Totaleclipse - Blog Posts

Eclipse 2017: A Unique Chance for Science

On Aug. 21, the Moon will cast its shadow down on Earth, giving all of North America the chance to see a solar eclipse. Within the narrow, 60- to 70-mile-wide band stretching from Oregon to South Carolina called the path of totality, the Moon will completely block out the Sun’s face; elsewhere in North America, the Moon will cover only a part of the star, leaving a crescent-shaped Sun visible in the sky.

Find eclipse times for your location with our interactive version of this map.

A total solar eclipse happens somewhere on Earth about once every 18 months. But because Earth’s surface is mostly ocean, most eclipses are visible over land for only a short time, if at all. The Aug. 21 total solar eclipse is different – its path stretches over land for nearly 90 minutes, giving scientists an unprecedented opportunity to make scientific measurements from the ground.

No matter where you are, it is never safe to look directly at the partially eclipsed or uneclipsed Sun. Make sure you’re prepared to watch safely, whether that’s with solar viewing glasses, a homemade pinhole projector, or online with us at nasa.gov/eclipselive.

Within the path of totality, the Moon will completely obscure the Sun’s face for up to 2 minutes and 40 seconds, depending on location. This will give people within the path of totality a glimpse of the innermost reaches of the Sun’s corona, the outer region of the atmosphere that is 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.

In fact, scientists got their first hint at these unusually high temperatures during the total solar eclipse of 1869, when instruments detected unexpected light emission. It was later discovered that this emission happens when iron is stripped of its electrons at extremely high temperatures.

This region of the Sun’s atmosphere can’t be measured at any other time, as human-made instruments that create artificial eclipses must block out much of the Sun’s atmosphere – as well as its bright face – in order to produce clear images.

We’re funding six science investigations to study the Sun’s processes on Aug. 21. Teams will spread out across the path of totality, focusing their instruments on the Sun’s atmosphere. One team will use a pair of retro-fitted WB-57F jets to chase the Moon’s shadow across the eastern US, extending the time of totality to more than 7 minutes combined, up from the 2 minutes and 40 seconds possible on the ground.

Our scientists are also using the Aug. 21 eclipse as a natural science experiment to study how Earth’s atmosphere reacts to the sudden loss of solar radiation within the Moon’s shadow.

One region of interest is Earth’s ionosphere. Stretching from roughly 50 to 400 miles above Earth’s surface, the tenuous ionosphere is an electrified layer of the atmosphere that reacts to changes from both Earth below and space above and can interfere with communication and navigation signals.

The ionosphere is created by ionizing radiation from the Sun. When totality hits on Aug. 21, we’ll know exactly how much solar radiation is blocked, the area of land it’s blocked over and for how long. Combined with measurements of the ionosphere during the eclipse, we’ll have information on both the solar input and corresponding ionosphere response, enabling us to study the mechanisms underlying ionospheric changes better than ever before.

The eclipse is also a chance for us to study Earth’s energy system, which is in a constant dance to maintain a balance between incoming radiation from the Sun and outgoing radiation from Earth to space, called the energy budget. Like a giant cloud, the Moon during the 2017 total solar eclipse will cast a large shadow across a swath of the United States.

Our scientists already know the dimensions and light-blocking properties of the Moon, and will use ground and space instruments to learn how this large shadow affects the amount of sunlight reaching Earth’s surface, especially around the edges of the shadow. This will help develop new calculations that improve our estimates of the amount of solar energy reaching the ground, and our understanding of one of the key players in regulating Earth’s energy system — clouds.

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.

Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com

All Eyes on the Sky for the August 21 Total Solar Eclipse

Just two months from now, the moon will completely block the sun’s face, treating part of the US to a total solar eclipse.

Everyone in North America will have the chance to see an eclipse of some kind if skies are clear. Anyone within a 70-mile-wide swath of land — called the path of totality — that stretches from Oregon to South Carolina will have the chance to see a total eclipse.

Throughout the rest of the continent, including all 50 United States — and even in parts of South America, Africa, Europe, and Asia — the moon will partially obscure the sun, creating a partial eclipse.

Photo credit: NASA/Cruikshank

An eclipse is one of nature’s most awesome sights, but safety comes first! When any part of the sun’s surface is exposed, use proper eclipse glasses (not sunglasses) or an indirect viewing method, like a pinhole projector. In the path of totality, it’s safe to look directly at the eclipse ONLY during the brief moments of totality.

During a solar eclipse, the moon passes between the sun and Earth, casting a shadow down on Earth’s surface. We’ve been studying the moon with NASA’s Lunar Reconnaissance Orbiter, and its precise mapping helped NASA build the most accurate eclipse map to date.

During a total solar eclipse, the moon blocks out the sun’s bright face, revealing the otherwise hidden solar atmosphere, called the corona. The corona is one of the sun’s most interesting regions — key to understanding the root of space weather events that shape Earth’s space environment, and mysteries such as why the sun’s atmosphere is so much hotter than its surface far below.

This is the first time in nearly 100 years that a solar eclipse has crossed the United States from coast to coast. We’re taking advantage of this long eclipse path by collecting data that’s not usually accessible — including studying the solar corona, testing new corona-observing instruments, and tracking how our planet’s atmosphere, plants, and animals respond to the sudden loss of light and heat from the sun.

We’ll be studying the eclipse from the ground, from airplanes, with research balloons, and of course, from space.

Three of our sun-watchers — the Solar Dynamics Observatory, IRIS, and Hinode, a joint mission led by JAXA — will see a partial eclipse from space. Several of our Earth-observing satellites will use the eclipse to study Earth under uncommon conditions. For example, both Terra and DSCOVR, a joint mission led by NOAA, will capture images of the moon’s shadow from space. Our Lunar Reconnaissance Orbiter will also turn its instruments to face Earth and attempt to track the moon’s shadow as it moves across the planet.

There’s just two months to go until August 21, so make your plans now for the big day! No matter where you are, you can follow the eclipse as it crosses the country with live footage from NASA TV.

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

Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com

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.