# It’s possible to make a rough estimate of how often planetary systems form by making some basic assumptions.

###### Question:

It’s possible to make a rough estimate of how often planetary systems form by making some basic assumptions. for example, if you assume that the stars we see have been born at random times over the last 10 billion years, then the rate of star formation is simply the number of stars we see divided by 10 billion years. the fraction of stars with detected extrasolar planets is at least 5 %, so this factor can be multiplied in to find the approximate rate of formation of planetary systems.
a) using these assumptions, how often does a planetary system form in our galaxy? (our galaxy contains at least 100 billion stars.)
b) how often does a planetary system form somewhere in the observable universe, which contains at least 100 billion galaxies? (express in seconds)

### Execucomp corporation's financial statements in the current year show a loss from discontinued operations,

Execucomp corporation's financial statements in the current year show a loss from discontinued operations, a prior period adjustment, and an unusual and infrequent gain. if execucomp's income statement is prepared according to generally accepted accounting principles (as illustrated in your text), w...

### What Twitter “tweet” could you write (using 280 characters or less) to warn teens about the dangers of using their phones

What Twitter “tweet” could you write (using 280 characters or less) to warn teens about the dangers of using their phones while engaged in another activity?...

### Regina makes skirts which need 3/4 ounces of beads per skirt. she has 5 5/14 ounces of beads, how many

Regina makes skirts which need 3/4 ounces of beads per skirt. she has 5 5/14 ounces of beads, how many can she make?...

### The systolic blood pressure of 18-year-old women is normally distributed with a mean of 120 mmHg and a standard deviation of 12 mmHg.a)

The systolic blood pressure of 18-year-old women is normally distributed with a mean of 120 mmHg and a standard deviation of 12 mmHg. a) What percentage of 18-year-old women have a systolic blood pressure that lies within 3 standard deviations of the mean. b) What level of systolic blood pressure i...

### Barney Humble wishes he had 100 sweaters to wear ​

Barney Humble wishes he had 100 sweaters to wear ​...

### Give 3 examples of quadratic equations that have x-intercepts at (1, 0) and (-3, 0), but that produces a different parabola.

Give 3 examples of quadratic equations that have x-intercepts at (1, 0) and (-3, 0), but that produces a different parabola....

### ANYONE WANNA TAL

ANYONE WANNA TAL...

### The amount of protein, in grams, Morgan gets from eating different food items each day for breakfast and lunch is shown

The amount of protein, in grams, Morgan gets from eating different food items each day for breakfast and lunch is shown in this table. Food Item Amount of Protein (g) Avocado (half) 1.45 Egg 6.0 Sandwich 31.7 White Bread (small piece) 2.75 What is the total amount of protein, in grams, Morgan will...

### Act II, Scene III According to Friar Lawrence, what two things reside in man and in the flowers he is

Act II, Scene III According to Friar Lawrence, what two things reside in man and in the flowers he is collecting? A) good and evil B) joy and sorrow C) reason and emotion D) strength and weakness...

### This parabola opens to the left. x=1/4y^2 a. true b. false

This parabola opens to the left. x=1/4y^2 a. true b. false...

### A population of 25 wolves was introduced into Yellowstone National Park in 2000. All of these wolves were marked with radio tags.

A population of 25 wolves was introduced into Yellowstone National Park in 2000. All of these wolves were marked with radio tags. 5 years later, it was determined that this population had grown to a total of 100 wolves (the original 25 plus 75 new wolves). While the original wolves remain tagged non...

### 4. What key ideas does Kennedy express about the United Nations in his'Inaugural Address'? Choose two options.A. The United Nations has little real

4. What key ideas does Kennedy express about the United Nations in his "Inaugural Address"? Choose two options. A. The United Nations has little real power B. The United Nations must become a more up-to-date body C. The United Nations has the full support of the United States D. The United Natio...

### Select the correct text in the passage. Which detail supports the idea that coral reefs play an important role in human

Select the correct text in the passage. Which detail supports the idea that coral reefs play an important role in human life? The Impact of Coral Reefs Hidden beneath the ocean waters, coral reefs are filled with life. [Coral reefs support more species than any other marine environment]. They even r...

### Catapult launches acannonball 105km away in 6 seconds. HowFAST did the cannonball go?

Catapult launches a cannonball 105km away in 6 seconds. How FAST did the cannonball go?...

### Bases are 26.5 and 30. the area is 791. what is the height?

Bases are 26.5 and 30. the area is 791. what is the height?...

### Which of the following describes a disadvantage of oral history compared to written history? a. oral

Which of the following describes a disadvantage of oral history compared to written history? a. oral history cannot be passed down to future generations of historians. b. oral history cannot be preserved if the people who have memorized the history are killed. c. oral history creates only secondary...

### Solve the following system of equations. y=4x+11 y=x+38

Solve the following system of equations. y=4x+11 y=x+38...