Phil Kenyan asked:
How long does it take for heat to reach us from the sun? It’s about 8 minutes, the distance between the sun and the Earth because light travels at about 1 billion km/h and the sun is about 150 million km away from the Earth.
Chris - The answer is that heat arrives in the form of light because it’s in the form of infra-red radiation, largely, that’s reaching us from the sun. It’s reaching us in the form of radiation so that too takes 8 minutes to get here.
Phil Kenyon asked the Naked Scientists: Hi Chris, I enjoy your section in the Redi Direko show on Cape Talk and wondered if you could discuss the following? I was thinking about what would happen if the sun suddenly 'went-out'! Would we have 8.5 minutes of sunlight and 14 years of heat? 299792 km/s - Speed of light 152000000 km to sun 507.02 seconds for sunlight to arrive 8.45 minutes for sunlight to arrive 0.34 km/s speed of sound 447058824 seconds for sound to arrive Therefore 14 years for sound to arrive Speed of sound = speed of heat Therefore it takes 14 years for heat to arrive? Regards, Phil Kenyon (Somerset West) What do you think? Phil Kenyon , Mon, 12th Jan 2009
Sound doesn't travel through a vacuum so 'heat' wouldn't get to us that way.
As the sun flickers out there will be no more photons coming our way.
Sorry for being nitpicking, heat is in the form of all the electromagnetic radiation. lightarrow, Mon, 12th Jan 2009
Feel free to pick all you like, my friend. I was being deliberately sloppy in an attempt to seem more approachable. I shall avoid it in future. :-)
Hmmm...yes, but, wouldn't you define heat as those energy exchanged between two bodies by virtue of a temperature difference of them? Just thinking. lightarrow, Mon, 12th Jan 2009
How about this definition of what would happen to our Earth if it cooled down by an absence of Sun :)
you suck my coch or die mudder fukker, Mon, 22nd Feb 2010