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Astronomy and E HIST
Question | Answer |
---|---|
What is the scientifically accepted age of the Earth? | 4.6 billion years old |
What does the Law of Superposition state? | A sedimentary rock layer is older than the layers above it and younger than the layers below it |
What does the Law of Cross-cutting Relationships state? | A fault or igneous intrusion is always younger than the rock layers it cuts through |
Radiometric Dating-what is half-life? What do the terms "parent and daughter isotopes" mean? | The half-life is the time it takes for half of the radioactive parent isotopes to decay into the stable daughter isotope |
What is Carbon-14 dating used for? | A method of dating fossils (wood, shells, bones, etc.) that are less than 70,000 years old |
What is an index fossil? | A fossil that occurs in a rock layer of a particular geologic age-lived for a short time, was very common and world-wide |
Why are there few fossils found in Precambrian rocks? | There were not a lot of life forms (mostly bacteria), no hard parts to fossilize |
What was the major cause of the Permian extinction? | Many of the inland seas dried up |
What is the major cause of the Cretaceous extinction? | Asteroid strike |
What marks the boundary between the Pleistocene and the Holocene epochs? | End of the last ice age |
What causes auroras | Caused by the interaction of the solar wind and Earth’s magnetosphere. |
What causes a geomagnetic storm | Disturbance in Earth's magnetosphere |
How does nuclear fusion create energy in the Sun's core? | On the Sun hydrogen is fused into helium. |
What is the average length of the sunspot cycle? | 11 yrs |
What is the scientifically accepted age of the universe? | 14 billion years old |
Explain the Big Bang Theory. | The theory that the universe began as a small point of matter that suddenly and rapidly began expanding outward |
What is the cosmic background radiation? | Low levels of energy that are distributed evenly throughout the universe. This is evidence that supports the Big Bang Theory |
What galaxy do we live in? | Milky Way galaxy |