posted by .

ly = light years

Stars P and Q have the same luminosity, but P is 30 ly from Earth and Q is 40 ly from Earth. What is the ratio of their brightness as viewed from Earth?

  • physics -

    their brightness ratio is the ratio of the inverse of the square of their distances

    bP / bQ = (dQ / dP)^2

  • physics -

    So it would be 900:1600
    = 9:16?

Respond to this Question

First Name

School Subject

Your Answer

Similar Questions

  1. Physical Science

    Galaxy A is 600 million light years from earth. Galaxy B is moving away from the earth at a speed that is 80% as large as that of Galaxy A. How far from earth is Galaxy B?
  2. Physics

    Two stars are 8 light years from earth (a light year is the distance light travels in one year). The 550 nm light from the two stars can be barely distinguished in the diffraction pattern of 90 cm wide single slit. How far apart are …
  3. science

    A distant spaceship carrying a red headlight, emitting light with wavelength 600nm, is heading towards the earth. Observers on the earth detect the light from the headlight as ultraviolet light with wavelength 200nm. What is the velocity …
  4. Physics

    Determine the ratio of Earth's gravitational force exerted on an 80-kg person when at Earth's surface and when 1000km above Earth's surface. The radius of Earth is 6370 km. I have tried (6370)^2/(7370)^2 = 0.747 and it is wrong?
  5. astronomy

    The peak luminosity of a white dwarf supernova is around 10^10LSun and it remains above 10^8LSun for about 150 days. In comparison, the luminosity of a bright Cepheid variable star is about 10000LSun.The Hubble Space Telescope is sensitive …
  6. astronomy

    The distance from Earth of the red supergiant Betelgeuse is approximately 643 light-years. If it were to explode as a supernova, it would be one of the brightest stars in the sky. Right now, the brightest star other than the Sun is …
  7. Science please help :)?

    3. which if the following factors determines how long a star will live ?
  8. Astronomy

    Hi, can you please check my work? I really need to do well on this. 1. What properties of a star are needed to calculate the stars luminosity?
  9. Astronomy

    1. What color are stars that are very hot and very bright?
  10. Moon Science

    What causes the phases of the moon as observed from the Earth?

More Similar Questions