3. CHARACTERISTICS COMET ASTEROID
Origin Kuiper Belt and Oort Cloud Main Asteroid Belt
Shape Varied/Irregular Varied/Irregular
Size range of diameter
(km)
1-10(nucleus only) 1-100++
Chemical Composition
Ice (Frozen Water); Frozen
gases (Ammonia,
Methane, and Carbon
dioxide); other organic
compounds (Carbon-
containing compounds)
Silicates (Olivine and
pyroxene), Iron, Nickel
Orbit Highly Elliptical More Rounded
Orbital period (years) 75 – 100,000++ 1-100
4. ORIGIN OF COMETS
• Oort Cloud – is beyond Solar
System.
Long period comets
All other comets that have
identified are classified as a long-
period comets.
6. ORIGIN OF COMETS
• KUIPER BELT – is beyond
Neptune’s orbit.
Short period comets
COMET HALLEY, the most famous
comet of the 20th century is the
only known short-period comet. It
takes 75-79 years to orbit the Sun.
8. ORIGIN OF ASTEROIDS
Originate from the Main Asteroid Belt between
Mars and Jupiter.
• MAIN ASTEROID BELT
- This belt is theorized by scientists to be
remnants of a planet that did not completely form.
ASTEROID 2012 DA14 made a very close
approach to Earth as it orbited the sun. It was
just 0.4 light year away from Earth.
ASTEROID TOUTATIS also made a near approach
to Earth but not close as Asteroid 2012 DA14.
10. CHEMICAL COMPOSITION OF
COMETS
• Ammonia, methane, and carbon
dioxide.
• Other organic compounds
• Sometimes, it may contain other
elements like Sodium or argon.
COMET HALE-BOPP
-contain argon which was believed
to explain the very bright
appearance of the comet in 1997.
12. IMPORTANCE:
• The composition of a comet is important in
helping scientists to understand how Earth has
liquid water, which in turn made the planet
liveable.
• By studying comets’ orbits and the chemical
composition of materials found in impact craters
found all over Earth, soil and ice samples
collected from drilling down Earth’s crust and
marine layers.
13. CHEMICAL COMPOSITION OF
ASTEROIDS
• Mostly composed of rock (silicates)
and metals (iron and nickel being
the usual metals).
• IMPORTANCE:
-important in providing clues for
scientists to discover more about the
chemical composition of Earth and
the other planets in the Solar system,
as well as how life on Earth was
affected by impacts in the past.
15. Evidence
• LUIS AND WALTER ALVAREZ
The discovery of high contents of Iridium in Oceanic
sedimentary layers in different parts of the world
during the late 1970s led geologists proposed the
Alvarez Hypothesis in 1980.
ALVAREZ HYPOTHESIS
-an asteroid with approximately 10 km in diameter
made impact with Earth 65 million years ago.
*They thought that the impact caused materials to be
thrown up in air, thus blocking sunlight, and bringing
about a period of winter long enough to cause a mass
extinction of plants and animals, including dinosaurs.
17. • A meteoroidusually all burns up when it
enters Earth’s atmosphere.
• When a fragment from the meteoroid
survives and makes it to the ground,
this space rock fragment is now
called a meteorite.
18. meteor
moves swiftly and seems to fall on the ground.
It “shoots” from a point in the sky, making
people think that it is a shooting or falling star.
METEOR SHOWER
is named after the constellation where they
seem to originate from, but this does not mean
that the meteoroids come from the associated
constellation.
Remember:
a meteor and a meteor shower are light
phenomena; they are not stars.
20. How much and how well you can
see meteors in the sky depend on
several factors:
1. Air pollution; light pollution;
2. the time of day;
3. weather conditions;
4. size of the meteoroids;
5. source of the meteoroid (comet versus
asteroid);
6. The number of meteors that can be seen
during a meteor shower vary.
*It starts with the appearance of a few meteors
per hour, increasing in frequency until it reaches
its peak of 1-2 meteors per minute, and then
declines.
21. IMPORTANCE
• Meteorites are of importance to
scientists in studying the
occurrence of different elements
and compounds on Earth.
• This information is in turn
important in studying our mineral
resources which is an important
industry in any country.
23. In the Philippines, there are only
five meteorites that have been
accepted internationally.
Editor's Notes
They are remnants from the formation of our solar system 4.6 billion years ago.
Scientists also discovered a faint sodium tail, a 3rd type of comet tail to add to the well-known dust and plasma (or ion) tails.
Scientists theorized that the EARLY impact of comets on Earth brought liquid water to the planet.
It’s the scientists’ belief that Earth, other planets, and asteroids are essentially similar in composition. In fact, ASTEROIDS are also called minor planets or planetoids.