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{at}NASA
 
 
Regards,
 
Roger

--- D'Bridge 3.99