Space physics

• What is a moons body?

  natural satellites
• what is a protostar?

  clouds and dust collapse

  increase in pressure
• what is a main star sequence?

  materials keep colliding

  when pressure and temperature high enough

  hydrogen nuclei fuse and form helium

  stable period
• how does the sun stay hot?

  energy released by nuclear fusion
• what happens if the speed of an orbit changes?

  the radius of the orbit also changes.

  If the radius of the orbit decreases, the speed increases as the gravitational attraction is greater

  If the radius of the orbit increases, the speed decreases as the gravitational attraction is smaller.
• what is a red giant?

  hydrogen fuel runs out

  star cools and expands

  fuses helium nuclei to release energy
• what is a white dwarf?

  helium fuel runs out, so the outward force reduces in size and the star collapses inwards

  there is a temperature increase

  hot core of star
• what is a black dwarf?

  completely cools

  no light or heat emitted
• red supergiant?

  nuclear fusion turns more and more of stars mass into energy
• supernova?

  largest stars explode
• what is redshift?

  when an object moves away, the wavelength the object emits gets longer

  the light gets redder as red has the longest wavelength