39 votes
Accepted

Why were both the sun and the moon red today?

Smoke. There was significant smoke across the USA, which attenuated the light from the sun/moon due to increased scattering. The smoke particles effectively cause the light to reflect in different ...
f.thorpe's user avatar
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22 votes
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Can living where (rare) earth magnetic ore is abundant provide any protection from cosmic radiation?

Absolutely not. First of all, "rare earth magnet ore", meaning the ores of metals like neodymium (Nd) and samarium (Sm), is not magnetic at all. It only becomes a magnet once you make a ...
Gimelist's user avatar
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11 votes

Can living where (rare) earth magnetic ore is abundant provide any protection from cosmic radiation?

No. Cosmic radiation are high-energy particles that create particle showers high up in the terrestrial atmosphere. Those particle shower are heavily beamed downwards, and although in principle some ...
AtmosphericPrisonEscape's user avatar
10 votes
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How come the tide is low when the moon is high in the sky

This is based on the overly-simplified model of tides being the result of tidal bulges. As I explained in my answer to a related question on the physics.SE sister site, those tidal bulges do not and ...
David Hammen's user avatar
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8 votes

Which Earth minerals would Moon colonists miss the most?

The composition of Moon rocks is pretty much the same as that of Earth. However, none of the processes that concentrate specific minerals in one location (i.e. into a mineral deposit useful for mining)...
Camilo Rada's user avatar
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7 votes
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Can the moon shadow angle change?

Yes. The moon is lit by the sun, so as its position relative to the sun changes, so does the angle from which it is lit. I recommend reading the Wikipedia page on lunar phase for a good overview, ...
Matt Hall's user avatar
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6 votes

Which Earth minerals would Moon colonists miss the most?

It is unlikely anything other than salt would be derived from sea water. The largest deposit of gold is dissolved within the worlds oceans - in terms of tonnes of metal. The problem with extracting ...
Fred's user avatar
  • 24.7k
6 votes

How is it possible that only the bottom half of the moon was showing?

It depends on the season and even more on latitude. At any given time, the same side of the Moon faces the Sun. Where you stand on Earth doesn't change which part of the Moon is lit, but if you ...
userLTK's user avatar
  • 5,857
6 votes

What has been the influence of the moon on Earth's temperature?

The complications of calculating the moon's contributions to earth's heat budget are touched on in Emergence of a Habitable Planet (2007) by Zahnle, et.al. in Space Science Reviews, a paper trying to ...
jeffronicus's user avatar
  • 3,492
6 votes

How to make a Python function return the Moon's gravitational force (acceleration) to calculate orbits?

From my understanding, it should be possible to follow a similar procedure as what is done for calculating the gradient of gravity potential for the Earth (ignoring the potential corrections due to ...
Rafa's user avatar
  • 233
6 votes

Why is the Lunar crust anorthite?

A base-level justification is that calcium is much more abundant than sodium or potassium - about 10 times in bulk earth, and double in the crust. Since the moon is thought to have formed as a result ...
desander's user avatar
  • 415
5 votes
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What is the difference between lunar and earth soil

The single biggest difference is the lack of chemical weathering in lunar soils which are subject to physical weathering almost exclusively. If you exclude biological processes, terrestrial rocks ...
Knob Scratcher's user avatar
5 votes

Why are there craters on the moon?

I'd like to expand on jamesqf's answer. But first, lit side of the moon and the dark There are no "lit" and "dark" sides of the moon. It rotates, and whatever is dark now will be lit in two weeks ...
Gimelist's user avatar
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5 votes
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What would be the effect of a geostationary moon?

First off, the geostationary Moon would have to be 115 times less massive as the actual one to match the gravitational pull. With that, one effect would be that the tidal pull would be stronger, but ...
Oscar Lanzi's user avatar
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4 votes

Can the moon shadow angle change?

The apparent angle of the moon is a function of the 28-day lunar orbit, the time of day/night one is looking at the moon, and the latitude from which it is viewed. So, for example, the current (14 May ...
Gordon Stanger's user avatar
4 votes

Why are there craters on the moon?

There are craters on the Earth, Arizona's Meteor Crater being perhaps the best-known example. The reason that there aren't a lot more (obvious) ones is that the Earth has lots of dynamic processes, ...
jamesqf's user avatar
  • 1,758
4 votes
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What is the characteristic time of the loss of the Earth atmosphere, how can it be calculated?

Even in the exosphere, at 1800 deg centigrade, the only components of the Earth's atmosphere that can currently attain escape velocity are hydrogen (3 kg per sec), and and helium (next to nothing). ...
Gordon Stanger's user avatar
4 votes
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What is the difference between a depleted mantle, and a fertile or enriched mantle?

Basically, a fertile mantle is a portion of mantle that has not experienced any melting. On the other hand, a depleted mantle has experienced partial melting, and subsequent extraction of this melt. ...
Jean-Marie Prival's user avatar
4 votes

Does the Moon affect earthquakes?

Actually, yes, but indirectly Well, the tidal forces produced by the Moon's gravity are not enough to distort the Earth's crust enough to produce any significant displacements of the crust, and ...
Alastor's user avatar
  • 261
4 votes
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Why was quartz not a major product of the Lunar Magma Ocean?

Fractional crystallization indeed makes magmas more silicic. However, you'll never reach a magma composition with 100 % silica, which could then cool and crystallize as quartz. The starting material (...
Jean-Marie Prival's user avatar
4 votes
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Relay structures in Rupes Recta

From Nahm & Schultz (2013): Detailed structural mapping of Rupes Recta has revealed the presence of four distinct fault segments (Fig. 6). Analysis of throw distributions can clarify which ...
Jean-Marie Prival's user avatar
3 votes

Melting basalt on the lunar surface - what would the resulting material be like?

Melting lunar dust of basaltic composition will result (unsurprisingly) in basalt lava. There might be some volatile loss - if for some reason the basalt had some H2O or CO2 trapped in the solid you ...
Gimelist's user avatar
  • 23.1k
3 votes
Accepted

How much energy released by the Theia-Gaia impact?

Here's a quick-and-dirty estimate. The gravitational self-energy of a uniform-density sphere is $$ U = \frac35 \frac{GM^2}R $$ Let's assume Theia had the same mass and density as Mars, and that Gaia ...
rob's user avatar
  • 451
3 votes
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Which Earth minerals would Moon colonists miss the most?

Feels like a space-ex question and I think a fair bit is likely to be missed in my post, but it's a fun question, so: The biggest problem with the Moon is no atmosphere. Other problems are no ...
userLTK's user avatar
  • 5,857
3 votes

Which Earth minerals would Moon colonists miss the most?

Which Earth minerals would Moon colonists miss the most? tl;dr All of them. As mentioned in the other answers here, it's about economics. Extracting an element from a mineral requires energy, ...
Gimelist's user avatar
  • 23.1k
3 votes

How much energy does the Moon transfer to the Earth, does this affect the Earth's surface temperature?

According to a slightly old estimate, the total power input from the tides is approx 3.7 TW [1]. Of this about 3.2 TW is from the moon (the rest is from the sun). Most of it goes into moving the ...
Semidiurnal Simon's user avatar
2 votes

Can living where (rare) earth magnetic ore is abundant provide any protection from cosmic radiation?

Magnetite is a type of iron ore and does not significantly affect the Earth's magnetic field. It would not protect you from cosmic radiation. However, cosmic radiation is more intense high in the ...
Michael Walsby's user avatar
2 votes

Is moonlight a significant condition for making life possible on earth?

One significant biological event that requires a specific "type" of moonlight is the reproduction of corals in Great Barrier Reef, in Australia. 'One week each year in spring, after a full moon, ...
Fred's user avatar
  • 24.7k
2 votes

Which Earth minerals would Moon colonists miss the most?

biologically produced ones like coal and other petrochemicals. Marble, limestone, Diatomaceous earth, and other such minerals are candidates as well. Manganese oxides may be a good candidate the ...
John's user avatar
  • 6,891

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