   VY Canis Majoris is a red hypergiant in the constellation Canis Major. It is one of the
    largest known stars by radius and also one of the most luminous of its type.
   The smallest star in the universe is a Red Dwarf known as Gliese 623b. Its mass is one
    tenth the mass of the sun.
   Stars are classified with a letter depending on their surface temperatures, either A, B, F, G,
    K, M, or O.
      Surface Temperature Ranges for
          Different Stellar Classes
Class      Temperature          Sample star
  O     33,000 K or more Zeta Ophiuchi
  B     10,500 – 30,000 K Rigel
  A      7,500 – 10,000 K Altair
  F       6,000 – 7,200 K    Procyon A
  G       5,500 – 6,000 K    Sun
  K       4,000 – 5,250 K    Epsilon Indi
  M       2,600 – 3,850 K    Proxima Centauri
   A black hole is a place in space where gravity pulls so much that even light cannot get out.
    The gravity is so strong because matter has been squeezed into a tiny space. This can
    happen when a star is dying.
   Because no light can get out, people can"t see black holes. They are invisible.
   Space telescopes with special tools can help find black holes.
   The special tools can see how stars that are very close to black holes act differently than
    other stars.
                                               Solar System
   It comprises the Sun and its planetary system of eight planets, a number of dwarf planets,
    satellites (moons), and other objects that orbit the Sun.
   The Solar System’s Mass is 99% Sun.
   The size of the solar system has been estimated to at about 105 AU.
   The center of the solar system is the Sun.