Assignment Cuti Raya 2018 Science Form 2.docx

MAKTAB RENDAH SAINS MARA KEPALA BATAS

SCRAP BOOK Homework for Semester 1 Break 2018 Science KSSM  Stars and Galaxies in the Universe  Solar System  Meteoroid, Asteroid, Comet

MUHAMMAD FAKHRURRAZI BIN RIDUAN 203

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INDEX 1)

2)

STARS AND GALAXIES IN THE UNIVERSE........................................................................................ 3 1.1

TYPES OF GALAXIES IN THE UNIVERSE ................................................................................... 3

i)

ELLIPTICAL GALAXY .................................................................................................................. 3

ii)

SPIRAL GALAXY ........................................................................................................................ 3

iii)

IRREGULAR GALAXY ................................................................................................................. 4

1.2

THE MILKY WAY ...................................................................................................................... 5

1.3

THE LIFE CYCLE OF A STAR ...................................................................................................... 6

1.4

BIRTH AND DEATH OF A STAR ................................................................................................ 7

1.5

RELATIVE SIZE COMPARISON ................................................................................................. 9

i)

RELATIVE SIZE COMPARISON OF PLANETS CLOSE TO THE SUN .............................................. 9

ii)

RELATIVE SIZE COMPARISON OF PLANETS IN THE SOLAR SYSTEM ......................................... 9

iii)

RELATIVE SIZE COMPARISON OF THE COMPONENTS OF THE SOLAR SYSTEM ....................... 9

iv)

RELATIVE SIZE COMPARISON BETWEEN THE SOLAR SYSTEM AND THE UNIVERSE .............. 10

1.6

CLASSIFICATION OF STARS .................................................................................................... 11

1.7

SIZES OF STARS...................................................................................................................... 12

i)

SUPERGIANT .......................................................................................................................... 12

ii)

GIANT..................................................................................................................................... 12

iii)

DWARF................................................................................................................................... 13

SOLAR SYSTEM .............................................................................................................................. 14 2.1

SOLAR SYSTEM ..................................................................................................................... 14

2.2

ASTRONOMICAL UNIT AND LIGHT YEARS............................................................................ 15

i)

ASTRONOMICAL UNIT ........................................................................................................... 15

ii) LIGHT YEARS .............................................................................................................................. 15 2.3

CONVERSION OF ASTRONOMICAL UNIT, LIGHT YEARS AND KILOMETRES ........................ 16

2.4

PLANETS IN THE SOLAR SYSTEM .......................................................................................... 17

2.5

ROTATIONAL DIRECTION OF PLANETS................................................................................. 18

2.6

NATURAL SATELLITES AND CHARACTERISTICS OF THE EARTH ........................................... 18

i)

NATURAL SATELLITES ............................................................................................................ 18

ii)

CHARASTERISTICS OF THE EARTH.......................................................................................... 19

2.7 3)

ECOLOGICAL FOOTPRINT ..................................................................................................... 20

METEOROID, ASTEROID, COMET.................................................................................................. 21 3.1

METEOROID, ASTEROID, COMET ......................................................................................... 21

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1) STARS AND GALAXIES IN THE UNIVERSE 1.1 TYPES OF GALAXIES IN THE UNIVERSE i)

ELLIPTICAL GALAXY

Elliptical galaxies are shaped like a spheriod, or elongated sphere. In the sky, where we can only see two of their three dimensions, these galaxies look like elliptical, or oval, shaped disks. The light is smooth, with the surface brightness decreasing as you go farther out from the center. Elliptical galaxies are given a classification that corresponds to their elongation from a perfect circle, otherwise known as their ellipticity. The larger the number, the more elliptical the galaxy is. Elliptical galaxies have no particular axis of rotation. ii)

SPIRAL GALAXY

Spiral galaxies have three main components: a bulge, disk, and halo. The bulge is a spherical structure found in the center of the galaxy. This feature mostly contains older stars. The disk is made up of dust, gas, and younger stars. The disk forms arm structures. Our Sun is located in an arm of our galaxy, the Milky Way. The halo of a galaxy is a loose, spherical structure located around the bulge and some of the disk. The halo contains old clusters of stars.

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iii)

IRREGULAR GALAXY

Irregular galaxies have no particular shape. They are among the smallest galaxies and are full of gas and dust. Having a lot of gas and dust means that these galaxies have a lot of star formation going on within them. This can make them very bright. The Large and Small Magellanic Clouds are examples of irregular galaxies. They are two small galaxies which orbit around our own Milky Way Galaxy. About 20% of all galaxies are irregulars.

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1.2 THE MILKY WAY

The Milky Way is the galaxy that contains our Solar System. The descriptive "milky" is derived from the appearance from Earth of the galaxy which is a band of light seen in the night sky formed from stars that cannot be individually distinguished by the naked eye. From Earth, the Milky Way appears as a band because its diskshaped structure is viewed from within. Galileo Galilei first resolved the band of light into individual stars with his telescope in 1610. Until the early 1920s, most astronomers thought that the Milky Way contained all the stars in the Universe. Following the 1920 Great Debate between the astronomers Harlow Shapley and Heber Curtis, observations by Edwin Hubble showed that the Milky Way is just one of many galaxies. The Milky Way is a barred spiral galaxy with a diameter between 100,000 and 180,000 light-years. It is estimated to contain 100–400 billion stars. There are probably at least 100 billion planets in the Milky Way. The Solar System is located within the disk, about 26,000 light-years from the Galactic Center, on the inner edge of the Orion Arm, one of the spiral-shaped concentrations of gas and dust. The stars in the innermost 10,000 light-years form a bulge and one or more bars that radiate from the bulge. The galactic center is an intense radio source known as Sagittarius A, likely a supermassive black hole. Stars and gases at a wide range of distances from the Galactic Center orbit at approximately 220 kilometers per second. The constant rotation speed suggests that much of the mass of the Milky Way does not emit or absorb electromagnetic radiation. This mass has been termed "dark matter” . The rotational period is about 240 million years at the position of the Sun. The Milky Way as a whole is moving at a velocity of approximately 600 km per second with respect to extragalactic frames of reference. The oldest stars in the Milky Way are nearly as old as the Universe itself and thus probably formed shortly after the Dark Ages of the Big Bang.

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1.3 THE LIFE CYCLE OF A STAR

Examples of the life cycle of a star

The solar nebular hypothesis describes the formation of our solar system from a nebula cloud made from a collection of dust and gas. It is believed that the sun, planets, moons, and asteroids were formed around the same time around 4.5 billion years ago from a nebular. It's believed that before our solar system was formed 4.5 billion years ago, a nebula, which is an interstellar cloud of gas and dust, was present in our location. As gravity does with everything, it began to condense the gas into varying regions of density. The denser regions began to grow into clumps of matter, which, over the course of time, would be the seeds for the formation of our sun, planets, and moons. As gravity condensed the gas, rotation of the gas increased, spreading the gas cloud into a rotating disk that would form the plane of the solar system as we know it today. Evidence of this can be seen because all of the planets revolve around the sun in the same plane and direction. The center of the disk of spinning gas experienced the least amount of centripetal force, which allowed a majority of mass from the nebula cloud to be attracted to the center by the force of gravity. As gravity compacted the material in the sun, mostly hydrogen gas, pressure began to increase and heat the gas. About 4.5 billion years ago, the mass reached a critical point, and the hydrogen at the center was under so much pressure that it fused with another hydrogen atom, creating helium. This fusion was the birth of our star, the sun.

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1.4 BIRTH AND DEATH OF A STAR i.

BIRTH OF A STAR

Birth of a star :- nebulae

A star is born when atoms of light elements are squeezed under enough pressure for their nuclei. All stars are the result of a balance of forces of gravity compresses atoms in interstellar gas until the fusion reactions begin. And once the fusion reactions begin, they exert an outward pressure. As long as the inward force of gravity and the outward force generated by the fusion reactions are equal, the star remains stable. Clouds of gas are common in our galaxy and in other galaxies like ours. These clouds are called nebulae. A typical nebula is many light-years across and contains enough mass to make several thousand stars the size of our sun. The majority of the gas in nebulae consists of molecules of hydrogen and helium but most nebulae also contain atoms of other elements, as well as some surprisingly complex organic molecules. These heavier atoms are remnants of older stars, which have exploded in an event we call a supernova. The source of the organic molecules is still a mystery.

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ii.

DEATH OF A STAR

Death of a star :- supernova

For stars the size of our Sun, when the core runs out of hydrogen fuel, it will contract under the weight of gravity. However, some hydrogen fusion will occur in the upper layers. As the core contracts, it heats up. This heats the upper layers, causing them to expand. As the outer layers expand, the radius of the star will increase and it will become a red giant. The radius of the red giant sun will be just beyond Earth's orbit. At some point after this, the core will become hot enough to cause the helium to fuse into carbon. When the helium fuel runs out, the core will expand and cool. The upper layers will expand and eject material that will collect around the dying star to form a planetary nebula. Finally, the core will cool into a white dwarf and then eventually into a black dwarf. This entire process will take a few billion years. While for stars more massive than the sun, When the core runs out of hydrogen, these stars fuse helium into carbon just like the sun. However, after the helium is gone, their mass is enough to fuse carbon into heavier elements such as oxygen, neon, silicon, magnesium, sulfur and iron. Once the core has turned to iron, it can burn no longer. The star collapses by its own gravity and the iron core heats up. The core becomes so tightly packed that protons and electrons merge to form neutrons. In less than a second, the iron core, which is about the size of Earth, shrinks to a neutron core with a radius of about 10 kilometers. The outer layers of the star fall inward on the neutron core, thereby crushing it further. The core heats to billions of degrees and explodes (supernova), thereby releasing large amounts of energy and material into space. The shock wave from the supernova can initiate star formation in other interstellar clouds. The remains of the core can form a neutron star or a black hole depending upon the mass of the original star. 8

1.5 RELATIVE SIZE COMPARISON i)

RELATIVE SIZE COMPARISON OF PLANETS CLOSE TO THE SUN

ii)

RELATIVE SIZE COMPARISON OF PLANETS IN THE SOLAR SYSTEM

iii)

RELATIVE SIZE COMPARISON OF THE COMPONENTS OF THE SOLAR SYSTEM

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iv)

RELATIVE SIZE COMPARISON BETWEEN THE SOLAR SYSTEM AND THE UNIVERSE

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1.6 CLASSIFICATION OF STARS Star Type

Color

Approximate Surface Temperature

O

Blue

over 25,000 K

10 Lacertra

B

Blue

11,000 - 25,000 K

Rigel, Spica

A

Blue

7,500 - 11,000 K

Sirius, Vega

F

Blue to White

6,000 - 7,500 K

Canopus, Procyon

G

White to Yellow

5,000 - 6,000 K

K

Orange to Red

3,500 - 5,000 K

Arcturus, Aldebaran

M

Red

under 3,500 K

Betelguese, Antares

Pictures

Examples

Sun, Capella

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1.7 SIZES OF STARS i)

SUPERGIANT

Supergiant stars are the largest stars in the universe. Supergiants come in a variety of sizes and temperatures, but they are generally classed as being either red or blue. Supergiant stars can burn all of their remaining hydrogen in just a few million years, compared to the several billion year lifetime of stars like our Sun. During this time they will shine at least 100,000 times brighter than the Sun. At the end of their life, red supergiant stars often explode as a supernova, producing either a neutron star or a black hole in the process. Blue supergiants are considerably hotter than red supergiants, but generally much smaller, only about 25 times the size of the Sun ii)

GIANT

Giant star, any star having a relatively large radius for its mass and temperature; because the radiating area is correspondingly large, the brightness of such stars is high. Subclasses of giants are supergiants, with even larger radius and brightness for their masses and temperatures red giants, which have low temperatures but are of great brightness; and subgiants, which have slightly reduced radii and brightness. Some giants have luminosities hundreds of thousands of times that of the Sun. Masses of giants and supergiants may be 10 to 30 times that of the Sun, but their volumes are often 1,000,000 to 10,000,000 times greater. Thus, they are low-density “diffuse” stars.

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iii)

DWARF

Dwarf star, any star of average or low luminosity, mass, and size. Important subclasses of dwarf stars are white dwarfs and red dwarfs. Dwarf stars include socalled main-sequence stars, among which is the Sun. The colour of dwarf stars can range from blue to red, the corresponding temperature varying from high which is above 10,000 K to low which is a few thousand K.

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2) SOLAR SYSTEM 2.1 SOLAR SYSTEM

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2.2 ASTRONOMICAL UNIT AND LIGHT YEARS i) ASTRONOMICAL UNIT

An Astronomical Unit (AU) is the average distance between Earth and the Sun, which is about 93 million miles or 150 million kilometers. Astronomical units are usually used to measure distances within our Solar System. For example, the planet Mercury is about 1/3 of an AU from the sun, while the farthest planet, Pluto, is about 40 AU from the sun. ii) LIGHT YEARS

A light-year is how astronomers measure distance in space. it’s defined by how far a beam of light travels in one year which is a distance of 9.5 trillion kilometres.

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2.3 CONVERSION OF ASTRONOMICAL UNIT, LIGHT YEARS AND KILOMETRES i)

LIGHT YEARS

ii)

ASTRONOMICAL UNIT

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2.4 PLANETS IN THE SOLAR SYSTEM PLANETS

MERCURY

VENUS

EARTH

MARS

JUPITER

SATURN

URANUS

NEPTUNE

PICTURES

DISTANCE TO SUN

RELATIVE MASS TO EARTH DENSITY (G CM -3) AVERAGE SURFACE TEMPERATURE (Celcius) TIME TAKEN TO ORBIT THE SUN TIME TAKEN TO COMPLETE ONE ROTATION ON ITS AXIS NUMBER OF MOONS MAIN ATMOSPHERIC CONTENT

57.9 MILLION KM 0.055 5.4 167

108.2 MILLION KM 0.723 5.2 457

149.6 MILLION KM 1 5.5 14

227.9 MILLION KM 0.107 3.9 -55

778.3 MILLION KM 317.8 1.3 -153

1429 MILLION KM 95.3 0.7 -185

2870 MILLION KM 14.6 1.27 214

4504 MILLION KM 17.23 1.6 -225

88 DAYS

224.7 DAYS

365 DAYS

687 DAYS

29.5 YEARS

84 YEARS

59 DAYS

243 DAYS

24 HOURS

25 HOURS

11.9 YEARS 10 HOURS

11 HOURS

17 HOURS

164.8 YEARS 16 HOURS

0

0

1

2

67

62

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89.6% H, 10.1% He, 0.3% OTHERS

96% H, 3% He, 0.4% OTHERS

NONE

96.5% CO2, 3.4% N, 0.1% OTHERS

78% N, 21% 96% CO2, O2, 0.1% 1.9% N, OTHERS 1.9% Ar, 0.2% O2

83.3% H, 15.5% He, 2.4% methane

80% H, 19% He, 0.1% OTHERS

CONDITION OF SURFACE

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2.5 ROTATIONAL DIRECTION OF PLANETS

Rotational angle and the direction of the planets in the solar system

All planets in the solar system rotate on their axis at different angles as shown above. All these planets rotate from west to east except Venus which rotates from east to west and Uranus which rotates on its side.

2.6 NATURAL SATELLITES AND CHARACTERISTICS OF THE EARTH

i)

NATURAL SATELLITES

The Earth is orbited by a natural satellite known as the moon. The fifth largest moon in the solar system, Earth's moon is the only place beyond Earth where humans have set foot. The brightest and largest object in our night sky, the moon makes Earth a more livable planet by moderating our home planet's wobble on its axis, leading to a relatively stable climate. It also causes tides, creating a rhythm that has guided humans for thousands of years. The moon was likely formed after a Mars-sized body collided with Earth.

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ii)

CHARASTERISTICS OF THE EARTH

Has a suitable temperature range for living organisms

Has a lot of water for living processes

THE EARTH Receives sunlight for plants to conduct photocyntesis

Has high oxygen content for respiratory system

Has gravity that keeps objects from floating

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2.7 ECOLOGICAL FOOTPRINT

WASTES

USED

SOURCES

Ecological Footprint accounting measures the demand on and supply of nature. The Ecological Footprint tracks the use of six categories of productive surface areas: cropland, grazing land, fishing grounds, built-up land, forest area, and carbon demand on land. If a population’s Ecological Footprint exceeds the region’s biocapacity, that region runs an ecological deficit. Its demand for the goods and services that its land and seas can provide which are fruits and vegetables, meat, fish, wood, cotton for clothing, and carbon dioxide absorptio which exceeds what the region’s ecosystems can renew.

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3) METEOROID, ASTEROID, COMET 3.1 METEOROID, ASTEROID, COMET

Asteroid

Meteoroid

Comet

i.

ASTEROID

An asteroid is a small rocky body orbiting the sun. Most asteroids in our solar system are found in the main asteroid belt, a region between Mars and Jupiter. But they can also hang out in other locations around the solar system. For example, some asteroids orbit the sun in a path that takes them near Earth. ii.

METEOROID

Sometimes one asteroid or comet can smash into another. This can cause small pieces of the asteroid to break off. Those pieces are called meteoroids. iii.

COMET

Comets orbit the sun, like asteroids. But comets seem to contain much more ice and gas, and sometimes comets even develop large and beautiful tails. As a comet’s orbit takes it toward the sun, the ice and dust begin to vaporize. That vaporized ice and dust becomes the comet’s tail. You can see a comet even when it is very far from Earth. However, when you see a meteor, it’s in our atmosphere.

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