tag:blogger.com,1999:blog-16899684.post2073728930025746806..comments2023-09-23T00:37:29.396-07:00Comments on Mom's Cancer Blog: Messenger to MercuryBrian Fieshttp://www.blogger.com/profile/16347700145666751363noreply@blogger.comBlogger2125tag:blogger.com,1999:blog-16899684.post-57004641816048672022008-01-17T12:39:00.000-08:002008-01-17T12:39:00.000-08:00I heard about this in Geology class; sounds pretty...I heard about this in Geology class; sounds pretty cool! And the "Messenger" was very well named too, since it will end up in Mercury's orbit.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-16899684.post-43040029891299114592008-01-17T11:22:00.000-08:002008-01-17T11:22:00.000-08:00Your last point is one I've been marveling about f...Your last point is one I've been marveling about for the past several days, usually in the context of boring young'uns about how long it took for us to see those Mariner 10 images in '74 and '75 from its three working flybys -- all of which were over the same hemisphere of the planet.<BR/><BR/><I>Messenger's</I> convoluted and long course to the third-closest planetary orbit also brings up an opportunity to point out a surprising bit of celestial mechanical trivia: Mercury is the hardest planet to get to in launch-energy terms. Earth orbits the Sun at about 67,000 miles per hour. Essentially all of that has to be canceled out to "drop" a probe down to Mercury, but less than half of that* has to be added to propel one out of the solar system altogether.<BR/><BR/>*1/sqrt2Sherwood Harringtonhttps://www.blogger.com/profile/09575868746160608731noreply@blogger.com