Astronomy | Astrophysics Answers

The mean distance of Mars from the Earth is 0.5 A.U. and its orbital period is 687 days. Calculate the orbital period of Jupiter given that its mean distance from the Earth is 4 A.U.

What is the nature of radiation generated in the Sun’s interior? How does it differ from the radiation we receive from the Sun?

The average density of a white dwarf of radius 109 cm is 106 gm/cm3. Is general theory of relativity needed to study the dynamics of this star? What happens if the star shrinks to a radius thousand times smaller?

Explain why sidereal day is shorter than the solar day. What is the magnitude of this difference? What effect does this have on the rising of stars in the evening?

Sketch the celestial equator, horizon, observer’s meridian and show the zenith and nadir on the celestial sphere for an observer at latitude 30° N.

Explain what you understand by the apparent magnitude of a star. How is it related
to the brightness of the star? An object A has an apparent magnitude of –5. Another
object B has an apparent magnitude of –10. Calculate the ratio of their brightness.

Two equal-mass stars maintain a constant distance apart of 9.0×1010 m and rotate about a point midway between them at a rate of one revolution every 12.6 yr.
PART A
Why don't the two stars crash into one another due to the gravitational force between them?
PART B
What must be the mass of each star?
Express your answer using two significant figures.

Before going to the beach, you try to estimate the tide level (high, low, or in between) by noting where in the sky the Moon is. It is high tide

(A) when the Moon is near its highest point in the sky.
(B) when the Moon is near the horizon.
(C) whenever the Moon is not visible.
(D) None of the above.

What is the speed of a 1850 kg meteorite when it hits the moon's surface? This meteorite had a velocity of 1.4 x 10^3 m/s heading directly toward the moon. when it was 15000 m above the moon's surface

A robot probe lands on a new, uncharted planet. It has determined the diameter of the planet to be 8 × 106 m. It weighs a standard 1 kg mass and determines that 1 kg weighs only 5 newtons on this new planet.

(a) What must the mass of the planet be?

(b) What is the acceleration due to gravity on this planet?