Mars Express, DLR, ESA
705 x 521, 52.3KB
On sol 156, Spirit roved 42 meters (138 feet) closer to a vantage
point where it could observe the hill outcrops. Some of the images that
Spirit sent back revealed a small and unusual rock
that piqued scientists' interest and was informally named
"End-of-Rainbow." Part of the sol 157 plan was to observe
End-of-Rainbow and use the alpha particle X-ray spectrometer, Mössbauer
spectrometer and microscopic imager to study the "Shredded" soil
target. However, the command load for sol 157 never made it to Spirit.
Further analysis indicated that the problem had to do
with the frequency drift associated with the colder temperatures on
Mars as the planet moves into its southern winter season. This was an
anticipated problem, and the rover team has already
imposed some strategies that will help to prevent the problem in the
Transits of Venus across the disk of the Sun are among the rarest of
planetary alignments. Indeed, only six such events have occurred since
the invention of the telescope (1631, 1639, 1761, 1769, 1874 and 1882).
Two transits of Venus are occuring within a few years of eachother -
the first was on June 08, 2004, the next will be June 06, 2012.
Transits of Venus are only possible during early December and early
June when Venus's orbital nodes pass across the Sun. If Venus reaches
inferior conjunction at this time, a transit will occur. Transits show
a clear pattern of recurrence at intervals of 8, 121.5, 8 and 105.5
years. The next pair of Venus transits occur over a century from now on
2117 Dec 11 and 2125 Dec 08.