Lectures Watched
Since January 1, 2014
1700+ courses starting
in July 2017
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influential people of the past.
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My Notes on Massive Open Online Course:
Imagining Other Earths
This course introduces core concepts in astronomy, biology, and planetary science that enable the student to speculate scientifically about this profound question and invent their own solar systems.
Notes on 1 Lectures I Watched in This Course:
Dwarf Planets and Beyond, Getting a Feel for Cosmic Distances
1 People I Have Learned About in this Course:
John Cromwell Mather (1946-)
American astrophysicist, cosmologist and Nobel Prize winner in Physics for his work on the COBE Satellite
  • partner on COBE project was George Smoot
  • COBE is an NASA satellite launched into Earth orbit on Nov. 18, 1989, and which revolutionized our understanding of the early cosmos by measuring and mapping the oldest light in the universe
  • the COBE satellite helped cement the big-bang theory of the universe, and can be regarded as the starting point for cosmology as a precision science
  • John Cromwell is also the project scientist for the James Webb Space Telescope (JWST), a space telescope to be launched to L2 no earlier than 2018
3 Vocabulary Words I Learned in this Course:
Kuiper Belt, n. [KIGH-per] a region of space in our solar system, shaped more like an ellipse than a circle, which is similar to an asteroid belt, while the asteroid belt is mostly metal and rock, the Kuiper Belt is composed almost entirely of icy chunks of various substances, similar to comets, located approximately 30 to 50 AU from sun  "The dwarf planet Pluto is thought to be one of the objects in the Kuiper Belt."
parallax, n. a displacement or difference in the apparent position of an object viewed along two different lines of sight and is measured by the angle between those two lines, astronomers use the principle of parallax to measure distances to the closer stars and dwarf planets.  "A simple everyday example of parallax can be seen in the dashboard of motor vehicles that use a needle-style speedometer gauge. When viewed from directly in front, the speed may show exactly 60; but when viewed from the passenger seat the needle may appear to show a slightly different speed, due to the angle of viewing."
parsec, n. an astronomical unit of length used to measure distances to objects outside the Solar System. About 3.3 light-years, or 31 trillion kilometres or 19 trillion miles in length  "The parsec is still less than the distance to the nearest star, Proxima Centauri, which is 1.3 parsecs from Earth."
6 Flashcards I Recorded in this Course:
how far away are we from the center of our galaxy?
8,000 parsecs, or 24,000 light years
how wide is the Milky Way galaxy
30,000 parsecs, or 90,000 light years
how close is the nearest star and how long would it take to get there traveling 10 km/s
4 light years away, and would take 120,000 years (Voyager is traveling at about 17k/s)
what is the brightest star
what is the nearest star
Alpha Centauri
what is another dwarf planet besides Pluto?