Without which natural activity ,Earth's average temperature becomes -73 degree celsius?

Question

Red house effect

Green house effect

Blue house effect

Answer 1

Without the Sun Earth's temperature would be approximately -273 C

But the Scientists are only guessing at temperatures.

They vastly underestimate the heat coming from the core through the crust.  Go deep into a cave and you'll find livable heat - well beyond crustal insulation.

Just look at Venus (which Enviros love to point to) - lots of surface magma which keeps temperatures a constant 470 degree C.

http://www.strangehorizons.com/2002/2002...

Answer 2

None of the above.

It is the Whitehouse effect generating a lot of hot air.

Answer 3

greenhouse but your numbers are a bit off. try -15 to 25 rather then the average of 15 degrees C that we are currently at,.

Answer 4

None of them.  The moon's average temperature is -18 degrees and it doesn't have any atmosphere at all.

Answer 5

Greenhouse effect.  Proven by Fourier in 1824, I believe.

Answer 6

Without greenhouse gases and water vapor trapping solar radiation the Earth would be about 33C cooler than it is today. Water vapor is part of the greenhouse effect even though it's not a gas, hence it's not a greenhouse gas, and it causes up to 90% of greenhouse warming by some accounts. Wiki will give you a different answer but they seem to have a rapidly increasing bias towards the global warming agenda.

Of course nearly all of the warming we get comes from the sun, but without the greenhouse effect we'd be much colder, not as cold as Mars but a big uninhabitable snowball.

Answer 7

None of the Above.  The correct answer is the reduction of solar output.