IS1101 Nothing to Something

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IS1101 Nothing to Something

• Mr Goh Hock Leong

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Content

• Definitions
• Star
• Planet
• Moon
• Constellations

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Definition

• Cosmology
• study of large scale structure, origin and
  evolution of evolution of the Universe
• Astronomy
• The science which investigates all the
  matter-energy in the universe its distribution,
  composition, physical states, movements, and
  evolution.
• The study of the universe, especially the objects
  in it. (Planets, stars, galaxies, ...) What are
  they? How did they form? and Do they change?
• Astrophysics
• The science treating of the physical
  characteristics of the stars and other heavenly
  bodies, their chemical constitution, light, heat,
  atmospheres, etc.

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Definition

• Space Science
• Planetary Science
• Astrology
• Universe
• Hard to define precisely
• Websters Totality of all things that exist
  creation cosmos

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A Star
A star is a large glowing ball of gas that
generates energy through nuclear fusion in its
core. A star is a self-luminous celestial object.
Our Sun is a star, unusual only in that it is
much closer than any other.
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• Planets and stars look very similar in the sky.
• Planet comes from the Greek language, and it
  means wanderer, in contrast with the fixed stars.

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Planets

• An object that orbits a star and that, while much
  smaller than a star, is relatively large in size.
  
• It is not self-luminous. It shines by reflected
  light from star.
• Planets may be rocky, icy, or gaseous in
  composition and they shine primarily by
  reflecting light from their star. Earth is a
  planet.

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The Solar System
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Definition of planet

• The International Astronomical Union (IAU),
  charged with classifying heavenly objects, has
  never had a definition on record for planets.
  Never needed one. Everyone instinctively knew
  what a planet was.

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ESP Extra Solar Planets

• Also called exoplanets
• First discovered in 1995 (orbiting the star 51
  Pegasi)
• 2 planets found in 47 Ursae Majoris (Big Dipper)

47 Ursae Majoris
Solar System
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Extra-Solar planets

• Epsilon Eridani
• a star named in some Star Trek books as being the
  home star of the fictional planet Vulcan.
• a star very similar to our own sun and only 3.22
  parsecs (10.5 light-years) from Earth
• A planet was found to orbit Epsilon Eridani

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Free Floating Planet

• Star
• nuclear fusion
• Self-luminous
• Brown dwarf
• Failed star (to small to start fusion)
• It is not self-luminous. So it cannot be a star.
• Minimum size 13 Jupiters size (mass above
  which deuterium burns )
• Free-floating planet
• Less than 13 Jupiters size
• But does not orbit any other star
• Label of planet still very contentious

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A Moon

• Aka satellite
• An object that orbits a planet. The term
  satellite is also used more generally to refer to
  any object orbiting another object.

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Constellation

• In the clear skies of the Tigris, Euphrates, and
  Nile valleys, where the earliest civilizations
  flourished more than 5000 years ago, watchers of
  the heavens singled out and named various
  groupings of stars, called constellations,
  primarily for calendrical and navigational
  purposes.

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Constellation

• To aid their memory, they imagined that they saw
  in these groupings the likenesses of mythological
  beings, animals, and monsters and named the
  constellations accordingly.

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Constellation

• The names and shapes of constellations are part
  of our heritage from ancient Greece, who in turn
  inherited them from these older civilizations.

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Orion
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Constellation

• Greek astronomers identified and named 48
  constellations.
• Forty more were added, most of them in southern
  skies, by European mapmakers and astronomers in
  the seventeenth and eighteenth centuries.

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Constellation

• Greek astronomers identified and named 48
  constellations.
• Forty more were added, most of them in southern
  skies, by European mapmakers and astronomers in
  the seventeenth and eighteenth centuries.
• All celestial objects lie within the borders of
  one of the 88 constellations.

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Orion