Venus's Atmosphere?

Question

Costing me five points to ask this, but enquiring minds, etc.,.

Earth's atmosphere remains in place mainly due to the planet's gravity. By itself though would that be enough to prevent the solar wind from sweeping it away given the billions of years involved? I'm assuming that to some extent Earth's magnetic field helps protect the atmosphere by deflecting the solar wind.

If the above assumptions are correct, how does Venus retain its atmosphere when it has virtually no magnetic field. At first I thought that its atmosphere was significantly denser than ours, but that's not the case.

Whaddaya think....?

Yep, I was wrong about Earth vs Venus atmosphere density. Should have researched that better. Hard to pick the best answer from among the several good ones submitted. Thanx to you all.

Answer 1

It is to do with the escape velocity of the planet.

Venus is almost as big as Earth and so has an escape velocity almost as high as Earth along with that the CO2 that makes up the majority of the atmosphere of Venus is heavier than the Nitrogen and Oxygen that make up Earths atmosphere which means that at the same temperature the average thermal speed will be lower making it less likely that a particle will reach escape velocity in a collision.

It is mainly the escape velocity and the fraction of molecules that are at escape velocity that determines how long an atmosphere will last although sputtering from the solar wind will also cause some leakage (but the atmosphere of Venus is thick enough for that to take a while).

Answer 2

Actually, Venus' atmosphere is far more dense that the Earth's. It's an interesting question; unfortunately, the answer is complicated.

On Earth, energy from the Earth's core is removed in one of two ways: through continental drift, and through volcanic eruptions. When volcanoes erupt, millions of tons of greenhouse gases are released into the atmosphere. These gases absorb radiation from the sun, converting it into heat and a rise in temperature. However, the Earth has a natural "air conditioning" system with the oceans and with life. Life creates the oxygen in the atmosphere, which combines with carbon and nitrogen. The oceans absorb huge amounts of CO2 and NOx, trapping the greenhouse gases in the oceans. This allows heat to escape from Earth to space through radiative heat transfer, and also significantly lessens the overall density. If the Earth gets too cold, an ice age develops, the oceans freeze over, and absorption and removal of greenhouse gases slow - which causes a greenhouse effect (over thousands or millions of years, since volcanoes are still erupting during this time). Temperatures rise, which melts the ice, allowing the oceans to again trap excess greenhouse gas. This self-correcting system has allowed the Earth to remain relatively stable in temperature and in air density over millions of years. Multicellular life arose in these conditions, which is why the Earth's temperature and air pressure is perfect for us.

Venus has no continental drift, meaning internal energy is only released through volcanic activity. Far more greenhouse gases are pumped into the Venusian atmosphere than the Earth pumps into it's atmosphere. The proximity to the sun also makes Venus much hotter. Without the oceans to mitigate the effects of volcanic activity, the massive amounts of greenhouse gases has created a hellish runaway greenhouse effect. The planet absorbs radiation from the sun and heats up until it becomes a blackbody radiator itself - which doesn't happen until the temperature is high enough to melt lead and about 92xs denser than our own atmosphere.

This is a basic, if imperfect, description of what's going on between the two planets.

Answer 3

Given the final dimensions and speed mentione, and assuming a just about-on the instant-line impression in the direction of the floor... It spends basically slightly below 5 seconds plowing interior the direction of the venusian ecosystem. the backside a million/2 of the asteroid seems to be sparkling/flaming for the final 3 seconds or so - ablating a million to 2 lots of fabric consistent with millisecond (call it 6 or 7 thousand lots of fabric ''burned off'' for the period of the plunge.... slightly a flea-bite. It impacts the floor at a slightly-slowed speed (be beneficiant and contact it 20 km consistent with sec) approximately 10 to 30 cubic miles of fabric would be affected - customarily hurled (temporarily) into the venusian ecosystem and orbit. (Secondary impacts from this fabric proceed on basically approximately constantly for a pair days, and significant impacts are nevertheless continung as much as a pair months later. 'Ash', grit, sand, and so forth - maintains to be in venusian ecosystem for 2 or 3 years.) Venus would income a temporarily seen (5 to 250 years), very faint 'ring'. Venus features a clean crater - seen to interior of sight radar - between 50 and 2 hundred miles in diameter Earth would get a 'bathe' of venusian factors - as much as a pair hundred lots of venusian land/mass (mixed with maintains to be of unique asteroid) would finally attain earth (commencing approximately 10 years after the impression and stretched out over one thousand years or extra)

Answer 4

The Venusian atmosphere is indeed significantly denser than the Earth's, about 90 times more dense. On-going, active volcanism keeps the atmosphere topped off.

Answer 5

I believe that it is about 100 times as dense. Probably enough to survive the slow bleed.

quote: "The atmospheric pressure at the planet's surface is 90 times that of the Earth"

Answer 6

the gravity of Venus is not strong as the Earth so it can retain the atmosphere. However, there is green house effect in venus that does not allow the heat from the sun to go out of the planet but it has very thick poisonous cloud which can push back the solar wind and thus protect the atmosphere of the planet

Answer 7

probably due to the insulating natureof the planet,or the
Global Magnetic Field Strength ?

Answer 8

Oh yes because 5 points is SOOO much for you braxton ;)

That's really interesting, I never actually thought about it....I can't even come up with any semi smart sounding theories either. I'll have to study up. :D