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Star formation is often best manifested by bright H II regions.These are regions of hydrogen which have been ionized by ultraviolet photons which are emitted from massive stars (typically stars more than 20 times the mass of the Sun). ... A narrowband filter image centered on this wavelength will then readily reveal these H II regions and hence the current sites of star formation in a galaxy, The luminous blobs that can be seen here are all H II regions . ... NGC 3558 Visual . NGC 3558 Infrared . ...

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The Sun is our nearest star and the source of energy for life on Earth. ... For centuries astronomers wondered whether they were clouds floating in the Sun's atmosphere, but we now know that they really are huge regions of magnetic field, about as intense as the field at the poles of an iron magnet. ... Such abrupt events were named solar flares , and what made them especially interesting was that occasionally, after a prominent flare, a magnetic storm would erupt on Earth. ...

... Our Sun is part of a huge wheel-shaped collection of stars. ... Astronomers have long suspected it was a very massive black hole, and that every galaxy had such a central mass, created early in the history of the universe. ... However, unless that object happens to be headed directly at the black hole (a relatively small target) it will just swing around and fly away again, like a comet making a pass at the Sun. The velocity acquired in falling towards the black hole also helps it escape. ...