Hot answers tagged

86

This strongly depends on definition of what smoothness is. The Discover Magazine blog addressed this in 2008 OK, first, how smooth is a billiard ball? According to the World Pool-Billiard Association, a pool ball is 2.25 inches in diameter, and has a tolerance of +/- 0.005 inches. In other words, it must have no pits or bumps more than 0.005 inches in ...


66

Has tuff found amongst the deposits at the Dinosaur National Monument? Yes. The most famous section of the rocks in Morrison Formation in Dinosaur National Monument, the Brushy Basin Member, is chock full of volcanic ash beds that have long since been converted to rock (1, 2, 3). It's also chock full of dinosaur fossils, which is what makes it so famous. ...


64

...but China only has 37% of the world's reserves Michael Karnerfors has provided evidence that China produces 95% of the world's rare earth elements. However, China does not hold that much of the world's reserves of such metals. The US Geological Survey mineral commodity summary for 2017 for rare earths gives China's 2016 rare earth's production at 105,...


56

I could not find any scientific evidence that the earth was once completely covered by water (not lava). However, Australian scientists have hypothesized that the land share on a planet 2.5 billion years ago was only 2-3%. If it is true, then the largest percentage of the Earth that was ocean is 98%. Also: According to the modern scientific views, the ocean ...


24

The title of this 2011 paper pretty much answers the question by itself: Global risk of big earthquakes has not recently increased. (For the record: Peter M. Shearer and Philip B. Stark, doi: 10.1073/pnas.1118525109 PNAS January 17, 2012 vol. 109 no. 3 717-721) They noted that there had been an increase in large earthquakes in 2004-2011, and some other ...


23

The story is slightly less dramatic than it sounds. The runways themselves are not being "shifted" (i.e. construction crews getting out and laying tarmac), but just renamed and signposted. From a Livescience report Runways are designated according to the points on a compass, and the drifting magnetic north means that they, periodically, need to be ...


22

There is induced seismicity in Oklahoma. There were 623 earthquakes above magnitude 3.0 in 2016. Some of these have been much stronger than 3.0, including a 5.8 magnitude earthquake in September 2016. The induced earthquakes appear to have begun around 2009, and the problem has grown since then: However, according to the US Geological Survey and other ...


21

I've long thought this graphic gives a good idea of the issue The problem at an airport is variation in local magnetic declination, not the variation in location of the magnetic north pole. Due to local magnetic anomalies, magnetic compasses rarely point at any magnetic north pole. As others have noted, Runway naming is mostly based on local magnetic north ...


20

The paper that sparked the news story states in its conclusion: Considering the historical documents attesting the occurrence in the “Old Jerusalem” of a disastrous earthquake in 33 A.D., the authors assume that a seismic event with magnitude ranging from the 8th to the 9th degree in the Richter scale could have produced a thermal neutron flux of up to ...


19

To restate your question, How can we statistically describe the intervals between mega-volcano eruptions? Do they follow a particular probability distribution with known parameters? Can we use this to make any conclusions at all about Yellowstone? We know of three eruptions 2.1 million years ago (mya), 1.2 mya, and 0.64 mya. This is an interval of 900,000 ...


18

I think vartec has the best answer so far. The quoted tolerance (specifications link) of 0.005 is for total size, not smoothness. The spec says 2.25+.005, not +/-, is that a typo or does it mean the balls must be at least 2.25 but not more than 2.255"? Most balls are actually manufactured to a higher tolerance, with good ones being under 0.001". The pic ...


16

TL;DR: "minted" was a misprint. It was supposed to be "mined" in the original claim. Original claim used incorrect "ever" weight of 16 tonnes ever mined, should be 9490 tonnes if we can trust the non-proven fact of "fits into 25ft^3 cube". Yearly production is ~150-200 tonnes (confirmed) Thus, 16 tons is ~600 times too small compared to real # But even if ...


15

No, continental rocks are not the same as ocean floor. Continents are mostly made up of minerals like granite, which are lighter than ocean floor minerals like basalt (sima, short for Silicon/Magnesium). Continental material is mostly sial (short for Silicon/Aluminium) which is lighter. Partially molten mantle material is pushed up at mid-ocean ridges, ...


15

According to Essentials of Oceanography (2012) at page 13 The physical expanse and distribution of the early ocean is a matter of some controversy. Most researchers hold that masses of rock have always protruded through the ocean surface to form continents. However, some recent studies suggest that water may have covered Earth's entire surface for some ...


13

China holds 95% of the world production of Rare-earth Elements When the letter says... The rare metals [...]. More than 85% of the world’s supply comes from China ...I believe the author means Rare-earth Elements/Rare-earth Metals. REMs are necessary elements in the production of electronics, computer chips of all kinds, computer/phone displays, solar ...


12

In addition to @hdhondt's answer (+1) The evidence for the existence of Pangea lies in the existence of matches between fossil records and rock formations in continents that are now thousands of miles apart, in addition to Wegener's observation that the (continental shelves) of the existing continents match quite closely like a jigsaw. If Pangea did not ...


12

I cannot confirm the numbers in the original image, although some of the recent numbers appear to be roughly consistent with USGS numbers. However, the general point seems to be correct: the number of earthquakes has been increasing per year. But, the pastor is not correct: the number of "great" earthquakes is not increasing (see the response by ...


12

No, lithium scarcity is not a barrier to the take-up of electric vehicles. From Bloomberg: The world’s largest untapped lithium reserve -- containing enough of the lightest metal to make batteries for more than 4.8 billion electric cars ... according to the U.S. Geological Survey.


11

There are several claims here. Let’s unravel them one by one. First claim Is there a deep, hot biosphere? Russell has answered this: yes, there is. Second claim Thomas Gold claims that oil is not aging vegetal or animal matter, but rather made continously from bacteria deep in the Earth's mantle (a 'deep hot biosphere') No, Thomas Gold made no such ...


11

No. But they definitely can reside inside the cracks and crevices of stones. Is it possible that a lizard (or in some cases, a beetle) lives inside a rock for thousands of years when that stone got formed? No. The longest living vertebrate is the Galapagos Tortoise which only lives for 100-200 years. And the oldest living insect is the Queen of ...


11

Short Answer NO, none of the data nor the "analysis" can predict effectively the earthquakes, because that impossible with our current detection capabilities and understanding of the earthquakes. Long Answer First, what is a "Scientific earthquake predictions"? Scientific earthquake predictions should state where, when, how big, and how probable the ...


11

The claimed air density is about 520 times higher than air denisty now. This means that, according to the ideal gas law, you need 520 times the air pressure - roughly 520 bar. Now the critical point of nitrogen (main consituent of air) is about 33bar, the critical point of oxygen about 50 bar. Both critical temperatures are far below 0°C. So at this density,...


10

Esker has no evidence to support the idea of the Earths atmosphere being more dense in the Jurrasic than it is now, other than the assertion that dinosaurs are too large to have existed otherwise. However this assertion has little support, as evolutionary adaptions (such as the unidirectional breathing discussed in the previous question) are able to explain ...


10

Yes, some of them clearly were, for example whale fossils have been found in the Sahara at the Wadi al-Hitan. However, while some deserts were once oceans/seas, that doesn't mean all deserts were once oceans.


10

Based on an CNBC piece with similar claims, the Guardian letter seems to be talking about cobalt: For example, China controls 80 percent of the market in chemical cobalt, a crucial ingredient in lithium-ion batteries, [Benchmark Mineral Intelligence analyst Caspar Rawles] he said. Oddly enough a techcruch piece is somewhat contradictory Approximately ...


9

By the very definition offered in the article: Geo means Earth and Patho means suffering. It means suffering from the earth which causes stress in the form of illness. The Earth has no nervous system and is not scientifically known to suffer, although we can certainly imagine it doing so. That's a feature of human psychology, which is what this boils ...


9

Nuclear fusion is the mechanism by which most atom nucleii have been formed from the original plasma present after the Big Bang. It requires incredibly hot temperatures not found in outer space. Since the Big Bang, nucleii have been formed in stars and then ejected in outer space at the end of the life of those stars. See for instance: Nasa's Cosmicopia ...


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