The Big Bang:
The Big Bang In 1929, Edwin Hubble discovered that the Universe is expanding at enormous speed . Hubble noted that galaxies outside our own Milky Way were all moving away from us . He quickly realized what this meant that there must have been an instant in time (now known to be about 14 billion years ago) when the entire Universe was contained in a single point in space. The Universe must have been born in this single violent event which came to be known as the "Big Bang."
Doppler Shift:
Doppler Shift
Doppler Shift:
Doppler Shift
The Universe: Red Shift / Blue Shift:
The Universe: Red Shift / Blue Shift
Expanding Universe:
Expanding Universe The light coming from distant objects would be red-shifted as it traveled through the expanding universe. The redshift would increase with increasing distance to the object . In 1929 Edwin Hubble , measured the redshifts of a number of distant galaxies. He also measured their relative distances. When he graphed redshift against relative distance, he found that the redshift of distant galaxies increased as distance increased . The only explanation for this observation is that the universe was expanding.
Galaxies:
Galaxies Spiral Galaxies The most common type of galaxy is called a "spiral galaxy." Not surprisingly, spiral galaxies look like spirals, with long arms winding toward a bright bulge at the center. Elliptical has a smooth, featureless appearance and an elliptical shape. Irregular Approximately 3% of galaxies observed cannot be classified as either elliptical or spirals. These galaxies have little pattern in their structure
Models of the Solar System:
Models of the Solar System Geocentric Earth-centered model Ptolemy Aristotle
Models of the Solar System:
Models of the Solar System Heliocentric Sun-centered model Copernicus Galileo