why is the mercury not the hottest planet even though its the nearest in the sun?

Answer 1

Physics.

For one thing, Mercury is tidally locked in orbit around the sun - it has one side facing the sun, and one away, all the time. It's only getting tanned on one side.

Venus is the greenhouse effect on crack. Methane in the air, trapped heat, volcanic reactions - lovely place. It's been a pressure cooker for how long now - one million years? three?

Jupiter is a huge ball of gas. The sun and stars are huge balls of gas too - but they are so big they ignite at the center. Jupiter isn't quite as hot as a star, so can't ignite - but it is a big ball of gas that is very hot.

Saturn is big ball of gas too, but not as big, and a bit further from the sun.

Answer 2

Although Mercury is very close to the sun, Venus has an atmosphere that contains high percentage of CO2, this causes the greenhouse effect and traps the heat that comes from the sun making Venus hotter and hotter.

Answer 3

Its because Mercury dosent have alot of atmospere. Venus is the hottest planet because it has a atmosphere and it trapps alot of heat in (greenhouse effect), so venus is very hot (900 degrees wow)!

Answer 4

First of all Mercury is not tidally locked. It rotates. We've known this since the last century.

http://cseligman.com/text/planets/mercuryrot.htm
http://www.solarviews.com/eng/mercury.htm

Secondly, Mercury (like all the other planets) gets hot on it's day side (the side facing the Sun) but it radiates that heat away into space on its night side. (This is why on Earth it gets colder on winter nights when there are no clouds, and why it is colder at higher altitude; the atmosphere of a planet helps trap heat).

Thirdly, what folks here are saying about the Venusian atmosphere is right. However they aren't giving you the whole picture, so it may be a bit hard to understand HOW hot and HOW thick their atmosphere is.
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Venus has a dense atmosphere, composed chiefly of carbon dioxide, which generates a surface pressure 90 times greater than that on Earth. This massive blanket of carbon dioxide is also responsible for a runaway greenhouse effect that heats the planet's surface to an average temperature of 467°C (872°F) – hot enough to melt lead.

Venus' atmosphere consists almost entirely (97%) of carbon dioxide, with clouds containing droplets of sulfuric acid along with compounds of chlorine and fluorine. These precipitate an acid rain called virga, which evaporates before it has the chance to reach the surface. In the upper part of the atmosphere, clouds swirl by at a rate of 300 km/h, driven by fierce winds.
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As Al Gore keeps telling us, Carbon Dioxide is a greenhouse gas, in that it helps to trap heat. The thing is, on Earth something like 0.04% or 0.035% of our atmosphere is carbon dioxide. Going from 0.04% to 0.048% isn't going to make that big a difference in the Earth's temperature, no matter what the politicians say.

Now for all the kerfluffel about CO2 it isn't a very good greenhouse gas (water vapor is about 3 times more powerful than CO2).

The key here is that although there is almost no water vapor in Venus's atmosphere, Venus has 90 times as much air as Earth, (or you could say "all the air in Earth's atmosphere combined would equal about 1/90 of the Venusian Atmosphere") and 97% that air is Carbon Dioxide!

That works out to something like 87 Earth atmospheres worth of pure Carbon Dioxide. If I did the math right Venus has almost 2200 times as much Carbon Dioxide as the Earth does!

(Put another way, for every CO2 molecule on Earth, there are 2200 on Venus).

That sort of atmosphere makes it very difficult for Venus to radiate the heat it absorbs from the Sun back into space, to say the least.

So Venus retains more of the heat it absorbs from the Sun than Mercury (or any other planet) does.

And that is why it is so much hotter than Earth, even though it is further from the Sun.


BTW the absolute BEST book on Venus is VENUS REVEALED by David Harry Grinspoon. (see link http://www.funkyscience.net/book.html )

Answer 5

Mercury has no atmosphere to retain the heat that it recieves from the sun.But Venus retains its heat by its thick atmosphere.So, Venus is hottest.

Answer 6

It is the samllest and is higher than venus. Venus i s in a straight line away from the sun and mercury is higher so there fore, Venus is the hottest.

Answer 7

Of course Mercury has a hot bright side and a cold dark side and the 'average' temperature should be less than that of Venus that has a dense atmosphere that traps and circulates solar energy all around it.

Answer 8

Venus is hotter because of its runaway greenhouse effect -- it has lots of CO2 in its very thick atmosphere and it traps the sun's heat inside like a blanket.

Answer 9

well mercury is not the hottest planet beacause venus has hot clouds on its rooftop which make that planet(venus) more hot.

Answer 10

Of all the planets, Mars' seasons are the most Earth-like, due to the similar tilts of the two planets' rotational axes. However, the lengths of the Martian seasons are about twice those of Earth's, as Mars's greater distance from the sun leads to the Martian year being approximately two Earth years in length. Martian surface temperatures vary from lows of approximately −140 °C (−220 °F) during the polar winters to highs of up to 20 °C (70 °F) in summers.[34] The wide range in temperatures is due to the thin atmosphere which cannot store much solar heat, the low atmospheric pressure, and the low thermal inertia of Martian soil.[35] -


http://en.wikipedia.org/wiki/Mars

** I find it amazing I got thumbs down when that information is from WIKIPEDIA!!! it isnt wrong!!!