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Hale-Bopp Comet and Sun of Jet Propulsion Laboratory (JPL)
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Comet Hale-Bopp in the Outer
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| Title |
Comet Hale-Bopp in the Outer Solar System |
| Explanation |
Whatever became of Comet Hale-Bopp [ http://antwrp.gsfc.nasa.gov/apod/ap010326.html http://apod.gsfc.nasa.gov/cgi-bin/apod/apod_search?Comet+Hale-Bopp ]? The brightest comet [ http://www.nineplanets.org/comets.html ] in recent years has continued into the outer Solar System [ http://www.exploratorium.edu/ronh/solar_system/ ] and is now farther from the Sun [ http://www.nineplanets.org/sol.html ] than Saturn [ http://www.solarviews.com/eng/saturn.htm ]. To the surprise of many, Comet Hale-Bopp [ http://www.jpl.nasa.gov/comet/ ] is still active, continuing to spew gas, ice and dust particles out into space. Pictured above earlier this month, Comet Hale-Bopp [ http://antwrp.gsfc.nasa.gov/apod/hale_bopp.html ] can be seen in the Southern Hemisphere [ http://antwrp.gsfc.nasa.gov/apod/ap001223.html ] with a moderate sized-telescope. The continued activity of Comet Hale-Bopp [ http://antwrp.gsfc.nasa.gov/apod/ap001227.html ] may be due to the large size of its nucleus [ http://antwrp.gsfc.nasa.gov/apod/ap000805.html ] - estimated to be about 50 kilometers across. The unusual dotted appearance [ http://www.eso.org/outreach/press-rel/pr-2001/phot-07-01.html#techinfo ] of most stars in the above image [ http://www.eso.org/outreach/press-rel/pr-2001/phot-07-01.html ] is due to the 14 discrete exposures that were centered on the comet and not the stars. |
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Announcing Comet Hale-Bopp
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Announcing Comet Hale-Bopp |
| Explanation |
The pictured fuzzy patch may become one of the most spectacular comets this century. Although it is very hard to predict how bright a comet [ http://seds.lpl.arizona.edu/billa/tnp/comets.html ] will become, Comet Hale-Bopp [ http://encke.jpl.nasa.gov/hale_bopp_info.html ], named for its discoverers [ http://encke.jpl.nasa.gov/hale_bopp/discoverers.html ], was spotted farther from the Sun [ http://antwrp.gsfc.nasa.gov/apod/ap950813.html ] than any previous comet - a good sign that it could become very bright, easily visible to the naked eye. This picture was taken on July 25th 1995, only two days after its discovery. A comet [ http://www.c3.lanl.gov/~cjhamil/SolarSystem/comet.html ] bright enough to see without a telescope occurs only about once a decade. The large coma [ http://antwrp.gsfc.nasa.gov/apod/lib/glossary.html#coma ] and long tail [ http://antwrp.gsfc.nasa.gov/apod/lib/glossary.html#comet ] of bright comets are so unusual and impressive that they have been considered omens of change by many cultures. A comet does not streak by in few seconds - but it may change its position and structure noticeably from night to night. Tomorrow's picture: An Orbiting Iceberg |
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Comet Hale-Bopp Update
| Title |
Comet Hale-Bopp Update |
| Explanation |
Will comet Hale-Bopp [ http://www.halebopp.com/ ] become the brightest comet of the Century in early 1997? Since its discovery in July [ http://antwrp.gsfc.nasa.gov/apod/ap950820.html ] this year, Hale-Bopp [ http://encke.jpl.nasa.gov/hale_bopp_info.html ] has caused much speculation. Even though it is still beyond the orbit of Jupiter it is astonishingly bright and expected to get much brighter as it plunges inward, toward the Sun. In this latest Hubble Space Telescope image [ http://www.stsci.edu/pubinfo/PR/95/41.html ] a bright clump of material (above center) has apparently been ejected by evaporation and the rotation of the icy nucleus [ http://antwrp.gsfc.nasa.gov/apod/lib/glossary.html#comet ] (below center). Astronomers are using this and other observations to try to figure out if Hale-Bopp is really a giant comet or a smaller object which will fizzle out sooner than expected as it approaches the Sun. |
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Comet Hale-Bopp Fades
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Comet Hale-Bopp Fades |
| Explanation |
Comet Hale-Bopp has faded in the past few weeks. For Hale-Bopp [ http://newproducts.jpl.nasa.gov/comet/ ], promised as the Great Comet of 1997, this was a bit of a disappointment -- but not entirely unexpected. Comet Hale-Bopp [ http://antwrp.gsfc.nasa.gov/apod/ap960729.html ] continues to approach the Sun [ http://antwrp.gsfc.nasa.gov/apod/ap960916.html ] - making the comet itself brighten, but now the Earth [ http://antwrp.gsfc.nasa.gov/apod/ap960819.html ] is moving away from it - making the comet appear to dim. Experts disagree on just how bright Hale-Bopp [ http://encke.jpl.nasa.gov/hale_bopp_info.html ] will become. Optimists hope it will eventually outshine Comet Hyakutake [ http://antwrp.gsfc.nasa.gov/apod/lib/hyakutake.html ], but some pessimists now expect no better than 3rd magnitude - hardly visible from well-lit cities [ http://antwrp.gsfc.nasa.gov/apod/ap960617.html ]. Comet Hale-Bopp [ http://www.eso.org/comet-hale-bopp/ ] still appears to be, however, a very large comet, and is sure to show much activity as it nears the Sun. The comet should reach peak brightness in March 1997. [ http://newproducts.jpl.nasa.gov/comets/ephemjpl3.html ] This image [ http://www.eso.org/comet-hale-bopp/comet-hale-bopp-summary-sep13-96-rw.html ] was taken on August 18th and shows gas shed from the nucleus of the comet. |
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A Hale-Bopp Triple Crown
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A Hale-Bopp Triple Crown |
| Explanation |
It was truly a busy sky. In one of the more spectacular photos yet submitted to Astronomy Picture of the Day [ http://www.phy.mtu.edu/apod/ ], Don Cooke of Lyme, New Hampshire [ http://www.state.nh.us/soiccnh/lyme.htm ] caught the Sun [ http://www.seds.org/nineplanets/nineplanets/sol.html ], Moon [ http://antwrp.gsfc.nasa.gov/apod/lib/moon.html ], Earth [ http://antwrp.gsfc.nasa.gov/apod/ap970130.html ], night sky [ http://antwrp.gsfc.nasa.gov/apod/ap970403.html ], Pleiades star cluster [ http://antwrp.gsfc.nasa.gov/apod/ap960903.html ], and Comet Hale-Bopp [ http://www.jpl.nasa.gov/comet/ ] all in one frame. The first leg of this "triple crown" exposure was of the Sun [ http://antwrp.gsfc.nasa.gov/apod/ap960518.html ], taken at 6:55 pm on April 10th 1997. Through a dark filter, the Sun [ http://antwrp.gsfc.nasa.gov/apod/lib/sun.html ] appears as the bright dot on the lower right of the image. A second filtered exposure was then taken after the Sun had set, one hour and 40 minutes later - this time featuring the Moon [ http://nssdc.gsfc.nasa.gov/photo_gallery/photogallery-moon.html ]. The Moon appears as a crescent superimposed on an odd-shaped dark circle protruding into the left of the image. This shadow is actually a silhouette of a driveway reflector mounted on an aluminum rod used to block out the bright moon - so as to allow a third exposure, this time unfiltered, of the background night sky. And what a beautiful sky it is. Highlights include Comet Hale-Bopp [ http://antwrp.gsfc.nasa.gov/apod/ap970610.html ], on the right, and the Pleiades star cluster [ http://www.seds.org/billa/twn/m45x.html ], near the center. But what, you may wonder, is that bright light near the center of the picture? Don't worry if you can't guess: it's a porch light from a house across the river! |
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Hale-Bopp: A Continuing Tail
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Hale-Bopp: A Continuing Tail |
| Explanation |
Where is Hale-Bopp now? The Great Comet of 1997 [ http://www.jpl.nasa.gov/comet/ ], one of the largest and most active comets ever, is outbound [ http://antwrp.gsfc.nasa.gov/apod/ap970910.html ] about 400 million miles from the sun. Too faint for viewing without telescopes or binoculars, Hale-Bopp is presently positioned in the very southerly constellation of Pictor. This "negative" image [ http://www.eso.org/outreach/press-rel/pr-1998/phot-05-98.html ] (black stars against white sky) of Hale-Bopp is the result of a 1 hour time exposure using the 1-metre European Southern Observatory [ http://search.eso.org:8080/lasilla/generalinfo/html/aboutls.html ] Schmidt telescope on January 5. Clearly the comet still has a substantial tail [ http://antwrp.gsfc.nasa.gov/apod/ap971215.html ], blown by the solar wind [ http://antwrp.gsfc.nasa.gov/apod/ap970217.html ], that points generally away from the sunward direction. But look closely. A spiky "anti-tail" is also visible [ http://cfa-www.harvard.edu/iauc/06800/06812.html ] pointing toward the sun! It is likely that this anti-tail is composed of dust grains released from the comet nucleus [ http://antwrp.gsfc.nasa.gov/apod/ap961210.html ] which are too large to be easily pushed by the solar wind. As Hale-Bopp recedes [ http://www.pha.jhu.edu/~weaver/hb_stis.html ] from the sun its activity will subside but astronomers are still uncertain as to how long its tails will last. After a swing through the outer solar system and the Oort cloud [ http://www.windows.umich.edu/comets/Oort_cloud.html ], Hale-Bopp will pass through the inner solar system again ... around the year 5400. |
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Hale-Bopp: The Crowd Pleaser
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| Title |
Hale-Bopp: The Crowd Pleaser Comet |
| Explanation |
In 1997, the bright comet Hale-Bopp [ http://antwrp.gsfc.nasa.gov/apod/ap970320.html] may have become the most viewed comet in history [ http://medicine.wustl.edu/~kronkg/past_comets.html ] -- visible even to casual skywatchers in light polluted [ http://antwrp.gsfc.nasa.gov/apod/ap970830.html ] cities around [ http://antwrp.gsfc.nasa.gov/apod/ap970408.html ] the globe [ http://antwrp.gsfc.nasa.gov/apod/ap970515.html ]. In this picture, taken by photographer Joe Orman [ http://members.home.com/rmscott/orman_index.html ] on the evening of May 8, 1997, Hale-Bopp easily competes with near twilight skies and a shining, over-exposed, crescent moon above Mobile, Arizona, USA. Where is Hale-Bopp now [ http://www.jpl.nasa.gov/comet/ ]? Still visible [ http://encke.jpl.nasa.gov/whats_visible.html ] to telescopic observers in the Southern Hemisphere, the comet is outbound [ http://antwrp.gsfc.nasa.gov/apod/ap970910.html ], presently about 537 million miles from the Sun. (Jupiter orbits at about 480 million miles.) The long lead time provided by the early discovery of Hale-Bopp [ http://antwrp.gsfc.nasa.gov/apod/ap950820.html ] has allowed extensive observing campaigns [ http://www.eso.org/outreach/info-events/hale-bopp/ report-rw-hbitp98.html ] producing a bonanza of information [ http://www.jpl.nasa.gov/comet/news102.html ] about this primordial chunk of our Solar System [ http://stardust.jpl.nasa.gov/comets/comets.html ]. |
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The Dust and Ion Tails of Co
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| Title |
The Dust and Ion Tails of Comet Hale-Bopp |
| Explanation |
In 1997, Comet Hale-Bopp [ http://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_ts?Bopp ]'s "intrinsic" brightness exceeded any comet since 1811 [ http://cometography.com/lcomets/1811f1.html ]. Since it peaked on the other side of the Earth's orbit, however, the comet "appeared" only brighter than any comet in two decades [ http://cometography.com/lcomets/1975v1.html ]. Visible above are the two tails [ http://antwrp.gsfc.nasa.gov/apod/ap960502.html ] shed by Comet Hale-Bopp [ http://www.jpl.nasa.gov/comet/ ]. The blue ion tail [ http://www-spof.gsfc.nasa.gov/istp/events/halebopp/disconnect/ ] is composed of ionized [ http://csep10.phys.utk.edu/astr162/lect/light/ionization.html ] gas molecules, of which carbon monoxide [ http://www.cpsc.gov/cpscpub/pubs/466.html ] particularly glows blue when reacquiring electrons [ http://www-spof.gsfc.nasa.gov/Education/welect.html ]. This tail [ http://antwrp.gsfc.nasa.gov/htmltest/gifcity/comet.html ] is created by the particles from the fast solar wind [ http://antwrp.gsfc.nasa.gov/apod/ap000318.html ] interacting with gas from the comet's head. The blue ion tail [ http://antwrp.gsfc.nasa.gov/apod/ap970514.html ] points directly away from the Sun [ http://www.seds.org/nineplanets/nineplanets/sol.html ]. The light colored dust tail [ http://antwrp.gsfc.nasa.gov/apod/ap970403.html ] is created by bits of grit that have come off the comet's nucleus [ http://antwrp.gsfc.nasa.gov/apod/ap000805.html ] and are being pushed away by the pressure of light [ http://antwrp.gsfc.nasa.gov/apod/ap000526.html ] from the Sun. This tail points "nearly" away from the Sun. The above photograph [ http://www.celestialimage.com/page101.html ] was taken in March 1997. |
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Comet Hale-Bopp Over the Sup
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Comet Hale-Bopp Over the Superstition Mountains |
| Explanation |
Four years ago, Comet Hale-Bopp [ http://galileo.ivv.nasa.gov/comet/ ] was discovered [ http://antwrp.gsfc.nasa.gov/apod/ap950820.html ] out near Jupiter [ http://www.seds.org/nineplanets/nineplanets/jupiter.html ] falling toward the inner Solar System [ http://spacelink.nasa.gov/Instructional.Materials/Curriculum.Support/Space.Science/Our.Solar.System/.index.html ]. Two years ago, it provided spectacular pictures [ http://antwrp.gsfc.nasa.gov/cgi-bin/cossc/apod_search?Hale-Bopp ] as it neared its closest approach to the Sun [ http://shutter.vet.ohio-state.edu/astronomy/faq/index.htm ]. Still today, spectacular pictures [ http://antwrp.gsfc.nasa.gov/apod/ap970723.html ] of the brightest comet of the 1990s are surfacing. Above, Comet Hale-Bopp was photographed in 1997 behind the Superstition Mountains [ http://www.goodnet.com/~rfidler/Page/Superstitions.htm ] in Arizona [ http://www.state.az.us/ ]. Clearly visible are the comets white dust tail [ http://antwrp.gsfc.nasa.gov/apod/ap960326.html ] that shines by reflected sunlight, and the blue ion tail [ http://antwrp.gsfc.nasa.gov/apod/ap970514.html ] that shines by glowing gas. Currently, there are several comets visible [ http://comets.amsmeteors.org/comets/current_comets.html ] from the proper location with a small telescope. A comet visible to the unaided eye [ http://encke.jpl.nasa.gov/bright_comet.html ] appears about once every five years. |
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