Semidiurnal Simon
  • Member for 7 years, 9 months
  • Last seen more than a week ago
  • UK
Global warming - why doesn´t mankind collect heat (thermal energy) and turn it into electricity or send it to space?
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29 votes

Collecting thermal energy is really hard. As others have said, things like heat pumps exist for moving heat around, but the laws of thermodynamics (which are fairly fundemantal in physics) require ...

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Why do Tsunamis travel slower than sound?
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22 votes

Tsunamis and sound waves are different types of wave - one is a transverse wave and the other is a longitudinal one. Let's look at the factors that influence the speed of each one. Tsunami - ...

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Is climate change a vicious circle?
21 votes

You've correctly identified a number of individual mechanisms which form "vicious circles". They're more formally known as "positive feedbacks". As you've noted, loss of albedo (reflectivity) from ...

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What are we seeing when we see the curvature of Earth?
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17 votes

the horizon is a circle centered at the viewer's position There are two things wrong with this. The first is the assumption that the Earth is entirely spherical - there are no hills, mountains or ...

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Do dams reduce the flow of river downstream?
14 votes

You're correct that simply putting a dam in place, once its lake is filled, doesn't change the average flow downstream by more than a few percent (those few percent can be lost to increased ...

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Effect on sea level if the Earth stopped rotating
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14 votes

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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How does anthropogenic heating affect global warming?
14 votes

Disclamer: I am not an atmospheric or climate scientist; corrections are welcome if I have anything wrong. Human heat production According to the IEA, world primary energy consumption in 2012 was ...

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Coriolis effect and Cyclones
12 votes

To correct your phrasing slightly: The Coriolis force acts to turn flows in the northern hemisphere to the right. This is not quite the same as "in a clockwise pattern", as will become evident in a ...

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Why would a Martian tsunami travel at only 200 km/hour, four times slower than on Earth?
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11 votes

The linked paper does numerical modelling of a hypothetical tsunami and predicts speeds between 60 m/s (at its point of origin) and 30 m/s (nearer to shore). We can try a back-of-an-envelope ...

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Are there any uncharted waters left on earth?
11 votes

A lot depends on the definition of "charted". How much detail must we know for an area to gain this status? As others have said, we have a low-resolution idea of all of the non-ice-covered seabed from ...

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Is there a standard definition of the term "mountain"?
11 votes

There does not appear to be an agreed international definition of a mountain. In the UK there is a colloquial definition that a mountain must be "a thousand feet high". This definition is ...

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What is the chasm in the Arctic on Google satellite map?
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10 votes

You probably realise this, but you're not seeing that directly from satellite photos. Google Earth (or the "satellite" view in Google Maps) shows direct imagery on land, but underwater it shows a ...

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How is sea level measured?
9 votes

There are two main approaches to measuring sea level (and thus its change): local and satellite-based. To measure local sea level we can set up gauges on the coast that record the water level every ...

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What is the weather data covering the range of 359 to 360 degree
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8 votes

Remember that 360° == 0°. They're the same line of longitude. So the gap between 359° and 0° is no more than the gap between 1° and 2°, and should be handled the same way.

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Why does computation cost increase 24 times when the spatial resolution doubles?
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8 votes

I can't answer why there's a 24x increase, according to the textbook - but it may well be the case for a specific model. In general, If you double the resolution of a 3D model in each dimension, you ...

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About an alternative type of wind energy facility
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8 votes

This has been tried to some extent; Strata in London was a skyscraper that was built with three wind turbines at the top, with a deliberate design to funnel wind into them. There are other examples. ...

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Equinoxes and solstices: start of the season or mid-season?
8 votes

This all depends on the context in which the word is used. From an astronomical perspective, the solstices are midsummer and midwinter, and the equinoxes are the middle of autumn and the middle of ...

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Is there value in using a model that fails at validation against measurements?
7 votes

A slightly different slant: As energynumbers has pointed out, all models are wrong in one way or another. A fully accurate model of reality would be as complex as reality, so some simplification is ...

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Wind profile below the aerodynamic roughness length
7 votes

$z_0$ is a theoretical construct that, while useful in its intended uses, cannot be thought of in too much detail as a physical reality. When using a log law to describe wind speed, it represents the ...

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Software for sediment transport modeling
7 votes

Large parts of Delft3D - including, I think, the sediment transport module - are available in an open source form. The GUI is not currently open source, but (a) Deltares have been offering licences ...

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Is it possible for a natural fluorescent mineral to glow from the sun's rays?
7 votes

I am not a minerals expert, and can't claim expertise on these particular materials. However, from a general physics / materials point of view I'm pretty sure the answer will be that, There is more ...

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How to reduce the atmospheric temperature artificially?
7 votes

I think a brief explanation of how the greenhouse effect1 works is in order here. The light coming from the sun has a broad spectrum, which has its peak roughly in the middle of the range that we see ...

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What is the difference between a high-resolution model and a regular model run?
7 votes

Just to add some more weight to one point of casey's excellent answer: There is no single definition of what "high resolution" means. Different fields, and hence different types of modelling, will ...

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What exactly is a published climatologist?
6 votes

Not answering the question asked, but the underlying motivation: The level of consensus hasn't been verified by a poll. The way the 97% figure has been arrived at, AIUI, is by going through every ...

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Why do wind speeds often jump from 20 knots to 40 knots
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6 votes

This is an (annoying) artefact of BBC weather forecasts, and not an actual feature of the weather. At low wind speeds, the speed shown is the expected average speed. At higher wind speeds, the speed ...

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How much energy would be required to actively reduce the temperature of the oceans of Earth by 1℃?
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6 votes

The question is slightly confused, because reducing the temperature of the oceans, in a direct sense, doesn't require energy - it releases it. The amount that is released is simply related to the mass ...

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How is sea level measured?
6 votes

(adding this as a separate answer as it's answering a different part of the question - one that wasn't there when I did my first answer...) To understand why a rise in sea level of as little as 10cm ...

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What does 5,000,000 tonnes of CO2 look like?
6 votes

The question is hard to give a definitive answer to, as it depends on the pressure at which the gas is kept in the tank. But to try to give an intuitive sense of how much gas this is, let's work out ...

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How does Antarctica stay frozen?
6 votes

userLTK has explained that not all of the ice in the Antarctic stays frozen all the time. But perhaps there's a more basic view needed : sunlight in temperate areas melts all of the ice quite quickly, ...

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How do I calculate Per capita $\ce{CO2}$ emissions?
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6 votes

You have the right idea, but you have your units and orders of magnitude confused. You have started with knowing that Canada has 34 million people, and emits 0.55Gt - i.e. $0.55 \times 10^9$ tonnes - ...

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