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Introduction to Astronomy Note

NTNU 星星月亮太陽─天文漫談

Back to Note Overview
tags: NTNU 通識 Science and Life Introduction to Astronomy
Moodle_Lecture Notes

88 constellation

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Glossaries

​​​​Horizon 地平線
​​​​Zenith 頂點
​​​​Meridian 子午線
​​​​Celestial Pole 天極
​​​​Celestial Equator 天體赤道
​​​​latitude 緯度
​​​​Ecliptic 黃道
​​​​Axial Tilt 軌道傾斜
​​​​Summer solstice 夏至
​​​​Winter solstice 冬至
​​​​Spring equinox 春分
​​​​Autumnal equinox 秋分
​​​​Polar region 極圈
​​​​Analemma 日行跡
​​​​Sundial 日晷

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Diurnal Motion 週日運動

Earth Spin

Earth Orbital Motion 地球軌道運動

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Ecliptic

​​​​The ecliptic is the mean plane of the apparent path in the 
​​​​Earth's sky that the Sun follows over the course of one year

Earth Orbit

Season

​​​​Axial Tilt + Earth Orbit = season
​​​​sun from left to right = north pole

Sidereal Day 恆星日 vs. Solar Day 太陽日

Sidereal Day Solar Day
Degree 360° 361°
Time 23hr 56min 24hr

說明

Earth Region

Tropic of Cancer 北迴歸線

​​​​When this line of latitude was named in the last centuries BC,
​​​​the Sun was in the constellation Cancer at Summer solstice.

Tropic of Capricorn 南迴歸線

​​​​When this line of latitude was named in the last centuries BC,
​​​​the Sun was in the constellation Capricornus at Winter solstice.

Analemma 日行跡

​​​​Earth Orbit + Axial Tiltx + Ellliptical Orbit

​​​​In astronomy, an analemma is a diagram showing 
​​​​the position of the Sun in the sky,
​​​​as seen from a fixed location on Earth 
​​​​at the same mean solar time,
​​​​as that position varies over the course of a year.
​​​​The diagram will resemble the figure 8.
​​​​Globes of Earth often display an analemma.

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Analemma on Mars

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precession of the earth 歲差

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Zodiac and Astronmy

Zodiac

wiki_Astrological sign

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Polaris 北極星

Polaris will not be "Polaris" any more.

9/25

Moon and Earth

real scale

picture of the distance between earth and the moon and the scale of it •••••••••

phase

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the animation of how the phase form

tide

picture of the tide caused by moon's phase picture of the tide during a day picture of the tide during a month(one month varations) picture of the tide during a yaer(one month varations) picture of how tide form(include earth and the moon) picture of elliptic earth orbit(exaggerated) picture of elliptic solar orbit(exaggerated)

Eclipse

Solar Eclipse

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picture of eclipse path

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Lunar Eclipse

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earth shine

Synchronous rotation 同步旋轉

Moon and Earth rotation（自轉） Q：Why Synchronous? A：Don't know(I think it is Tidal locking)

Libration 天平動

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Moon Origin

How was the moon created？ How the Moon Formed: 5 Wild Lunar Theories

  • Fission
  • Capture
  • Co-formation
  • Colliding planetesimals
  • Giant impact

Tools of Modern Astronomy

  • Angle
    • unit of angle=degree
    • Angular Separation
    • Angular Distance
    • Angular Size
      • d=2Dtan(δ/2)
      • Arc Approx d=D*
      • d=Dδ
      • δ～0.5degree(30arc min)～0.0087266randian
  • Distance
    • AU
    • lightyear
    • 1parsce(pc)～3.26lightyear(ly)
      • D(pc)= 1/angle(arc second)
      • The angle that is used in the equation is formed by earth-star line and Sun-star line
    • Redshift(z)～4000Mpc
      • d=v/H
        o        =cz/H
        o
      • v=recessional velocity
      • z=redshift
      • H
        o        =Hubble constant

Solar System

History and Background

Kepler's law

  1. The orbit of every planet is an ellipse with the sun at a focus.
  2. A line joining a planet and the sun sweeps out equal areas during equal intervals of time.
  3. The square of the orbital period of a planet is directly proportional to the cube of the semi-major axis of its orbit.
    ∝

Retrograde motion

Planets move backwards in the sky.

Planet

Mercury

highlights of what we know about Mercury

  • Not much is known, because it is difficult to reach
  • Very eccentric orbit(eccentricity~0.2)
  • No satellite
  • No thick atmosphere
  • Similar to Earth Moon
  • Dense(5.427g/cm3: second highest in solar system)
  • Relatively strong magnetic field
  • Suspected …

Venus

highlights of what we know about Venus

  • Earth twin, almost the same size
  • Atmosphere is very thick(~90atm)
  • Atmosphere is made of C0
    2
  • Surface is very hot(~400 ℃)
  • Magnetic field is weak
  • No evidemce of plate tectonics
  • Rain of Surfanic Acid(H
    2    SO
    4    )

Mars

highlights of what we know about mars

  • 1/100 of earth air pressure
  • Mostly CO
    2
  • No Ozone layer
  • Possible water in the past
  • Temporary surface water ?
  • No current sign of life
  • Water ice and CO
    2     ice
  • Roman god of war
  • Smaller than the Earth (almost half the size of Earth)
  • Percival Lowell(USA) thought that there are canals on Mars{Mariner 4 proved wrong}

Jupiter

  • Atmosphere is mainly made of Hydrogen
  • iquid oceans may exist under Euroqa's icy surface
  • Galileo made the first observation of ammonia clouds in another planet's atmosphere. The atmosphere creates ammonia ice particles from material coming up from lower depths.
  • Ganymade possesses its own, substatial magnetic field.
  • Europa,Ganymede and Callisto may have a liquid-saltwater layer under the visible surface

Saturn

Space probes to Mars

  • Mariner 4(水手四號) 1964
    • First Mars flyby
  • Viking 1 & 2(海盜一號&二號) 1975-1976
    • First successful landing on Mars
    • took photos on the surface
    • conducted soil experiments
  • Mars Pathfinder & Sojourner(火星拓荒者&旅居者號) 1996-1997
    • First rover(Sojourner) landing on Mars
    • Mars Pathfinder is just the carrier
    • took lots of pictures and analyzed the chemical properties near the lander
  • Spirit / Opportunity (精神號/機會號) 2004
    • Both rovers
    • climbed montains
    • saw little tornados
    • saw Earth from Mars
    • saw the two moons of Mars
    • Spirit died in 2010
    • Opportunity died in 2019
  • Phoenix(Lander)(鳳凰號) 2008
    • can dig
    • try to find permafrost -> water
  • Curiosity(好奇號) 2012
    • rover

Space probes to Venus

  • Mariner 2 & 5(水手)
    • flyby mission
  • Mariner 10
    • flyby mission
    • also went to mercury
  • Venera 7 & 8(金星計劃)
    • lander
    • no cameras
  • Venera 9 & 10
    • lander
    • colorless camera
  • Venera 13 & 14
    • lander
    • full color camera
    • survived for ~2 hrs
  • Venera 15 & 16
    • satelite
    • radar mapper
  • Pioneer-Venus 1 & 2(先鋒金星)
    • satelite
    • radar mapper
  • Magellan(麥哲倫號)
    • satelite
    • radar mapper

Space probes to Mercury(they all went to Venus)

  • Mariner 10(水手)
    • first gravatiy assist probe
    • flyby
  • Messenger(信使號)
    • satelite
    • gravatiy assist

Space probes to Jupiter

  • Pioneer 10 & 11(先鋒)
    • flyby
    • has golden plated board with human info
    • Pioneer 11 went to Saturn
  • Voyager 1 & 2(航海家)
    • flyby
    • both went to Saturn
    • Voyager 2 went to Uranus & Neptune
  • Galileo mission(伽利略號)
    • satelite
    • Venus gravatiy assist
    • has entery probe

Space probes to Saturn

  • Voyager 1 & 2(航海家)
    • flyby
    • both went to Juputer
    • Voyager 2 went to Uranus & Neptune
  • Cassini(satelite)-Huygens(lander) mission(卡西尼-惠更斯號)
    • Venus gravatiy assist
    • went to Venus & Jupiter
    • saw weird hexagon on the pole
    • landed on Titan
    • speculation of lakes on Titan

Extended Solar System

{%hackmd @NTNUCSIE112/solarsystemnote %}

  • Small solar system bodies(SSSB) ~minor planets
    • Trans Neptunian Objects(TNO)
      • Kuiper Belt Objects(KBO) (stable orbit)
      • Oort Cloud (spherical)
      • Hills’ Cloud
      • Scattered Disk (dynamic/unstable orbit)
    • Centaurs
    • Asteroids

The outermost planet - Pluto

  • New Horizon ： First to take a pic

Asteroids

  • 221945+ asteroids are numbered
  • ~15000 have names
  • Gaileo Spacecraft

    • made the first flyby of asteroids en route to Jupiter

    • 1991 951 Gaspra

    • 1992 243 Ida

Comets

Stars

Star Life - Stellar Evolution

Red Giant Star

Planetary Nebula

Supernova

Neutron Star

Pulsar(aka Neutron Star)

​Has this name because it has streams coming out of it and it spins very fast. So it looks like it 'pulses'.

Black Hole

Solar System Note
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