Celestial Sources of Terrestrial Mass Extinctions
1) National Geographic: What are mass extinctions and what causes them?
2) American Museum of Natural History: Episode Twelve: Six Extinctions in Six Minutes
3) BBC: Gamma-ray burst “hit Earth in 8th Century”
4) Nature: Gamma-ray burst linked to mass extinction
5) Phys.org: Researchers learn more about the possible role of gamma ray bursts on life extinction in the universe
6) CNN Space Science: Multiple star explosions may have contributed to a mass extinction on Earth
7) Space.com: Did a supernova cause Earth’s mass extinction 360 million years ago?
8) Space.com: Did Supernova Explosion Contribute to Earth Mass Extinction?
9) Space.com: An asteroid and volcano ‘double punch’ doomed the dinosaurs, study suggests
10) National Geographic: This asteroid is one of the most likely to hit Earth. Here’s what it means for our future.
11) National Geographic: Why NASA’s high-stakes maneuver to redirect an asteroid surprised its own scientists
12) NASA SSERVI: The Asteroid Impact Hazard: Historical Perspective
13) Johns Hopkins Applied Physics Laboratory: Double Asteroid Redirection Test (DART)- NASA’s First Planetary Defense Mission
Respond to the following items in your paper.
Paragraph 1: (Use Sources 1 & 2.)
In your first sentence, define the term “mass extinction”.
Describe briefly the known past major mass extinctions. For each one, include the name of each extinction, the time in millions of years since each one began, the percentage of species that became extinct and some examples of species that became extinct. (Focus on these items, not the possible causes. Address those in the paragraphs below.)
Paragraph 2: (Use Sources 3, 4, 5 and Wikipedia.)
Define the term “GRB” and what astronomers think happens in order to produce one.
Did the Earth experience one in the Eighth Century? Describe what some researchers suggest is evidence that one did strike the Earth at that century.
Which major extinction event do some researchers think might have occurred due to a GRB? How would the GRB have affected the Earth to produce that mass extinction?
Paragraph 3: (Use Sources 6, 7, 8 and Wikipedia.)
Define the term “supernova” and what is thought to occur in order to produce one.
Of the major mass extinctions, which one could have been caused by a single supernova or multiple supernovae? How would these events have affected the Earth to produce that mass extinction?
Some researchers suggest that there may have been a minor mass extinction about 2.6 million years ago. Outline their hypothesis and the effects it could have had on the Earth.
Paragraph 4: (Use Sources 2, 9,10 and Wikipedia.)
Define the term “asteroid”. Include in your definition where most of them are found, what they are made of and how they were formed.
There is one major mass extinction for which there is very good evidence that an asteroid impact was responsible. Describe what is thought to have happened during that event and the chief evidence that supports that hypothesis. How did this event affect the evolution of mammals?
Paragraph 5: (Use Sources 10, 11, 12, 13 and Wikipedia.)
Define the term “NEA”.
What is “Bennu”? Should we be concerned about it? Explain briefly.
What was the aim of the DART mission? How do we know the mission was successful?
(Answer this item with reference to the concepts of inertial motion, gravity and centripetal force as it was discussed in the lecture videos. Which of these three things did the mission aim to modify?)
Look at the graph in Slide Four of the Source 13 presentation. In total, about how many NEAs have been discovered as of 2020. List the FIVE points shown in white capital letters in Slide Five that should be part of a Planetary Defense program.
