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Rendezvous with a Comet

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1 Rendezvous with a Comet
Challenger Mission: Rendezvous with a Comet

2 Rendezvous To meet up in a location

3 A probe entering a comet
Courtesy: Pat Rawlings - Deep Impact -NASA & JPL

4 Simulation Acting out an activity (space mission)

5 Our Solar System

6 Earth is a part of The Solar System

7 Our Solar System is part of the Milky Way Galaxy
Which is part of the Universe.

8 Galaxies

9 Our Sun Hot ball Of gases

10 Inner Planets

11 Outer Planets

12 Asteroids, Meteoroids and Comets

13 asteroids Rocky metallic objects that orbit the sun

14 Year Giuseppe Piazzi discovered the first asteroid, Ceres
1801 Year Giuseppe Piazzi discovered the first asteroid, Ceres

15 4.6 Earth years it takes the asteroid Ceres to travel around the sun (Ceres – Biggest Asteroid with a 960 km circumference)

16 2880 Year asteroid 1950 DA will pass close to Earth – The greatest known impact hazard

17 Asteroids Asteroids are small, rocky worlds.
Most asteroids revolve around the sun between the orbits of Mars and Jupiter. (asteroid belt)

18 Earth has been struck many times in its history by asteroids.



21 100 km 212 Million years old Canada




25 A S T E R O I D B L

26 meteorite Meteor shower A chunk of metal or rock that reaches Earth
from space meteorite

27 Meteoroid A meteoroid is a chunk of rock, metal, or dust in space.

28 A Meteor: “A shooting star”
Shooting stars are not actually stars. These flashes of light across the sky are small bits of rock burning up in the Earth’s Atmosphere.

29 Meteorite Meteoroids that survive as they pass through the atmosphere and hit Earth’s surface are called meteorites.

30 There are three major types of meteorites: stone, iron and stony-iron.
There are three major types of meteorites: stone, iron and stony-iron.

31 Barringer Meteor Crater, Arizona
A meteorite can make a hole, or crater, in the ground when it hits it. The larger the meteorite, the bigger the hole.

32 METEOROID: A piece of stone or metal that travels in outer space.
METEOR: An object from space that becomes glowing hot when it passes into Earth's atmosphere. METEORITE: A piece of stone or metal from space that falls to Earth's surface.

33 comets Lumps of ice and dust that periodically come to the center of the solar system from the outer reaches.

34 Dirty Snowballs Comets are dusty chunks of ice
During each orbit around the sun they partially vaporize Have elliptical orbits They are about the size of an earth mountain. (dirt and ice) Comets’ orbits are usually very long, narrow ellipses. They produce tails of gas and dust when they approach the sun. Courtesy: Calvin J. Hamilton

35 History Unlike the other small bodies in the solar system, comets have been known since antiquity. There are Chinese records of Comet Halley going back to at least 240 BC. The famous Bayeux Tapestry, which commemorates the Norman Conquest of England in 1066, depicts an apparition of Comet Halley. As of 1995, 878 comets have been cataloged and their orbits at least roughly calculated. Of these 184 are periodic comets (orbital periods less than 200 years); some of the remainder are no doubt periodic as well, but their orbits have not been determined with sufficient accuracy to tell for sure.

36 Comets have been regarded as omens, even as recently as 1986.
The history of comet watching dates back to 1000 BC from the Chinese records and Chaldea, a place in present Iraq. Comets have been regarded as omens, even as recently as 1986. Battle of Hastings Today astronomers study comets from scientific perspectives, and our understanding of these fascinating objects have grown tremendously.

37 Structure of a Comet Solar heat vaporizes the nucleus to produce
Coma - Hydrogen gas Envelope Dust tail Ion tail Courtesy: Deep Impact - NASA & JPL

38 Parts of a Comet When they are near the Sun and active, comets have several distinct parts: nucleus: relatively solid and stable, mostly ice and gas with a small amount of dust and other solids; coma: dense cloud of water, carbon dioxide and other neutral gases sublimed from the nucleus; hydrogen cloud: huge (millions of km in diameter) but very sparse envelope of neutral hydrogen; dust tail: up to 10 million km long composed of smoke-sized dust particles driven off the nucleus by escaping gases; this is the most prominent part of a comet to the unaided eye; Ion tail: as much as several hundred million km long composed of plasma and laced with rays and streamers caused by interactions with the solar wind.

39 Comet Nucleus (plural: Nuclei)
A drawing of what the surface of a comet might look like. The nucleus of a comet is the central portion of the head of a comet. It is a solid part of the comet, made of a special sort of dust which is called "fluffy" because it could be as light weight and full of holes as a sponge. The holes of this "sponge" are filled with ices like water, carbon dioxide (dry ice), and carbon monoxide (what comes out of your car).

40 Coma This cloud, called the coma, is the atmosphere of the comet and can extend for millions of miles. The cloud is very thin, however, 10,000 times thinner than a cloud in the Earth's atmosphere! The neutral particles that are in the coma can actually become excited by the solar wind causing the particles to become ions. A continual stream of neutral particles is produced as long as the nucleus is evaporating, and these neutral particles are continually converted to ions. These ions are what help form the comet tail.

41 Tails A comet generally has two tails, not one. One tail is due to the comet's dust particles, the other is due to ionized gas from the comet coma. Dust particles form the first tail. This comet tail generally points back along the comet path (so if the comet is traveling right, the dust tail extends to the left). Ions (electrically charged particles), which first come from the nucleus as (neutral) gaseous particles, are swept into the second comet tail. Because of the special interaction with the Sun's magnetic field, this tail always points directly away from the Sun.

42 Schematic of a Comet This image is a schematic of a comet. The center part of the comet, or nucleus, is represented by the flame. The solar wind particles are shown as green dots with arrows. And the ionized particles are shown as green/red dots with arrows. Neutral particles are shown by the other dots (without arrows).

43 Orbits of Comets Aphelion distance Comet Sun Earth Perihelion distance
Elliptical in Shape Randomly oriented Aphelion distance Comet Sun Earth Perihelion distance

44 Comet Hunters Comet are named by International Astronomical Union (IAU) after the person who first discovers them. Many comets are discovered by amateur astronomers. Charles Messier, E. E. Bernard, Shoemaker and Levy, Hale and Bopp, Ikeya, Seki and Hayakutake are popular comet hunters.

45 Origins of Comets Comets are thought to be the left over debris from during the time of formation of the solar system. The elliptical orbits of comets suggest that they underwent gravitational pull from the giant planets. This all lead us to infer two possible locations where comets could start their journey towards the sun.

46 Possible Homes for Comets
Kuiper Belt Oort Cloud Courtesy - Deep Impact - NASA - JPL


48 Kuiper Belt Discovered by Gerard Kuiper in 1951
The belt is 30 to 500 AU from the Sun The plane of the belt is close to the ecliptic Probably contains more than 100,000 objects Some of these objects are 100 km or larger in diameter

49 Oort Cloud Hypothesized by a Dutch Astronomer Jan Oort in 1950.
Shape is spherical distribution around the Sun. 50,000 AU from the Sun. May contain 5 trillion objects. Probably created 4.6 billion years ago.

50 Comets and their Spectra
Spectroscopy is a technique in which light is broken into its component colors. Each chemical element show their fingerprint in the spectrum of the object. We can thus find the composition of comets by identifying the fingerprints. Most of the information on comets comes from infrared radiation, because comets are cold objects they radiate strongly at infrared radiation.

51 Comet Collisions Comet collisions with Earth can bring devastation to life on Earth. Jupiter in our solar system is the largest planet and thus exerts greater gravitational pull on incoming Comets. Study of Shoemaker-Levey collision with Jupiter gave us important facts about Comet collisions.

52 Comet Collisions Courtesy: NASA/JPL

53 Halley’s Comet…. Orbits every 76 years

54 Halley’s Comet Orbit… next seen in 2062

55 Winter and early spring of 1997
Comet: Hale-Bopp Winter and early spring of 1997 Next sighting: 4380

56 Facts Comets are invisible except when they are near the Sun. Most comets have highly eccentric orbits which take them far beyond the orbit of Pluto; these are seen once and then disappear for millennia. Only the short- and intermediate-period comets (like Comet Halley), stay within the orbit of Pluto for a significant fraction of their orbits.

57 Approaching the Sun As a comet approaches the Sun, it begins to evaporate, forming the coma and a spectacular comet tail. Evaporation is not quite the correct term to describe what happens to a comet as it approaches the sun. The correct term is sublimation. The term describes what happens when a frozen material changes to gaseous form. (Evaporation describes what happens when a liquid changes to a vapor).

58 Sublimation The most common example of sublimation is that of dry ice, which is the common name of frozen CO2. When dry ice is exposed to the air it begins to sublimate, or change to vapor, before your very eyes. This happens to dry ice because at room temperature the frozen gas would rather be a gas than frozen solid.

59 Long Period Comets A comet with an orbital period of more than 200 years.

60 Short Period Comets A comet with an orbital period of less than 200 years. Short period fade over time as more and more of their ices melt with each passage of the Sun. Examples: Comet Halley, 76-year orbit; Comet Encke, 3.3-year orbit; Comet Wild 2, 6.2 year orbit.

61 orbit The path a planetary body makes as it revolves around the sun
The orbit of a comet tends to be far more elliptical than planet’s orbits.

62 Circle A geometric shape where all points on a plane are the same distance from the center

63 ellipse A geometrical shape where all the points on a curve is the constant sum of the distances from two fixed points, called focal points.

64 Perihelion The point where an object orbiting the Sun is closest to the Sun

65 Astronomical unit (AU)
One AU is equal to the average distance between the Sun and Earth, approximately 150 million kilometers (93 million miles)

66 Ejecta The debris that is ejected from the site of impact when a crater forms

67 Gravity Force of attraction between two objects
Just as Earth pulls on you, you pull on Earth with the exact same amount of force.

68 mass The amount of matter in an object
The measure of an object’s inertia. Mass is not the same as weight, which measures the gravitational force on an object. Your mass is the same everywhere, whether you are at home, on the Moon, or floating in interplanetary space.

69 particle A tiny quantity of a substance

70 Flight Director The commander working with the crew in mission control

71 Image A picture that can be sent from Mission Control to the spacecraft to assist you with your work

72 Data Log Used in Mission Control to record experimental data

73 Mission Commander The Commander working with the crew in the spacecraft

74 Mission Status A television monitor that shows the task each team is working on and the time left in the mission

75 Monitor A screen that shows mission activities

76 Priority Something that is very important

77 Start Code A number entered into the computer system when a spacecraft crew member is starting a new task

78 Flight Manual Step-by-step instructions for each task found in Mission Control

79 Task Card Step-by-step instructions for each task found in the spacecraft

80 Data Team: Data Information collected during the crew’s experiments

81 Data Team: Image A digital picture of equipment or materials used by a team on the Spacecraft

82 Isolation Team: Balance
A scale for weighing materials

83 Isolation Team: CPM (counts per minute); the number of radioactive particles striking the sensor of a Geiger counter during each minute.

84 Isolation Team: Filter
A device used to separate impurities from the air

85 Isolation Team: Geiger Counter
A device for measuring radioactivity

86 Isolation Team: Isolation Chamber
An airtight, enclosed work area

87 Isolation Team: Micrometeoroid
Tiny bits of asteroids that travel at 18,000 miles per hour in earth’s orbit: can damage spacecraft upon impact

88 Isolation Team: Radioactivity
A physical property of some hazardous materials that causes the material to emit particles that can be measured with a Geiger counter

89 Isolation Team: Transmittance
The penetration of radioactive particles through materials such as water and aluminum

90 Remote: Balance An electronic scale used for measuring mass

91 Remote: Glovebox A special experiment area that is enclosed to protect your experiments

92 Remote: Mass A measurement of the amount of matter within any object

93 Remote: Volume A measurement of the amount of space an object takes up

94 Medical: Auditory Reaction Time
How long it takes to react to a sound you hear

95 Medical: Blood Pressure
The pressure of the blood on the walls of the blood vessels

96 Medical: Peripheral Vision
The field seen in a surrounding space while looking straight ahead

97 Medical: Gravity The force that pulls bodies toward the center of the planet

98 Medical: Pulse Rate The pressure in the arteries due to the beating of the heart

99 Medical: Respiration Rate
The number of breaths per minute

100 Medical: Skin Temperature
External temperature of the body; lower than internal temperature

101 Medical: Visual Reaction Time
How long it takes to react to a light you see

102 Probe: Airlock The special drawer in which the probe is securely kept

103 Probe: Cable A wire that carries electricity from one component to another in the probe

104 Probe: Component An electronic part that is plugged into the probe

105 Probe: Deploy Launch

106 Probe: Probe A data-collecting device which will explore a comet

107 Life Support: Ammeter A device for measuring light

108 Life Support: Barometer
An instrument for measuring air pressure

109 Life Support: Beaker A laboratory device for measuring liquid

110 Life Support: Dissolve
To change from a solid to a liquid state

111 Life Support: Environmental Conditions
The temperature, air pressure and humidity in the spacecraft

112 Life Support: Graduated Cylinder
A laboratory device for measuring liquids

113 Life Support: Hygrometer
An instrument used to measure relative humidity

114 Life Support: Indicator
A chemical used for testing if a liquid is acid base or neutral

115 Life Support: Liter The basic unit of volume in the metric system; one liter equals 34 fluid ounces, or 1.06 quarts

116 Life Support: MA (milliamperes or Milliamps); the units attached to the number determined by the ammeter , one thousandth of an Ampere

117 Life Support: milli- One thousandth of something

118 Life Support: mL One thousandth of a liter

119 Life Support: pH A number which tells how acidic or basic a liquid is

120 Life Support: ppm (parts per million); the units attached to the number determined by the TDS meter

121 Life Support: Solar Energy
Energy provided by the sun

122 Life Support: TDS (total dissolved solids); a number telling how much solid material is dissolved in water, measured by the TDS meter

123 Life Support: Valve A device used to control the flow of air or water

124 Navigation Team: Angle
The point formed by the joining of two lines

125 Navigation Team: Detector
A device used to gather information

126 Navigation Team: Grid A system of X and Y coordinates used in launching detectors

127 Navigation Team: Initialize
To begin or name something

128 Navigation Team: Particle density
A number telling how tightly packed the material in a comet is

129 Navigation Team: Star Chart
A paper map of the stars

130 spectrometer An instrument used to obtain and record a spectrum of an astronomical object A spectrum is a series of colors that is produced when light is spread out in order of wavelength.

131 Navigation Team: Starfield
A group of stars in view of the spacecraft’s camera

132 Navigation: Density Mass of a substance contained per unit of volume

133 Navigation: Coma The atmosphere of a comet, which surrounds the nucleus

134 Navigation: Nucleus The solid part of a comet made up of rocks, dust, gas and ice (dirty snowball)

135 Navigation: Tail The longest part of the comet caused by solar wind

136 Navigation: Constellation
A group of stars that form a pattern in the sky

137 Navigation: Declination
The label for the Y-axis on a star chart. The declination of an object is its distance in degrees above or below the celestial equator. Decline numbers range from 0 degrees to +90 degrees and 0 degrees to -90 degrees. It is similar to latitude on Earth

138 Navigation: Right Ascension
The label for the X-axis on a star chart. The right ascension of an object in the sky is its position, simply put relative to the vernal equinox. It is measured in hours minutes and seconds from 0 hours, 0 minutes and 0 seconds of right ascension at the starting point (vernal equinox), to 23 hours, 59 minutes of right ascension. Right ascension is equivalent to longitude.

139 Navigation: Eccentricity
A numerical value for the shape of an orbit ranging from 0, which equals a circular orbit, to 1 which equals a flattened, elliptical orbit. Planets , moons, asteroids and short period comets have eccentricity values close to 0. long period comets have eccentricity values of 0.5 or more

140 Navigation: Short Period Comet
A comet with an orbital period of less than 200 years. (Comet Halley is 76 years and comet Encke is 3.3 years.

141 Navigation: Long Period Comet
A comet with an orbital period of more than 200 years. (Hale-Bopp is 2425 years and Hyakutake is 15,000 Years)

142 Navigation: Magnitude
A numerical value for the brightness of a celestial object. The brighter an object appears in the sky, the smaller its magnitude the dimmer an object appears in the sky, the larger its magnitude.

143 Navigation: Stellar Object
A celestial object that produces its own light (the sun)

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