Chihuahua Dog Breed. First discovered in Mexico, the Chihuahua is best known for being the smallest dog breed in the world. Extremely loyal to its owner, the breed has recently become a popular culture icon in the United States, most notably Paris Hilton's Chihuahua, Tinkerbell. Physical Characteristics.
Earth formed around 4.54 billion years ago by accretion from the solar nebula. Volcanic outgassing probably created the primordial atmosphere and then the ocean; but the atmosphere contained almost no oxygen and so would have been toxic to most modern life including humans.
The first oceans began to form around 4 billion years ago. They formed from the outgassing of water vapor from volcanoes as well as water transported to the surface via astero â¦ ids and comets. As the Earth cooled water vapor in the atmosphere turned into clouds which rained down the water that would create the oceans.