"The International Union of Pure and Applied Chemistry (IUPAC) defines an element to exist if its lifetime is longer than 10^−14 seconds (0.01 picoseconds, or 10 femtoseconds), which is the time it takes for the nucleus to form an electron cloud." — What does this mean? | AskScience Blog

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Sunday, October 13, 2019

"The International Union of Pure and Applied Chemistry (IUPAC) defines an element to exist if its lifetime is longer than 10^−14 seconds (0.01 picoseconds, or 10 femtoseconds), which is the time it takes for the nucleus to form an electron cloud." — What does this mean?

"The International Union of Pure and Applied Chemistry (IUPAC) defines an element to exist if its lifetime is longer than 10^−14 seconds (0.01 picoseconds, or 10 femtoseconds), which is the time it takes for the nucleus to form an electron cloud." — What does this mean?


"The International Union of Pure and Applied Chemistry (IUPAC) defines an element to exist if its lifetime is longer than 10^−14 seconds (0.01 picoseconds, or 10 femtoseconds), which is the time it takes for the nucleus to form an electron cloud." — What does this mean?

Posted: 12 Oct 2019 02:50 PM PDT

The quote is from the wikipedia page on the Extended Periodic Table — https://en.wikipedia.org/wiki/Extended_periodic_table

I'm unable to find more information online about what it means for an electron cloud to "form", and how that time period of 10 femtoseconds was derived/measured. Any clarification would be much appreciated!

submitted by /u/GoogieK
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Why do we lose control over our voices because of emotions? Why can some people control their voices better than others in that case?

Posted: 12 Oct 2019 11:18 AM PDT

Do cellulose based plastics pose any of the same hazards as petroleum based plastics?

Posted: 13 Oct 2019 06:31 AM PDT

If not, is the only reason for not switching to primarily cellulose plastic money?

submitted by /u/sanfermin1
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How do we know that our solar system is in the arm of a spiral galaxy, far from the galaxy's center or is this actually just well supported hypothesis?

Posted: 12 Oct 2019 06:48 PM PDT

Humanity has observed Supernovae. But have we also seen stars appear? I.e. them starting the fusion process?

Posted: 13 Oct 2019 01:02 AM PDT

In the absence of artificial light, will women menstrual cycle sync with the lunar cycle?

Posted: 12 Oct 2019 08:48 PM PDT

There is lots of myths and lore about the menstrual cycle being influenced by the moon that goes back thousands of years. It's interesting that the moon cycle and menstrual cycle are pretty close, so is there any truth to this idea? I saw one study of over 6 million women that showed that menstruation was random, however, the test subject were all in modern society with artificial lighting. Does anyone know of data that explores this idea in a culture without artificial lighting? Thanks!

submitted by /u/DefeatingAnxiety
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What does the bacteriophage do once it injects it’s DNA into the host cell?

Posted: 12 Oct 2019 08:16 PM PDT

For example, the bacteriophage T4 inserts it's DNA into the E. coli and the virion stays outside of the cell. Are there DNA cells left within or does the cell just die? I'm thinking if it does die it's a small sacrifice since many more virions will replicate within the host and eventually burst.

Thank you!

submitted by /u/DeliriousD0LL
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Do animals demonstrate traumatic responses to "sexual violence"?

Posted: 12 Oct 2019 10:46 AM PDT

I've read that much reproduction in the animal world is what we would consider rape if they were humans. I was wondering if there are any studies that examine the response of females before an after forces reproduction / "rape". (I put the phrases "sexual violence" and "rape" in quotation marks because I don't want to act as if human sexual assault is "no worse than" as animal reproduction, it obviously is horrible.)

submitted by /u/moby__dick
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Is color "tempature" a learned concept or is it inherent?

Posted: 12 Oct 2019 06:02 PM PDT

Did we decide that certain colors were "warm" and others were "cool" or did we associate color warmth with things that were actually warm, like fire? Similarly if we had a blue star instead of a yellow one, would we consider blue a "warm" color?

submitted by /u/deathworlds
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In wireless power transmission using electromagnetic radiation, how is the optimal frequency determined?

Posted: 12 Oct 2019 09:24 PM PDT

Since the 1960's there's been talk about sending energy from solar satellites to earth through the use of masers. Generally, I've seen that this was done at a frequency of about 2.45GHz, or 5.8 Ghz. Is there a reason for choosing these frequencies?

I've had a quick look at the atmospheric absorption of electromagnetic radiation at different frequencies, and it seems that below about 14GHz, there's very little absorption. So, would there be any benefit in using a higher frequency signal? Thanks

submitted by /u/TheFallen018
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What is 'the island of stability' in the Table of Elements, and why is it thought to exist?

Posted: 12 Oct 2019 04:21 PM PDT

All the elements that have been added to the Table of Elements fairly recently are pretty instable. However, I've heard quite a lot of people stating that there is to be expected to be 'an island of stability' when you go further down Element lane; meaning that there will exist a group of new elements that are a LOT more stable than their neighbourhood.

Now, three questions.

1) Why is it thought to be this way?

2) How did we come to this conclusion?

3) How can we get to this 'island' and what might be some applications of those new elements?

4) If it doesn't exist, how do we know that?

submitted by /u/PivotPsycho
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What is the reason for dial up internet to make the weird screechs and dings when it first connects to the internet?

Posted: 12 Oct 2019 11:00 AM PDT

How many species of ornithischian dinosaurs are there? There is about 700 dinosaurs discovered, but how many are ornithischians?

Posted: 12 Oct 2019 11:47 AM PDT

Is it possible to chromatophore cells to create green pigment? Where is the cell located? And what are their structures?

Posted: 12 Oct 2019 01:44 PM PDT

Thx in advance. Before anyone says anything, it is NOT homework, it is just a curiosity that I wanted to talk to my class.

submitted by /u/Its_a_me_Malio
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Can someone explain the "Ultraviolet Catastrophe" that led to the creation of Planck's Constant and the birth of Quantum Physics?

Posted: 12 Oct 2019 02:17 PM PDT

I understand that contemporary theories of the time about how black bodies would radiate energy led to certain bodies radiating infinite amounts of energy, but what was it about those old theories that led to such a result? Every reference I have come across just brushes over this and focuses more on our understanding now. Please help me understand why we were so wrong back at the turn of of the 20th century and what we were thinking before we realized that we were wrong.

I believe it is helpful to everyone to know exactly how we were wrong, before any individual can then set forth with confidence on a new path of learning what is right. Thank you.

submitted by /u/charliezbh
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How do torches behave under high pressure?

Posted: 12 Oct 2019 01:17 PM PDT

I'm researching a manufacturing process that requires aerodynamic levitation. (ie the trick with the hovering beachball) This will occur within the jet of a torch flame. The work piece I'm pursuing is too heavy for this to work at standard temperature and pressure at a gas velocity that won't cause the torch to blow out. (So I'm told)

If ambient pressure is increased, can the maximum mass of the work piece go up? The jet will be more dense which lets the torch work at lower velocity but higher volume, which might allow it function.

Assuming ambient pressure of 500ATM and comparable pressure differential to the fuel tank...how would a torch behave? I'm expecting a hotter burning flame which is desirable...but after that, I'm not sure of the hang ups. What would happen?

submitted by /u/kdharbert
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Sun exposure health effects on dogs and cats. Similar to human?

Posted: 12 Oct 2019 02:16 PM PDT

What are the health effects of sun exposure on dogs and / or cats ? Are they similar to human effects - where a moderate exposure produces some small levels of vitamin D and is believed to reduce high blood pressure, heart disease and strokes (etc.) ? Or are dogs and cats immune to those effects due to their fur ?

submitted by /u/uniagi
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Do babies inherit disease immunity from their parents, or does each baby need to develop their own immunities individually?

Posted: 12 Oct 2019 09:35 AM PDT

I was thinking about how if we were able to snatch a newborn baby out of say, 300 BCE and raised it in the modern era, it would probably not know the difference i.e. fully adapt to modern culture and technology. Then I had the thought of diseases and whatnot, and if the time travelling baby would be more vulnerable to modern diseases than a baby that was born today, or if both babies would have equal challenge avoiding modern diseases.

I hope that all makes sense (to some degree anyways).

submitted by /u/Theolaa
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Can the decay half-life of a substance be affected by temperature?

Posted: 12 Oct 2019 07:58 AM PDT

I had the idea when reading in a thread about carbon dating frozen mummies, and was curious if those dates were accurate and if they could have actually been older due to slower decay. After reading a bit on what affects random radioactive decay I concluded: not likely. I doubt the temperatures able to be reached on earth could change the decay at all. After this I was asking myself if a body were put into space and it's mummified remains were discovered some thousands of years later could they effectively use carbon dating? Or would the near absolute zero temperature slow down the random decay of C-14.

After reading more on carbon dating and seeing that it is formed by bombarding cosmic rays, I got to wondering if being unshielded in space would result in more C-14 isotopes forming in the mummy? So could this mummy actually appear younger than it is due to excess C-14 formation as well as external temperature affecting the decay of its native C-14?

submitted by /u/OrionJohnson
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Medically, how does mindful breathing/box breathing reduce anxiety?

Posted: 12 Oct 2019 09:18 AM PDT

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