« previous next »

Author Question: A standard candle is A) a 7-cm-long wax candle. B) another name for a main-sequence star. C) ... (Read 197 times)

maegan_martin

  • Hero Member
  • *****
  • Posts: 532
on: Jul 27, 2018
A standard candle is
 
  A) a 7-cm-long wax candle.
  B) another name for a main-sequence star.
  C) another name for a barred-spiral galaxy.
  D) a light source of known luminosity.

Question 2

Briefly summarize current knowledge about the term Np in the equation Number of Civilizations = Np  flife  fcivilization  fnow.
 
  What will be an ideal response?


potomatos

  • Sr. Member
  • ****
  • Posts: 338
Reply #1 on: Jul 27, 2018
Answer to Question 1

D

Answer to Question 2

We have evidence now for more than a dozen planets around other stars, and evidence for protoplanetary disks around many more stars. Although we cannot yet give a precise value to Np, it now seems likely that it is quite largeperhaps as large as the number of stars in the Milky Way Galaxy.


Related Topics

Need homework help now?

Ask unlimited questions for free

Ask a Question
« previous next »
 

Did you know?

Cucumber slices relieve headaches by tightening blood vessels, reducing blood flow to the area, and relieving pressure.

Did you know?

According to the American College of Allergy, Asthma & Immunology, more than 50 million Americans have some kind of food allergy. Food allergies affect between 4 and 6% of children, and 4% of adults, according to the CDC. The most common food allergies include shellfish, peanuts, walnuts, fish, eggs, milk, and soy.

Did you know?

Illicit drug use costs the United States approximately $181 billion every year.

Did you know?

Hyperthyroidism leads to an increased rate of metabolism and affects about 1% of women but only 0.1% of men. For most people, this increased metabolic rate causes the thyroid gland to become enlarged (known as a goiter).

Did you know?

Every flu season is different, and even healthy people can get extremely sick from the flu, as well as spread it to others. The flu season can begin as early as October and last as late as May. Every person over six months of age should get an annual flu vaccine. The vaccine cannot cause you to get influenza, but in some seasons, may not be completely able to prevent you from acquiring influenza due to changes in causative viruses. The viruses in the flu shot are killed—there is no way they can give you the flu. Minor side effects include soreness, redness, or swelling where the shot was given. It is possible to develop a slight fever, and body aches, but these are simply signs that the body is responding to the vaccine and making itself ready to fight off the influenza virus should you come in contact with it.

Long-term studies of the Glanville fritillary butterfly, Melitaea cinxia, have provided exceptional Long-term studies of the Glanville fritillary butterfly, Melitaea cinxia, have provided exceptional
The nurse is using Standard Precautions to draw blood. The nurse is using Standard Precautions to draw blood.
Shooting star Shooting star
Standard precaution guidelines. Additional guidelines/protocols may be utilized depending on the ... Standard precaution guidelines. Additional guidelines/protocols may be utilized depending on the ...
Standard reduction potentials of the major respiratory electron carriers Standard reduction potentials of the major respiratory electron carriers
Genes are composed of a sequence of nucleotides in a DNA molecule Genes are composed of a sequence of nucleotides in a DNA molecule
Video: Cleavage and Implantation Animation

For a complete list of videos, visit our video library