About how many stars has the Hipparcos mission given us accurate distance data on?
A) about 3,000, about half of what you can see with the naked eye alone
B) over 6000, the visible naked eye stars and some seen in binoculars
C) 60,000, those within about 100 light years of us
D) a million, those with parallaxes of .005" or larger
E) over 100 billion, almost every star in the galaxy
D
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A Life Calendar: Make a "life calendar" for hypothetical person. Assume that this person lived 80 years and represent the 80 year period as a single calendar year in which he or she was born on January 1st and died on December 31st
Estimate the calendar dates on which this person reached various life milestones. For example, when did he or she take their first step? Speak their first word? Start elementary school? Finish high school? When did he or she retire? Does your life calendar for this particular person give any insight into human lives in general?
In a therapeutic clinical trial, both the experimental group and the control group are composed of patients who have the disease for which a therapy is being tested.
a. true b. false
Collisions in which kinetic energy is conserved are said to be ineleatic collisions
Indicate whether the statement is true or false
The magnetic fields carried by jets coming from active galactic nuclei are generated by:
A) the combined magnetic fields of the many stars near the galaxy's center. B) the central black hole. C) the movement of the interstellar matter of the galaxy. D) the movement of the stars in the galaxy. E) charged matter in the accretion disk of the central black hole.