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

Author Question: The _______________ time is the amount of time it took light to travel from a celestial object to ... (Read 139 times)

c0205847

  • Hero Member
  • *****
  • Posts: 531
on: Jul 27, 2018
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
Reply #1 on: Jul 27, 2018
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.


c0205847

  • Hero Member
  • *****
  • Posts: 531
Reply #2 on: Jul 27, 2018
Thank you!


kthug

  • Sr. Member
  • ****
  • Posts: 332
Reply #3 on: Jul 27, 2018
Always glad to help...


« previous next »
 

Did you know?

If all the neurons in the human body were lined up, they would stretch more than 600 miles.

Did you know?

Nearly 31 million adults in America have a total cholesterol level that is more than 240 mg per dL.

Did you know?

The first successful kidney transplant was performed in 1954 and occurred in Boston. A kidney from an identical twin was transplanted into his dying brother's body and was not rejected because it did not appear foreign to his body.

Did you know?

Children of people with alcoholism are more inclined to drink alcohol or use hard drugs. In fact, they are 400 times more likely to use hard drugs than those who do not have a family history of alcohol addiction.

Did you know?

Walt Disney helped combat malaria by making an animated film in 1943 called The Winged Scourge. This short film starred the seven dwarfs and taught children that mosquitos transmit malaria, which is a very bad disease. It advocated the killing of mosquitos to stop the disease.

Adults in late middle adulthood frequently look forward to spending more time with their partner Adults in late middle adulthood frequently look forward to spending more time with their partner
Light rays coming from an object to the retina. Light rays coming from an object to the retina.
The first commercially successful typewriter, manufactured in quantity beginning in 1874, surely fue The first commercially successful typewriter, manufactured in quantity beginning in 1874, surely fue
Sterilization Time Requirements Sterilization Time Requirements
The relationship of substrate con- version (as measured by optical density) to the amount of patient ... The relationship of substrate con- version (as measured by optical density) to the amount of patient ...
Change in Bone Mass over Time In your early years, more bone mass is added than lost in your body Change in Bone Mass over Time In your early years, more bone mass is added than lost in your body
Video: Multiple Sclerosis Animation

For a complete list of videos, visit our video library