The Learn Tracker
...life-long learning: structured, organized, searchable...
924
Lectures Watched
Since January 1, 2014
Hundreds of free, self-paced university courses available:
my recommendations here
Peruse my collection of 275
influential people of the past.
View My Class Notes via:
Receive My Class Notes via E-Mail:

VIEW ARCHIVE

Contact Me via E-Mail:
edward [at] tanguay.info
Notes on video lecture:
Dwarf Planets and Beyond, Getting a Feel for Cosmic Distances
Notes taken by Edward Tanguay on June 2, 2014 (go to class or lectures)
Choose from these words to fill the blanks below:
overhead, transfer, Saturn, Piazzi, elongation, 2004, parallax, Kuiper, hydrostatic, sunset, binary, 2005, massive, Dawn, 2015, planets, 200, spiral, 50, Sirius, 100, parsecs, interstellar, Dysnomia, Mars, ices, four, Neptune, bulge, Galileo
•
solar system
•
dwarf planets besides Pluto
•
Eris
•
most                of the dwarf planets
•
1% of earth's mass
•
discovered in         
•
has one moon                 
•
Ceres
•
the largest object in the asteroid belt, which lies between the orbits of          and Jupiter
•
a ball of rock and ice 950 km in diameter, containing a third of the mass of the asteroid belt
•
the largest asteroid, and the only dwarf planet in the inner Solar System
•
it was the first asteroid to be discovered, on 1 January 1801 by Giuseppe              in Palermo, at first considered to be a planet
•
the unmanned          spacecraft is scheduled to arrive at Ceres in early         
•
named after the Roman Goddess of Agriculture
•
Haumea
•
located beyond Neptune's orbit
•
discovered in         
•
named after Haumea, the Hawaiian goddess of childbirth
•
its extreme                      makes it unique among known dwarf planets, nonetheless, its gravity is believed sufficient for it to have relaxed into                        equilibrium, making it a dwarf planet
•
Makemake
•
perhaps the largest              belt object (KBO)
•
has no known satellites, which makes it unique among the largest KBOs and means that its mass can only be estimated
•
discovered on March 31, 2005
•
the name derives from Makemake in the mythology of the Rapanui people of Easter Island
•
many others
•
nearest star is Alpha Centauri
•
4.37 light years from the Sun
•
277,600 AU
•
actually a              star system
•
this pair of stars have an 80 year orbit around a common center, and are about as close to each other as              and the Sun
•
how long would it take to travel from Earth to Mars at 20,000 km/hr (Voyager 1 is traveling about 61,000 km/hr)
•
if the planets didn't move it would take about        days
•
since both are orbiting the sun, you would have to travel in a                  orbit, so it would take about        days
•
Voyager 1
•
as of September 2013, Voyager 1 was at a distance of 18.7 billion kilometers (125.3 AU) from the Sun, and escaping the solar system at a speed of about 3.6 AU per year
•
this year Voyager 1 space craft crossed into                          space
•
the earth
•
distance from sun
•
150 million kilometers
•
1 AU, or astronomical unit
•
some planets are 10 or 20 AU from their sun
•
Saturn: 9 AU - 10.1 AU from Sun
•
the Kepler telescope has been exploring planets of other stars and has found planets even a 0.3 AU from their sun
•
planets
•
stars twinkle and planets don't
•
brightest start is             
•
Greek for "glowing"
•
actually two stars, Sirius A and Sirius B, distance between them varies between 8.2 and 31.5 AU
•
Venus always close to the Sun
•
will always see it soon after              or right after sunrise
•
Jupiter is always very bright
•
often seen directly                 
•
with binoculars, you may be able to see          moons
•
first discovered by               
•
Sumerians referred to the "stars" that moved "wanderers", these were               
•
because planets are so much closer
•
moon
•
cratered structure
•
fascinated Galileo
•
craters reflect the history of the moon
•
old view of solar system
•
Pluto was seen as a planet but had an odd orbit, actually crossing in closer than                at times
•
the current system is much more messy, Pluto is just one of      known dwarf planets that make up the Kuiper Belt
•
Pluto is not that special anymore, actually smaller than Eris and about the same size as 2003 EL61
•
Eris: 67.69 AU
•
Pluto: 39.54 AU
•
dwarf planets are discovered through a concept called                 
•
displacement or difference in the apparent position of an object viewed along two different lines
•
90377 Sedna
•
three times as far from Sun as Neptune
•
surface is largely a mixture of water, methane and nitrogen         
•
surface is one of the reddest in the Solar System
•
Sirius (Dog Star) - bright in northern hemisphere
•
Alpha Centuri - bright in southern hemisphere
•
parallax is used to measure distances to distant stars as well
•
the parallax that a typical star would have is about:
•
one arc second
•
1 parsec
•
3.26 light years
•
206,000 astronomical units
•
most of the solar system is mostly space
•
Neptune is 30 AU
•
nearest star is 206,000 AU
•
our galaxy the Milky Way
•
center of our galaxy forms a           
•
distance to the center of our galaxy is about 8000 parsecs or 24,000 light years
•
our galaxy is one of many galaxies
•
the width of our galaxy is about 30,000               , or 90,000 light years
•
most of the young stars are forming in the              arms

Vocabulary:

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."
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."
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."

People:

######################### (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

Flashcards:

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
Sirius
what is the nearest star
Alpha Centauri
what is another dwarf planet besides Pluto?
Eris

Ideas and Concepts:

Via tonight's Imagining Other Earths class: "With the new discoveries of dwarf planets in the Kuiper Belt within the last 10 years, it was either degrade Pluto from planet to dwarf planet status, or upgrade all the newly discovered dwarf planets to planet status, and thus make elementary students everywhere memorize more than 50 additional planets, most of which have names consisting almost completely of numbers."
Scientific discovery principle of the day, via this morning's Imagining Other Earths class: "parallax, n. the displacement in the apparent position of an object viewed along two different lines of sight and measured by the angle between those two lines, e.g. astronomers use the principle of parallax to measure distances to the closer stars and to dwarf planets. A simple everyday example of parallax can be seen in the dashboard of a car that uses a needle-style speedometer gauge, when viewed directly from the 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."
Dwarf Planets and Beyond, Getting a Feel for Cosmic Distances