The Sun
Question: What object contains approximately 99 percent of the mass in our solar system?
Answer: The Sun.
Question: Why do sunspots appear darker than the surrounding areas of the Sun?
Answer: They are cooler than their surroundings.
Question: What type of star system consists of two stars moving around a common center of mass?
Answer: A binary star system.
Question: What are groups of stars named after animals, mythological characters, or everyday objects called?
Answer: Constellations.
Question: What is a cloud of interstellar gas and dust from which a star can form called?
Answer: A nebula.
Question: What is the name of the Sun's visible surface?
Answer: The photosphere.
Question: What are violent eruptions of particles and radiation from the Sun called?
Answer: Solar flares.
Question: What is the term for the ancient Greek classification system based on how bright a star appears?
Answer: Apparent magnitude.
Question: Ursa Major contains which familiar group of stars?
Answer: The Big Dipper.
Question: What happens to a nebula as it contracts during star formation?
Answer: Its rotation causes it to flatten into a disk, with a hot, condensed object forming at the center.
Question: What is the name of the stream of charged particles that flows outward through the solar system from the Sun's corona?
Answer: The solar wind.
Question: What are areas of low density in the corona from which particles escape called?
Answer: sun spots
Question: What is the term for a star's energy output per second?
Answer: Luminosity.
Question: What type of constellation is Ursa Major?
Answer: A circumpolar constellation.
Question: What is the hot, condensed object at the center of a contracting nebula that will become a new star called?
Answer: A protostar.
Question:Due to the Sun's extremely high temperature what is the composition of the interior?
Gas
Question: What is an arc of gas ejected from the photosphere called?
Answer: A prominence.
Question: What is the name of the unit used to express energy emitted per second?
Answer: The watt.
Question: What is the apparent shift in a nearby star's position when observed from Earth called?
Answer: Parallax.
Question: As a star ages, what causes its internal composition to change?
Answer: Rising temperature.
Question: What are the three main layers of the Sun's interior, listed from the center outward?
Answer: The core, radiation zone, and convection zone.
Question: What is the Sun's activity cycle associated with, according to the review material?
Answer: The peak number of sunspots.
Question: What is the brightness an object would have if it were placed 10 parsecs away?
absolute magnitude
Question: According to the H-R diagram, which type of stars are the most common?
Answer: Main-sequence stars.
Question: According to the review, what can a star that begins with more than about 20 times the Sun's mass eventually become?
Answer: A black hole.