Abstract
The gravitational lens of the Sun has a drawback: the solar corona. This is discussed at length in Chapter 8 of [19] and exemplified by Figure 14.1. Electrons in the corona make electromagnetic waves “diverge” and this “pushes the focus out” to distances greater than 550 AU. For instance, at the CMB peak frequency of 160 GHz, the true focus lies at 763 AU. Thus, it would be safer to position the FOCAL spacecraft at 1,000 AU.
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Maccone, C. (2012). Belt of focal spheres between 550 and 17,000 AU. In: Mathematical SETI. Springer Praxis Books(). Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-642-27437-4_14
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DOI: https://doi.org/10.1007/978-3-642-27437-4_14
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