Question

sizes in the galaxy & units of measure
name:
date: 9/25/2025 hour 4
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

Explanation:

a. The universe is the entirety of space - time, all matter, energy, and the physical laws that govern them.
b. A galaxy is a massive system of stars, stellar remnants, interstellar gas, dust, and dark matter bound together by gravity.
c. A star is a luminous sphere of plasma held together by its own gravity, generating energy through nuclear fusion in its core.
d. A planet is a celestial body that orbits a star, is massive enough to be rounded by its own gravity, 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, rocky body in space that, when near the sun, heats up and releases gas and dust, forming a coma and sometimes a tail.
g. An asteroid is a rocky, airless small body orbiting the sun, primarily 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.

Answer:

a. The entirety of space - time, matter, energy, and physical laws.
b. A massive star - system bound by gravity.
c. A luminous plasma sphere from nuclear fusion.
d. A celestial body orbiting a star with cleared orbit.
e. A natural satellite of a planet.
f. An icy - rocky body that releases gas near the sun.
g. A rocky, airless body orbiting the sun.
h. A small rocky or metallic body in space.