{"id":28834,"date":"2019-01-01T12:00:00","date_gmt":"2019-01-01T01:00:00","guid":{"rendered":"http:\/\/astro3d.org.au\/?p=28834"},"modified":"2021-05-06T13:38:22","modified_gmt":"2021-05-06T03:38:22","slug":"the-fighter-jet-of-the-ionosphere","status":"publish","type":"post","link":"https:\/\/astro3d.org.au\/the-fighter-jet-of-the-ionosphere\/","title":{"rendered":"The \u201cFighter Jet\u201d of the Ionosphere"},"content":{"rendered":"
January 2019\u2019s \u201cMonthly Media\u201d is a series of observations from Dr\u00a0Chris Jordan<\/a><\/span>\u00a0that he has affectionately named \u201cThe Fighter Jet\u201d, showing the positional offset due to the ionosphere of known radio sources as they pass overhead of the\u00a0Murchison Widefield Array<\/a><\/span>\u00a0(MWA).<\/p>\n Radio sources (such as distant galaxies) can appear to be shifted from their expected position in observations due to density lumps in the Earth\u2019s ionosphere.<\/p>\n<\/div> Layers of the Earth\u2019s atmosphere. The Ionosphere ranges from the Mesosphere to the Exosphere and is where the aurora Australis and Borialis occur. This region of the atmosphere can change the apparent location of radio sources when it\u2019s \u201cpoorly behaved\u201d.<\/i><\/span><\/p>\n<\/div> These density lumps refract light, causing the sources to appear shifted from where they would have been in an image if the ionosphere were not there, and are more common when the ionosphere is behaving \u201cpoorly\u201d.<\/p>\n A \u201cpoorly behaved\u201d ionosphere can be thought of like ripples on the surface of water \u2013 when you want to image something underneath, the ripples confuse things.<\/p>\n<\/div> You can see the radio sources (the dots) passing overhead through the course of the observations. The colours of the radio sources indicate which direction the source has been shifted from where it should be in the image.<\/i><\/span><\/p>\n<\/div><\/span><\/div><\/div><\/div>
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