What do astronomers mean by a selection effect. Explain why the ...

[bobbie]

What do astronomers mean by a selection effect. Explain why the detection of giant planets in close orbits does not necessarily mean our Solar System is unusual.
 
  What will be an ideal response?

Question 2

The Greenhouse Effect works by trapping
 
  A) incoming ultraviolet radiation from the Sun.
  B) outgoing ultraviolet radiation from the Earth.
  C) incoming infrared radiation from the Sun.
  D) outgoing infrared radiation from the Earth.
  E) the heat from the Sun in Earth's atmosphere.

[yifu223]

Answer to Question 1

A selection effect is a bias in a detection technique. The technique is most sensitive to a certain class of objects and these kinds of objects therefore tend to be selected. In the case of extrasolar planet detection, the indirect methods of detection rely on the gravity of the planet (Doppler and astrometric methods) or its size (transit method) and therefore massive, large planets tend to be found. Further, because observations have only been going on for a relatively short time, only short periods can be measured, corresponding to planets in close-in orbits around their stars. The planet search methods are currently unable to detect planets with similar sizes, masses, and orbits as in our Solar System and we are therefore unable to say, at this point, whether our Solar System is unusual.

Answer to Question 2

D

[bobbie]

Excellent

[amit]

TYSM