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

Author Question: The mass of visible matter in a galaxy can be estimated by measuring its luminosity. When this is ... (Read 21 times)

ss2343

  • Hero Member
  • *****
  • Posts: 548
on: Jul 27, 2018
The mass of visible matter in a galaxy can be estimated by measuring its luminosity. When this is compared with the measured mass of the galaxy, astronomers find that ____.
 
  a. the measured mass is about ten times the estimated mass, due to the effects of the central black hole
  b. the measured mass is approximately equal to the estimated mass
 c. there is no clear relationship between the estimated and measured mass
 d. the measured mass is about ten times the estimated mass, due to the effects of dark matter
 e. the estimated mass is about ten times the measured mass, due to the effects of dark matter

Question 2

What technique often requires the use of a laser guide star?
 
  a. active optics
 b. photometry
 c. adaptive optics
 d. comparison spectrum
 e. representational color imaging


Related Topics

Need homework help now?

Ask unlimited questions for free

Ask a Question
Marked as best answer by a Subject Expert

ErinKing

  • Sr. Member
  • ****
  • Posts: 362
Reply #1 on: Jul 27, 2018
Answer to Question 1

d

Answer to Question 2

c


ss2343

  • Hero Member
  • *****
  • Posts: 548
Reply #2 on: Jul 27, 2018
Thanks


ErinKing

  • Sr. Member
  • ****
  • Posts: 362
Reply #3 on: Jul 27, 2018
Welcome :)


« previous next »
 

Did you know?

Bacteria have been found alive in a lake buried one half mile under ice in Antarctica.

Did you know?

Urine turns bright yellow if larger than normal amounts of certain substances are consumed; one of these substances is asparagus.

Did you know?

Congestive heart failure is a serious disorder that carries a reduced life expectancy. Heart failure is usually a chronic illness, and it may worsen with infection or other physical stressors.

Did you know?

The Food and Drug Administration has approved Risperdal, an adult antipsychotic drug, for the symptomatic treatment of irritability in children and adolescents with autism. The approval is the first for the use of a drug to treat behaviors associated with autism in children. These behaviors are included under the general heading of irritability and include aggression, deliberate self-injury, and temper tantrums.

Did you know?

Dogs have been used in studies to detect various cancers in human subjects. They have been trained to sniff breath samples from humans that were collected by having them breathe into special tubes. These people included 55 lung cancer patients, 31 breast cancer patients, and 83 cancer-free patients. The dogs detected 54 of the 55 lung cancer patients as having cancer, detected 28 of the 31 breast cancer patients, and gave only three false-positive results (detecting cancer in people who didn't have it).

Young Circumstellar Disks of Matter Young Circumstellar Disks of Matter
Dred Scott and his wife and children are featured on the cover of Frank Leslie’s Illustrated Newspap Dred Scott and his wife and children are featured on the cover of Frank Leslie’s Illustrated Newspap
Calculation of body mass index. To determine your BMI, find the value for your height on the left ... Calculation of body mass index. To determine your BMI, find the value for your height on the left ...
Polar ice caps lose mass as surface ice melts Polar ice caps lose mass as surface ice melts
Air-Mass Source Regions for North America Air-Mass Source Regions for North America
Mass spectrometry for identifying an unknown protein isolated from a 2D gel Mass spectrometry for identifying an unknown protein isolated from a 2D gel
Video: Cerebral Cortex Animation

For a complete list of videos, visit our video library