Recent comments in /f/askscience

Necessary-Lack-4600 t1_jd43ocp wrote

Reply to comment by [deleted] in Has the HIV virus become less deadly? by shaun3000

I grew up at around the same time and you seem to have forgotten that the press - not government education, the press - loved to write about the relation between AIDS and sex, especially among gay man. Whether that's a good or bad thing is another story, but the press loving sex stories is as ancient as hot water.

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BurnOutBrighter6 t1_jd4293b wrote

Reply to Why aren’t distant galaxies warped across the sky?? by bol-nooney22

You're right, and its shape IS distorted. The effect is just so tiny it's not noticeable. It helps to put some numbers on it:

  • Our galaxy is ~87,000 light years across. So to an observer, the light from far edge would be 87,000 years older
  • But it takes our galaxy 250,000,000 years to complete 1 rotation!! So you're right, there IS a distortion - the light from the back edge appears to be shifted by 0.0003 of a rotation.

The amount it has moved through the universe is just negligible compared to how fast light is compared to stuff.

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LoyalSol t1_jd417r3 wrote

Reply to comment by Chemomechanics in Can a single atom be determined to be in any particular phase of matter? by Zalack

One bit of nitpick. Entropy is still very well defined even at the atomic level. A lot of excitation phenomena are dictated by entropy.

There's many different types of entropy, but they all are related to the same underlying concept.

It's one of the few bulk properties that actually has a near one to one correspondence to it's micro scale counterpart.

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nobody_in_here t1_jd408q9 wrote

Reply to Can a single atom be determined to be in any particular phase of matter? by Zalack

Don't mean to hijack the post, OP has a great question, but their question made me want to ask something similar: salt, like let's say sodium chloride, from what I understand it dissociates into it's consituent ions when in water. Like it becomes free Na and Cl just floating around in water right? Would that mean if you saw free Na and free Cl ions swimming around, and they're not bonding, you could assume it's a liquid or no?

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dalnot t1_jd3rsxv wrote

Reply to Can a single atom be determined to be in any particular phase of matter? by Zalack

It’s not really any specific form of matter because of the reasons elsewhere in this thread, but a single atom is certainly most similar to gaseous state. This is because gases are the state where the atoms interact the least with each other. In outer space, it’s mostly individual atoms flying around, but we still call it a gas, just an incredibly dilute one

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Cheetahs_never_win t1_jd3oga1 wrote

Reply to Can a single atom be determined to be in any particular phase of matter? by Zalack

A singular atom traversing the vacuum of space, belting out Bobby Vinton? No. Liquids, gases, and solids are functions of temperature and pressure, which are defined by proximity to other atoms.

If you have one molecule of every (non-reactive) gas possible sharing space in a teeny tiny pressure vessel, it could still be deemed a gas mixture if it doesn't sublimate or condense. We just don't have the kinematic equations to describe how that mixture works in a specific sense, just that it still acts like a gas in a general sense.

CO2 is still a gas entrained in soda, even if the H2O molecules separate each CO2 molecule out by a thousand miles. We say this because if we agitate all million square miles, the CO2 comes out and floats off with the rest of the gases.

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