Exam 1 Flashcards
If astronomers near Onion Nebula were able to see Earth clearly, what would they see? Why?
a tiny, pale blue dot against the backdrop of a much brighter, expansive nebula.
What kind of stars did Edwin Hubble use as standard candles to determine the distance galaxies?
Cepheid Stars
What do we call the earliest time in our Universe when it was very dense and very hot?
Big Bang
What proof exists of a young hot Universe?
Cosmic microwave background
Where are elements heavier than iron formed?
Stars, form during supernova explosions, death of massive stars
What percent of the solar nebula out of which the Solar System formed ended up in the Sun?
99.8%
Why are the planets that formed closer to the Sun composed primarily of silicates and iron compounds?
Too hot to hold the volatile gases that dominate the solar nebula
Why are the planets in the outer solar system so large?
Large size, large gravitational attraction (accelerates growth). They captured a large amount of hydrogen and other gases from the surrounding nebula with their enormous gravity
How do we explain the large exoplanets orbiting close to their stars that we have found?
migration
What features of the Solar System can be explained as a consequence of the Grand Tack Hypothesis
Small mars, asteroid belt, no super earth, no hot Jupiter
What features of the Solar System can be explained as a consequence of the Nice Model?
How the outer planets came to their present orbits, how the trojan asteroid in the outer solar system came into their orbital configurations. The migration of the outer planets caused instability among small bodies
What does the word planet mean?
Wanderer
How did the Ptolemaic Model explain retrograde motion?
Epicycles, circling the planet but circles the circle, used for 13 centuries
Who gave us the three laws of planetary motion?
Kepler
What is eccentricity?
It tells you how stretched out the orbit is
Who demonstrated that Kepler’s Law are a consequence of his theory of gravity?
Isaac Newton
What criteria must be met for an object in the Solar System to be called a planet?
Orbits the sun, nearly round shape, has cleared its orbit
What event involving Venus was used to determine the length of an astronomical unit?
the transit of venus
What planet has the greatest orbital speed?
Mercury (88 Earth Days)
Why do the Moon and the Sun have the same angular size in the sky?
The sun is about 400 times farther away from Earth than the Moon and is also 400 times larger than the Moon
Which planet has the highest densitty?
Earth
Which planet has the lowest density?
Saturn
Which planet has the highest albedo (brightness)?
Venus
What is obliquity?
The angle between a perpendicular to its orbital plane and its spin axis - the tilt of its axis