# Tag Info

1

$CO_2$: Without greenhouse gases, Earth would be about 30 degrees colder. Everyone sensible agrees that $CO_2$ contributes to this, but also that it only directly causes part of the warming. Water vapor is the other important greenhouse gas. There are feedback relationships between temperature, $CO_2$ levels, and water vapor levels, e.g. if the world gets ...

0

Your roof won't rise in this case. Your roof will simply crush. If tornado wants to lift your roof, its outer air would exert an equal downward force on ground. If its of exact diameter that force would be exerted on your walls that support roof and crush down your roof.

3

The gravitation of the stars in our galaxy keep the solar system in it. I'm not sure whether that's important for earth or for life on earth though, but it makes for nicer night skies. Gamma ray bursts, if close enough and (im)properly oriented, affect earth. A gamma ray event from a "soft gamma repeater", SGR 1900+14, is known to have affected earth's ...

1

The distant stars are also responsible for cosmic rays, which in turn can affect the Earth's weather

1

Machs principle, that inertia is caused by the distribution of distant stars was a principle that Einstein tried to incorporate into GR, but failed. However Barbour, quite recently incorporated an aspect of Machs principle into his theorising of time: ephemeris time An ephemeris gives the position of celestial bodies, and duration is deduced in terms of ...

6

The stars in our galactic neighbourhood do have a dynamical, gravitational effect on the inner workings of the solar system: They built the Oort cloud The Oort cloud is a roughly spherical cloud of icy bodies that is thought to act as a reservoir of long-period comets (and which we speculate exists to explain said comets' existence). These icy bodies ...

5

The other answers talk about some of the effects. This is a complementary answer that attempts to put a number to the force behind one of the effects - gravitational attraction. Proxima Centuri is the closest star to our solar system. It is about 4 × 1016 m away and has a mass of 2.45 × 1029 kg. The mass of Earth is about 5.97 × 1024 kg. Plugging these ...

3

Gravitationally, there is little immediate effect on earth on a daily basis, though over very long periods of time, stars that pass near enough to the sun could disrupt the orbits of Oort cloud objects and send them towards the sun (and earth or other planets in our Solar System). Culturally, stars have a very big impact on our species. Religion, art, ...

22

A lot (to put it mildly) of elements are created in stars and supernovae. These elements then travel through space until they fall to Earth (or, to be exact, some microscopic portion of them reach us). Earth itself wouldn't exist if stars hadn't generated elements which then clumped into dust, into minerals, and so on until a big ball of matter started to ...

6

I don't think that light from the stars other than Sun is of much practical use nowadays except for the classic navigation, where it's essential of course. I guess any effect comes from the limitless reach of the gravitational force, which drops with the square of the distance but grows linearly with the mass exerting the force. A star most obviously ...

0

Weather models have significant positive feedback loops built in because without them the return to average is too fast for accurate prediction. This is due to the grossly inadequate spatial density of weather collection stations, and results in weather models being subject to the butterfly effect. However, the actual circumstances in which significant ...

2

Air density decreases as height increases. It is typically much lower than $1,225$kg.m$^{-3}$ at a height of a few tenths of km.

2

Could a butterfly flapping its wings cause a hurricane? Yes. However, only if the required conditions (which are very precise) existed elsewhere. There would be a critical state of the atmosphere after which a hurricane will form, and a small injection of energy from a butterfly flapping its wings could cause this threshold to be crossed. Is it likely that ...

30

This question already has an answer (by me) on Earth Science: The butterfly is a colourful illustration of Chaos Theory, and the word butterfly came from the diagram of the state space (see below). (Apparently, my claim on the origin of the word butterfly may be historically inaccurate. Could be of interest for HSM SE) A system that is chaotic is ...

4

Suppose I go outside, flap my hands in the air and then go about my business as usual. A few months later I see on the news that some town in the US has been devastated by a tornado. Is the counterfactual statement that says that had I not flapped my hands, the town would not have been hit by the tornado, a rigorously correct statement? Let's assume for ...

164

Does the flap of a butterfly's wing in Brazil set off a tornado in Texas? This was the whimsical question Edward Lorenz posed in his 1972 address to the 139th meeting of the American Association for the Advancement of Science. Some mistakenly think the answer to that question is "yes." (Otherwise, why would he have posed the question?) In doing so, they ...

13

The butterfly effect is a popularization of chaos theory. This diagram is part of the narrative of chaos theory for the hoi polloi. A plot of Lorenz attractor for values r = 28, σ = 10, b = 8/3 It does look like a butterfly after all :; ( tongue in cheek) . Let us set up the chaos backround first, from the Wiki article: Chaos theory is the ...

0

Yes - but only as far as one is willing to believe the mathematical model fits reality. In the mathematics we can demonstrate the butterfly effect; the sensitivity of particular nonlinear dynamic system models to initial conditions. And we can contrive certain experiments of systems that seem to behave in the context of a butterfly effect. But even for ...

4

The effect is real in the sense that the movement of the butterfly may have a huge effect on the weather in a far away place. There is however no way to control this. Don't imagine some mad scientist holding the world for ransom with a cage full of butterflies. It is better to think of it as an illustration of the theory of chaos. The idea is that chaotic ...

3

First the statement is a poetical way to express how in chaotic systems, small changes can trigger drastically different results. This statement does not attempt to relate butterfly movement to large scale weather changes. I would say we have elements to say it is not, for example, waves are a chaotic behaviour of the sea surface, but we have never found ...

4

Obviously the effect needs time to propagate (probably the speed of sound), but the effect is quite real. Imagine a incalculably large pool table where half of table has balls, if you shot the cue ball so it clipped one of the balls on the half with balls, the effect could propagate to the end of the table, but if you missed that half nothing would happen. ...

2

An egg has to reach an inner temperature of 100C to cook and in water the egg shell is kept at 100C for five minutes in a heat bath. Thus your question is answered by "can the egg shell be heated to 100C by the much hotter thin gas in the thermosphere" In vacuum the egg will radiate away and go close to 0 kelvin, so in the thermosphere it will be a fight ...

1

EDIT : The egg I am considering doesn't have a shell Temperature is a measure of the average kinetic energy of particles in a gas. In the thermosphere, the highly energetic solar radiation collide with the (having very less pressure) air, and are thus given very high velocities and so have a high temperature. However, the temperature shouldn't play a big ...

0

the Earth curves at the rate of 157mrad per km travelled. The refractive index of dry air at sea level is 1.00029, but at a height of 1km, the air pressure is 12% less and (neglecting temperature density and humidity), the refractive index would be 1 + 0.00029 * 88%. The difference, 0.000035 means that light at 1km altitude travels 35mm further for every km, ...

0

Any gas behaves as an ideal gas under high temperature an low pressure. Atmospheric oxygen is at 25deg celcius which is greater than it's critical temperature which is -150 deg celcius. And the pressure is somewhere around 159 mm of Hg. Hence atmospheric gases is said to behave like that of an ideal gas.

1

A rule of thumb exists if coriollis force is the dominant force balancing the pressure gradient. This is known as the geostrophic balance : $$\overrightarrow{V_g} = {\hat{k} \over f} \times \nabla_p \Phi$$ However if only a pressure gradient is being maintained by some source then the velocity will keep increasing as the pressure gradient results in ...

0

From a quite different perspective - consider that air is comprised mainly of nitrogen and oxygen. If you liquefy the air and separate the two gases each into separate, clear dewers the nitrogen will appear clear (transparent), but the oxygen will appear a light blue color.

2

is Randall wrong? No, Randal is simplifying. His point is that the colour we perceive from various objects and materials is produced by a tremendous variety of physical phenomenon. Generally the lay public are not interested in the deeper causes. He gives the example of the green appearance of the statue of liberty. People who ask why it is green ...

2

I have no direct experience with meteorology, but if you want the "rule of thumb", study the Euler equations. Specifically: $$\nabla p = - \rho\frac{\mathrm{D}\vec{v}}{\mathrm{D}t}$$ where D denotes the material derivative. That's the root of all other derivations.

2

Air is blue. White light is incident on it, and the scattered light that reaches your eye is blue. A leaf is green. White light is incident on it, and the scattered light that reaches your eye is green. Smoke is gray. Chlorine gas is yellow-green (I think. I really don't know what color chlorine is.) Air is blue, but only very faintly so. So faint ...

0

Sunlight reaches Earth's atmosphere and is scattered in all directions by all the gases and particles in the air. Blue light is scattered in all directions by the tiny molecules of air in Earth's atmosphere. Blue is scattered more than other colors because it travels as shorter, smaller waves. This is why we see a blue sky most of the time. Closer to the ...

3

A cooled surface is your best bet. Pressure-related phenomena are also a valid choice (basically, anything that changes the properties of the air-vapour mixture into conditions above saturation is fine), or combination of both. A cooled surface must have high thermal conductivity to drain the excess latent heat that is emitted during condensation (metal is ...

0

Conservation of energy works pretty well. Assume that instead of a squirting fountain and a paddle wheel, you had a cylinder and a piston to allow the compressed water to do work. The work done would be $\int PdV$. At the end of the expansion the water in the lower container is at atmospheric pressure. Now we can either repressurize by opening the red ...

0

You will not be able to produce any useful energy with this system. The previous answers have picked up on a number of the issues... Water is nearly incompressible, so the gain in pressure that you are counting on is too small to do any significant work. Don't forget that the work required to fill a 1km tall pipe with water is part of the system. The ...

0

In order to send it back to the container you have to do work against gravity. The energy obtained by rotating wheels would be from the kinetic energy of the fluid which came into existence because of the work we did. The energy from wheel would equal the work we did to pour the fluid back in. So energy gain would be 0. Moreover the efficiency of the wheel ...

2

There are two possibilities: water (or whatever fluid you're using) is compressible or it's incompressible. If it is incompressible, when the red valve is closed the tank pressure drops to zero, and opening the yellow valve produces no effect on the generator. If it is compressible, its pressure remains constant when the red valve is closed, and it ...

3

Some energy would come from the part where "the water would be collected and sent back into the container", which you somewhat glossed over.

1

A sound wave moving through a gas requires a small scale bulk movement of gas molecules back and forth as pressure at any locations builds or falls. Therefore, the sound wave can not possibly move through the gas at a speed greater than that of the individual molecules themselves, and in fact must move at a lower speed than that due to the random nature of ...

1

From a non-technical viewpoint, I would say that the simplest way I understand this is the following one. Yes, it has to do with pressure. Actually, it might be easier to think that it has to do with density. Consider the dominoes effect. If the dominoes are more apart from each other, that is, if the density of dominoes is lower, it will take longer for a ...

3

it has to do with the temperature lapse with altitude. since the speeed of sound is related to temperature by: $a = \sqrt{\gamma RT}$, where $\gamma$ and R are gas properties and T is temperature and the temperature profile follows (generally) like the left of these three plots: The area of interest for airliners is in the lowermost region where the ...

Top 50 recent answers are included