Astronomy Basics

Astronomy

Definition and Branches

• Astronomy is the scientific study of celestial objects, space, and the physical universe as a whole.
• Branches of astronomy:
  • Astrophysics: study of the physical nature of celestial objects.
  • Planetary science: study of planets, moons, and other objects in our solar system.
  • Cosmology: study of the origin, evolution, and fate of the universe.

Celestial Objects

• Stars:
  • Types: main sequence, red giant, white dwarf, neutron star, black hole.
  • Life cycle: protostar, main sequence, red giant, white dwarf.
• Galaxies:
  • Types: spiral, elliptical, irregular.
  • Our galaxy: Milky Way, a barred spiral galaxy.
• Planets:
  • Terrestrial planets: Mercury, Venus, Earth, Mars.
  • Gas giants: Jupiter, Saturn.
  • Ice giants: Uranus, Neptune.

Telescopes and Observations

• Types of telescopes:
  • Optical telescopes: refracting, reflecting.
  • Radio telescopes: detect radio waves.
  • Space telescopes: Hubble, Kepler.
• Observations:
  • Spectroscopy: study of light spectra.
  • Astrometry: measurement of celestial object positions and distances.

Key Concepts

• Light-year: unit of distance, equivalent to the distance light travels in one year (9.46 trillion km).
• Parsec: unit of distance, equivalent to 3.26 light-years.
• Redshift: shift towards longer wavelengths, indicating celestial object movement away from us.
• Dark matter: invisible matter that affects galaxy rotation curves.

Notable Astronomers

• Ancient Greeks: Aristotle, Eratosthenes, Hipparchus.
• Renaissance astronomers: Copernicus, Galileo, Kepler.
• Modern astronomers: Hubble, Hawking, Sagan.

Astronomy

Definition and Branches

• Astronomy is the scientific study of celestial objects, space, and the physical universe as a whole.
• Branches of astronomy include:
  • Astrophysics: study of the physical nature of celestial objects.
  • Planetary science: study of planets, moons, and other objects in our solar system.
  • Cosmology: study of the origin, evolution, and fate of the universe.

Celestial Objects

Stars

• Types of stars include: main sequence, red giant, white dwarf, neutron star, and black hole.
• Life cycle of stars: protostar, main sequence, red giant, white dwarf.

Galaxies

• Types of galaxies include: spiral, elliptical, and irregular.
• Our galaxy is the Milky Way, a barred spiral galaxy.

Planets

• Terrestrial planets include: Mercury, Venus, Earth, and Mars.
• Gas giants include: Jupiter and Saturn.
• Ice giants include: Uranus and Neptune.

Telescopes and Observations

Telescopes

• Types of telescopes include:
  • Optical telescopes: refracting, reflecting.
  • Radio telescopes: detect radio waves.
  • Space telescopes: Hubble, Kepler.

Observations

• Spectroscopy: study of light spectra.
• Astrometry: measurement of celestial object positions and distances.

Key Concepts

• Light-year: unit of distance, equivalent to the distance light travels in one year (9.46 trillion km).
• Parsec: unit of distance, equivalent to 3.26 light-years.
• Redshift: shift towards longer wavelengths, indicating celestial object movement away from us.
• Dark matter: invisible matter that affects galaxy rotation curves.

Notable Astronomers

• Ancient Greeks: Aristotle, Eratosthenes, Hipparchus.
• Renaissance astronomers: Copernicus, Galileo, Kepler.
• Modern astronomers: Hubble, Hawking, Sagan.

Chemistry

Branches of Chemistry

• Inorganic Chemistry deals with inorganic compounds, derived from mineral sources, and lacks carbon-hydrogen bonds.
• Organic Chemistry focuses on organic compounds, derived from living organisms, and features carbon-hydrogen bonds.
• Physical Chemistry explores the physical properties and behavior of matter at the molecular and atomic level.
• Analytical Chemistry is concerned with the analysis of the chemical composition of substances.
• Biochemistry examines the chemical processes that occur within living organisms.

Atomic Structure

• Protons are positively charged particles residing in the nucleus of an atom.
• Neutrons have no charge and are found in the nucleus of an atom.
• Electrons are negatively charged particles occupying the electron cloud surrounding the nucleus of an atom.
• The atomic number, determined by the number of protons in an atom's nucleus, defines the element.
• The mass number, calculated by the total number of protons and neutrons in an atom's nucleus, is a unique identifier.

Chemical Bonding

• Ionic Bonding involves the transfer of electrons between atoms to form ions with opposite charges.
• Covalent Bonding occurs when atoms share electrons to form a bond.
• Polar Covalent Bonds are formed when atoms with different electronegativities share electrons, resulting in partial positive and negative charges.
• Hydrogen Bonds are weak bonds between atoms with a hydrogen atom bonded to a highly electronegative atom.

Chemical Reactions

• Chemical Equations represent chemical reactions using chemical formulas and symbols.
• Reactants are the substances that undergo a chemical change in a reaction.
• Products are the substances formed as a result of a chemical reaction.
• Catalysts are substances that speed up a chemical reaction without being consumed or altered.
• Activation Energy is the minimum energy required for a chemical reaction to occur.

Learn about the definition and branches of astronomy, including astrophysics, planetary science, and cosmology, as well as types of celestial objects like stars.