Is there enough gravity to support the atmosphere on Mercury?
339606
no. mercury is too small to have a powerfull enough pull to hold an atmosphere
480696
The mean surface temperature of Mercury is 452 K (178.8 °C /353.9 °F), but it ranges from 90 K (-183.15 °C /-297.7 °F) to 700 K (426.85 °C /800 °F); by comparison, the temperature on Earth varies by only about 150 K (150 °C /270 °F). The sunlight on Mercury's surface is 6.5 times as intense as it is on Earth, with the solar constant having a value of 9.13 kW/m².
27642
Probably not much on the planet itself.  Neptune is a gas giant, meaning it does not have a surface, not to mention it is covered with horrible wind storms like the Great Blue Spot.  We could launch probes into Neptune and recieve a signal until the pressure and winds destroyed it.  In the distant future, we may be able to colonize the rocky moons of Neptune, or build orbiting cities above it (again they would have to be in orbit because of the lack of a surface).
193128
Something more powerful than the Sun's gravitational influence on Mercury.
336444
Well, you would need a floating home equiped with oxygen, heat, and self-replenishing food/water. Since Saturn is a gas giant planet, there is no solid surface to stand on, just a steadily thickening atmoshere of hydrogen, helium, and methane that gradually turns to compressed liquid that is the only thing you see until the planet's small, molten core, approximately 30,000 miles below the cloud tops. Living on Saturn is not worth the trouble, the risk, etc, though it would be a very interesting scientific endeavor.
98562
Yes!  Gravity has nothing to do with air, or the lack there of.  People tend to accociate vacuums with the absense of gravity because of the vacuum of space.  However, gravity is what keeps the moon orbiting the Earth and the Earth orbiting the sun, even though there is no air in space.
877416
earth is weightless in space. \n but your concept is interesting as applied to mass. gas also has mass so I do not think anything ever disappears. it just changes form. the gravity of the earth is what causes "weight" so the gravity of earth hangs onto the gases that develop and we all may strangle in them, but the earth and its atmosphere inclusive do not lose mass overall. saturn is a planet whos major mass is gases with a tiny ball inside of solid rock, about the size of earth. maybe we will gradually warm to a  huge gasball with a tiny rock in the middle with one person left on it smoking a cigarette and sitting in his motorhome with the motor running.
352366
no, but the sun is getting bigger and it is predicted that it will absord mercury and venus on its way to us, but it may or may not consume us.  This will only occur in the next 5 billion or so years.  But you can look at this question two ways, yes it is getting closer because it is expanding, or you could say no because it is not physically moving toward us even though we are going in an eliptical orbit (oval for you simpletons)\n\nConsidering also that we are significantly smaller than the sun, and the laws of physics state that (in simple terms) the larger the object is = stronger the force of gravity.  Thus meaning that the sun cannot actually get closer to us, but we could if we did not maintain the correct amount of centripetal force that allows us to rotate in an eliptical orbit so that we do not fall into the sun.  \n\nPS i am in 10th grade
182763
mrcury...cause mercury has more specific gravity than a steel and water, meaning to say mercury will settle down and steel will float on it ...i think water has 1 s.g and mercury has 13.6 s.g. not sure bout steel...
373196
If earth's gravity is 1, Jupiter's gravitational pull is 2.64 times that of earth, So the fall would be much faster. The gravitational pull on Jupiter is over 2 and a half times stronger than Earth's. Imagine a roller coaster falling twice as fast!\n  \nThe gravitational pull of Mercury is .38 times that of earth. \nOn Mercury the gravity is so small that the fall would have to be about three times as long to get the same speed as on Earth.
966827
Mercury consists of approximately 70% metallic and 30% silicate material. The density of the planet is the second-highest in the solar system at 5430 kg/m³, only slightly less than Earth's density.\n\nA high percentage of iron.
619092
not really. To have planets and moons it has to have a gravitational pull
403307
Not Mars and DEFINITELY not Venus. Mars is too cold and has almost no oxygen. Venus it WAY WAY too hot, hot enough to melt lead, even hotter than Mercury due to a runaway greenhouse effect, and also has almost no oxygen. There is no planet that we know of (yet) that can support plant or animal life like we have on Earth. Maybe one will be discovered in another star system some time in the future, but there is no such planet in our own solar system, other than Earth.
217077
Keep trying. The problem is that we know that the sun is a hydrogen reactor at very extreme temperatures. Stars need to have this nuclear process to provide the energy that they do. You mentioned that planets are the remains of burnt out stars. However, stars have a very distinct lifecycle resulting in phenomena such as super nova, red giants, white dwarfs etc. Given the ratio of planets to stars in our observable universe and timescales involved. I don't think you have thought about your proposal deep enough. As for your law - gravity is universal - all masses are subject to  gravitational influence. Given this, your water droplet is counter acting the effects of gravity due to a temperature related process. The surface temperature of the tin exhibits a hydrophobic effect. Whereas at lower temperatures the tin is no longer hydrophobic.
573477
Although the gravity on Venus is very similar to Earth's (about 0.95 G), the other conditions of Venus' surface would not make for a very pleasant visit by an unprotected human.\n\nThe atmospheric pressure at 'sea' level on Venus is about 95 times that of Earth's atmosphere, which would be an equivalent pressure to being half a mile deep in the ocean.  The open pockets and cavities in our bodies would be completely crushed, and we would be unable to breathe.\n\nThat's assuming we'd want to breath.  Most of Venus' atmosphere is carbon dioxide, which is not exactly conducive to human respiration.  What isn't carbon dioxide is rather high in a number of sulfur compounds, including hydrogen sulfide (the stuff in sour gas wells that kills people very very dead very very quickly), and sulfuric acid (which is also not fun to breath, or even have on your skin).\n\nAssuming we had some kind of super-duper hard shell pressurized, armoured, acid-proof space suit with suitable oxygen supplies, we'd still have problems.\n\nThe average temperature on Venus is about 480 degrees Celcius (somewhere in the realm of 900 F), which is hot enough to melt lead, and the rivers of molten sulfur probably wouldn't be too hospitable either.\n\nThe only thing the planet might have going for it would be mineral resources, but we can probably get those just easily from the moon or even the asteroids.  That atmosphere is just too darned hostile.
66190
Mercury = 15,329.1 km\nVenus = 38025 km\nEarth (equator) = 40,076 km\n\nFor the rest visit the following site.\nhttp://solarsystem.nasa.gov/planets/profile.cfm?Object=Mercury&Display=Facts
526135
It's about 1/6 earth gravity. (But don't forget to add in 1/6 of the spacesuit you have to wear, too.)