PISMP SCE 3110 Bumi dan Angkasa

Lepas

Jabatan Sains

IPG Kampus Pendidikan Teknik

Minggu 1

PISMP Sn Ambilan Jan 2012

Apakah yang anda tahu tentang Angkasa Lepas?

Mengapa manusia bergantung kepada kedudukan bulan,

matahari atau bintang untuk bercucuk taman?

Bintang atau buruj manakah yang digunakan untuk navigasi?

Apa yang anda tahu tentang cara bulan, bintang dan matahari

bergerak?

Arah manakah anda pandang untuk melihat matahari terbit?

Bagaimana anda menentukan arah Utara?

Di manakah bulan terbit?

Bagaimana bulan berubah fasa?

Adakah bulan sentiasa dapat dilihat di langit setiap malam?

Adakah bulan dapat dilihat waktu siang?

Adakah pasang-surut berkaitan dengan pergerakan bulan?

Adakah bintang juga terbit dan terbenam macam matahari?

Apakah Buruj Belantik?Apakah nama bintang-bintang

dalam buruj Belantik?

Adakah astrologi berkaitan dengan astronomi?

MENJEJAKI OBJEK LANGIT

Bagaimana anda menentukan kedudukan objek dil angit?

Konsep Sfera Samawi

Kedudukan relatif jasad samawi yang hendak dihisab terhadap kedudukan kita (pencerap) di bumi boleh digambarkan dalam satu sistem yang dikenali sebagai Sistem Sfera Samawi.

Sfera Samawi adalah merupakan satu sfera yang berpusat pada pencerap di bumi dan mempunyai jejari yang infiniti.

Jarak antara jasad samawi terhadap kita pencerap di bumi tidak menjadi persoalan utama tetapi yang dipentingkan adalah perubahan kedudukan relatif jasad tadi terhadap kita dari masa ke semasa.

Gambarajah 1 memberikan sekilas pandang sistem sfera samawi.

Sistem koordinat ufuk

Kedudukan objek langit ditentukan dengan menggungakan sudut azimuth dan altitud

Sistem koordinat ini merujuk kepada pencerap sebagai rujukan, dengan ini ianya bermaksud pencerap menentukan ufuknya sendiri, Dan ufuk di sekeliling pencerap ini dianggap sebagai suatu satah(hamparan). Azimuth di ukur menggunakan iaitu 0° hingga 360°, dengan utara ialah titik rujukan sebagai 0° dan sudutnya bertambah mengikut putaran jam dengan timur ialah 90° dan selatan ialah 180°. Altitud diukur dengan menggunakan 0° hingga 90°, kedudukan 90° (titik tegak di atas kepala) dinamakan titik Zenith.

Titik Zenith juga ialah merupakan kutub langit kepada sistem koordinat ini.

Bintang Canopus

+169020’59”/+32044’50”

MASALAH

Masalah - contoh

Shaun (10.00pm Brisbane, Australia) dan Aziz (08.00 pm Kuala Lumpur) sedang memerhatikan bintang Sirius pada masa yang sama.

Mereka akanmemberikan koordinat azimuth dan altitud Sirius yang berlainan.

Perkara ini tidak boleh terjadi!!!

Bagaimana para astronomi seluruh dunia boleh merujuk objek langit sama supaya mereka faham?

Sistem koordinat Khatulistiwa

Para Ahli Astronomi melakarkan garis bayangan secara tegak dan mendatar pada sfera langit sama seperti garis tegak dan garis mendatar pada permukaan Bumi.

Garis-garis ini dilakarkan agar ahli Astronomi dapat menentukan objek di langit dengan mudah, dan berkongsi mengenainya dengan ahli astronomi yang lain.

Sistem koordinat Khatulistiwa Sistem ini menggunakan sistem RA

(Right Ascension),a dan Declination,d. RA diukur menggunakan nilai

0j sehingga 24j. Manakala 0° hingga +90°, declination

untuk kutub Utara Langit dan 0° hingga -90° untuk Kutub Selatan Langit

Khatulistiwa Bumi diunjurkan ke infiniti menjadikannya sebagai khatulistiwa langit ataupun satah rujukan, manakala kutub Utara Bumi diunjurkan ke infiniti juga menjadi Kutub Utara Langit, dan ianya dirujukkan kepada satu bintang yang kelihatan tetap sehingga ke hari ini. Begitu juga dengan Kutub Selatan langit, ia adalah unjuran daripada Kutub selatan Bumi.

 RA di terjemahkan sebagai Jarak Hamal(Aries) dan Declination diterjemahkan sebagai Sudut Istiwa.

Titik sifar, 0j Jarak HamalRA adalah merujuk kepada titik awal Hamal (first point of Aries) yang mengambil titik bilamana Matahari bersilang dengan Khatulistiwa Langit, iaitu pada bulan Equinox bulan Mac.

Jelas?

Sila buat pembacaan lanjut

Broadfoot, J. B., Ginns, I., & Lucas, K. B. (2003). The changing sky: Observational exercises in astronomy. Brisbane: QUT

Seeds, M. A. (2007). Foundation of Astronomy. 9th Edition. Belmont: Thomson.

Jumpa malam esok 8.00 pm

Dataran muafakat

CUKUP UNTUK SETAKAT INIMinggu hadapan …

Asal usul alam semestaTeori evolusi alam semesta Penjelajahan alam semestaGalaksiNebulaLohong hitamKerdil putih dan raksasa merah BintangBuruj

Sejarah perkembangan astronomiKepercayaan awalAhli astronomi purba dan perkembangan astronomi

Astrolabe

Make your own astrolab

http://www.joh.cam.ac.uk/library/library_exhibitions/schoolresources/astrolabe/build

http://cse.ssl.berkeley.edu/AtHomeAstronomy/activity_07.html

http://oceanservice.noaa.gov/education/projects/makeyourownastrolabe.pdf

SEKARANG ANDA SUDAH SEDIA UNTUK MENJEJAK OBJEK LANGIT

What are their characteristics?

Compare the size of the earth with other planets

Now compare it with Jupiter, Saturn, Uranus & Neptune

Now Earth against Sun

Against Sun, Earth is like a dot ! Think !! Where do you find yourself now??

Stars at the Poles

Retrograde

Kepler’s 1st LawThe orbit, of a planet about a star, is an ellipse with the star at one focus.

Kepler’s 2nd Law

time from 1 to 2 = time from 3 to 4 area 1-2-S = area 3-4-S

A line joining a planet and its star, sweeps out equal areas during equal intervals of time.

Historical developmentsin astronomy

ancient astronomy and beliefs ancient observatories light and dark zodiacal signs famous early astronomers scientific measurements the solar system celestial objects - planets, asteroids,

comets, stars, clusters, nebulae, galaxies

In this lecture you will learn about …

Archaeoastronomy

What are some of the famous archaeoastronomy sites?

Nabta: Megalithic Site – 1000 years before Stonehenge. Circle of stones marking solstices and

cardinal points more than 6000 years ago in Southern Egypt.

Stonehenge: 3100 BC to 2000 BC

Mesoamerican sites: 1500 BC to 1500 AD

Nazca Lines in Peru: 300 BC to 800 AD

• The study of the astronomical sites which have left us with no written records or names of the people who set up the ruins that we study today.

• It is understanding how these sites were used, and the determination of what these ancients knew by studying the geometry and alignments of the sites.

Ancient observatoriesStonehenge (~2400 BC on)an observatory

that clearly documented the motion of the Sun and Moon

Ancient Chinese Depiction of the Celestial Sphere

Places near the North Pole were assigned to nobility, with lesser

beings relegated to lower latitudes. This image dates from the T'ang

Dynasty (600-800 a.d.) (The Granger Collection)

Ancient Building in India

This is Konarak, a temple (c. 1240 a.d.) located on the Bay of Bengal, south of Calcutta. It is dedicated to Surya, the

Hindu sun god, and is constructed with astronomical alignments. (J. M. Malville).

The Caracol Tower at Chiche Itzá

This is one of the most significant of the many astronomically oriented structures in Mesoamerica. (J. A. Eddy)

Do you know any other ancient astronomical sites?

Theories obout space

Light and dark

Moon receives light from the SunThales of Liletos (625 – 545 BC)

Day and night are due to light and dark hemispheres revolving around earth; Sun is a bright spot reflected from EarthEmpedocles of Agrigentum (493 – 433 BC)

Sun and stars glow due to fast motion Leucippes Miletos (circa 440 BC)

The moon is darkened when the Earth comes between it and the Sun Anaxagoras (500 – 428 BC)

Thales: 625 to 545 BC

Said to have predicted a solar eclipse in 585 BC

Greeks already knew about the 19 year cycle for lunar eclipses.

Measured height of the pyramids by understanding “similar triangle” theory: measure the shadow length at the time of day when your shadow is as long as your height.

Systematic records of events

Halley’s Comet: Earliest: 613 BC by Zuo Zhuan Complete record to 1910 (29 times)

A drawing of Han dynasty http://dbs.bao.ac.cn/cas/pic/old3.gif

Venus is a morning and evening star Parmenides (circa 450 BC)

Milky Way is a collection of faint stars, not a cloud or reflection Democritos of Addera (456 – 370 BC)

Zodiacal and other constellations

3500 BC - Lion and Bull in Near Eastern art

1100 BC - Scorpio and Leo recorded on Mesopotamian stone

450BC - 12 Zodiacal constellations recorded Babylonian cuneiform text and Phaenomena (Eudoxus of Cnidus)

Science vs. Astrology

Astrology: “planets exert force at birth”Science: “gravity only known planetary

force”Doctor produces larger effect than planet!

Astrology: “planets affect personality”people born in given month share similar personalities

Science:people w/ similar traits have birthdates distributed

equally through year

There is NO scientific support for astrology!!

Models of the Solar System

Plato’s Universe

Geocentric - earth-centred

Pythagorean beliefs (Ptolemaic model)

Harmony of spheres related to musical scales

Geocentric

Hereclides geo-heliocentric system

Venus and Mercury shown orbiting the Sun

Explains motion of inferior planets

Copernicus

Heliocentric

http://www.youtube.com/watch?v=GmwAr54L_pM&feature=related

Galileo

Telescope Observed: the Moon, Jupiter,

Jovian moons, Saturn, and Venus.

1. Sunspots • Sun not perfect

2. Mountains, Craters, and Valleys on Moon• Moon not perfect

3. Moons orbiting Jupiter• Objects can orbit other bodies, not Earth!

4. Phases: Venus had both crescent and gibbous• Verified Heliocentric model predictions

Tycho Brahe

Tycho's geocentric model put the Earth at the centre (A) of the universe, with the Sun (B) revolving around it, and the planets revolving around the Sun.

Johannes Kepler

German astronomer who discovered three major laws of planetary motion, conventionally designated as follows: (1) the planets move in elliptical orbits with the Sun at one focus; (2) the time necessary to traverse any arc of a planetary orbit is proportional to the area of the sector between the central body and that arc (the “area law”); and (3) there is an exact relationship between the squares of the planets' periodic times and the cubes of the radii of their orbits (the “harmonic law”)

Kepler’s 1st LawThe orbit, of a planet about a star, is an ellipse with the star at one focus.

Kepler’s 2nd Law

time from 1 to 2 = time from 3 to 4 area 1-2-S = area 3-4-S

A line joining a planet and its star, sweeps out equal areas during equal intervals of time.

Kepler’s 3rd Law of Planetary motionThe square of the sidereal period, of an orbiting planet, is directly proportional to the cube of the orbit's semimajor axis.

Tutorial questions:

Discuss and write a summary on how Erathosthenes calculate the radius of the Earth.

The Copernican explanation of retrograde motion.

How Galileo showed that the earth orbits the sun.

Read Chapter 1, 2, 5, 6, & 7

Seeds, M. A. (2007). Foundation of Astronomy. 9th Edition. Belmont: Thomson.

Read the beliefs and arguments of astronomers through history: •Ptolemy, •Plato, •Aristotle, •Copernicus, •Galileo, •Tycho, •Kepler.

THANK YOU