This topic contains a solution. Click here to go to the answer

Author Question: Describe the Ptolemaic model of the solar system. How did Ptolemy account for the apparent ... (Read 84 times)

tichca

  • Hero Member
  • *****
  • Posts: 554
Describe the Ptolemaic model of the solar system. How did Ptolemy account for the apparent retrograde motion of the planets?
 
  What will be an ideal response?

Question 2

Using an orbit size of 8 kpc, and a period of 225 million years, the mass of our Galaxy is found to be closest to
 
  A) 106 solar masses.
  B) 108 solar masses.
  C) 1010 solar masses.
  D) 1011 solar masses.
  E) 1012 solar masses.



Related Topics

Need homework help now?

Ask unlimited questions for free

Ask a Question
Marked as best answer by a Subject Expert

Ptupou85

  • Sr. Member
  • ****
  • Posts: 334
Answer to Question 1

Although Ptolemy's model was an Earth-centered model of the solar system, it was sufficiently accurate to remain in use for 1,500 years. His model used the ancient idea that all motions in the heavens must be perfect circles. Therefore, the planets moved on circles that orbited on larger circles around Earth. This circle upon circle motion accounted for the apparent retrograde motion of the planets. Ptolemy carefully selected sizes for the circles to reproduce the motions seen in the sky. He also placed Earth slightly off-center to improve model predictions even more.

Answer to Question 2

D



tichca

  • Hero Member
  • *****
  • Posts: 554
Both answers were spot on, thank you once again



Ptupou85

  • Sr. Member
  • ****
  • Posts: 334

 

Did you know?

Patients should never assume they are being given the appropriate drugs. They should make sure they know which drugs are being prescribed, and always double-check that the drugs received match the prescription.

Did you know?

Patients who have undergone chemotherapy for the treatment of cancer often complain of a lack of mental focus; memory loss; and a general diminution in abilities such as multitasking, attention span, and general mental agility.

Did you know?

Elderly adults are at greatest risk of stroke and myocardial infarction and have the most to gain from prophylaxis. Patients ages 60 to 80 years with blood pressures above 160/90 mm Hg should benefit from antihypertensive treatment.

Did you know?

A recent study has found that following a diet rich in berries may slow down the aging process of the brain. This diet apparently helps to keep dopamine levels much higher than are seen in normal individuals who do not eat berries as a regular part of their diet as they enter their later years.

Did you know?

Signs and symptoms of a drug overdose include losing consciousness, fever or sweating, breathing problems, abnormal pulse, and changes in skin color.

For a complete list of videos, visit our video library