The Luyten 726-8 binary system is approximately 9 light-years ...

[j.rubin]

The Luyten 726-8 binary system is approximately 9 light-years away. If we send a spacecraft to visit this system traveling at 90 of the speed of light, how long will a one- way trip take as measured from the Earth?
 
  A) it's impossible to tell unless we know the spacecraft's method of propulsion
  B) more than 10 years
  C) 10 years
  D) less than 10 years

Question 2

The Earth is able to recover from a snowball phase by
 
  A) the gradual melting of snow and ice by solar radiation
  B) the gradual buildup of heat beneath the snow and ice layer
  C) the breaking up of the snow and ice layer by plate tectonics
  D) carbon dioxide gradually building up in the atmosphere from volcanism

[carolinefletcherr]

Answer to Question 1

C

Answer to Question 2

D

[j.rubin]

Excellent

[nanny]

TYSM