<HTML><BODY style="word-wrap: break-word; -khtml-nbsp-mode: space; -khtml-line-break: after-white-space; "><DIV><BR class="khtml-block-placeholder"></DIV><DIV><BR class="khtml-block-placeholder"></DIV>Mars, at opposition is almost at perihelion - only an additional ~.4 AU, but at its furthest is actually ~.65 AU. So opposition isn't the average.<DIV><BR class="khtml-block-placeholder"></DIV><DIV><SPAN class="Apple-style-span">Earth's surface is ~1 kw/m^2, which is true, but on Mars it is less than 600w/m^2 = ~60%, i.e. <I>substantially less. </I>At Jupiter we're down to ~50 w/m^2, Saturn ~15.</SPAN></DIV><DIV><I><BR class="khtml-block-placeholder"></I></DIV><DIV>We also have to consider the rate that light drops off as a distance from its source, and that the albedo of Mars is about half that of Earth's.</DIV><DIV><BR class="khtml-block-placeholder"></DIV><DIV><BR class="khtml-block-placeholder"></DIV><DIV>]3</DIV><DIV><BR class="khtml-block-placeholder"></DIV><DIV><BR class="khtml-block-placeholder"></DIV><DIV><BR><DIV><DIV>On Jul 30, 2005, at 12:14 PM, Mike Lorrey wrote:</DIV><BR class="Apple-interchange-newline"><BLOCKQUOTE type="cite"><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">--- Bret Kulakovich <<A href="mailto:bret@bonfireproductions.com">bret@bonfireproductions.com</A>> wrote:</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><BR></DIV> <BR><BLOCKQUOTE type="cite"><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><BR></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">At the distance of Mars, there is substantially less light, Jupiter <SPAN class="Apple-converted-space"> </SPAN></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">and Saturn even less. The images we see are being "pushed" into our <SPAN class="Apple-converted-space"> </SPAN></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">range of brightness.<SPAN class="Apple-converted-space"> </SPAN></DIV> <BR></BLOCKQUOTE><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><BR></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">Mars, at opposition, is only about 40 million miles away, which is</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">about 40% further from the Sun than Earth (at 93 million miles).</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">Sunlight at Earths surface is 40% LESS than in Low Earth Orbit because</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">of the thickness of our atmosphere (orbital solar flux in the visible</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">range is over 1.4 kw/m^2, sea level solar flux is about 1.0 kw/m^2). As</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">Mars' atmosphere is quite thin, only about 6 millibars, it does not</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">attenuate Mars orbit solar flux by a significant percent. Therefore it</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">follows that the brightness of sunlight on the surface of Mars is</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">relatively close to that on the surface of Earth.</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><BR></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">You are otherwise correct vis a vis Jupiter and Saturn.</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><BR></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">Mike Lorrey</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">Vice-Chair, 2nd District, Libertarian Party of NH</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">"Necessity is the plea for every infringement of human freedom.</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">It is the argument of tyrants; it is the creed of slaves."</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-converted-space"> </SPAN>-William Pitt (1759-1806)<SPAN class="Apple-converted-space"> </SPAN></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">Blog: <A href="http://intlib.blogspot.com">http://intlib.blogspot.com</A></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><BR></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">__________________________________________________</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">Do You Yahoo!?</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">Tired of spam?<SPAN class="Apple-converted-space"> </SPAN>Yahoo! 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