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.
White crowned sparrow
Astronomers identified 12-billion-year-old white dwarf stars only 100 light years away from Earth
he White-throated Bee-eater, Merops albicollis is a near passerine bird in the bee-eater family Mero
Diphtheria. The bacteria that cause this disease, called Corynebacterium diphtheriae, proliferate in
Frederick Douglass, having escaped from slavery in 1836, attracted large audiences as an antislavery
a) Standard PCR machine used for genotyping and (b) agarose gel to detect DNA fragments.