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

Author Question: The _______________ time is the amount of time it took light to travel from a celestial object to ... (Read 132 times)

c0205847

  • Hero Member
  • *****
  • Posts: 531
The _______________ time is the amount of time it took light to travel from a celestial object to Earth.
 
  Fill in the blank(s) with correct word

Question 2

Why are reflecting telescopes cheaper to build than refracting telescopes?
 
  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

kthug

  • Sr. Member
  • ****
  • Posts: 332
Answer to Question 1

lookback
look-back

Answer to Question 2

Mirrors are much less expensive than lenses because light reflects off the front surface; therefore, only the front surface of a mirror needs to be made with a precise shape. Lenses are much more difficult to manufacture than a mirror of the same size. The interior of the glass must be flawless and pure, and must be made of two different kinds of glass requiring four precisely ground surfaces. Refracting telescopes larger than 1 m would be prohibitively expensive.




kthug

  • Sr. Member
  • ****
  • Posts: 332

 

Did you know?

Critical care patients are twice as likely to receive the wrong medication. Of these errors, 20% are life-threatening, and 42% require additional life-sustaining treatments.

Did you know?

About 3% of all pregnant women will give birth to twins, which is an increase in rate of nearly 60% since the early 1980s.

Did you know?

The first documented use of surgical anesthesia in the United States was in Connecticut in 1844.

Did you know?

Drug-induced pharmacodynamic effects manifested in older adults include drug-induced renal toxicity, which can be a major factor when these adults are experiencing other kidney problems.

Did you know?

Cytomegalovirus affects nearly the same amount of newborns every year as Down syndrome.

For a complete list of videos, visit our video library