Science 9Space Exploration: 10.1

Ariana ZandiBlock DFebruary 24th, 2015Mr Horton

It all started with a Big Bang:

❖ The Big Bang Theory is a theory that Georges Lemaitre, a Belgian priest and physicist, discovered in 1927. His theory was that approximately 13.7 billion years ago a very tiny volume of space all of a sudden expanded to immense size rapidly and kept growing and expanding, as seen in the picture on the right. Before this, there were no celestial bodies, no atoms, no protons and no electrons. Improved technology, like the Hubble Telescope, has given us a good picture of the Big Bang and the structure of the cosmos.

❖ Many scientists have tried to re-create the Big Bang event. The most sophisticated accelerator is located at CERN, in Switzerland. They fire off two beams of protons in opposite directions so that individual protons will crash into each other and break into their smaller particles.

❖ Video explaining: https://www.youtube.com/watch?v=wNDGgL73ihY

Evidence for the Big Bang Theory

❖ Cosmic Background Radiation: (radiation: the transmission of energy in waves.) In the 1960’s, two astronomers named Arno Penzias and Robert Wilson were monitoring microwave radiation in space and they picked up a background noise/interference. They concluded that this was left over cosmic energy from the Big Bang.

❖ Hubble’s Proposal about universal expansion.

❖ Data gathered by the COBE ( Cosmic Background Explorer ), which is a satellite launched in 1989 that gathers cosmic radiation data and the WMAP ( Wilkinson Microwave Anisotropy Probe ), which is also a satellite that has also collected information about the cosmic radiation, helped corroborate the Big Bang Theory.

Expanding Universe: Hubble’s Proposal

❖ Edwin Hubble was an american astronomer who was the first to discover other galaxies other than the Milky Way. Galaxies are a system of millions or billions of stars, together with gas and dust, held together by gravitational attraction. He discovered that the galaxies were moving away from each other and that more distant galaxies are moving away faster than near by galaxies.

❖ Hubble’s Proposal: the universe is expanding in all directions and that the expansion is accelerating. As well, he suggested that all galaxies have taken the same amount of time to reach their present positions from an original starting point.

❖ Hubble based his proposal on evidence from the Red Shift Analysis.

Cosmological Red Shift

❖ Edwin Hubble noticed that the spectrum of the galaxies he was studying showed spectral lines that were shifted toward the end of the spectrum. The « red shift » happens because of the light’s wavelengths becoming longer. It indicates that an object is receding from us (or that the distant galaxies are moving away from us).

❖ This idea provoked the idea that space itself was expanding.

Red Shift Analysis

❖ Electromagnetic radiation is energy that is carried or radiated in the form of waves. Examples: microwaves, radio waves, X-rays, ect. Stars and galaxies emit different forms of electromagnetic radiation. Waves can come in a variety of forms. The longer the wavelength, the lower the energy, like radio waves. The shorter the wavelength, the higher the energy, like gamma rays.

ELECTROMAGNETIC RADIATION

Red Shift Analysis ❖ When light shines through a

prism, the light separates into a pattern of colors. The pattern of colors is called a spectrum. Each color of a spectrum represents different wave lengths.

❖ A spectroscope is an optical instrument that acts like a prism to separate light into its basic colors. It also allows the viewer to view the spectral lines produced by a light source and to measure wave-lengths.

❖ Standing out across the bands of color in a star’s spectrum are lines called spectral lines.

SPECTRAL PATTERNS