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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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Comet Hale-Bopp Over Val Par
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| Title |
Comet Hale-Bopp Over Val Parola Pass |
| Explanation |
Comet Hale-Bopp became much brighter than any surrounding stars. It was seen even over bright city lights [ http://antwrp.gsfc.nasa.gov/apod/ap970408.html ]. Out away from city lights, however, it put on quite a spectacular show. Here Comet Hale-Bopp was photographed above Val Parola Pass in the Dolomite mountains [ http://www.geocities.com/Yosemite/Trails/6876/ ] surrounding Cortina d'Ampezzo [ http://www.sunrise.it/cortina/ ], Italy [ http://www.cia.gov/cia/publications/factbook/geos/it.html ]. Comet Hale-Bopp's blue ion tail was created when fast moving particles from the solar wind [ http://antwrp.gsfc.nasa.gov/apod/ap000318.html ] struck expelled ions from the comet's nucleus [ http://antwrp.gsfc.nasa.gov/apod/ap000805.html ]. The white dust tail [ http://antwrp.gsfc.nasa.gov/apod/ap001227.html ] is composed of larger particles of dust and ice expelled by the nucleus that orbit behind the comet [ http://www.nineplanets.org/comets.html ]. Observations showed that Comet Hale-Bopp's nucleus spins about once every 12 hours. |
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Announcing Comet Hale-Bopp
| Title |
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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Hale-Bopp, Jupiter, and the
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| Title |
Hale-Bopp, Jupiter, and the Milky Way |
| Explanation |
Shining brightly, the mighty Jupiter [ http://antwrp.gsfc.nasa.gov/apod/lib/jupiter.html ] rules this gorgeous Kodacolor photo of the Milky Way near Sagittarius [ http://antwrp.gsfc.nasa.gov/apod/ap960605.html ]. Astronomer Bill Keel [ http://crux.astr.ua.edu/keel/billkeel.html ] took the picture earlier this month (July 7) while standing near the summit of Hawaii's Mauna Kea [ http://antwrp.gsfc.nasa.gov/apod/ap951216.html ] contemplating the sky [ http://crux.astr.ua.edu/keel/fam/fam.html ] in the direction of the center of the Galaxy [ http://antwrp.gsfc.nasa.gov/apod/ap950908.html ] (right of picture center). In addition to the gas giant planet, which is well placed for evening viewing [ http://NewProducts.jpl.nasa.gov/galileo/jup_sky/ ], the image contains an impressive sampler of celestial goodies. Many famous emission nebulae [ http://antwrp.gsfc.nasa.gov/apod/lib/glossary.html#emis_neb ] are visible as reddish patches - M16, the Eagle nebula [ http://antwrp.gsfc.nasa.gov/apod/ap951106.html ], is just above and right of center, with the Horseshoe nebula, M17, just below it and farther to the right. Also, look for the Lagoon Nebula, M8 [ http://antwrp.gsfc.nasa.gov/apod/ap960127.html ], as the brightest red patch at the right of the picture with the Trifid Nebula, M20 [ http://antwrp.gsfc.nasa.gov/apod/ap951221.html ], just above it and to the left. The milky glow of distant unresolved stars [ http://antwrp.gsfc.nasa.gov/apod/ap960213.html ] in the plane of our Galaxy (thus the term Milky Way) runs through the image cut by dark, absorbing, interstellar dust [ http://antwrp.gsfc.nasa.gov/apod/ap960125.html ] clouds. The much anticipated comet Hale-Bopp [ http://newproducts.jpl.nasa.gov/comets/index.html ] is also clearly visible. Where's the comet? "Click on the picture to view the comet's location flanked by superposed vertical lines". The comet was discovered while still beyond the orbit of Jupiter [ http://antwrp.gsfc.nasa.gov/apod/ap950820.html ] a year ago today independently by Alan Hale and Thomas Bopp [ http://encke.jpl.nasa.gov/hale_bopp/discoverers.html ]. Astronomers monitoring Hale-Bopp's activity [ http://antwrp.gsfc.nasa.gov/apod/ap951030.html ] report that having now brightened to almost 6th magnitude [ http://liftoff.msfc.nasa.gov/academy/universe/MAG.HTML ] it is still on track for becoming an extremely bright naked-eye comet [ http://antwrp.gsfc.nasa.gov/apod/lib/hyakutake.html ] in early 1997. |
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Hale-Bopp on Schedule
| Title |
Hale-Bopp on Schedule |
| Explanation |
Late March and early April of 1996 marked a banner season for viewing the spectacular naked-eye comet Hyakutake [ http://antwrp.gsfc.nasa.gov/apod/lib/hyakutake.html ]. The spring of 1997 could well offer a similar cometary wonder, Comet Hale-Bopp [ http://antwrp.gsfc.nasa.gov/apod/ap960723.html ]. Discovered last year [ http://newproducts.jpl.nasa.gov/comets/discovery.html ] while approaching the inner solar sytem Hale-Bopp has been eagerly watched [ http://www.eso.org/comet-hale-bopp/ ] for signs that it will indeed brighten spectacularly. So far, things look good! This recent image [ http://www.eso.org/comet-hale-bopp/phot-29-96.html ] of the comet was made on May 14 at the European Southern Observatory when the comet about 340 million miles from Earth. It is shown here using false colors to indicate relative brightness. Stars are visible through the expanding coma [ http://antwrp.gsfc.nasa.gov/apod/lib/glossary.html#coma ]. Recent reports are that its level of activity, the rate of dust and gas production from the solar heating of the icy nucleus [ http://antwrp.gsfc.nasa.gov/apod/ap950821.html ] is as expected. An analysis of its orbit [ http://newproducts.jpl.nasa.gov/comets/ephemjpl1.html ] indicates that this comet will approach to within nearly 120 million miles of Earth on March 22, 1997. The orbital calculations also reveal that Hale-Bopp has visited the inner solar system before ... about 4200 years ago. |
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A Dust Jet From Hale-Bopp
| Title |
A Dust Jet From Hale-Bopp |
| Explanation |
Approaching the inner Solar System, comet Hale-Bopp [ http://antwrp.gsfc.nasa.gov/apod/ap960725.html ]'s icy nucleus is heated by sunlight, accelerating its production of dust and gas. Shrouded in the resulting cloud, known as the coma, the cometary nucleus remains hidden from direct view. However, astronomers using a 2.2 meter telescope at the European Southern Observatory in May, were able to detect an enormous jet of dust [ http://www.eso.org/comet-hale-bopp/phot-29-96.html ] extending northward (up) from the nuclear region as seen in this false color image. Dust jets may arise [ http://www.aas.org/ApJ/v461n2/5610/sc0.html ] from vents on the surface of the nucleus. Early estimates of the size [ http://www.arcorp.com/Hale-Bopp.html ] of Hale-Bopp's nucleus have indicated that it could be as large as 40 kilometers (24 miles) in diameter -- several times larger than comet Halley [ http://antwrp.gsfc.nasa.gov/apod/ap950821.html ]'s. Hale-Bopp's copious dust production bodes well for it becoming a bright naked-eye comet in the spring of 1997 [ http://newproducts.jpl.nasa.gov/comets/index.html ]. |
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Comet Hale-Bopp Fades
| Title |
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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Hale-Bopp and the North Amer
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| Title |
Hale-Bopp and the North American Nebula |
| Explanation |
Comet Hale-Bopp [ http://galileo.ivv.nasa.gov/comet/ ]'s recent encounter with the inner Solar System [ http://antwrp.gsfc.nasa.gov/apod/ap961214.html ] allowed many breath-taking pictures. Above, Comet Hale-Bopp [ http://encke.jpl.nasa.gov/hale_bopp_info.html ] was photographed on March 8th in the constellation of Cygnus [ http://astro.gmu.edu/constellation/CYG.html ]. Visible on the right in red is the North American Nebula [ http://antwrp.gsfc.nasa.gov/apod/ap960606.html ], a bright emission nebula [ http://antwrp.gsfc.nasa.gov/apod/lib/glossary.html#emis_neb ] observable from a dark location with binoculars. The North American Nebula [ http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1989A%26A%2E%2E%2E222%2E%2E%2E82S&db_key=AST&nosetcookie=1 ] is about 1500 light years away, much farther than the comet, which was about 8 light minutes away. Several bright blue stars from the open cluster [ http://antwrp.gsfc.nasa.gov/apod/ap970128.html ] M39 are visible just above the comet's blue ion tail [ http://antwrp.gsfc.nasa.gov/apod/ap960502.html ]. |
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Comet Hale-Bopp Over Indian
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| Title |
Comet Hale-Bopp Over Indian Cove |
| Explanation |
Comet Hale-Bopp, the Great Comet of 1997 [ http://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search?great+comet+1997 ], was quite a sight. No comets [ http://www.nineplanets.org/comets.html ] of comparable brightness have graced the skies of Earth [ http://antwrp.gsfc.nasa.gov/apod/ap010204.html ] since then. During this next month, however, even besides the fleeting Comet Bradfield [ http://antwrp.gsfc.nasa.gov/apod/ap040419.html ], "two" comets have a slight chance of rivaling Hale-Bopp [ http://www2.jpl.nasa.gov/comet/ ] and a good chance of putting on a memorable [ http://antwrp.gsfc.nasa.gov/htmltest/gifcity/comet.html ] sky show. Unfortunately, most of the show will be confined to sky gazers in Earth's southern hemisphere [ http://antwrp.gsfc.nasa.gov/apod/ap021222.html ]. Both comets are already visible [ http://encke.jpl.nasa.gov/RecentObs.html#02T7 ] to the unaided eye from there. The first, Comet C/2002 T7 (LINEAR) [ http://cometography.com/lcomets/2002t7.html ], should be at its best before dawn during the first weeks of May from the south. The second, Comet C/2001 Q4 (NEAT) [ http://cometography.com/lcomets/2001q4.html ], should be visible in early May from all over the Earth. Both comets [ http://www.space.com/spacewatch/comet_double_040319.html ] appear to be approaching [ http://skyandtelescope.com/observing/objects/comets/article_1037_1.asp ] the inner Solar System [ http://www.nineplanets.org/overview.html ] for the first time and so it is very hard to predict [ http://www.exploratorium.edu/exploring/space/kohoutek.html ] how bright each will become. In the above photograph [ http://www2.jpl.nasa.gov/comet/pach17.html ] taken 1997 April 6, Comet Hale-Bopp was imaged from the Indian Cove Campground in the Joshua Tree National Forest [ http://www.nps.gov/jotr/ ] in California [ http://www.state.ca.us/ ], USA [ http://www.cia.gov/cia/publications/factbook/geos/us.html ]. A flashlight [ http://www.geocities.com/~stuarts1031/flashlight.html ] was used to momentarily illuminate foreground rocks during this six minute exposure. |
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A Hale-Bopp Holiday
| Title |
A Hale-Bopp Holiday |
| Explanation |
Seen from the Pik Terskol Observatory [ http://www.mpae.gwdg.de/mpae_projects/gbo/terskol.html ] in the northern Caucasus mountains, comet Hale-Bopp [ http://antwrp.gsfc.nasa.gov/apod/ap971215.html ] and the bright stars of the constellation Perseus [ http://www.astro.wisc.edu/~dolan/constellations/ constellations/Perseus.html ] hang above the snowy, moon-lit landscape [ http://antwrp.gsfc.nasa.gov/apod/ap970327.html ]. Although it reminds Northern Hemisphere [ http://antwrp.gsfc.nasa.gov/apod/ap971221.html ] dwellers of an idyllic Winter [ http://antwrp.gsfc.nasa.gov/apod/ap951225.html ] scene, this picture was actually recorded [ http://www.astro.uni-bonn.de/~skohle/comets/hbxmas.html ] in the spring - on April 13th of this year. Seasons Greetings [ http://antwrp.gsfc.nasa.gov/apod/ap961225.html ] and Best Wishes from APOD [ http://antwrp.gsfc.nasa.gov/apod/ap960616.html ]! |
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Hale-Bopp: A Continuing Tail
| Title |
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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Comet Hale-Bopp Over the Sup
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| Title |
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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