# Tag Info

36

what evidence do we have that the asteroids indeed formed at the same time as earth? It depends on what is your definition as "the same time". The formation of the solar system and Earth did not happen at a particular second in time but was rather a continuous process. It also depends on what you define as "asteroids". I'll try to put some things in order. ...

28

That would have many consequences. For example the Coriolis force would change the sign. Thus wind around pressure systems would switch the direction from north and south hemisphere, but also the Ekman spiral in the ocean would be affected. Surface heating at sloped terrain will different, as the sun would rise in the West. This would change thermal induced ...

28

Your assumption that there is not a lot of water elsewhere in the solar system is incorrect. According the this article on NASA's website; Missions in recent years have overturned our view of a dry solar system, returning mounting evidence of ample water from a vast array of locations. Comets from the remote corners of our solar system are made of water ...

23

The water was already present when the Earth assembled itself out of the accretionary disk. Continued outgassing of volcanoes transferred the water into the atmosphere which was saturated with water. And rain transferred the water onto the surface. Compared to other planets and smaller solar system object Earth has a big advantage. It is large enough to ...

23

The speed of rotation of Earth is controlled by its angular momentum. And the conservation of angular momentum is a very serious law of physics (perhaps even stricter than conservation of mass). So in the same way that for the Earth to lose mass, that mass have to go somewhere. For the Earth to lose angular momentum, it'd have to go somewhere. Earth's ...

22

Depending on the assumptions you make, the Moon would suddenly have a retrograde orbit. If the moon had a retrograde orbit, it would have tremendous consequences. Retrograde orbits tend to become less distant over time, meaning the moon would either be much closer to the Earth with huge tidal effects or come more close in the future. At some point, the Moon ...

21

Well for one, this will surely be the speed of planetary rotation and the wind speeds your atmosphere can generate in North-South-direction. In my understanding those cells form as N-S winds flow and become deflected from this direction. So the number of cells will be determined by the winds that start either at the equator or the pole and the distance that ...

20

Is there geological (or other physical) evidence here on Earth that confirms the moon once collided with the Earth? No, there isn't. This is, however, plenty of evidence that the moon formed due to a collision of a third body (sometimes referred to as Theia) with the Earth, and the moon formed from the ring of debris that resulted from the collision. This ...

18

The short answer is "Probably Yes". The longer answer is that it is debatable whether Earth's rotation will become tidally locked to the moon due to tidal drag, at which point it will not be rotating relative to the moon, or whether the sun's exhaustion of hydrogen and the fusion of Helium will result in the sun's expansion vaporizing the earth first. As ...

17

Here's how astronomers of the late 19th century thought the Moon would appear: Recreations in Astronomy by H. D. Warren D. D., published in 1879, via http://en.wikipedia.org/wiki/Selenography. Here's what Apollo 15 astronauts saw: Apollo 15 Lunar Module Falcon at the Hadley-Apennine landing site. Hadley Delta in the background rises approximately 4,000 ...

17

Note: This response is bereft of references. I'll try to add them later. There is no definitive answer. There are a lot of conjectures, however. Whatever the cause, the Earth is markedly void of carbon compared to Venus. The amount of CO2 in Venus atmosphere corresponds to a 0.88 km thick layer of carbonate. The Earth's geosphere (lithosphere plus oceans ...

17

The bad part about geo-engineering are the unknown unknowns, to paraphrase a certain US politician. Our climate models are wrong. All models are wrong, but some are useful.. Our models are useful, but not quite useful enough to trust them when they tell us massively spraying stuff into the stratosphere or the oceans is mostly harmless. Our models can't ...

15

Earth's Spin Earth rotating clockwise is the result of a chain reaction that started when Earth's star formed as the result gas clouds collapsing. During the collapse of the gas, one direction was shorter and a disc formed. Due to the law of conservation of angular momentum, the disc gained an overall spin, which was passed to all the objects of notable ...

14

If you ascribe to the giant impact hypothesis, which most scientists do, whatever rotation the Earth had prior to the formation of the Moon was lost thanks to that 'giant impact'. That was a massive impact involving a Mars-sized body colliding with the proto-Earth. A "little" impact wouldn't change the Earth's rotation by much at all. Note very well: ...

14

The oceanic plates are themselves formed from the divergent boundary, so probably not. Even if a new rifting occurred exactly at the boundary, the result would eventually be that the ocean floor surrounds the divergent boundary. A very simplified model of an ocean would have a divergent boundary in the middle. This oceanic spreading center might have ...

13

Look at Earth's orbit around the Sun. The orbit is an ellipse, but Earth never gets close enough for the Sun to cause any mass extinction. The Earth orbits the Sun every year, and because the orbit is stable, on average we are about 8 light minutes from the Sun. One way the Earth's orbit might change is if the Sun has a sister companion, that is, a binary ...

12

Plate tectonics appears to require multiple factors all arraigned in feedback loops. The planet must be large enough that it's surface to volume ratios is low enough to trap enough heat from radioactive decay to power tectonic motion. Convection requires a minimal threshold of energy trapped in the material before that trapped energy causes mechanical ...

12

The formation of a T-Tauri star spells the beginning of the end of the protoplanetary disk from which planets and asteroids can form. The end is nigh when that star ignites. The large solar winds and solar radiation pressure sweep the disk clean of all small objects. Some spirals inward, some outward. There's no dust and no gas from which new planets and ...

12

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 the core which might be able to sustain chemosynthetic life in small colonies. However, this is a pretty minor amount of energy compared to what we usually ...

11

If I understood it correctly, the important point is the temperature difference between mars and earth. On earth increasing obliquity, as you wrote, leads to increased melting of ice, ie. you increase the amount of liquid water on earth. On mars average temperatures even during summer are too low to allow for liquid water. Higher obliquity doesn't really ...

11

The Moon is not "full" of helium-3. 3He is at most fifty parts per billion of the lunar regolith1 and that "high" concentration pertains only to permanently shadowed craters. The Moon is bombarded by a steady stream of helium-3 while sunlit. Some of this incoming helium-3 is temporarily embedded in the lunar regolith. Without this steady supply, the helium-3 ...

11

For all intents and purposes, the Earth represents one frame of reference, as @kwinkunks states. Therefore no effect. Yes the gravitational field on top of a mountain is slightly less than at sea level. This is very small though. Variations in gravity over the Earth's surface typically vary at most by a few hundred milligals (ie. "one part in 10,000" order ...

11

How do archaeologists address time dilation when analyzing carbon dating results? They don't. There is NO point in doing so. Compare two hypothetical substances at the peak of Chimborazo (the highest peak in the world with respect to distance from the center of the Earth). Suppose one of those substances spent all of the last 4.5 billion years at several ...

11

Most dust storms occur down-wind from areas with a lack of moisture, little vegetation, and high soil content. Vegetative roots help to keep the soil intact when there is a lack of moisture. So any shift in the future that leads to a net decrease in vegetation, net decrease in precipitation, or an increase in exposed soil content will increase dust storm ...

11

I would think this is questionable, though we don't have a definitive answer yet. We usually think Jupiter has a roughly solar composition, which according to the solar abundance measurments of Asplund et al. 2009 would mean the total carbon mass of Jupiter is about $10^{-3}$ of Jupiter's total mass. So there's roughly $0.3$ Earth masses of carbon floating ...

11

The occurrences of Hurricanes, Harvey, Irma, Katia and Jose, east of Mexico and a magnitude 8.1 earthquake southwest of Mexico within a few weeks of the American solar eclipse of August 21, 2017 are purely co-incidental. Hurricane Katrina, which devastated New Orleans in 2005 was not associated with any type of eclipse - solar or lunar. Likewise the ...

10

[I am going to preface this by saying that I am not in one camp or the other in this discussion, as I think there are pros and cons to each side] This links to the "Gaia Theory" proposed by James Lovelock, wherein the Earth is considered a self regulating organism. In this hypothesis, Earth is an organism in that it will try to maintain certain conditions....

10

One way to approach this is to treat the Earth as an oblate ellipsoid. This would mean the errors arise from the uncertainties in the Earth's equatorial radius and the flattening. From Groten, "Fundamental Parameters and Current (2004) Best Estimates of the Parameters of Common Relevance to Astronomy, Geodesy, and Geodynamics," Journal of Geodesy 77:10-11, ...

10

Mathematics and computer science are exact sciences. If something is discovered and known, it is not wrong. With time, there may be better or new ways of doing something, but the old stuff is still correct. This is why you can get a textbook from the 60s and study it. Cauchy's laws are still correct and Euler's theorem is still correct. This is not the case ...

Only top voted, non community-wiki answers of a minimum length are eligible