The first results from a new NASA sun-studying spacecraft are in, and they reveal a complex and intriguing picture of Earth's star. <\/p>\n
NASA'sInterface Region Imaging Spectrographprobe (IRIS) has observed 'bombs' of plasma on the sun, nanoflares that rapidly accelerate particles, and powerful jets that may drive the solar wind, among other phenomena, five new studies report. <\/p>\n
While spacecraft can enter planetary atmospheres, they cannot fly through the outer atmosphere of the sun, where temperatures reach 3.5 million degrees Fahrenheit (2 million degrees Celsius). Probes like IRIS instead must study the star from a safe distance. Unlike previous instruments, IRIS can take far more detailed observations of the sun, capturing observations of regions only about 150 miles (240 kilometers) wide on a time scale of just a few seconds. [See images from IRIS] <\/p>\n
\"The combination of enhanced spatial and spectral resolution, [which are] both three to four times better than previous instruments, allows a much closer look [at the sun's atmosphere],\" Hardi Peter of the Max Planck Institute for Solar System Research in Germany told Space.com by email. Peter was the lead author on a study of hot plasma 'bombs' on the sun. <\/p>\n
The surface of the sun, or photosphere, is the region visible to human eyes. Above the photosphere lie the hotter chromosphere and transition regions, which emit ultraviolet light that can only be observed from space. This is because Earth's atmosphere absorbs most of this radiation before it reaches land-based instruments. The outer part of thesolar atmosphereis calledthe corona. <\/p>\n
While much of the sun's energy is generated in its core through hydrogen fusion, temperatures rise in the exterior layers moving out farther from the heat source. This means that something is powering that outer region, and scientists think the magnetic fields generated by the churning solar plasma provide at least part of the answer. <\/p>\n
In emerging active regions,magnetic fieldsrise through the surface into the upper atmosphere, like a string pulled upward. When the energy carried by the field lines becomes too great, they snap, disconnecting from one another and reconnecting with other broken field lines in a process known as magnetic reconnection. <\/p>\n
Paola Testa, of the Harvard-Smithsonian Center for Astrophysics, led a team that used IRIS to study the footprints of these loops, where he found that the intensity changed over a span of 20 to 60 seconds. Investigating possible causes, Testa determined that the variations were consistent with simulations of electrons generated fromcoronal nanoflares. <\/p>\n
\"Nanoflares are short heating events releasing amounts of energy about a billion times smaller than large flares,\" Testa said. <\/p>\n
Although smaller than their larger cousins, nanoflares occur more frequently, likely due to magnetic reconnection. Energy released during magnetic reconnection accelerates some particles to high energies, where they are emitted as radio waves and the highest energy X-rays. Scientists have observed these signals in medium and large flares, but for nanoflares, the rapidly moving electrons are too faint to detect directly using current instrumentation. <\/p>\n
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What's a plasma bomb? NASA probe reveals clues about the sun.<\/a><\/p>\n","protected":false},"excerpt":{"rendered":" The first results from a new NASA sun-studying spacecraft are in, and they reveal a complex and intriguing picture of Earth's star. NASA'sInterface Region Imaging Spectrographprobe (IRIS) has observed 'bombs' of plasma on the sun, nanoflares that rapidly accelerate particles, and powerful jets that may drive the solar wind, among other phenomena, five new studies report. While spacecraft can enter planetary atmospheres, they cannot fly through the outer atmosphere of the sun, where temperatures reach 3.5 million degrees Fahrenheit (2 million degrees Celsius). Continue reading