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

Author Question: Why do astronomers conclude that the spiral arms are places of active star formation? What will ... (Read 71 times)

notis

  • Hero Member
  • *****
  • Posts: 596
Why do astronomers conclude that the spiral arms are places of active star formation?
 
  What will be an ideal response?

Question 2

How can tidal forces affect the rotation of celestial bodies and their orbital motion?
 
  What will be an ideal response?



Related Topics

Need homework help now?

Ask unlimited questions for free

Ask a Question
Marked as best answer by a Subject Expert

gcook

  • Sr. Member
  • ****
  • Posts: 343
Answer to Question 1

The spiral arms are home to spiral tracers, including OB associations, emission nebulae, and young open star clusters. All of these objects are young objects, and it is the OB associations that make the arms so clearly visible. If all of the objects that trace the arms are young, they must have formed near their current location; hence spiral arms must be active sites of star formation.

Answer to Question 2

Earth rotates eastward, and friction with the ocean beds drags the tidal bulges slightly eastward out of a direct EarthMoon line. These tidal bulges are massive, and their gravitational field pulls the Moon forward in its orbit. As a result, the Moon's orbit is growing larger by about 3.8 cm a year, an effect that astronomers can measure by bouncing laser beams off reflectors left on the lunar surface by the Apollo astronauts.




notis

  • Member
  • Posts: 596
Reply 2 on: Jul 27, 2018
Wow, this really help


covalentbond

  • Member
  • Posts: 336
Reply 3 on: Yesterday
YES! Correct, THANKS for helping me on my review

 

Did you know?

Asthma is the most common chronic childhood disease in the world. Most children who develop asthma have symptoms before they are 5 years old.

Did you know?

Patients who cannot swallow may receive nutrition via a parenteral route—usually, a catheter is inserted through the chest into a large vein going into the heart.

Did you know?

Colchicine is a highly poisonous alkaloid originally extracted from a type of saffron plant that is used mainly to treat gout.

Did you know?

Your heart beats over 36 million times a year.

Did you know?

The tallest man ever known was Robert Wadlow, an American, who reached the height of 8 feet 11 inches. He died at age 26 years from an infection caused by the immense weight of his body (491 pounds) and the stress on his leg bones and muscles.

For a complete list of videos, visit our video library