Question

sizes in the galaxy & units of measure
name:
date:
hour:
directions: complete the charts below by defining each of the following.
a. universe
b. galaxy
c. star
d. planet
e. moon
f. comet
g. asteroid
h. meteoroid
units of measure:
a. astronomical unit au
b. light year ly
c. year
d. month
e. day
f. hour

Explanation:

a. The universe is the entirety of space - time, including all matter, energy, galaxies, and the physical laws that govern them.
b. A galaxy is a massive, gravitationally - bound system that consists of stars, stellar remnants, an interstellar medium of gas and dust, and dark matter.
c. A star is a luminous sphere of plasma held together by its own gravity, generating energy through nuclear fusion reactions in its core.
d. A planet is a celestial body that orbits a star, is massive enough for its gravity to make it spherical, and has cleared its orbit of other debris.
e. A moon is a natural satellite that orbits a planet.
f. A comet is a small, icy body in the solar system that, when near the sun, heats up and releases gas and dust, forming a visible coma and sometimes a tail.
g. An asteroid is a rocky, airless body that orbits the sun, typically found in the asteroid belt between Mars and Jupiter.
h. A meteoroid is a small rocky or metallic body in space, smaller than an asteroid.
a. An astronomical unit (AU) is the average distance between the Earth and the Sun, approximately 149.6 million kilometers.
b. A light - year (LY) is the distance that light travels in one year in a vacuum, about 9.461 trillion kilometers.
c. A year is the time it takes for the Earth to complete one orbit around the Sun, approximately 365.24 days.
d. A month is a unit of time based on the motion of the Moon around the Earth, with different types of months (e.g., lunar month, synodic month) having varying lengths, but on average about 30 or 31 days.
e. A day is the time it takes for the Earth to complete one rotation on its axis, approximately 24 hours.
f. An hour is a unit of time equal to 60 minutes or 3600 seconds.

Answer:

a. The entirety of space - time with all matter, energy, etc.
b. Massive, gravitationally - bound system of stars, etc.
c. Luminous sphere of plasma generating energy by fusion.
d. Celestial body orbiting a star, spherical and cleared its orbit.
e. Natural satellite of a planet.
f. Small, icy body releasing gas/dust near the sun.
g. Rocky, airless body orbiting the sun.
h. Small rocky/metallic body in space.
a. Average Earth - Sun distance (about 149.6 million km).
b. Distance light travels in a year (about 9.461 trillion km).
c. Time for Earth to orbit the Sun (about 365.24 days).
d. Time based on Moon's motion around Earth (about 30/31 days on average).
e. Time for Earth to rotate on its axis (about 24 hours).
f. Unit of 60 minutes or 3600 seconds.