Review 2 Flashcards
Who determined that planets orbit in ellipses, and not in circles?
Kepler
What is the ‘point of no return’ of a black hole called?
event horizon
Which process allows energy from the sun to reach the Earth?
radiation
When fusion begins in a high mass protostar, which kind of star is formed?
blue star.
How are mass and luminosity related?
Larger mass implies more luminosity
About how many stars does an average galaxy contain?
100 billion
Who first attached a spectroscope to a telescope to study the spectrum of stars?
Angelo Secchi
What is believed to be at the center of most galaxies?
supermassive black holes
What is another name for a ‘shooting star?’
Meteor
Who proposed that temperatures at the core of the sun were hot enough for thermonuclear fusion?
Arthur Eddington
How long does it take our sun to revolve around the center of the Milky Way galaxy?
200,000,000 years
What is the dimmest magnitude star that can be seen with the naked eye?
+6
Which satellite is the largest one in the Solar System?
Ganymede
Which of the following describes how bright a star appears to an observer on Earth?
apparent magnitude
The sun shines most directly on the Tropic of Cancer on which day? (Northern Hemisphere)
summer solstice
There are certain gaps in the Asteroid Belt caused by Jupiter’s gravity. What are these gaps called?
Kirkwood gaps
Who devised a method to measure the circumference of the Earth?
Eratosthenes
How many times brighter is a magnitude +1 star than a magnitude +2 star?
2 ½ times brighter
What is the difference between a meteoroid and an asteroid?
Meteoroids are small; asteroids are large.
Which kind of star allows astronomers to estimate the distance to galaxy up to about 15 million light-years away?
Cepheid variable stars
Which two gasses is Jupiter mostly made up of?
hydrogen & helium
Which color of light has the lowest frequency?
red
Which lunar phase occurs immediately after full moon?
waning gibbous
What is the solid part of a comet called?
nucleus
Why doesn’t Venus have a magnetic field like the Earth?
Venus does not rotate fast enough.
Where did the majority of stars fall on the H-R diagram?
main sequence
What is the region called where most of the comets reside?
Oort cloud
Who discovered 228 asteroids in the early 1890s by using photographic techniques?
Max Wolf
What is the name of Pluto’s satellite?
Charon
Which stage of development is the sun at?
yellow star
Which method allows us to estimate the distance to the furthest galaxies observable?
Brightest galaxy in cluster
To which galactic cluster does our solar system belong?
Local Group
What are the four categories that galaxies are classified in?
spiral, barred spiral, elliptical, and irregular
