-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

EVOLUTION OF AN IMPACT: Since July 19th, when Anthony Wesley of Australia discovered the scattered remains of a Mystery Impactor in the high clouds of Jupiter, amateur astronomers around the world have been photographing the planet every night. "German astronomer Hans Joerg Mettig has converted some of the best images into polar projections," says Theo Ramakers, "and I have stitched them together to make a movie." Click on the image to set the scene in motion:

Animations: large, small, zoom

The 3-week animation, which begins with Wesley's discovery image and ends August 8th, shows the cindery cloud expanding, swirling, and ultimately being torn into three pieces by turbulent south polar winds. "The spot has really progressed dramatically," says Ramakers.

No one knows how the movie will end. Planetary scientists say the debris could evolve in interesting and unexpected ways before it finally disperses some weeks from now. Astronomers who wish to contribute scenes can monitor the cloud near Jupiter's System II longitude 210°. For predicted times when it will cross the planet's central meridian, add 2 hours to Sky and Telescope's predicted transit times for Jupiter's Great Red Spot.

more images: from Rick Schrantz of Nicholasville, Kentucky; from Joel Warren of Amarillo, Texas; from Mike Salway of Central Coast, NSW Australia; from Raffaello Lena of Rome, Italy; from Alphajuno of League City, Texas; from Mike Hood of Kathleen, Georgia

NOTE THAT THE IMPACT OCCURRED IN JUPITER's SOUTH POLAR REGION.

EARTH-BASED TELESCOPIC IMAGES USUALLY SHOW UPSIDE DOWN VIEWS

MAKING THE IMPACT ARTIFICIALLY APPEAR IN THE NORTH

BUT IN THOSE INVERTED IMAGES SOUTH IS UP.

THE HUBBLE SPACE TELESCOPE SHOWS IMAGES CORRECTLY WITH

NORTH AIMED UPWARD.

THE ASTRONOMY PICTURE OF THE DAY FOR 2009 July 31

Hubble View: Jupiter Impact

Credit: NASA, ESA, H. Hammel (Space Science Institute, Boulder, Co.), and the Jupiter Impact Team

Explanation: This sprawling dark marking is Jupiter's latest impact scar, a debris plume created as a small asteroid or comet disintegrated after plunging into the gas giant's atmosphere. Located in Jupiter's south polar region, the new feature was discovered by Australian amateur astronomer Anthony Wesley on July 19. On July 23rd Wesley's discovery was followed up by the Hubble Space Telescope with its newly installed Wide Field Camera 3, creating this sharpest view of the evolving debris plume. Estimates indicate that the impacting object itself was several hundred meters across. Similar impact markings were created when about two dozen pieces of Comet Shoemaker-Levy 9 slammed into Jupiter's cloud bands in July of 1994.

JUPITER'S IMPACT CLOUD EXPANDS: Jupiter's impact cloud is expanding. On July 19th, when it was discovered by amateur astronomer Anthony Wesley, the dark mark near Jupiter's south pole was barely visible in backyard telescopes. Five days later Wesley photographed the impact cloud again and found that it had approximately tripled in size:

High-resolution images from the Hubble Space Telescope reveal what's happening: turbulence and jet streams in Jupiter's atmosphere are causing the cloud to spread out. The vast impact site is now tens of thousands of times wider than the 100m-class comet or asteroid that created it.

The expansion of the cloud makes it easier than ever to see through a backyard telescope: sky map. The cloud is located near Jupiter's System II longitude 210°. For the predicted times when it will cross the planet's central meridian, add 2 hours and 6 minutes to Sky and Telescope's predicted transit times for Jupiter's Great Red Spot.

more images: from Tom King of Watauga, Texas; from Mike Salway of Central Coast, NSW Australia; from Mike Hood of Kathleen, Georgia; from Alphajuno of League City, Texas; from Jim Melka of Chesterfield, Missouri,; from Giovanni Soligo of Formia (Latina), Italy; from Dennis Put of Brielle, Netherlands; from Ricardo Kuehn of Salvador, Bahia, Brazil; from Paul Kinzer of Galesville, Wisconsin; from Juan Miguel González Polo of Cáceres, Spain; from Tom Jorgenson of Hartmann Creek State Park near Waupaca, WI; from Tom Murdic of Franklin, Tennessee;

JUPITER IMPACT CLOUD: Debris from the July 19th mystery-impact on Jupiter has split into three clouds. The trifurcation is evident in this August 7th image taken by Rick Schrantz using a 10-inch telescope at his backyard observatory in Nicholasville, Kentucky:

Other observers have noticed the same thing. "There appear to be 3 distinct impact scars now, somewhat linear in shape and perhaps larger than previous days," reports Joel Warren of Amarillo, Texas. He took these pictures using an 8-inch telescope.

Jupiter's upper atmosphere is a dynamic place. The cindery impact debris appears to be caught up in a cascade of turbulent swirls and eddies, which is literally ripping the cloud apart. Amateur astronomers can monitor what happens next: The impact is located near Jupiter's System II longitude 210°. For the predicted times when it will cross the planet's central meridian, add 2 hours and 6 minutes to Sky and Telescope's predicted transit times for Jupiter's Great Red Spot.

more images: from Mike Salway of Central Coast, NSW Australia; from Raffaello Lena of Rome, Italy; from Alphajuno of League City, Texas; from Mike Hood of Kathleen, Georgia, USA

JUPITER SMACKED: Evidence is mounting that something hit Jupiter no more than a few days ago. The impact site was discovered by amateur astronomer Anthony Wesley on July 19th. Using a 14.5-inch telescope at his backyard observatory in Murrumbateman, Australia, he photographed a dark scar in Jupiter's clouds. NASA astronomers rushed to confirm the find, and with this photo from the Infrared Telescope Facility in Hawaii, they did:

The bright spot is near-infrared sunlight reflected from particulate matter floating through the top of Jupiter's atmosphere. These particulates are likely debris from something that hit the planet and exploded. "This has all the hallmarks of the comet Shoemaker-Levy 9 impacts of July 1994," says Leigh Fletcher of JPL who gathered the infrared data along with colleague Glenn Orton.

If the impact hypothesis is indeed correct, the "scar" should become spread out by jet streams in the days ahead. Amateur astronomers can monitor events using mid-sized backyard telescopes: sky map. The spot is located near Jupiter's System II longitude 210°. For the predicted times when it will cross the planet's central meridian, add 2 hours and 6 minutes to Sky and Telescope's predicted transit times for Jupiter's Great Red Spot.

more images: from Anthony Wesley of Murrumbateman, Australia; from Ian Sharp of Ham, West Sussex, England, UK; from David Kolb of Lawrence, Kansas; from David Storey of Isle of Man, Great Britain; from Frank Ryan Jr of Shannon, Ireland; from Russell Hawker of Eastleigh, Hampshire; from Lars Zielke of Tvis, Denmark;

POSSIBLE IMPACT EVENT ON JUPITER: Did something just hit Jupiter? On 2009 July 19th, a black "scar" appeared in Jupiter's clouds similar to the Shoemaker-Levy 9 impacts of 1994. Veteran Jupiter observer Anthony Wesley photographed the feature from his observatory in Murrumbateman, Australia:

"The jet-black mark is near Jupiter's south pole (south is up in the image)," says Wesley. "I have imagery of that same location from two nights earlier without the impact mark, so this is a very recent event. The material has already begun to spread out in a fan shape on one side, and should be rapidly pulled apart by the fast jetstream winds. I recorded a lot of footage, and will be generating more images and a rotation animation soon."

Amateur astronomers around the world should train their telescopes on Jupiter tonight to monitor the progress of this possible impact event: sky map. Stay tuned for more images and updates.

FOR AN ENLARGED UNLABELLED VIEW OF JUPITER'S IMPACT MARK SEE JUST BELOW:

THE ASTRONOMY PICTURE OF THE DAY FOR 2009 January 6

Jupiter Occulting Ganymede

Credit: NASA, ESA, and E. Karkoschka (U. Arizona)

Explanation: How hazy is Jupiter's upper atmosphere? To help find out, astronomers deployed the Hubble Space Telescope to watch Jupiter occult its moon Ganymede. Ganymede circles Jupiter every 7.155 days, and with a diameter of 5262 km is the largest satellite in the Solar System. This occultation was captured in great visual detail in April 2007. When near Jupiter's limb, Ganymede reflects sunlight though Jupiter's upper atmosphere, allowing astronomers to search for haze by noting a slight dimming at different colors. One result of this investigation was the above spectacular image, where bands of clouds that circle Jupiter are clearly visible, as well as magnificent swirling storm systems such as the Great Red Spot. Ganymede, at the image bottom, also shows noticeable detail on its dark icy surface. Since Jupiter and Ganymede are so bright, many occultations (blockages) and eclipses (shadows) can be seen right here on Earth with a small telescope.

THE ASTRONOMY PICTURE OF THE DAY FOR 2009 September 20

Ganymede Enhanced

Credit: Galileo Project, DLR, JPL, NASA

Explanation: What does the largest moon in the Solar System look like? Ganymede, larger than even Mercury and Pluto, has a surface speckled with bright young craters overlying a mixture of older, darker, more cratered terrain laced with grooves and ridges. Like Earth's Moon, Ganymede keeps the same face towards its central planet, in this case Jupiter. In this historic and detailed image mosaic taken by the Galileo spacecraft that orbited Jupiter from 1995 to 2003, the colors of this planet-sized moon have been enhanced to increase surface contrasts. The violet shades extending from the top and bottom are likely due to frost particles in Ganymede's polar regions. Possible future missions to Jupiter are being proposed that can search Europa and Ganymede for deep oceans that may harbor elements thought important for supporting life.

NOTE THAT ALTHOUGH GANYMEDE IS LARGER THAN MERCURY IT IS MUCH LESS DENSE AND THEREFORE HAS MUCH LESS

MASS THAN MERCURY.

EUROPA OCCULTS GANYMEDE: On 2009 May 8th, Anthony Wesley of Murrumbateman, Australia, recorded a very rare event--one of Jupiter's moons occulting each another. "Here," says Wesley, "is an animation of Europa passing directly in front of Ganymede."

He made the movie using a 13-inch telescope and a digital video camera. "Seeing was not good, so I was only able to use 250 of the 1200 frames I collected." Nevertheless, it is an extraordinary observation, showing the distant moons as genuine world-like disks as they pass in "mutual occultation."

Earth is moving through the orbital plane of Jupiter's satellites, allowing the moons to line up for events such as Wesley recorded on May 8th. This special geometry comes along approximately once every 6 years (Half a Jovian orbital period. ) The last time was in 2002-2003, and now it is happening again. Between April and December of 2009, observers around the world can see Jupiter's moons passing one in front of another as they circle the giant planet. As part of the International Year of Astronomy, professional astronomers are organizing a worldwide observing campaign to record as many of these events as possible. Click here for details.

LAUNCH THE Jupiter's Moons PROGRAM

Jupiter's Moons Dance for You!

FROM SKY & TELESCOPE:

Right now the planet Jupiter is oriented such that its equator and the orbits of its four big moons are almost exactly edge-on to the Sun and Earth. This alignment happens every six years, on opposite sides of Jupiter's 11.86 year orbit around the Sun.

At such times its four Galilean satellites undergo mutual phenomena: they often get occulted and eclipsed not just by big Jupiter and its shadow but also by one another. Amateur Christopher Go recently recorded a striking example of the latter.

Christopher Go in his home City of Cebu in Io and its shadow overtake larger Ganymede

the Phillipines with his Celestron 11 telescope in this 14 image sequence taken every few minutes

used to make the movie at right >>>>>>>>>> from 16:38 - 17:39 UT on 2009 Aug 16 from Cebu City

in the Phillipines by Christopher Go.

During a mutual occultation, for example, you can watch two satellites appear to merge and, in the middle of the merger, slightly dim. During an eclipse, a lone moon fades and rebrightens as it's crossed by the shadow of one of its siblings.

Although these little encounters are great fun simply to watch, anyone who records their light curves accurately with a photometer can help to refine the satellites' orbits.

Listed below are the mutual occultations and moderately deep eclipses through the end of 2009, when you'll find Jupiter conveniently placed for viewing in the evening sky. (Thanks to Belgian astro-calculator Jean Meeus for providing the list!)

Events are listed by their date and Universal Time, which is 4 hours ahead of Eastern Daylight Time. The next column tells which satellite occults (o) or eclipses (e) another. For example, 4o3 means that satellite IV (Callisto) occults satellite III (Ganymede) by passing in front of it. Similarly, 1e2 means that satellite I (Io) casts its shadow onto satellite II (Europa). Sometime these notations are followed by A for annular or T for total; otherwise the event is partial. The six possibilities are shown schematically here.

Event size indicates how much of the more distant satellite's diameter is obscured during an occultation, measured as the percentage drop in its light. The table lists only those events for which the dropoff is at least 25% (0.3 magnitude).

Although this table lists only those events easily observable from North America, Sky & Telescope has prepared a comprehensive tabulation

of all pairings for the entire year. So find the events that occur at night for you when Jupiter is up, and mark your calendar!

NOTE THAT UT BELOW INDICATES UNIVERSAL TIME WHICH IS

4 HOURS AHEAD OF EDT AND 5 HOURS AHEAD OF EST

WHICH BEGINS ON 2009 NOVEMBER 2nd

----------------------------------------------------------------------------------------------------------------------------------------------------------------------------

THE SHARPEST PHOTO FROM AN EARTH BASED TELESCOPE OF JUPITER BELOW

ASTRONOMY PICTURE OF THE DAY FOR 2008 NOVEMBER 6

A Sharper View of a Hazy Giant

Credit: ESO, F.Marchis, M.Wong (UC Berkeley); E.Marchetti, P.Amico, S.Tordo (ESO)

Explanation: This dramatic image of Jupiter is touted as the sharpest picture of the entire gas giant ever taken from the ground. The picture was made using a prototype instrument known as MAD (Multi-conjugate Adaptive optics Demonstrator) mounted on one of the European Southern Observatory's 8-meter diameter Very Large Telescope units in Chile. Working at infrared wavelengths the MAD instrument removes atmospheric blurring, the bane of earthbound telescopes, by using multiple guide stars and deformable mirrors to sense and correct for the distortions produced by turbulence in Earth's atmosphere. Hydrogen and methane deep in Jupiter's own thick atmosphere absorb light at infrared wavelengths. So, this sharper view shows the infrared sunlight reflected from the giant planet's high level haze prominent in the equatorial regions and near the poles. It reveals features as small as 300 kilometers across. The promising technique can also be applied to imaging other extended objects like star clusters and nebulae.

NOTE THAT JUPITER WILL BE EXACTLY OPPOSITE SATURN ON 2010 MAY 23,

BUT WILL ONLY BE 6.1' (TENTH OF A DEGREE) FROM SATURN ON 2020 DEC 21 AT 1:21 PM EST (ALSO THE WINTER SOLSTICE ON EARTH).

________________________________________________________________________________________________________________

RADIO STORMS ON JUPITER: On April 11th, the loudspeaker of Thomas Ashcraft's 21 MHz radio telescope in New Mexico suddenly began to hiss and crackle. The sounds grew louder as Jupiter rose in the blue morning sky. "I am pleased to report," says Ashcraft, "a successful recording of Jovian S-bursts--the first of 2009." Click on the image to listen:

The staccato pops sound like lightning in the loudspeaker of a car radio, but lightning did not make these sounds. S-bursts are caused by natural radio lasers in Jupiter's magnetosphere that sweep past Earth as Jupiter rotates. Electrical currents flowing between Jupiter's upper atmosphere and the volcanic moon Io can boost these emissions to power levels easily detected by ham radio antennas on Earth. Jovian S-bursts and L-bursts can mimic the sounds of woodpeckers, whales, and waves crashing on the beach. Here are a few audio samples: S-bursts, S-bursts (slowed down 128:1), L-Bursts

"I recorded the storm in broad daylight," notes Ashcraft. "One of the advantages of this long solar minimum is that the daytime ionosphere is quieter and more transparent to decametric radio waves. There will definitely be more good Jupiter storms in the months to come."

FROM SPACEWEATHER.COM FOR APRIL 14

______________________________________________________________________________________________________________

This article is from Wikipedia