29 votes

Is a complete global flood physically possible on Earth?

Just to add some further discussion to @Pont and @fre0n excellent answers. The problem of the water needed to submerge the world during the Genesis flood have been discussed for centuries. The ...
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  • 5,896
23 votes

What would be the first thing which will render the Earth uninhabitable?

I'll try to put time scales on each of these events. The Sun as a red giant - 5 to 6 billion years$^1$ The Sun is currently on the main sequence, which means that it's a "full grown" star - think of ...
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23 votes
Accepted

Is a complete global flood physically possible on Earth?

there is not enough existing water inside this geosystem IMO for such a thing to occur. Let's see these figures here: One estimate of global water distribution Oceans, Seas, & Bays 1,338,000,000 ...
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  • 2,623
21 votes

Is a complete global flood physically possible on Earth?

The "precipitation rate" part is easy to answer, at least to a first approximation. We have 40 days and nights (960 hours) in which to raise sea level above the peak of Mount Everest (let's round up ...
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  • 5,380
18 votes
Accepted

What woud happen to me if I touched the aurora?

The lowest reaches of an aurora is ~100 km in the air. Your problem won't be the ionized gas, it'll be that the air pressure is close to zero. Also, aurora are very diffuse, with at most a few ...
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  • 296
14 votes

Can a cosmic impact break Earth's crust in large area exposing the magma ocean?

Let me first correct a small misconception. Where you are talking about 'the magma ocean', you are implying that one exists. This is in fact false. There is no 'magma ocean' in the Earth at the moment ...
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  • 22.2k
14 votes
Accepted

Effect on sea level if the Earth stopped rotating

Let's assume that the earth didn't suddenly stop spinning (because intertia and conservation of angular momentum would do all sorts of "interesting" things that are deserving of a What-If answer), and ...
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12 votes

Would life on Earth survive without the Sun?

The answer is No, the Earth would not remain in any recognizable form without the Sun. There would still be a husk of a dead planet with a small amount of energy coming from the residual heat of ...
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10 votes

What woud happen to me if I touched the aurora?

Even the extremely dim light of the aurora is accumulated from massive volumes of air. This means that a small volume of air emits almost no light by itself. If you were in the middle of a filament ...
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10 votes
Accepted

Hypothetically, what would happen to the earth if a large hole was drilled through the center?

The best place to ask this question is going to be at xkcd: http://what-if.xkcd.com/ but I will give it a shot. I'm not a geophysicist, but I'll try to give you a reasonable enough answer. As you ...
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  • 22.2k
9 votes

What sort of climate zones would be present if Earth was tilted like Uranus?

A paper on this topic just appeared: Multiple Climate States of Habitable Exoplanets: The Role of Obliquity and Irradiance. In case of 90° obliquity, summer and winter would appear together with day ...
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  • 91
9 votes

Effect on sea level if the Earth stopped rotating

This is covered in an episode of the National Geographic TV series Aftermath called "When The Earth Stops Spinning". It's also covered by "If the Earth Stood Still: Modeling the absence of ...
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  • 191
8 votes

Would life on Earth survive without the Sun?

The Earth is as it currently is and has been since most of the Phanerozoic (542 Ma), the Eon of life, because of some important (not exhaustive) characteristics presented here, being: its inclination ...
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  • 2,623
8 votes

What would be the first thing which will render the Earth uninhabitable?

You've missed a number of calamities: Everything dies because all plant life dies from ever decreasing levels of CO2 in the atmosphere. This is projected to happen within less than a billion years. ...
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  • 20.4k
8 votes
Accepted

What would happen if we could revert $\mathrm{CO}_2$ production but took it too far?

The average global warming due to greenhouse gases corresponds to a 33 Kelvin temperature increase. If you remove all greenhouse gases the average global temperature would then decrease 33 Kelvin (...
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  • 12.7k
7 votes

What sort of climate zones would be present if Earth was tilted like Uranus?

Too much tilt will cause extreme seasons, and that will lead to an extreme climate. For a planet with a tilt of 90˚ - that is, lying on its side - the Arctic and Antarctic circles coincide with the ...
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6 votes

What would be the first thing which will render the Earth uninhabitable?

According to a recent Scientific American article, in about a half-billion years the Sun will have expanded enough and the Earth's orbit decayed enough that Earth will no longer be in the "habitable ...
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  • 160
5 votes

Is a complete global flood physically possible on Earth?

1.Given the amount of water on Earth (including all the water as liquid, solid, and gas, in all possible places: the atmosphere, the surface, and underground), is there enough water to flood the whole ...
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  • 5,912
4 votes

Would life on Earth survive without the Sun?

Popular science has a good write up on this. In short, everything on the surface is doomed in a year or two. Life in the Oceans would last several hundred thousand years. After that, it's probably ...
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4 votes
Accepted

How much reduction of insolation (solar energy) would be required to stop global warming?

It's not that hard to make an estimate. CO2 traps about 2 watts per square meter. Direct sunlight at 1 Astronomical Unit is about 1,360 watts per square meter, but spread out over the earth, ...
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  • 5,727
4 votes

What would happen if we removed Earth's moon?

This has sat untouched for a while, so I did a quick search and found this article which sums it up nicely. They key factors with regard to earth science would be: 1) Less extreme tides. The tides ...
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4 votes
Accepted

What would the equilibrium temperature be at the poles in a world without seasonality?

If we consider that by "Assume daily cycle and convection and so on operate as usual" you meant that all heat transport from/to the pole remain as it is today. Then, we can do a back of the envelope ...
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  • 17.1k
4 votes

What woud happen to me if I touched the aurora?

As others have pointed out, you cannot really touch it as such. What you can do, potentially, is to fly through it on a sub-orbital flight. It might be beautiful; indeed, aurora is from a large ...
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  • 11.1k
4 votes

What would happen if Earth suddenly stopped rotating and revolving at the same time?

Two very different processes! First, if the Earth suddenly stopped rotating then the angular momentum would result in everyone and everything on the Earth's surface being flung sideways at a rate ...
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4 votes

What will be the temperature on Earth when Sun finishes its main sequence?

Answers will be different because they must be tied to a model of solar evolution, and all models are a bit different. So to answer your question we have to select a model. A pretty standard and ...
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  • 17.1k
3 votes

How big is the influence of tree leaves on global windsystems?

Wind is largely driven by differences in atmospheric pressure. The effect of trees and forests is to force the winds to flow over the forests. The loss of leaves in forests would result in winds ...
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  • 21.8k
3 votes

How would weather change on a tidally-locked terrestrial planet?

My best estimate on what would happen is the following: - At the twilight zone there would be tremendously fierce and constant windstorms as the heavier cold air rushed from the dark side to ...
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3 votes
Accepted

What happens if it rains above the boiling point of water?

Pressure and temperature are not all the same when going up vertically. See average temperature and pressure profiles. The evaporation of any liquid has a pressure-dependent equilibrium point, see ...
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