04 - Earth
at aphelion (farthest from Sun) at
8h UT. The Sun - Earth distance
0000is
1.01675 a.u. or about 152.1 million km.
06 - Moon
near Mars at 16h UT (evening sky).
Mag. +1.7.
16 - Moon
near Saturn at 20h UT (evening sky).
Mag. +0.8.
19 - Jupiter
at opposition at 8h UT (mag. -2.7).
Bes time to observe the largest
0000planet
in in the solar system.
10 - Mars 0.64 from Saturn
at 16h UT (47° from Sun, evening sky) Mag.+1.7
& +0.8.
17 - Moon near Jupiter at 14h
UT (midnight sky). Mag. -2.7.
18 - Full Moon at 7:59 UT.
The full moon of July is called the "Thunder
Moon"
0000or
"Hay Moon" .
29 - Mercury at superior conjunction
at 20h UT (not visible). Passes into
the evening sky.
00 0 0
0 0 0//
Get the complete calendar version
at skymaps.com
7 -
The
Outrageous Tales of a Space Shuttle Astronaut
- On February 1, 1978, the first group of space shuttle
astronauts, twenty-nine men and six women, were introduced
to the world. Among them would be history makers, including
the first American woman and the first African American
in space. This assembly of astronauts would carry NASA
through the most tumultuous years of the space shuttle
program. Four would die on Challenger. Mullane vividly
portrays every aspect of the astronaut experience --
from telling a female technician which urine-collection
condom size is a fit; to walking along a Florida beach
in a last, tearful goodbye with a spouse; to a wild,
intoxicating, terrifying ride into space; to hearing
"Taps" played over a friend's grave. Mullane is brutally
honest in his criticism of a NASA leadership whose bungling
would precipitate the Challenger disaster.
Thursday, January 04, 2007
Titan Has Liquid Lakes, Scientists Report in Nature
Scientists report definitive evidence of the presence of lakes filled with liquid methane on Saturn’s moon Titan in this week’s journal Nature cover story. Radar imaging data from a July 22, 2006, flyby provide convincing evidence for large bodies of liquid on Titan today. A new false-color radar view gives a taste of what Cassini saw.
Lake Characteristics:
-Radar-dark patches are interpreted as lakes based on their very low radar reflectivity and morphological similarities to lakes, including associated channels and location in topographic depressions. -Radar-dark surfaces are smooth and most likely liquid, rock, ice or organics. More than 75 radar-dark patches or lakes were seen, ranging from 3 kilometers (1.8 miles) to more than 70 kilometers (43 miles) across. -Some lakes appear partly dry, while others seem liquid-filled. Some of the partly filled lakes may never have filled fully, or may have partly evaporated at some point in the past. The dry lakes have margins or rims and a radar brightness similar to the rest of the surrounding terrain, making them appear devoid of liquid. -The varying states of how full the lakes are suggest that lakes in this region of Titan might be temporary on some unknown timescale. -Approximately 15 of the dark patches seem filled and show no clear evidence of erosion. These dark patches resemble terrestrial lakes confined within impact basins (for example, Clearwater Lakes in Canada) or within volcanic calderas (for example, Crater Lake, Oregon). The nest-like nature of these lakes and their limited range of sizes make it unlikely that they originated from an impact. A volcanic origin for the depressions is possible, given their appearance. -Some lakes have steep margins and very distinct edges, suggesting a topographic rim. These lakes are consistent with seepage or groundwater drainage lakes. -Other lakes have diffuse, more scalloped edges, with a gradual decrease in radar brightness towards the center of the lake. These lakes are more likely to be associated with channels, and may be either drainage lakes or groundwater drainage lakes. -Yet other lakes have curvy channel-like extensions, similar in appearance to terrestrial flooded river valleys (for example Lake Powell). -Bright patches near the lake edges could be small islands peeking through the surface. Floating “icebergs” are unlikely because most materials would not float in liquid hydrocarbons.
The
Oort cloud, is a postulated spherical cloud
of comets situated about 50,000 to 100,000 AU from
the Sun. This is approximately 1000 times the distance
from the Sun to Pluto or roughly one light year, almost
a quarter of the distance from the Sun to Proxima
Centauri, the star nearest the Sun. The Oort cloud
would have its inner disk at the ecliptic from the
Kuiper belt. Although no direct observations have
been made of such a cloud, it is believed to be the
source of most or all comets entering the inner solar
system (some short-period comets may come from the
Kuiper belt), based on observations of the orbits
of comets. Source: Wikipedia
