If the sun were to die out how long would it take for the earth to freeze over?

Answer 1

If the sun was to suddenly stop producing enery, the surface temperature of the planet would dip below freezing everywhere in a few days at most.
The energy that Earth receives from the sun is 1.74E17 W, this represents 1366 W per square metre, of which 1020 W / m^2 make it to the ground (equator at noon), but because the Earth is not getting hotter at a rate comparable to that of an oven, most of this power is radiated out to space in the form of infrared energy.
Since the equator is 40000000 m around, but that an equivalent projected band only 13000000 m is exposed to the sun at any time, we get that a narrow strip of equator 40000000 m^2 receives 3.12E11 W-hr of energy in 24 hours, or 7800 W-hr per day per square metre, or 28 million joules. Since 4185 J equals one large calorie, this energy is equal to 6700 calories per square metre, with each calorie being defined as the energy able to increase the temperature of 1 kg of water by 1 C.
This is the energy that comes IN, and must be equal to the energy that the earth loses trough redaition, or else its average temperature would not be constant overall (let's neglet global warming, which is only a fraction of a degree per year anyway)
Let's assume that we'd call the world "frozen" when it is frozen to a depth of 1 m. So we have to see how much energry would be needed to be lost for 1000 kg of it to freeze (we will assume that the Earth is made of water, which is not far from the truth as 75% of it is covered by ocean), from an equatorial average temperature of 25 C.
So, 25 C to lose for 1000 kg, that is 25000 calories. Right now, the unit of ocean is getting 6700. So there you have it. Earth frozen solid 1 m thick at the equator in less than 4 days.
(One may argue that the heat loss will reduce as the temperatrue gets lower, as the radiation level decreases. I will not get into black body radiation to refine a calculation that may delay the tragic fate by less than one extra day. Final result is that we'd still all be icicles in much less than a week.)

(Oh, and Night Guy is wrong: the Earth is 8.3 light minutes from the Sun, not 4)

Answer 2

It takes light and heat about 4 minutes to reach the earth, so we will only be affected in 4 minutes. It would take a few hours for the earth to freeze over on account of the radiation and expansion of the sun.

Answer 3

The typical change in temperature from day to night is about 20 degrees. If the sun never came up again the temperature would continue to fall at the rate of about 20 degrees every 12 hours until it dropped to near absolute zero.

Answer 4

Actually the sun is expanding and will eventual over take the planet Mercury then Venus and the earth will slowly become hotter until is our turn to be over taken by the sun. Of coursee by that time well will have discovered a new planet to live on and of course pollute.

Answer 5

About the same amount of time waiting for Yankees to win another World Series.

Answer 6

prolly not very long, if you think about it it gets about 20 degrees here in the fall there for if the sun died out it would just continue to drop in tempurature

Answer 7

as the sun dies it will grow and vaporise the first 3 planets
but don't worry you have billions of years left