Astrophysics

• How many types of galaxies are there?

  Three types of galaxies
• What are the three types of galaxies?

  Spiral, elliptical, and irregular
• What is our galaxy called?

  Milky Way
• What type of galaxy is the Milky Way?

  Spiral galaxy
• What is the approximate diameter of the Milky Way?

  100,000 light years
• Where is our solar system located in the Milky Way?

  In an outer spiral arm
• What is the sun's status in the solar system?

  It is a star
• What percentage of the solar system's mass does the sun comprise?

  Over 99%
• How many planets are in our solar system?

  Eight planets
• What are the four gaseous planets in our solar system?

  Jupiter, Saturn, Uranus, Neptune
• How do the planets in the solar system travel around the sun?

  In the same direction and plane
• What happens to a planet's average surface temperature as its distance from the sun increases?

  It decreases
• Why is Venus's average surface temperature higher than Mercury's?

  Venus has a thick atmosphere trapping heat
• What are dwarf planets?

  Objects that orbit the sun like Pluto
• What are moons?

  Natural satellites orbiting planets
• What is the difference between natural and artificial satellites?

  Natural satellites are not man-made
• Where does the asteroid belt lie?

  Between Mars and Jupiter
• What are comets made of?

  Dust and ice
• What happens to a comet as it approaches the sun?

  Its ice melts and forms a tail
• What are meteoroids?

  Rocky fragments from asteroids and comets
• What is the gravitational force?

  Attractive force between all objects with mass
• What does Newton's law of gravitation state?

  Force is proportional to mass product
• How does distance affect gravitational attraction?

  Inversely proportional to the square of distance
• What happens if the mass of one object is doubled?

  The forces between them are doubled
• What happens if the distance between two objects is doubled?

  The forces are quartered
• What does Newton's third law of motion state?

  Every action has an equal and opposite reaction
• What is gravitational field strength?

  Force exerted per unit mass at a point
• How is gravitational field strength measured?

  In Newtons per kilogram
• What is the direction of gravitational field strength?

  Towards the mass
• How does mass affect gravitational field strength?

  Stronger with greater mass
• What is the gravitational field strength of Earth?

  Approximately 10 Newtons per kilogram
• How does gravitational field strength change with distance?

  It decreases as you move further away
• What is the role of gravitational forces in orbits?

  They provide centripetal force for orbits
• Why are moons considered natural satellites?

  They orbit planets due to gravitational pull
• How does the sun's mass affect the solar system?

  It pulls planets into orbits around it
• What happens to the orbital speed of planets as they move farther from the sun?

  It decreases
• What is the shape of comets' orbits?

  Highly elliptical
• What happens to a comet's speed as it approaches the sun?

  It increases due to gravitational pull
• What is the relationship between kinetic and potential energy in a comet's orbit?

  Kinetic energy converts to potential energy
• What is the formula for calculating orbital speed?

  $V =$$\frac{2 \pi R}{T}$