This topic contains a solution. Click here to go to the answer
« previous next »

Author Question: Describe the Ptolemaic model of the solar system. How did Ptolemy account for the apparent ... (Read 88 times)

tichca

  • Hero Member
  • *****
  • Posts: 554
on: Jul 27, 2018
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
Reply #1 on: Jul 27, 2018
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
Reply #2 on: Jul 27, 2018
Both answers were spot on, thank you once again


Ptupou85

  • Sr. Member
  • ****
  • Posts: 334
Reply #3 on: Jul 27, 2018
Great! Please up vote :D


« previous next »
 

Did you know?

The liver is the only organ that has the ability to regenerate itself after certain types of damage. As much as 25% of the liver can be removed, and it will still regenerate back to its original shape and size. However, the liver cannot regenerate after severe damage caused by alcohol.

Did you know?

Methicillin-resistant Staphylococcus aureus or MRSA was discovered in 1961 in the United Kingdom. It if often referred to as a superbug. MRSA infections cause more deaths in the United States every year than AIDS.

Methicilli ...
Did you know?

ACTH levels are normally highest in the early morning (between 6 and 8 A.M.) and lowest in the evening (between 6 and 11 P.M.). Therefore, a doctor who suspects abnormal levels looks for low ACTH in the morning and high ACTH in the evening.

Did you know?

No drugs are available to relieve parathyroid disease. Parathyroid disease is caused by a parathyroid tumor, and it needs to be removed by surgery.

Did you know?

Illicit drug use costs the United States approximately $181 billion every year.

Growth of yeast cells in culture fits the logistic growth model. Growth of yeast cells in culture fits the logistic growth model.
Health Belief Model Health Belief Model
Model of a sequential study in which two cohorts were followed beginning at age 20. One cohort was f Model of a sequential study in which two cohorts were followed beginning at age 20. One cohort was f
Longshore Transport System Longshore Transport System
The Male Reproductive System The Male Reproductive System
Opener Model showing how the lac repressor and catabolite-activating protein Opener Model showing how the lac repressor and catabolite-activating protein
Video: Homologous chromosomes during prophase I - Animation

For a complete list of videos, visit our video library