An Edge-On Close Encounter with Jupiter
 
Feb 6, 2015: Every 13 months, Earth and Jupiter have a close encounter.
Astronomers call it an "opposition" because Jupiter is opposite the Sun in the
sky. Our solar system's largest gas planet rises in the east at sunset, and
soars overhead at midnight, shining brighter than any star in the night sky.
 
This year's opposition of Jupiter occurs on Feb. 6th.  It isn't an ordinary
close encounter with Earth (approximately 640 million kilometers), but in Feb.
2015, Jupiter is edge on to the Sun.
 
http://science.nasa.gov/media/medialibrary/2015/02/04/4shadows.jpg
 
Efrain Morales Rivera of Aquadilla, Puerto Rico, photographed multiple shadows
transiting the face of Jupiter on Jan. 24th. A full-sized version of his image
matches each shadow to a moon.
 
In a rare coincidence, Jupiter's opposition on Feb. 6th coincides almost
perfectly with its equinox on Feb. 5th when the Sun crosses Jupiter's
equatorial plane. It is an edge-on apparition of the giant planet that sets
the stage for a remarkable series of events.  For the next couple of months,
backyard sky watchers can see the moons of Jupiter executing a complex series
of mutual eclipses and transits.
 
The eclipses have already started.  On Jan. 24th, for example, three of
Jupiter's moon's, Io, Europa, and Callisto, cast their inky-black shadows on
Jupiter's swirling cloudtops.  The "triple shadow transit" happened while
Jupiter was high in the sky over North America, and many backyard astronomers
watched the event.
 
)As Earth's crosses the plane of Jupiter's equator in the weeks and months
ahead, there will be many mutual events.  For instance, on Feb. 5th, volcanic
Io will cast its shadow on Mercury-sized Ganymede, Jupiter's largest moon.  On
Feb. 7th, icy Europa, home to what may be the solar system's largest
underground ocean, will cast its shadow on IEvents like these will continue,
off and on, until July 2015.
 
During the last edge-on apparition in 2009, some observers managed to obtain
the first resolved time-lapse videos of mutual phenomena. Experienced amateur
astronomers recorded satellites ducking in and out of one another's shadows,
moons in partial and total eclipse, and multiple shadows playing across the
face of Jupiter.  Backyard telescopes have come a long way in the past 6
years, so even better movies can be expected this time.
 
You don't have to be an experienced astronomer to experience Jupiter's
opposition.  Anyone can see the bright planet rising in the east at sunset. It
outshines by far anything else in its patch of sky.  Point a small telescope
at the bright light and, voila!--there are Jupiter's cloud belts and storms,
and the pinprick lights of the Galilean satellites circling the gas giant
below.
 
Try it.  640 million kilometers won't seem so far away at all.
 
Credits:
 
Author: Dr. Tony Phillips | Production editor: Dr. Tony Phillips | Credit:
Science@NASA
 
 
Regards,
 
Roger

--- D'Bridge 3.99
 * Origin: NCS BBS - Houma, LoUiSiAna (1:3828/7)