Is it true that if the Earth鈥檚 atmosphere extended all the way to the sun, then the noise the sun makes would deafen us all? How much sound energy does the sun create? And what other effects would manifest themselves?
We and the sun are in each other鈥檚 atmospheres already, but most of the gas between us is so tenuous that the sound of the solar wind against our magnetosphere cannot compete with our traffic, pop music and strife. Even if that gas was as dense as our atmosphere at sea level, the loudest solar noises would probably be inaudible infrasonic rumblings, and much weakened after such a journey.
鈥淭he atmosphere would have a mass thousands of times greater than the sun plus all its planets鈥�
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We would have more than noise to worry about, however. The sun would hardly be seen: our atmosphere would be too dense for much light to penetrate if it extended the 150 million kilometres to the sun. Also, it would have a mass of well over 15 x 1030 tonnes 鈥� thousands of times greater than the sun plus all its planets. It would collapse and the resulting blast could probably sterilise any planet within several light years.
Jon Richfield, Somerset West, South Africa
A sea-level atmosphere stretching to the sun鈥檚 photosphere would block observation of the sun, visual or auditory. The huge depth of air would block the sun鈥檚 radiation: sunrises and sunsets demonstrate this effect on a small scale, as they dim and redden sunlight at dawn and dusk.
As far as sound is concerned, we already have a comparable effect. We do not hear a continual barrage of thunderclaps, even though they are always taking place around the world, because of the limited distance sound travels in the atmosphere. So we would not be deafened by noisy sunspots but frozen by the insulating effect of the wall of air.
The scenario ignores the fact that atmospheres around planets vary in density due to gravity. If the Earth鈥檚 atmosphere were to spread as far as the sun and have sufficient density to conduct sound, it would probably be solid ice for most of the distance, causing strange gravitational and orbital effects and burying a human observer on the Earth鈥檚 surface.
Michael Burberry, Oxford, UK
I know it is not in the spirit of 鈥淭he Last Word鈥� to challenge the premise of its questions, but to form an image implied by this question would need some sort of pre-Copernican or geocentric model of the solar system. I cannot quite conceive of an Earth that can drag around an atmosphere which reaches the sun. It is much easier to think of the sun鈥檚 atmosphere extending all the way to the Earth 鈥� which, in a sense, it does.
Actually, the answer may eventually be tested experimentally, but not for a while. As the sun reaches the end of its life, it will become a red giant that will engulf the Earth, and presumably we will be first hit by its upper atmosphere. If life as we know it is to survive it will need to move away from the doomed Earth, but perhaps those who leave last, as well as turning the lights out, could be persuaded to leave a few microphones around just to see what happens.
Bryn Glover, Cracoe, North Yorkshire, UK