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Author Question: What makes white-dwarf supernovae good standard candles? A) They are very bright, so they can be ... (Read 60 times)

TVarnum

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on: Jul 27, 2018
What makes white-dwarf supernovae good standard candles?
 
  A) They are very bright, so they can be used to determine the distances to galaxies billions of light-years away.
  B) They should all have approximately the same luminosity.
  C) They occur so frequently that we can use them to measure the distances to virtually all galaxies.
  D) We have had several occur close to us in the Milky Way, so we have been able to determine their luminosities very accurately.
  E) both A and B

Question 2

Which of the following statements best reflects our current knowledge about the term flife in the equation Number of Civilizations = Np  flife  fcivilization  fnow?
 
  A) The value of flife must be either 0 percent or 100 percent.
  B) The value of flife is between 0 percent and 100 percent.
  C) The value of flife is between 0 percent and 1 percent.
  D) The value of flife is roughly 50 percent.
  E) The value of flife is presently unknown but should be well known within just a few years.


tjayeee

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Reply #1 on: Jul 27, 2018
Answer to Question 1

E

Answer to Question 2

B


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When Gabriel Fahrenheit invented the first mercury thermometer, he called "zero degrees" the lowest temperature he was able to attain with a mixture of ice and salt. For the upper point of his scale, he used 96°, which he measured as normal human body temperature (we know it to be 98.6° today because of more accurate thermometers).

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Since 1988, the CDC has reported a 99% reduction in bacterial meningitis caused by Haemophilus influenzae, due to the introduction of the vaccine against it.

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According to the Migraine Research Foundation, migraines are the third most prevalent illness in the world. Women are most affected (18%), followed by children of both sexes (10%), and men (6%).

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Fatal fungal infections may be able to resist newer antifungal drugs. Globally, fungal infections are often fatal due to the lack of access to multiple antifungals, which may be required to be utilized in combination. Single antifungals may not be enough to stop a fungal infection from causing the death of a patient.

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Most childhood vaccines are 90–99% effective in preventing disease. Side effects are rarely serious.

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