears gray, while snow-covered ice appears white. The small, dark features on many of the floes are likely melt ponds. Read more.

2013: A Lava Lamp Look at the Atlantic

Stretching from tropical Florida to the doorstep of Europe, this river of water carries a lot of heat, salt, and history. The Gulf Stream is an important part of the global ocean conveyor belt that moves water and heat across the North Atlantic from the equator toward the poles. It is one of the strongest currents on Earth, and one of the most studied.

This image shows a small portion of the Gulf Stream as it appears in infrared imagery. Data for this image was acquired on April 9, 2013, by the Thermal Infrared Sensor (TIRS) on the Landsat 8 satellite. TIRS observes in wavelengths of 10.9 micrometers and 12.0 micrometers. The image above is centered at 33.06° North latitude, 73.86° West longitude, about 500 kilometers (300 miles) east of Charleston, South Carolina. Read more.

2016: Curious Ensemble of Wonderful Features

When John Wesley Powell explored the Colorado River in 1869, he made the first thorough survey of one of the last blank spots on the map. The expedition began in May at Green River, Wyoming, and ended three months later at the confluence of the Colorado and Virgin Rivers in present-day Nevada.

About two months into their journey, the nine men of the expedition found themselves in Glen Canyon. As the men traveled along the serpentine river channel, they encountered what Powell later described in Canyons of Colorado as a “curious ensemble of wonderful features.”

From above, the view of Glen Canyon is equally arresting. In 2016, an astronaut aboard the International Space Station took several photographs that were combined to make a long mosaic. The water has an unnatural shade of blue because of sunglint, an optical phenomenon that occurs when sunlight reflects off the surface of water at the same angle that a camera views it. Click here to see the long mosaic.

2019: Lena Delta Shakes Off Water

For most of the year, the Lena River Delta—a vast wetland fanning out from northeast Siberia into the Arctic Ocean—is either frozen over and barren or thawed out and lush. Only briefly will you see it like this.

After seven months encased in snow and ice, the delta emerges for the short Arctic summer. The transition happens fast. The animation above, composed of images from the Moderate Resolution Imaging Spectroradiometer (MODIS) on our Aqua satellite, shows the transformation from June 3-10, 2019. Read more.

2020: Making Waves in the Andaman Sea

When tides, currents and gravity move water masses over seafloor features, they can create wave actions within the ocean. Oceanographers began studying these internal waves from ships in the 1960s, and the modern era of satellites has made it possible to see them on a grand scale. The Operational Land Imager (OLI) on Landsat 8 captured these images of the Andaman Sea on November 29, 2019. The reflection of the Sun on the ocean—sunglint—helps make the internal waves visible.

Internal waves form because the ocean is layered. Deep water tends to be colder, denser and saltier, while shallower water is often warmer, lighter and fresher. The differences in density and salinity cause layers of the ocean to behave like different fluids. When tides, currents, gravity and Earth’s rotation move these different water masses over seafloor formations (such as ridges or canyons), they create waves within the sea. Read more.

These images were taken from NASA Earth Observatory! 

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Are you scared about going up into space?

I’m not scared, but I have a healthy amount of nervousness because I don’t know exactly what to expect. I have a lot of great advice, but you don’t know until you actually get there.

We’re sending people to space this week 🚀 Here’s your chance to ask a past Flight Director in Mission Control your questions!

Ginger Kerrick will be taking your questions in an Answer Time session on Friday, September 27 from 12pm - 1 pm ET here on NASA’s Tumblr! Ginger served as a Flight Director in Mission Control for 11 years and is now the Flight Integration Division Chief at Johnson Space Center. Find out what it’s like to send humans to space and learn more about her position as our first female Hispanic flight director. Make sure to ask your question now by visiting http://nasa.tumblr.com/ask!

Ginger Kerrick, as a child, dreamed of growing up to be either a basketball player or an astronaut. When neither dream came to fruition, Kerrick developed a fresh perspective – best summed up by the phrase “It just wasn’t meant to be” – and later became part of our team, serving in the Mission Control Center at the NASA Johnson Space Center as a Flight Director who has, to date, supported 13 International Space Station and five joint space shuttle missions. It was there that Kerrick, a few years earlier, became the first non-astronaut Capsule Communicator (CapCom), the flight controller that speaks directly to the astronaut crew in space, on behalf of the rest of the Mission Control team. 

Today, Ginger Kerrick is the Flight Integration Division Chief at our Johnson Space Center. Her department is responsible for crew safety and training, among a list of other duties. She has worked for NASA since 1994, and interned here while she was earning a bachelor’s degree in physics from Texas Tech University. She also has a master’s degree in physics from the university.

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Is it fun working at NASA?

Let’s launch some science to space!

The day has finally arrived. After years of work, a team of scientists is at Kennedy Space Center in the hopes of seeing their research liftoff to the International Space Station.

Join #NASAExplorers for the countdown, the emotion and, hopefully, the launch! 

Watch episode 5 here:

Follow NASA Explorers on Facebook to catch new episodes of season 4 every Wednesday!

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