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 33 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?

People about to have surgery must tell their health care providers about all supplements they take.

Did you know?

Eating food that has been cooked with poppy seeds may cause you to fail a drug screening test, because the seeds contain enough opiate alkaloids to register as a positive.

Did you know?

Many medications that are used to treat infertility are injected subcutaneously. This is easy to do using the anterior abdomen as the site of injection but avoiding the area directly around the belly button.

Did you know?

HIV testing reach is still limited. An estimated 40% of people with HIV (more than 14 million) remain undiagnosed and do not know their infection status.

Did you know?

A headache when you wake up in the morning is indicative of sinusitis. Other symptoms of sinusitis can include fever, weakness, tiredness, a cough that may be more severe at night, and a runny nose or nasal congestion.

(A) Lymphatic vessel with valves within tissue cells; (B) photomicrograph of lymphatic vessel with v (A) Lymphatic vessel with valves within tissue cells; (B) photomicrograph of lymphatic vessel with v
Seyfert Galaxy NGC 1566 Seyfert Galaxy NGC 1566
Measuring Humidity Measuring Humidity
Measuring Precipitation: Rain Gauges Measuring Precipitation: Rain Gauges
Air-mass thunderstorms—mT air masses Air-mass thunderstorms—mT air masses
Air-Mass Source Regions for North America Air-Mass Source Regions for North America
Video: Junction Types - Tight and Adherens Junctions

For a complete list of videos, visit our video library