study guide 3

study guide 3 - Test 3 Study Guide Chapter 9 Space Big Bang...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
Test 3 Study Guide Chapter 9: Space Big Bang Theory o Says our universe began about 13.7 billion years ago with a cosmic explosion o Everything was packed into a really dense ball, then it exploded o Our solar system formed about 4.5 billion years ago Nebular hypothesis o In 1755 Kant develops his nebular hypothesis – origin of our solar system can be traced to a rotating cloud of gas and fine dust o Since his hypothesis, we have found similar clouds which we call nebulae (made of hydrogen and helium) Formation of the sun o Under the pull of gravity, the matter from the cosmic explosion began to drift towards the center, accumulating into a protostar , which would become our present sun. The high heat of the sun causes nuclear fusion – when hydrogen atoms fuse to form helium. When this happens, some of the mass from the fusion is converted into energy. This sun releases some of that energy as sunshine (so, the light and heat given off by the sun is a result of nuclear fusion) Formation of the Planets o Solar nebula – a disk of gas and dust that remained after the proto-sun was formed, enveloping the proto-sun The nebula became really hot as it flattened into a disk Once formed, it begins to cool, gases condense into a solid or liquid form Gravity caused them to stick together during collisions as small planetesimals Then the planetesimals stuck together to form moon-sized bodies Finally a few of these larger bodies (after impacts) swept up others to form our 9 planets in orbit o The composition of the inner planets is very different from the outer planets. Most of this is due to the distance from the sun
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Inner Planets vs. Outer Planets o Inner There are 4: Mercury, Venus, Earth, Mars Known as the “terrestrial” planets Small, made of rocks and metals Little or no atmosphere Most volatile materials (those that become gases) boiled away from these planets because it was too hot so close to the sun The process started 4.56 billion years ago, we (Earth) grew to planetary size in about 10 million years o Outer There are 4: Jupiter, Saturn, Uranus, Neptune (not sure where Pluto falls) Volatile materials from the terrestrial planets were carried to the cold, outer regions of the SS (Solar System) Made of mostly ices and gases Have rocky and metal rich cores, but are in general composed of mostly hydrogen and helium Material from solar nebula that didn’t become major planets o Some planetesimals collected between Mars and Jupiter, forming as asteroid belt There are about 300 there, the largest is Ceres o Meteorites – tiny pieces of asteroid ejected during collisions from one another o Comets – aggregations of dust and ice that condensed in the cooler, outer SS Most comets orbit the sun far beyond the outer planets forming “halos” around the SS Sometimes collisions or near misses will send one into our inner SS, we see them as bright objects with gaseous tail Planet Formation
Background image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 12/05/2009 for the course GEOL 1001 taught by Professor Baksi during the Spring '07 term at LSU.

Page1 / 20

study guide 3 - Test 3 Study Guide Chapter 9 Space Big Bang...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online