Astronomy | Astrophysics Answers

time period of a planet whose semi major axis is 3.5 × 10⁹ m is found to be 100 years. find the time period of a planet whose semi major of axis is twice of it.

A ball is released from a height H and falls freely to the ground. It takes 3.0 s to reach the ground. Use g = 10 m/s2
What is the height of the ball above the ground after 2.0 seconds?

What features of the earth enablea life to exist

Two identical spheres of radius 30mm and mass 2kg on the surface of the earth are placed in contact. Find the gravitational attraction between them.

What would be the period of a planet whose orbit has a semi major axis of 4 AU?

Imagine that you live in a universe in which parallel lines eventually meet. what could you deduce about your universe from this?

Select all the answers that match
1) Ω>1
2)k is less than 0
3)The universe is infinite.
4)The universe will end in a Big Crunch.
5)If you travel far enough in a straight line, you will return to where you started.
6)The internal angles of a large enough triangle will add up to less than 180 degrees.
π is less than 3.14159265359... on large scales.

1.1What features of the earth (our planet) enables life to exist?
1.2. Match column A with column B
COLUMN A Column B
1.2.1. black dwarf-a star left at the core of a planetary nebula.
1.2.2.white dwarf - a red super giant star explodes.
1.2.3.nebula-what a medium mass star becomes at the end of its life.
1.2.4.protostar-a large cloud of gas or dust in a space.
1.2.5.supernova-exerts such a strong gravitational pull that no light escape.
1.2.6.neutron star-the earliest stage of a star's life.
1.2.7.black hole - the remains of a high mass star.

1.Draw a timeline on the modern history of the solar system in the last three centuries.
2.discuss the important discoveries in astronomy by different people in the last 100 years.

Activity 1.10
1.what is vernal equinox?
2.when does the vernal equinox occur?
3.ehat causes the different seasons?
4.if you were able to look down at our solar system from above, would the earth be rotating clockwise or counter clockwise? Motivate your answer..
5.what and when are the solstice and equinoxes?
6.during each solstice and equinox, what season is it in the northern hemisphere and Southern hemisphere?
7.during each solstice and equinox, are the rays of the sun hitting the northern hemisphere directly, indirectly, or the same as in the southern hemisphere?
8.during each solstice and equinox, is the North pole tilted toward the sun, away from the sun, or neither?
9.what is the relationship between the seasons and the number of daylight hours?
10.why do we have day and night?

The Schwarzschild radius of a black hole depends on its mass m, the speed of light
c, and the gravitational constant G, which has units of m3/(kg · s2). Use dimensional analysis
to write down an expression for the Schwarzschild radius in terms of these three quantities.
Explain your reasoning. (Hint: The Schwarzschild radius has dimension of length)