Solar System
Phenomena
for June 2006 |
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The hour listings are in Universal Time. For conversion
to U.S. time zones, see Conversion of Universal Time to Civil
Time. Terms in
boldface can be found in
Astronomical Terms.
If
you wish to know more about certain events in this
guide, please refer to our Viewing
Guide. It takes you on a more thorough
walk-through.
| Day | Phenomenon | Hour |
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| 3 | FIRST QUARTER | 2300 | | 4 | The Moon is at apogee. | 0200 | | 7 | Spica, the brightest star in the constellation Virgo, is 0° 1' south of the Moon. Occultation of Spica by the Moon. | 0900 | | 8 | Jupiter is 5° north of the Moon. | 1900 | | 10 | Antares, the brightest star in the constellation Scorpius, is 0° 1' north of the Moon. Occultation of Antares by the Moon. | 2300 | | 11 | FULL MOON | 1800 | | 15 | Neptune is 3° north of the Moon. | 2100 | | 16 | The Moon is at perigee. | 1700 | | 16 | Pluto is at opposition. | 1700 | | 17 | Uranus is 0° 6' north of the Moon. Occultation of Uranus by the Moon. | 1700 | | 17 | Mars is 0° 6' north of Saturn. | 2300 | | 18 | LAST QUARTER | 1400 | | 19 | Uranus appears to be motionless in the sky as it goes from direct motion to retrograde motion. | 1600 | | 20 | Mercury is at its greatest elongation, at 25° east of the Sun. | 2000 | | 20 | Mercury is 6° south of Pollux. | 2300 | | 21 | Solstice | 1200 | | 23 | Venus is 6° south of the Moon. | 0300 | | 25 | NEW MOON | 1600 | | 26 | Ceres, the largest asteroid, appears to be motionless in the sky as it goes from direct motion to retrograde motion. | 1200 | | 27 | Mercury is 5° south of the Moon. | 1400 | | 28 | Saturn is 3° south of the Moon. | 1100 | | 28 | Vesta, the third-largest asteroid, is 0° 2' north of the Moon. Occultation of Vesta by the Moon. | 1900 | | 28 | Mars is 2° south of the Moon. | 2100 |
Thank you to Fact Monster for
the help with our Monthly Planet
Phenomena
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Saturn's
Yin-Yang
Moon |
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See
also Dark-stained
Iapetus......
Cassini's landmark investigation of
Saturn's yin-yang moon Iapetus, with its bright and dark
hemispheres, continues to provide insights into the
nature of this intriguing body.
These two views of Iapetus primarily show terrain in
the southern part of the moon's dark leading hemisphere
-- the side of Iapetus that is coated with dark
material. The bright south pole of Iapetus is visible,
along with some terrain (at the bottom) that lies on the
bright trailing hemisphere.
The dark terrain known as Cassini
Regio is uniformly dark between the equator and about 30
degrees south latitude. From there down to about 50 to
60 degrees south latitude, the dark material looks
"patchy" because south-facing crater walls are bright
(being largely devoid of the dark material). South of
this region, only some northward-facing crater walls are
still dark, while the bright terrain has a somewhat
reddish
color.
Read
more........
Text
& Image Credit:
NASA
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| NASA
set to launch Reconnaissance Orbiter in 2008
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After successful completion of its mission
confirmation review on Wednesday, May 17, NASA's Lunar
Reconnaissance Orbiter project has been given the
authority to proceed to the implementation
phase.
The confirmation review represents NASA's
formal decision for authorizing additional work and sets
the project's cost estimate. The mission was deemed to
be within budget and on schedule to launch in October
2008.
 After a 30-year hiatus, the
orbiter represents NASA's first step towards returning
humans to the moon. The spacecraft will spend an
unprecedented year mapping the moon from an average
altitude of approximately 30 miles. It will carry six
instruments and one technology demonstration to conduct
investigations specifically targeted at preparing for
future human exploration.
The orbiter is being
built at NASA's Goddard Space Flight Center in
Greenbelt, Md. The instruments are being provided by
various organizations throughout the U.S. and one in
Russia. The instruments will generate a global map of
the moon; to determine which potential landing sites are
free from hazards; to measure light and temperature
patterns at the moon's poles; to search for potential
resources, such as water; and to assess the deep-space
radiation environment and its potential effects on
humans.
The next spacecraft milestone is the
critical design review, scheduled for later this year.
This review represents the completion of detailed system
designs and marks the transition into the manufacturing,
assembly, and integration phase of the mission
development cycle.
Text
& Image credit:
NASA |
| ESA's
new
camera follows disintegration
of
a comet.
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This map of Saturn’s moon Titan shows the
location of the April 30, 2006, Titan flyby and the
areas mapped so far by the Cassini radar mapper using
its synthetic aperture radar imaging mode.
 Longitudes are labeled at the bottom of the map.
The radar swaths are superimposed on a false-color image
made from observations by NASA’s Hubble Space Telescope.
The swath shown in light green represents the
area that was imaged on April 30 flyby. It went
right across an optically bright region of Titan known
as Xanadu. See HERE
for another view of this pass.
The far left
image shows the location of the radar swath for the Oct.
28, 2005, flyby. On the top right is the radar swath
from the first Titan flyby, on Oct. 26, 2004. The second
from the top image is from the second radar pass of
Titan, on Feb. 15, 2005 (near-equatorial). The bottom
right swath is from the Sept. 7, 2005, flyby.
Cassini’s radar has revealed a variety of
geologic features, including impact craters, wind-blown
deposits, channels and cryovolcanic features.
The Cassini-Huygens mission is a cooperative
project of NASA, the European Space Agency and the
Italian Space Agency. The Jet Propulsion Laboratory, a
division of the California Institute of Technology in
Pasadena, manages the mission for NASA's Science Mission
Directorate, Washington, D.C. The Cassini orbiter was
designed, developed and assembled at JPL. The radar
instrument was built by JPL and the Italian Space
Agency, working with team members from the United States
and several European
countries.
Read
more ......
Image & Text
Credit:
ESA |
| ESA's
Cluster flies through Earth's electrical
switch
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Sketch of the Earth
magnetosphere |
| ESA’s
Cluster satellites have flown through regions of the
Earth’s magnetic field that accelerate electrons to
approximately one hundredth the speed of light. The
observations present Cluster scientists with their first
detection of these events and give them a look at the
details of a universal process known as magnetic
reconnection.
On 25 January 2005, the four
Cluster spacecraft found themselves in the right place
at the right time: a region of space known as an
electron diffusion region. It is a boundary just a few
kilometres thick that occurs at an altitude of
approximately 60 000 kilometres above the Earth’s
surface. It marks the frontier between the Earth’s
magnetic field and that of the Sun. The Sun’s magnetic
field is carried to the Earth by a wind of electrically
charged particles, known as the solar wind.
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Electron diffusion
region | An electron diffusion region is like an
electrical switch. When it is flipped, it uses energy
stored in the Sun’s and Earth’s magnetic fields to heat
the electrically charged particles in its vicinity to
large speeds. In this way, it initiates a process that
can result in the creation of the aurora on Earth, where
fast-moving charged particles collide with atmospheric
atoms and make them glow.
There is also a more sinister side to the electron
diffusion regions. The accelerated particles can damage
satellites by colliding with them and causing electrical
charges to build up. These short circuit and destroy
sensitive equipment.
Nineteen times in one hour, the Cluster quartet found
themselves engulfed in an electron diffusion region.
This was because the solar wind was buffeting the
boundary layer, causing it to move back and forth. Each
crossing of the electron diffusion region lasted just
10-20 milliseconds for each spacecraft and yet a unique
instrument, known as the Electron Drift Instrument
(EDI), was fast enough to measure the accelerated
electrons.
The observation is important because it provides the
most complete measurements yet of an electron diffusion
region. “Not even the best computers in the world can
simulate electron diffusion regions; they just don’t
have the computing power to do it,” says Forrest Mozer,
University of California, Berkeley, who led the
investigation of the Cluster data.
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Schematic of magnetic
field lines during
reconnection |
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data will provide invaluable insights into the process
of magnetic reconnection. The phenomenon occurs
throughout the Universe on many different scales,
anywhere there are tangled magnetic fields. In these
complex situations, the magnetic fields occasionally
collapse into more stable configurations. This is the
reconnection and releases energy through electron
diffusion regions. On the Sun, magnetic reconnection
drives the solar flares that occasionally release
enormous amounts of energy above sunspots.
This work may also have an important
bearing on solving energy needs on Earth. Nuclear
physicists trying to build fusion generators attempt to
create stable magnetic fields in their reactors but are
plagued by reconnection events that ruin their
configurations. If the process of reconnection can be
understood, perhaps ways of preventing it in nuclear
reactors will become clear.
The huge solar event of 28 October
2003
However, that still lies in the future.
“We need to do a lot more science before we fully
understand reconnection,” says Mozer, whose aim is now
to understand which solar wind conditions trigger the
reconnection events and their associated electron
diffusion regions seen by
Cluster.
Text & Image Credit:
ESA |
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