24
votes
Accepted
What is the fastest the Earth has ever spun?
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 ...
- 17.6k
19
votes
Accepted
How bad is geo-engineering?
The bad part about geo-engineering are the unknown unknowns.
Our climate models are wrong. All models are wrong, but some are useful.. Our models are useful, but not quite useful enough to trust ...
- 11.6k
14
votes
Accepted
Plate Tectonics: Is it possible to have an ocean-continent divergent boundary
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 ...
- 5,936
11
votes
Are old geophysics textbooks useful?
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 ...
- 23.1k
11
votes
Accepted
Diamond at the core of Jupiter
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 ...
- 3,152
11
votes
Eclipse, Hurricanes, Earthquake....Related Events?
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 ...
- 24.6k
10
votes
Carbon dioxide on Mars, Venus and Earth
Firstly, Mars is farther away from the sun than Venus or Earth, so it gets less heat from the sun. Secondly, Venus & Earth are volcanically active, whereas Mars is volcanically inert. Thirdly, the ...
- 24.6k
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 ...
- 91
9
votes
Accepted
Is there any evidence for higher air pressures in the geological past?
Yes, there is.
But the data is still very sparse and errors are large.
Past atmospherics pressures have been estimated by at least three different methods:
Isotopic composition of fluid inclusions ...
- 17.6k
9
votes
Accepted
How far up do you have to go before most of the atmosphere is below you?
Roughly 5.5 km, although the exact value depends on the weather. All you need to do is to solve the hydrostatic equation and find the height at which the pressure is 50% of the height at sea level (...
- 11.6k
9
votes
How far up do you have to go before most of the atmosphere is below you?
It turns out that the answer is a bit simpler than you think.
Atmospheric pressure (neglecting small weather variations) is due to the weight of the column of air above a given point. If we divide ...
- 91
9
votes
Does the global temperature vary daily (hotter and colder days)?
The site http://www.karstenhaustein.com/climate.php comes closer to answering your main question with a daily anomaly graph:
Indeed it's still not the actual average temperature... and I too was ...
- 8,713
8
votes
How bad is geo-engineering?
Seconding eveything that @gerrit mentioned.
Additionally, another major problem with geo-engineering is that once we've started these processes and essentially borrowed time to offset mitigation ...
- 572
8
votes
What time and date is the sun directly overhead a given place on Earth?
Having the sun directly overhead can happen only between the Cancer and Capricorn tropics. That is, only the places between 23.5° of latitude north and 23.5° of latitude south.
On the Cancer tropic (...
- 17.6k
8
votes
Accepted
What "g" would be needed to keep helium on Earth?
Atmospheric escape is the loss of planetary atmospheric gases to outer space. You'd never be able to contain ALL of any gas forever by gravity. Ultimately you end up in the rarefied atmosphere where ...
- 511
8
votes
Which physical parameters can we actually measure to confirm the existence of the Greenhouse Effect (GHE)?
The physical parameters you need to measure to confirm the existence of the greenhouse effect are few and simple. Measure the electromagnetic properties of constituent molecules in the atmosphere. ...
- 14.1k
8
votes
Do scientists ever make rock vapor in a laboratory? If so, is it ever used to study planetary or lunar formation?
Not quite "rock vapour", but scientists do study gas-rock interactions. Some of that is used to understand processes forming in the moon.
For example, this paper looked at volatile metals (...
- 23.1k
8
votes
Is it possible for tsunamis to occur on deep water planets?
Tsunami are caused by sudden changes in the sea floor. An earthquake that causes a slump or surge in the seabed can cause a tsunami.
Tsunami travel as shallow water waves; they have a wavelength ...
- 797
7
votes
Accepted
Is there a time difference between two points at the same longitude but at different latitudes?
Earth's rotation has a fixed angular speed, therefore time is the same across the entire surface.
Even though the tangential speed (speed of the point in the surface) is different in each place of ...
- 596
7
votes
Are there any photographs of mountains without significant erosion (on Earth or otherwise)
Fresh shield volcanoes that are dome-shaped may be of interest to you.
Shield volcanoes on Venus - The Pancake Domes
Shield volcanoes on Earth - The Galapagos Islands
- 13.5k
7
votes
What would a planet's sky look like with different chemical compositions, such as low nitrogen, high methane etc?
Except for Rayleigh scattering (Is the color of the sky the same everywhere on earth?) gases typically do not add any color to atmospheres, they are usually transparent in visible light. The Halogen ...
- 1,207
7
votes
Accepted
How do tectonics work on other planets?
It's a huge field of research and a lot of interesting studies have been published over the years, but also a lot of speculation. Models and theories are mostly based on surface structures observed by ...
- 5,936
7
votes
Accepted
What are Ordovican trace fossils, and what do they look like?
Trace fossils are marks or things left behind by living things do their thing, they are indirect remains of organisms, coprolites (poop), footprints, egg shells, ect. If we found a fossilized beehive ...
- 6,878
7
votes
How would a world entirely covered in oceans get the nutrients to support life?
If the planet is geologically/volcanically active hydrothermal vents are a way by which nutrients, in the way of minerals and chemicals, can enter the ocean.
Certain types of bacteria can consume the ...
- 24.6k
6
votes
Mechanism for Pluto's young surface
Prior to the New Horizons flyby, a popular model for Pluto’s surface involved frost migration. Delsanti & Jewitt (2006) explain that at different points during the year, there should be seasonal ...
- 928
6
votes
How and why did the oceans form on Earth but not on other planets?
An important issue to realize is that water must have been very abundant in the protosolar disc, as tobias already stated.
To expand on that I just want briefly touch upon the atomic abundances that ...
- 3,152
6
votes
How does water still exist on the Earth?
Lava doesn't destroy water it evaporates it into steam. This steam rises high into the atmosphere, cools and condenses into rain which it falls back onto the Earth's surface where it gets hot again, ...
- 5,847
6
votes
How would a world entirely covered in oceans get the nutrients to support life?
On an ocean planet, nutrients can come either from space or from the bottom of the ocean, where they can leak from the crust trough different processes, perhaps with the help of submarine volcanoes or ...
- 17.6k
6
votes
Accepted
How do you stop the Australian wildfires?
As of 7 January 2020, the total area burnt by the fires in the whole of Australia is 8.4 million hectares (21 million acres; 84,000 square kilometres; 32,000 square miles. That is equivalent in area ...
- 24.6k
Only top scored, non community-wiki answers of a minimum length are eligible