Earth science 2

• Early Theories: It explained how the earth was formed.
• : Modern theories stated that need to find how the universe has formed then automatically we will be able to find the formation of the earth
• The sun with its very high-temperature projects hot material called the prominences.
• Primitive Sun: The primitive sun is the early stage of the sun.
• Intruding Star: In comparison to the primitive sun, it was much larger and larger.
• The companion star's explosion produced a cloud of incandescent gases, which he refers to as the "Supernova stage."
• Star formation begins when a giant cloud of gas and dust collapses under its own gravity
• disc-shaped objects (called proplyds) in the Orion Nebula
• The icy mantles of the grains begin sticking together and eventually grow to metersized rocky boulders called planetesimals.
• planetesimals collide and accrete into larger bodies that are tens of kilometers in diameter called protoplanets.
• Density – mass per unit of volume
• Earth’s center is called its core
• outermost layer of the Earth is its crust
• The second process that changed Earth’s early atmosphere was photosynthesis
• a type of organism called cyanobacteria evolved on the early Earth and began carrying out photosynthesis.
• Photosynthesis uses carbon dioxide and energy from the Sun to produce sugar and oxygen
• O3 molecules —a particular type of oxygen molecule
• The ozone layer is in the upper part of the atmosphere
• anaerobic - organisms that do not need oxygen to live.
• North America and Greenland formed one giant landmass called Laurentia
• absolute dating methods, sometimes called numerical dating
• Relative dating is used to arrange geological events and the rocks they leave behind, in a sequence
• Relative dating does not provide actual numerical dates for the rocks.
• Relative dating – subdivisions of the Earth's geology in a specific order based upon relative age relationships most commonly in vertical/stratigraphic position
• Absolute dating – numerical ages
• Relative dating methods estimate whether an object is younger or older than other things found at the site
• Relative dating is qualitative. This technique helps determine the relative age of the remains.
• Relative dating is comparatively less expensive and time-efficient
• relative dating. It works best for sedimentary rocks having layered arrangement of sediments.
• Stratigraphy: The oldest dating method which studies the successive placement of layers.
• Biostratigraphy: An extended version of stratigraphy where the faunal deposits are used to establish dating
• Cross dating: This method compares the age of remains or fossils found in a layer with the ones found in other layers.
• Fluorine dating: Bones from fossils absorb fluorine from the groundwater
• Absolute Dating

  It provide more specific origin dates and time ranges, such as an age range in years
• Absolute dating is quantitative. This technique helps determine the exact age of the remains.
• Radiometric dating: This technique solely depends on the traces of radioactive isotopes found in fossils.
• Amino acid dating: Physical structure of living beings depends on the protein content in their bodies
• Thermoluminescence: It determines the period during which certain object was last subjected to heat.
• Dendrochronology: Each tree has growth rings in its trunk. This technique dates the time period during which these rings were formed.
• fossils inspired legends of monsters and other strange creatures