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, February 22, 2007
Spitzer Captures Feeble Lights from Distant Worlds
NASA's Spitzer Space Telescope has captured for the first time enough light from planets outside our solar system, known as exoplanets, to identify signatures of molecules in their atmospheres. The landmark achievement is a significant step toward being able to detect possible life on rocky exoplanets and comes years before astronomers had anticipated.
Spitzer, a space-based infrared telescope, obtained the detailed data, called spectra, for two different gas exoplanets. Called HD 209458b and HD 189733b, these so-called "hot Jupiters" are, like Jupiter, made of gas, but orbit much closer to their suns.
The data indicate the two planets are drier and cloudier than predicted. Theorists thought hot Jupiters would have lots of water in their atmospheres, but surprisingly none was found around HD 209458b and HD 189733b. According to astronomers, the water might be present but buried under a thick blanket of high, waterless clouds.
Those clouds might be filled with dust. One of the planets, HD 209458b, showed hints of tiny sand grains, called silicates, in its atmosphere. This could mean the planet's skies are filled with high, dusty clouds unlike anything seen around planets in our own solar system. Source:NASA's Spitzer News Release
A new image from NASA's Hubble Space Telescope shows the colorful "last hurrah" of a star like our sun. The picture was taken on Feb. 6, 2007 , by Hubble's Wide Field and Planetary Camera 2, which was designed and built by NASA's Jet Propulsion Laboratory, Pasadena , Calif.
The star is ending its life by casting off its outer layers of gas, which formed a cocoon around the star's remaining core. Ultraviolet light from the dying star makes the material glow. The burned-out star, called a white dwarf, is the white dot in the center. Our sun will eventually burn out and shroud itself with stellar debris, but not for another 5 billion years.
Our Milky Way galaxy is littered with these stellar relics, called planetary nebulae. The objects have nothing to do with planets. Eighteenth- and nineteenth-century astronomers named them that because through small telescopes they resembled the disks of the distant planets Uranus and Neptune. The planetary nebula in this image is called NGC 2440. The white dwarf at the center of NGC 2440 is one of the hottest known, with a surface temperature of nearly 200,000 degrees Celsius (400,000 degrees Fahrenheit). The nebula's chaotic structure suggests that the star shed its mass episodically. During each outburst, the star expelled material in a different direction. This can be seen in the two bow tie-shaped lobes. The nebula also is rich in clouds of dust, some of which form long, dark streaks pointing away from the star. NGC 2440 lies about 4,000 light-years from Earth in the direction of the constellation Puppis. The colors in the image correspond to material expelled by the star. Blue corresponds to helium; blue-green to oxygen, and red to nitrogen and hydrogen.
The HiRISE camera on NASA's Mars Reconnaissance Orbiter can take interesting astronomical pictures, team scientists report today. The High Resolution Imaging Experiment (HiRISE) based at the University of Arizona Lunar and Planetary Laboratory in Tucson has produced a view of Jupiter as seen from Mars orbit. The scientists used the HiRISE camera to take a 10 megabyte image of Jupiter and its major satellites when they were calibrating the camera's pointing and color response on Jan. 11, 2007.
The powerful vision of NASA's Hubble Space Telescope has allowed astronomers to study for the first time the layer-cake structure of the atmosphere of a planet orbiting another star. Hubble discovered a dense upper layer of hot hydrogen gas where the super-hot planet's atmosphere is bleeding off into space.
The planet, designated HD 209458b, is unlike any world in our solar system. It orbits so close to its star and gets so hot that its gas is streaming into space, making the planet appear to have a comet-like tail. This new research reveals the layer in the planet's upper atmosphere where the gas becomes so heated it escapes, like steam rising from a boiler.
HD 209458b is located 150 light-years from Earth in the constellation Pegasus.
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
