Xelloss

Three times larger in what way? If you are talking about the diameter, then I don't think a planet that large would be even solid. At the very least, you would still have to contend with the pressure of the hypothetical atmosphere (it will most certainly be larger than on a smaller planet; and quite possibly there would probably be a planet-wide ocean of some sort), which would probably crush any genetically modified lungs. Our bodies are optimized specifically for Earth gravity. On a planet with less gravity, your muscles would probably have long term problems with atrophy, and your immune system would be weaker. I think it would be a wiser idea to find planets with similar gravity, or even ones with slightly higher gravity than our own.

I don't think it would be necessary to make the calculations that complicated; if we can figure out how much of the methane was emitted from their manure then we have a good enough estimate. The only problem is, is that we don't really know how much manure a typical brontosaurus would have produced. Now if we can find a creature with its manure fossilized, it would make the task a lot easier. Though it is unlikely that such a thing would be fossilized after millions of years... Alternatively, the above calculations could be done if the stomach was somehow fossilized; then we would know how much the things actually ate (or even what they could have possibly eaten).

Are you sure? As far as I know, cloud and surface albedo is indeed counted as a radiative forcing. The key point is that greenhouse gas emissions have a much larger positive radiative forcing. You can see the graph below for more details: SOURCE: IPCC To make a long story short, there is much more energy being poured into Earth's climate system than is being reflected out. Therefore the planet is warming. The source of the excess carbon dioxide and other greenhouse gases is caused primarily by fossil fuel combustion. This effect is very well known. Also keep in mind that a warmer atmosphere holds more water; thereby making the surface drier (i.e. there is on average less cloud formation and rain). Though there will be more water vapor in the atmosphere, that doesn't necessarily mean that there will be more clouds in the future. First, water vapor is not the main leg of anthropogenic global warming. Second, water vapor doesn't really stay in the atmosphere for a long enough time to contribute greatly to temperature rise. That's why it is seen only as something that has an amplifying effect; it will make the effect of CO2 even bigger than it would be. Where are you getting these figures from??? If you are cite figures, at least post a graph or a table.

There are several areas where stars are formed that are not located anywhere near the galactic center. For example, the Eagle Nebula (approx. 6500 light years; this nebula is where the "Pillars of Creation" are located) and the Orion Nebula. Star formation also takes place in the spiral arms in general, which can extend all the way out to the edge of the galaxy. Probably not. There is no indication that the sun's orbit is spiraling outward by anywhere near the magnitude necessary for this to be possible. More likely, the sun formed in a nebula or in one of the arms (i.e. the Orion arm).