SDO

The Solar Dynamics Observatory (SDO) will study the influence of the Sun on Earth and the inner solar system by studying the solar atmosphere simultaneously in several wavelengths.

SDO will discover how the sun builds up and explosively releases magnetic energy, which powers severe space weather.

Storms from the sun can knock our finely tuned technological civilization off balance, disrupting satellites, power grids, and radio communication, including the Global Positioning System. Radiation from solar storms can cause cancer in astronauts on unshielded areas, like the moon's surface.

Heat from nuclear fusion in the sun's core makes its outer layer churn like a pot of boiling water. Solar storms are born deep in this outer layer, with tangled magnetic fields generated by the sun's churning electrically conducting gas (plasma). Like a rubber band that has been twisted too far, solar magnetic fields can suddenly snap to a new shape, releasing tremendous energy as a solar flare or a coronal mass ejection (CME).

Solar flares are explosions in the sun's atmosphere, with the largest equal to billions of one-megaton nuclear bombs. Solar magnetic energy can also blast billions of tons of plasma into space at millions of miles (kilometers) per hour as a CME. This violent solar activity often occurs near sunspots, dark regions on the sun caused by concentrated magnetic fields. Sunspots and stormy solar weather follow a cycle that repeats approximately every eleven years, from few sunspots and quiet conditions to many sunspots and active, and back again.

Key to predicting solar storms and the solar activity cycle is an understanding of the flows of plasma inside the sun. Magnetic fields are frozen into the solar plasma, so plasma currents within the sun transport, concentrate, and help dissipate solar magnetic fields. Currently, the Sun's activity is at its minimum, but by the time of the SDO launch, the activity level is expected to rise significantly.

Although the general process of solar activity and its cyclic behavior are known, many of the details are not, such as exactly what magnetic structures lead to flares and CMEs. These details need to be discovered before solar storm predictions improve, and SDO's suite of three instruments is designed to do just that.

The Helioseismic and Magnetic Imager (HMI) can look inside the sun to map out the flows of plasma that generate solar magnetic fields. Helioseismology traces sound waves reverberating inside the sun to build up a picture of the interior, similar to the way an ultrasound scan is used to create a picture of an unborn baby. HMI will also be able to measure the strength and direction of the magnetic fields emerging on the sun's surface. HMI will help discover the mechanisms causing the sun's 11-year activity cycle and reveal how magnetic fields become concentrated by active regions, the areas around sunspots.

The Atmospheric Imaging Assembly (AIA) will take pictures of the sun's atmosphere relatively close to the surface where solar magnetic fields suddenly change shape and release energy. It will be used with HMI to link changes on the surface to interior changes. The two instruments together will reveal how active regions concentrate and then violently disperse magnetic fields. Also, as the AIA observes flares and CMEs, scientists can link them to specific surface magnetic structures and interior plasma flows seen by HMI. Just as a hook-shaped structure in Doppler radar of thunderstorms indicates a possible tornado, scientists will discover what kinds of plasma flows and magnetic field shapes warn of imminent solar outbursts.

AIA will reveal how much this magnetic shape-shifting, called reconnection, heats the solar atmosphere. It can also indicate how much of a boost reconnection gives to the solar wind, a thin stream of plasma blown constantly from the sun through the solar system and beyond. Some magnetic storms are caused by solar wind. Thus, one needs to understand properties of the solar wind in order to predict those storms.

The Extreme Ultraviolet Variability Experiment (EVE) will measure the sun's ultraviolet brightness. The sun's extreme ultraviolet output constantly changes. The small solar flares that happen almost every day can double the output while the large flares that happen about once a month can increase the ultraviolet a thousand times in minutes. This harmful ultraviolet radiation is completely absorbed in the atmosphere, which means we can only observe it from satellites.

Rapid changes in the ultraviolet radiation of the sun can cause outages in radio communications and affect satellites orbiting the Earth. Increases in solar ultraviolet radiation from flares heats Earth's upper atmosphere, causing it to expand. The expansion makes the air denser at low-Earth-orbit altitudes, where many satellites fly. The denser air increases the drag on these satellites, slowing them down and causing them to prematurely burn up in the lower atmosphere if there is no more fuel on board to give them a boost.

EVE will take measurements of the sun's brightness as often as every ten seconds, providing space weather forecasters with warnings of communications and navigation outages. Pictures taken at the same time with AIA will tell scientists where the change in brightness came from and whether it was a flare, a CME, or some other event. HMI will reveal the magnetic and plasma flow activity behind the event.

A Nasa lançou nesta tarde o satélite Solar Dynamics Observatory (SDO), o Observatório da Dinâmica Solar, para estudar como surge a atividade solar e como essa ela afeta o chamado "clima espacial". A sonda fará observações do interior do Sol, seu campo magnético e da corona, a atmosfera solar.

As partículas e a energia lançadas ao espaço pelo Sol, por meio de labaredas e ejeções de massa, podem causar alterações em redes elétricas, de telecomunicações, nos satélites em órbita e também têm o potencial de modificar as características da alta atmosfera terrestre, como a camada de ozônio.

A atividade do Sol segue um ciclo de intensificação e queda de aproximadamente 11 anos. A intensidade de cada ponto do ciclo é avaliada pelo número de manchas solares observadas. A última máxima solar ocorreu 2000.

Tempestades solares também representam um risco para astronautas: em 2003, um jato de partículas emitido pelo Sol forçou a tripulação da Estação Espacial Internacional (ISS) a se refugiar num compartimento especial, para escapar da radiação.

A Nasa espera que a ciência produzida durante a missão do SDO permita prever ocorrências do tipo e facilitar a mitigação dos danos. A duração da missão é prevista em cinco anos.

El nuevo observatorio solar de la NASA proporcionará más detalle y más conocimiento sobre los mecanismos internos de la estrella y su efecto sobre la Tierra. El Solar Dynamics Observatory (SDO), que mide 4,5 metros de altura por más de dos metros de ancho y de largo, se elevó sobre un cohete Atlas V desde cabo Cañaveral, camino de su objetivo, una órbita geoestacionaria inclinada.

Este telescopio avanzado se añade al ya veterano Soho ,que es un proyecto de colaboración con la ESA, y a los gemelos Stereo, también de la NASA. Lleva tres instrumentos de observación, en los que han colaborado instituciones de otros países, como el Rutherford Appleton Laboratory (RAL) británico y puede tomar una imagen del Sol cada 0,75 segundos. Todos los días mandará a su estación de control en Nuevo México 1,5 terabytes de datos, equivalentes a 380 películas cinematográficas.

El observatorio puede estudiar la atmósfera solar a pequeña escala en el espacio y en el tiempo, así como en muchas longitudes de onda simultáneamente, informa la NASA. El objetivo es comprender las variaciones solares mediante el estudio de cómo se genera y se estructura el campo magnético solar y cómo esta energía magnética almacenada se convierte y se libera en la heliosfera y el geospacio en forma de viento solar, partículas energéticas y variaciones en la radiación solar.

Con este conocimiento se espera poder predecir los efectos del Sol sobre la Tierra y sus alrededores.

Ahora, el Sol está iniciando un periodo de gran actividad, tras un largo tiempo de menor actividad en su ciclo. Dos grandes manchas solares se pueden ver en su superficie, que pueden provocar tormentas que envíen chorros de partículas ionizadas hacia la Tierra y afecten a las comunicaciones.