Physical Science

• The concept of the expanding universe was first proposed by Edwin Hubble based on his observation of redshift in the light from distant galaxies.
• The Big Bang Theory explains the way the universe began as a single point that expanded and stretched to grow as large as it is today
• Georges Lemaître was the first to theorize that the recession of nearby galaxies can be explained by an expanding universe
• Edwin Hubble provided evidence that the recessional velocity of a galaxy increases with its distance from Earth, supporting the idea that the universe is expanding
• Vesto Slipher's observations of the radial velocities of spiral galaxies provided the first evidence supporting the expanding-universe theory
• Georges Lemaître concluded that the Universe arose from a single "point" or singularity, leading to the emergence of time and space
• The universe existed as a singularity, smaller than a subatomic particle, roughly 13.7 billion years ago according to the Big Bang theory
• The expansion of the universe led to the formation of light elements like Hydrogen and Helium through Big Bang Nucleosynthesis
• Deuterons, a combination of proton and neutron, were formed in the process of Nucleosynthesis
• After the Big Bang, protons and neutrons combined to form light elements like Helium and Lithium
• 75% of the universe consisted of Hydrogen and 25% of Helium after 15 minutes of the universe's expansion
• The formation of heavier elements after the Big Bang occurred due to the energy from the Sun, which is the main source of energy for forming new elements
• Stellar Nebulae, the birthplace of stars, collapse due to gravity and undergo Nuclear Fusion to form new elements like Helium
• Hydrogen atoms combine to form Helium through nuclear fusion, releasing energy in the process
• When the hydrogen in a star runs out, it depends on the type of star; for example, medium stars like the Sun become red giants and continue fusion with helium to form heavier elements
• Massive stars become red supergiants and can create elements like Ne, Si, Fe through fusion, leading to a supernova explosion
• Elements like Cu, Au, and Ag are created through Neutron Capture during a supernova explosion
• The remaining core after a supernova explosion can become a Neutron Star or Black Hole
• Neutron stars colliding can lead to Neutron Star Mergers, creating elements heavier than Iron
• According to Georges Lemaitre, everything past, present, and future, even space and time themselves, are being produced out of this initial singular quantum physical state of extreme density and temperature
• The process of light elements is called nucleosynthesis
• The process of elements heavier than iron is called nucleosynthesis
• Stars that use the process of nuclear fusion are medium stars
• Stars that can create or fuse elements like Ne, Si, Fe are medium stars
• The current value of the Hubble Constant is 70 km/s/Mpc
• The radiation after the Big Bang, which continues to travel in the galaxy with energy lesser than when it started, is called Cosmic Microwave Background
• According to Georges Lemaitre, both time and space emerged out of the singularity
• The process of hydrogen atoms combining to form helium and releasing energy is called nuclear fusion
• The birthplace of stars is stellar nebulae
• The main source of energy to form a new element without the higher temperature coming from the strong radiation of the Big Bang is Cosmic Microwave Background
• When neutron stars collide, it is called neutron star mergers
• The highest temperature is boiling water
• Big Bang Theory:

  • Astronomers explain the way the universe began
  • The universe started as a single point and expanded to grow as large as it is now
  • The universe is still stretching
• Vesto Slipher:

  • American astronomer
  • Systematic observations (1912-25) of radial velocities of spiral galaxies
  • Provided first evidence supporting the expanding-universe theory
  • Discovered that galaxies are moving far away from Earth
• Georges Lemaître:

  • Belgian Catholic priest
  • First to theorize that the recession of nearby galaxies can be explained by an expanding universe
  • Observationally confirmed by Edwin Hubble
• Edwin Hubble:

  • Provided evidence that the recessional velocity of a galaxy increases with its distance from Earth
  • Hubble's law implies that the universe is expanding
  • Provided evidence that light from many nebulae was strongly red-shifted
• Georges Lemaître:

  • Concluded that the Universe arose from a single "point" or singularity
  • Time and space emerged from this "primeval atom"
  • Everything, including past, present, future, space, and time, emerged from this initial state
• 15. When neutron stars collide, it is called Neutron Star Mergers

  16. The highest temperature is Boiling Water

  17. The lightest element is H

  18. The heaviest element is Fe
• 8. Stars creating fusion like Ne, Si, Fe are Red Super Giants

  9. The current value of Hubble Constant is 70 km/s/Mpc

  10. The radiation after the Big Bang, with decreasing energy, is Cosmic Microwave Background

  11. According to Georges Lemaître, time and space emerged from a singularity

  12. The process of hydrogen atoms combining to form helium and releasing energy is Nuclear Fusion

  13. The birthplace of stars is Stellar Nebulae

  14. The main source of energy for forming new elements after the Big Bang is Cosmic Microwave Background
• Multiple Choice Questions:

  1. Edwin Hubble provided the first evidence of red-shifted light from nebulae

  2. According to Edwin Hubble, the relationship between a galaxy's distance and speed is known as Hubble's Law

  3. Georges Lemaître was the first to theorize the expanding universe

  4. According to Georges Lemaître, everything emerged from an initial singular quantum physical state of extreme density and temperature

  5. The process of light elements is called Nucleosynthesis

  6. The process of heavier elements than Fe is Nucleosynthesis

  7. Stars using nuclear fusion are Red Super Giants