Recent comments in /f/askscience

CrustalTrudger t1_je5th5x wrote

Sand is just a particular grain size for a material, but for a rock having been broken into sand sized particles reflects that it has experienced a combination of weathering and erosion. No rocks (at the surface) are immune from weathering or erosion, but some minerals that make up rocks are less stable at surface conditions and so will not persist as sediment (sand sized or otherwise) for too long, though when thinking about geologic time, a short time can still be hundreds of thousands to millions of years. Minerals that easily dissolve in water or weak acids (e.g., halite, calcite, etc) or generally tend to react easily at surface conditions and form other minerals (e.g., olivines, pyroxenes, etc) are all components of rock that you wouldn't expect to make up large components of your average sand. But there are definitely exceptions, e.g., sand formed from the weathering of basalts can be predominantly olivine and pyroxene. It's more that all told, these are not particularly stable minerals at the surface so these don't make up much of sand on a global scale.

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That_Biology_Guy t1_je5rnu0 wrote

During development yes, but not as adults. All flying insects have determinate growth, meaning that they go through a specific number of stages before reaching a final adult stage, at which point they no longer grow. This is in contrast to some other arthropods (e.g. spiders, lobsters, and some non-flying insects like silverfish), which can continuously molt and never really stop growing. In all flying insects, only the final adult form is capable of flight (with the exception of mayflies, where the last pre-adult stage can also fly), so any time you see a flying insect, it's already in the ultimate stage of its life and won't grow any more.

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Weed_O_Whirler t1_je5nsop wrote

The Sun will not supernova, but it will red giant. The reason being as the sun "uses up" it's hydrogen (in reality, it will only fuse about 10% of the hydrogen before transitioning), it will transition to new fusion chains which don't last nearly as long, but create energy significantly faster.

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wolfcede t1_je5n855 wrote

There’s been lots of talk about micro plastics being of measurable quantity in the human body. Do we have a more precise instrument recently for observing these micro plastics or was this known before and just not widely discussed? Is it a new blood test? What’s the instrumentation needed to observe this phenomenon and how accurate is it? Is it possible that plastic is being stored in parts of the body other than blood that we still can’t observe accurately?

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Weed_O_Whirler t1_je5m1in wrote

> can the crossing point exceed the speed of light?

Sure.

> does this mean you can essentially send information faster then the speed of light?

No. While there's no limit to how fast that "point" can move (since that "point" isn't a physical thing, just a concept), there's still a lag between you moving your levers, and the point of crossing moving.

A similar example, that is perhaps easier to understand- if you shine a really bright laser pointer at the moon, and then flick your wrist, you can make the "dot" of the laser pointer move across the surface of the moon as quickly as you want. That dot could move way faster than 'c'. But it doesn't break anything- because there's still the lag you'd expect from the time you pushed the button on the laser pointer, until the dot hit the moon to begin with.

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PoetryandScience t1_je5ifjo wrote

Indulgent and excessive eating or drinking of anything is injurious to health.

Unbalance nutrition is injurious to health.

Total starvation or avoidance of critical foods is injurious to health.

Avoid fads and fashions, keep active, keep trim (not thin) and you will live happily.

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