Post on 30-Dec-2015
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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