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- 3. Our universe started with a BIG BANG.
- 4. big bang n. (cosmology) the cosmic explosion that is hypothesized to have marked the origin of the universe.
- 5. After the BIG BANG, the universe started to expand.
- 6. The first seconds after the BIG BANG, it was very hot.
- 7. Then, the universe started to cool down.
- 8. Right after the BIG BANG, the p+, the n0 and the e- were flying around without control.
- 9. When it started to cool down, the quarks started making primitive elements:
- 11. 1 2 Hydrogen, 1 proton, 1 neutron
- 12. 2 3 Helium, 2 protons, 1 neuron
- 13. 2 4 Helium, 2 protons, 2 neurons
- 14. Those elements started forming stars.
- 15. Star n. a self-luminous gaseous spherical celestial body of great mass which produces energy by means of nuclear fusion reactions .
- 16. In the stars, because of high pressure, the elements started bonding and forming heavier elements
- 17. HOW WILL WE END?
- 18. We all started with the BIG BANG…
- 19. … but how will we end?
- 20. Some scientists are sure that the universe will continue to expand forever.
- 21. However, there is a theory that our universe will end in “big crunch”
- 22. It states that someday the universe will stop expanding and crunch together.
- 23. There is no proof for that theory.
- 24. . . . . . . . . . . . . . . . . . . Clas . sifying Stars . . . . . .
- 25. TO RECOGNISE STARS, SCIENTISTS HAVE TO CLASSIFY THEM
- 27. TEMPERATURE
- 28. COLOR
- 29. size size size
- 30. brightness
- 31. If the star is blue, it means it is very hot . (≈50,000 C°)
- 32. . . . . . . . . . ..... . . .... . . .... ....... . . ... Cold stars are red.
- 33. The bigger or hotter the star is, the brighter it is.
- 34. Brightness is measured in 2 ways:
- 35. apparent brightness (brightness seen from earth)
- 36. absolute brightness (the “real” brightness of the star)
- 37. Stars are mostly made out of hydrogen.
- 38. Helium is about ¼ of the stars’ composition.
- 39. Enjar Hertzsprung and Henry Norris Russell made a diagram that classifies stars.
- 41. Scientists measure distance between stars using parallax
- 42. Parallax n. apparent change in apposition of an object when you look at it from different places
- 43. Scientists watch the positions of stars during different times of the year to figure out it’s position.
- 44. LIVES OF STARS
- 45. Stars do not live forever.
- 46. The larger a star is, the shorter its life is.
- 47. Stars are born in nebulas.
- 48. Nebula n. a large cloud of dust in space
- 49. Gravity pulls dust together so it forms a protostar
- 50. Protostar n. an early stage in the evolution of a star, after the beginning of the collapse of the gas cloud from which it is formed, but before sufficient contraction has occurred to permit initiation of nuclear reactions at its core.
- 51. As the protostar gets denser and denser, it forms a star
- 52. as the star becomes older, it becomes a red giant
- 53. red giant= star uses up its energy and becomes cooler, so it expands
- 54. Layers of the red giant fall off, releasing dust and gas into space.
- 55. It is called a planetary nebula.
- 56. The remaining star is very dense and bright.
- 57. It is a white dwarf.
- 58. When a white dwarf stops glowing, it is called a black dwarf.
- 59. high-mass stars are different.
- 60. When they die, they make a supernova – a giant explosion.
- 61. After the supernova, the star becomes either a neutron star or a black hole.
- 62. a neutron star: a white dwarf that has very high pressure and temperature
- 63. A black hole is a neutron star with gravity so strong that nothing, even light, can escape.
- 64. CAREERS
- 65. Nucleosynthesis is been studied by physicists and astronomers.