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The Earth's atmosphere absorbs electromagnetic radiation - Edexcel - GCSE Physics - Question 6 - 2012 - Paper 1
Question 6
The Earth's atmosphere absorbs electromagnetic radiation. The diagram shows how the amount absorbed changes with wavelength. (i) How much of the visible light from... show full transcript
Worked Solution & Example Answer:The Earth's atmosphere absorbs electromagnetic radiation - Edexcel - GCSE Physics - Question 6 - 2012 - Paper 1
Step 1
Step 2
Suggest why radio telescopes do not have to be placed high up a mountain.
Answer
Radio telescopes can operate effectively at lower altitudes because radio waves are less affected by atmospheric conditions compared to optical light, allowing them to capture signals from space even when positioned at lower elevations.
Step 3
Explain why scientists had to wait until the development of space flight before they could study this radiation in detail.
Answer
Prior to space flight, the Earth's atmosphere obstructed much of the cosmic background radiation at the wavelength of about 1 mm. It was only after space missions enabled telescopes to be placed outside the atmosphere that scientists could accurately study this radiation, avoiding atmospheric interference.
Step 4
Suggest why, when a galaxy has a very large red-shift, some of its visible light is not detected through the Earth's atmosphere.
Answer
A very large red-shift indicates that the galaxy is moving away from us at a significant speed, shifting its visible light towards the infrared spectrum. Much of this infrared radiation is absorbed by the Earth's atmosphere, preventing it from being detected by ground-based telescopes.
Step 5
Describe how careful observation of electromagnetic radiation from distant galaxies as well as from the whole of space gave evidence supporting the Big Bang Theory.
Answer
Careful observations of the cosmic microwave background radiation indicate uniformity in all directions, consistent with predictions of the Big Bang theory. Furthermore, the observation of red-shifts in distant galaxies supports the conclusion that the Universe is expanding, leading to the inference that all matter originated from a singular event.