Recent comments in /f/askscience

itsybitsybiter t1_ja0q026 wrote

Reply to Water on Earth is not Constant. Why ? by ItsDivyamGupta

"Water" is not elemental. It's made from two hydrogens and an oxygen (H2O).

The H and O elemental atoms are conserved no matter what the earth's biochemistry does. But they can be separated from each other easily, and different Hs and Os can come together from other sources and processes to make "new" water.

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MissChievous8 t1_ja0nwgl wrote

Reply to Would two people who look identical but who are not related have similar matching DNA? by OhMyThiccThighs

I remember reading an article about 6 months ago regarding finding evidence of people who look the same share similar genetics despite not being related at all. Doppelgangers. They're apparently more likely to share lifestyle traits as well. Ive heard everyone has approximately 6 doppelgangers out there somewhere. Anyone met one of your own?

https://www.smithsonianmag.com/smart-news/doppelgangers-dont-just-look-alike-they-also-share-dna-180980635/#:~:text=Doppelg%C3%A4ngers%20share%20strikingly%20similar%20physical,%2C%20at%20least%2C%20siblings).

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0oSlytho0 t1_ja0nozm wrote

Reply to comment by goose966 in How do scientists know where the mutation in a gene originated and how long ago the mutation occured? by goose966

The way they track these mutations in time is by creating a huge family tree and puzzling the way back up. If a group of people is known to have split up e.g. 5000 years ago and none of them have that mutation, it likely occured less than 5000 years ago in the main population. It's not perfect but with enough samples and meta info we can create accurate philogenetic trees.

It also helps a lot that we have found a couple mummified people with intact DNA from different places and points in time.

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Ech_01 t1_ja0n7c0 wrote

Reply to Does the length of the fingers serve a purpose or could two fingers be the same length? by Hairy_Lengthiness_41

Fingers could be the same length. Women tend to have same sized ring and index fingers, meanwhile the ring finger tends to be longer than the index finger in male population (especially men exposed to higher concentrations of testosterone during fetal period.

Some studies suggest that larger fingers may give you an advantage in some sports, but it’s not fully understood whether fingersize really matters evolution wise.

Don’t hesitate to correct me if I am wrong.

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kilotesla t1_ja0lrto wrote

Reply to comment by Movpasd in Would the magnitude of the electric field at a point away from the center of a sphere depend on the radius of the sphere? by cozymikey

This is a good answer. Like the other answers, it assumes that the sphere of metal is far away from other charged or polarizable objects. If the two spheres being discussed were close to each other, the charge would no longer be uniformly distributed on either of them and the analysis isn't as simple.

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kilotesla t1_ja0lh1v wrote

Reply to What determines the size of an Eddy Current? by Gopher_Lad

Yes, smaller loops of current do form. The current in a given loop is proportional to the rate of change of magnetic flux through it, and is inversely proportional to the resistance around the loop. With the slits as shown, the flux through each is much smaller than the total flux, and the resistance around the loop starts going up once the copper is divided into strips: The path length is roughly constant at double the length of a strip, and the conduction area gets smaller as it gets divided more. So the current per loop goes down as the square of the number of slits, and the effect become negligible.

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Dorocche t1_ja0kz6b wrote

Reply to comment by Chiperoni in Would two people who look identical but who are not related have similar matching DNA? by OhMyThiccThighs

This has happened, too

I remember reading about a man who was wrongfully convicted of a crime because the actual perpetrator was identical and had the same name. He was exonerated by DNA evidence years later.

I can't find that now though, so take it with a grain of salt; here's a similar fluff piece about baseball players instead:

https://nypost.com/2023/01/11/identical-strangers-with-the-same-name-and-job-took-dna-test/

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robot_egg t1_ja0ks2o wrote

Reply to comment by NoKnee4545 in What makes ice 'sticky'? by insane_contin

I'm not sure how to think about pressure at that ice-glass interface. Not saying "no", but I'm *guessing* not. I'm an organic chemist; maybe a physical chemist or a physicist could chime in.

Surface *energy* effects at interfaces are very important for adhesion. You can calculate a work of adhesion by summing up the relative surface energies of all the solid/solid and solid/gas interfaces. Both glass and metals tend to have rather high surface energy, making them easy to stick to.

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