Stars of types ________ and ________ are found only in the ...

[Metfan725]

Stars of types ________ and ________ are found only in the youngest star clusters.
 
  Fill in the blank(s) with correct word

Question 2

If we detected an Earth-like planet in the habitable zone around another star, how might we learn whether it harbored life?
 
  What will be an ideal response?

[ynlevi]

Answer to Question 1

O; B

Answer to Question 2

Future technology (such as large space-based interferometers) will be able to measure the far-infrared spectrum of the planet's atmosphere. Ozone produces a strong feature in the earth's atmosphere and would be detectable in the spectrum of hypothetical extrasolar planet. Ozone is related to oxygen, which is highly reactive and would rapidly disappear (through oxidation) from the atmosphere were it not being constantly replenished. Converting oxides back to oxygen requires energy and such a chemical reaction would not spontaneously. In the earth's case, the energy comes from the sun via photosynthesis in plants. Therefore, the detection of ozone in the spectrum of another planet would be a strong indicator of life.

[Metfan725]

Wow, this really help

[peter]

Thanks for the timely response, appreciate it