Download A More Reasonable Comet Recipe Dennis Schatz

Hale-Bopp: The Great Comet of 1997 Credit & Copyright: Jerry Lodriguss (Catching the Light) 2007 March 31
Explanation: Ten short years ago, Comet Hale-Bopp rounded the Sun and offered a dazzling spectacle in planet
Earth's night. This stunning view, recorded shortly after the comet's perihelion passage on April 1, 1997, features the
memorable tails of Hale-Bopp -- a whitish dust tail and blue ion tail. Here, the ion tail extends well over ten degrees
across the northern sky, fading near the double star clusters in Perseus, while the head of the comet lies near
Almach, a bright star in the constellation Andromeda. Do you remember Hale-Bopp? The photographer's sons do,
pictured in the foreground at ages 12 and 15. In all, Hale-Bopp was reported as visible to the naked eye from roughly
late May 1996 through September 1997.
Comet Hyakutake Passes the Earth Credit & Copyright: Doug Zubenel (TWAN) 2009 December 16
Explanation: In 1996, an unexpectedly bright comet passed by planet Earth. Discovered less than two months before,
Comet C/1996 B2 Hyakutake came within only 1/10th of the Earth-Sun distance from the Earth in late March. At that
time, Comet Hyakutake, dubbed the Great Comet of 1996, became the brightest comet to grace the skies of Earth in 20
years. During its previous visit, Comet Hyakutake may well have been seen by the stone age Magdalenian culture, who
17,000 years ago were possibly among the first humans to live in tents as well as caves. Pictured above near closest
approach as it appeared on 1996 March 26, the long ion and dust tails of Comet Hyakutake are visible flowing off to the
left in front of a distant star field that includes both the Big and Little Dippers. On the far left, the blue ion tail appears to
have recently undergone a magnetic disconnection event. On the far right, the comet's green-tinted coma obscures a
dense nucleus of melting dirty ice estimated to be about 5 kilometers across. A few months later, Comet Hyakutake
began its long trek back to the outer Solar System. Because of being gravitationally deflected by massive planets,
Another Tail for Comet Garradd
Image Credit & Copyright: Olivier Sedan (Sirene Observatory) 2012 March 3
Explanation: Remarkable comet Garradd (C2009/P1) has come to be known for two distinctive tails. From the perspective of
earthbound comet watchers the tails are visible on opposite sides of its greenish coma. Seen here in a telescopic view, the
recognizable dust tail fans out to the right, trailing the comet nucleus in its orbit. Streaming away from the sunward direction, a
familiar bluish ion tail sweeps to the left. But the comet also seems to have, at least temporarily, sprouted a second ion tail
recorded in this image from February 24. Other comet imagers have recently captured changing structures in Garradd's ion tail
created as the plasma is buffeted by the magnetic fields in the solar wind. Now moving more quickly through northern skies, on
March 5th comet Garradd will reach its closest approach to planet Earth, about 10.5 light-minutes distant.
Comet Lulin Tails Credit & Copyright: Joseph Brimacombe 2009 February 7
Explanation: Sweeping through the inner solar system, Comet Lulin is easily visible in both northern and southern
hemispheres with binoculars or a small telescope. Recent changes in Lulin's lovely greenish coma and tails are featured
in this two panel comparison of images taken on January 31st (top) and February 4th. Taken from dark New Mexico
Skies, the images span over 2 degrees. In both views the comet sports an apparent antitail at the left -- the comet's dust
tail appearing almost edge on from an earth-based perspective as it trails behind in Lulin's orbit. Extending to the right of
the coma, away from the Sun, is the beautiful ion tail. Remarkably, as captured in the bottom panel, Comet Lulin's ion tail
became disconnected on February 4, likely buffeted and torn away by magnetic fields in the solar wind. In 2007 NASA
satellites recorded a similar disconnection event for Comet Encke. Don't worry, though. Comet tails can grow back.
Tail Wags of Comet Ikeya-Zhang Credit & Copyright: Michael Karrer 2002 May 15
Explanation: As Comet Ikeya-Zhang approached the Sun two months ago, it developed a complex blue ion tail. The tail was composed of
ions that boiled off the nucleus and were pushed away from the Sun by the out-flowing fast-moving particles of the solar wind. Complexity in
the tail is created by comet nucleus rotation, variability in the comet surface evaporation rate, and variability of the Sun's magnetic field and
solar wind. The above animation documents how Comet Ikeya-Zhang's tail changed over 30 minutes in ten consecutive 3-minute exposures
on March 11. Comet Ikeya Zhang is now fading as it heads back to the outer Solar System. It should remain visible through a small telescope
for another month.
Golden Comet Holmes Credit & Copyright: Don Goldman 2007 November 3
Explanation: Surprising Comet Holmes remains easily visible as a round, fuzzy cloud in the northern constellation
Perseus. Skywatchers with telescopes, binoculars, or those that just decide to look up can enjoy the solar system's latest
prodigy as it glides about 150 million kilometers from Earth, beyond the orbit of Mars. Still expanding, Holmes now appears
to be about 1/3 the size of the Full Moon, and many observers report a yellowish tint to the dusty coma. A golden color
does dominate this telescopic view recorded on November 1, showing variations across the coma's bright central region.
But where's the comet's tail? Like any good comet, Holmes' tail would tend to point away from the Sun. That direction is
nearly along our line-of-sight behind the comet, making its tail very difficult to see.
Three Month Composite of Comet Holmes Credit & Copyright: John Pane 2008 February 5
Explanation: How has Comet Holmes changed? Since brightening unexpectedly by nearly one million fold in late
October, the last three months have found the coma of Comet 17P/Holmes both expanding and fading. This spectacular
composite image shows how the coma and tail of Comet Holmes have changed. Due to Earth's changing vantage point,
Comet Holmes, out beyond the orbit of Mars, was seen in November nearly head-on, but in recent months is seen more
from the side. Additionally, the comet's motion, when combined with Earth's changing perspective, has caused the comet
to have shifted relative to the background stars. The curved path of Comet Holmes shows it to be undergoing apparent
retrograde motion as the Earth orbits quickly in front of it. The extent of the coma currently makes Comet Holmes over
five times the physical size of our Sun. Anecdotal evidence holds that the comet is hard to see without long photographic
exposures, but on such exposures the comet may still be an impressive sight.
Crumbling Comet
Credit: William Reach (SSC/Caltech), et al., JPL, Caltech, NASA 2006 May 13
Explanation: This false-color mosaic of crumbling comet Schwassmann-Wachmann 3 spans about 6 degrees (12 full
moons) along the comet's orbit. Recorded on May 4-6 by an infrared camera on board the Spitzer Space Telescope, the
picture captures about 45 of the 60 or more alphabetically cataloged large comet fragments. The brightest fragment at the
upper right of the track is Fragment C. Bright Fragment B is below and left of center. Looking for clues to how the comet
broke up, Spitzer's infrared view also captures the trail of dust left over as the comet deteriorated during previous passes.
Emission from the dust particles warmed by sunlight appears to fill the space along the cometary orbit. The fragments are
near their closest approach in the coming days, about 10 million kilometers away, and none pose any danger to our fair
planet.
Comet Lovejoy: Sungrazing Survivor Credit: LASCO, SOHO Consortium, NRL, ESA, NASA 2011 December 17
Explanation: Like most other sungrazing comets, Comet Lovejoy (C/2011 W3) was not expected to survive its close
encounter with the Sun. But it did. This image from a coronograph onboard the sun-staring SOHO spacecraft identifies the
still inbound remnants of the tail, with the brilliant head or coma emerging from the solar glare on December 16. The Sun's
position, behind an occulting disk to block the overwhelming glare, is indicated by the white circle. Separated from its tail,
Comet Lovejoy's coma is so bright it saturates the camera's pixels creating the horizontal streaks. Based on their orbits,
sungrazer comets are thought to belong to the Kreutz family of comets, created by successive break ups from a single
large parent comet that passed very near the Sun in the twelfth century. Most have been discovered with SOHO's
cameras, but unlike many sungrazers, this one was first spotted by Australian astronomer Terry Lovejoy from an earthbased observatory. Comet Lovejoy is estimated to have come within 120,000 kilometers of the Sun's surface and likely had
a large cometary nucleus to have survived its intense perihelion passage. Remarkable videos of the encounter from the
Solar Dynamics Observatory can be found here.
Comet Tempel 1 from Stardust-NeXT Spacecraft Credit: NASA, JPL-Caltech, Cornell 2011 February 16
Explanation: No comet has ever been visited twice before. Therefore, the unprecedented pass of the Stardust-NeXT
spacecraft near Comet Tempel 1 earlier this week gave humanity a unique opportunity to see how the nucleus of a
comet changes over time. Changes in the nucleus of Comet Tempel 1 were of particular interest because the comet
was hit with an impactor from the passing Deep Impact spacecraft in 2005. Pictured above is one digitally sharpened
image of Comet Tempel 1 near the closest approach of Stardust-NeXT. Visible are many features imaged in 2005,
including craters, ridges, and seemingly smoother areas. Few firm conclusions are yet available, but over the next few
years astronomers who specialize in comets and the understanding the early Solar System will be poring over these
images looking for new clues as to how Comet Tempel 1 is composed, how the 2005 impact site now appears, and
how general features of the comet have evolved.
Comet Halley's Nucleus: An Orbiting Iceberg Credit & Copyright: Halley Multicolor Camera Team, Giotto Project, ESA
2010 January 4
Explanation: What does a comet nucleus look like? Formed from the primordial stuff of the Solar System, comet nuclei were
thought to resemble very dirty icebergs. But ground-based telescopes revealed only the surrounding cloud of gas and dust of
active comets nearing the Sun, clearly resolving only the comet's coma, and the characteristic cometary tails. In 1986,
however, the European spacecraft Giotto became one of the first group of spacecraft ever to encounter and photograph the
nucleus of a comet, passing and imaging Halley's nucleus as it approached the sun. Data from Giotto's camera were used to
generate this enhanced image of the potato shaped nucleus that measures roughly 15 kilometers across. Some surface
features on the dark nucleus are on the right, while gas and dust flowing into Halley's coma are on the left. Every 76 years
Comet Halley returns to the inner Solar System and each time the nucleus sheds about a 6-meter deep layer of its ice and
rock into space. This debris shed from Halley's nucleus eventually disperses into an orbiting trail responsible for the Orionids
meteor shower, in October of every year, and the Eta Aquariids meteor shower every May.
700 Kilometers Below Comet Hartley 2 Credit: NASA, JPL-Caltech, UMD, EPOXI Mission 2010 November 8
Explanation: What kind of comet is this? Last week, NASA's robotic EPOXI spacecraft whizzed past Comet
103P/Hartley, also known as Comet Hartley 2, and recorded images and data that are both strange and fascinating.
EPOXI was near its closest approach -- about 700 kilometers away -- when it snapped the above picture. As expected,
the comet has indeed shown itself to be a tumbling iceberg orbiting the Sun between Earth and Jupiter. However,
unexpected features on the images have raised many questions. For example, where are all the craters? Why is there a
large smooth area around the middle? How much of Comet Hartley 2 is a loose pile of dust and ice shards? Future
analyses and comparisons to other comet nuclei may answer some of these questions and, hopefully, lead to a better
general understanding of comets, meteors, and the early Solar System.
A Comet Recipe
Place in a large mixing bowl:
9 billion tons of water ice
800 million tons of dry ice (carbon dioxide)
50 million tons of ammonia ice
Carbon monoxide ice to taste
140 million tons of carbonaceous particles
9 million tons of silicate sand
A pinch of cosmic seasonings (sodium, potassium, calcium, iron,
copper, etc.)
Miniscule amount of organic material
Combine all ingredients and stir well.
Place in a freezer and freeze at a temperature of -200 C until hard.
Yield: One 10 billion ton cometary nucleus
A More Reasonable Comet Recipe Dennis Schatz, Pacific
Science Center
2 cups water (H2O)
2 spoonfuls of carbon (charcoal)
dash of ammonia (NH3)
drop of organic material
pinch of salt (NaCl)
pinch of sand (Silicates)
2 cups crushed dry ice (frozen carbon dioxide, CO2)Combine all
ingredients, except the dry ice, in a pail lined with heavy plastic.
Use a wooden spoon to mix all ingredients.
Wearing gloves, add the dry ice and stir until the mixture becomes
stiff.
Carefully lift the plastic by the corners and squeeze almost closed
just above the comet.
Using two hands (thus more than one person is needed), carefully,
but forcefully form the comet into a ball through the plastic.
Place on table and unwrap the newborn comet.
Yield: One 15-cm cometary nucleus