Looking through the Sun

Looking through the Sun

. The arcing trajectories of sound waves from the far side of the Sun are reflected internally before reaching the front side, where they are observed with the Michelson Doppler Imager, abbreviated MDI, aboard the SOlar and Heliospheric Observatory, or SOHO for short, or the Global Oscillation Network Group, abbreviated GONG. Here we show a two-skip correlation scheme (left) and a one-skip/three-skip correlation scheme (right) of seismic holography used to image active regions (focal point) on the otherwise unseen far side of the Sun. These methods permit complete seismic imaging of the entire far hemisphere of the Sun, provided daily at http://soi.stanford.edu/data/full_farside/ or http://gong.nso.edu/. This permits scientists to detect potentially threatening active regions on the far side of the Sun before the Sunís rotation brings them around to the front side that faces the Earth. [Adapted from Douglas C. Braun and Charles Lindsey, Astrophysical Journal (Letters) 560, L189 (2001).]

Copyright 2010, Professor Kenneth R. Lang, Tufts University