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General Science / Re: How would you explain or define calculus in a sentence or two?

« on: 29/12/2022 15:37:41 »

Calculus is something quite simple and yet it has an inexplicable and unreasonable effectiveness.  It can be taught to school children and they can use it to solve a very large set of problems.

In this case you could summarise calculus as the mathematics of things that change, but I doubt that the audience would be any the wiser.

The analysis of functions of variability.

Isaac Azimov's inspiration for his Foundation saga was primarily two things: the collapse of the Roman Empire (At least Edward Gibbon's take on it) and calculus. The protagonist on Foundation uses math to predict the future. Interesting.

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Physics, Astronomy & Cosmology / Re: What is the Triangulum Galaxy's "supper massive black hole"?

« on: 17/12/2022 15:46:15 »

1.    As @evan_au  pointed out in the reference,  there is thought to be at least one black hole,  just not necessarily a super-massive one at the centre.

2.   Gravity is complicated.  Even Newtonian gravity is complicated.   We can find good solutions for what is called the two-body problem,  which literally just involves two bodies and gravity acting between them.  We can even make a bit of progress with a three-body problem,  however you get to four-bodies and the whole thing is just a "pig"  ("pig" just means difficult).   Most of the "solutions" or information about multi-body problems are just obtained from simulations and numerical approximation techniques and not from any analytical or exact solutions to the problem.
      Having a super-massive black hole at the centre of a galaxy is one easy way to have a stable structure that is a galaxy.   In a numerical approximation, the whole thing does behave a lot like a two body problem for everything close to the black hole.   You have the body you are considering (planet or star etc.) and the only other body of any importance is the black hole because nothing else has the mass to compete with that and so you can just neglect it.
    We don't know for certain that the Triangulum Galaxy doesn't have a SMBH at it's centre but let's assume it doesn't.  Then it just is another possible solution (a distribution of the diffuse matter like Hydrogen gas and the more dense bodies like planets in the system) for the multi-body problem that produces a stable structure like a galaxy.   There are going to be quite a few solutions.

3.       When analysing structures like galaxies and the orbit of certain things,  one of the approximations that can be used is just to draw a circle (well a 3-D spherical surface) around the point which the body seems to orbit out to a radius that is the radius of its orbit  (well more or less if it's elliptical or odd shaped)  and assume that there is a roughly uniform distribution of mass outside of that sphere.   We have results like the shell theorem which suggest the only thing(s) providing a net gravitational pull on that body and hence influencing the orbit of that body is the mass inside of that sphere.    I haven't seen the data for the Triangulum galaxy but I'm fairly confident that these are the sorts of techniques that would have been used to suggest that there wasn't much mass  (e.g. a SMBH) on the interior of some of the orbiting objects you mentioned   ("...its core stars orbit slowly...").   However, the core of the galaxy is not the only thing holding the galaxy together.  As you look at objects further out, that circle (or 3-D spherical surface - but for a fairly flat galaxy it's just a flat circle that you'll be interested in) which is the boundary of their orbit is much bigger.  This means there is more mass on the interior of that circle and hence much more that can be binding them.

4.    I'm not sure exactly what you meant with the sentence about binding and attracting stars in some H2 dense regions.   If you meant attracting H2 gas so as to form a new star.... well  stellar formation is accelerated by all sorts of processes and conditions.  Hydrogen gas might be getting driven into where these stars are forming rather than merely being attracted by the mass of whatever seed for a star was already there.   Also Hydrogen gas isn't all that heavy or "massive" is the correct term .  You don't need a lot of mass in your seed for a new star to attract some hydrogen gas, especially if the gas is already close to it.  The rate of star production is likely to be much more of an indication of the density or availability of H2 gas in that region rather than any indication that there is a lot of mass in that region.

Best Wishes.

Thanks for the reply, you're clearly very smart (I'm not being facetious). However, I take issue with your overuse of the spacebar. The attached file illustrates what I'm talking about. It's guys like you that are causing chaos on our forums... Get your act together.

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Just Chat! / Not avocado spread

« on: 05/12/2022 14:27:02 »

"Mass-produced avocados are very, very harmful to the environment they are grown in. I am from Chile and avocado trees are literally leaving people without water to drink or use in their own farming zones. Petorca (the town that suffers the most from overly-produced avocados) is literally dried out by these super-thirsty vegetables. I'm glad Americans are becoming more and more aware of how damaging avocados are." - Youtuber (paraphrased)
How to substitute them: in a food processor mix chic peas, green peas, onion powder, sage, tarragon, rosemary, parsley, salt, cooking oil, nutritional yeast, and lemon juice or extract. You're welcome.

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Just Chat! / Why do so many people find the sound of thunder and lightening soothing?

« on: 21/08/2022 13:34:40 »

My late father has discs of them for some reason. George Washington was known to hate them, probably because it reminded him of cannon fire. Napoleon loved them, probably because it reminded him of cannon fire.

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Just Chat! / Re: How many people have studied history?

« on: 10/05/2022 18:48:46 »

masters (Hopefully soon to be PhD) in history, Syracuse University. Bam!

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Just Chat! / Re: What is your main area of interest or expertise?

« on: 09/04/2022 06:47:52 »

History, preservation.

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Just Chat! / Re: Is Nuclear War imminent?

« on: 05/03/2022 07:45:54 »

If we avoided it during the Cold War, we can avoid it here. Putin wants to show the world how big his dick is. This is a game of phalluses, and Putin is the most eager to prove how big his is and how powerful his orgasms are.
Also, Anonymous says Putin is gay. A clue is in his personal diary where he refers to the invasion of Ukraine as "An Extreme Makeover". I personally see nothing wrong or unmanly about homosexuality, but the vast majority of his country seems to.
Solution: we need to covertly snap a picture of Putin's penis, which experts surmise to be the opposite of gargantuan. We then threatened to show it to the world if he fails to stop this war.

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Physiology & Medicine / Why don't pills kill neck and back pain?

« on: 25/10/2021 14:02:44 »

Therapeutic stretches I find on youtube are the only answers for this. If my field was medicine, I would acknowledge that millions or billions of people are too lazy for such stretching and would try to find a way to solve this medicinal-wise and make billions of dollars.

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Just Chat! / Re: Why is there a growing movement to deny reality in America?

« on: 02/10/2021 00:19:28 »

I think Brits to this day still see Americans the same way they did in colonial times, and that that we are the "herd" and should be insulted at any opportunity.

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Just Chat! / Re: Why is this site called thenakedscientists?

« on: 01/10/2021 22:58:22 »

The domain "TheScientists" was taken and someone on the staff made the observation that they're always working in the nude, and... the name came.

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General Science / Can someone healthily raise a cat or dog with meatless food?

« on: 01/10/2021 20:32:57 »

This is a huge dilemma for vegetarians/vegans. All the nutrients and what-not can be artificially produced, but some still think it will slowly kill their pet somehow as if there is a magical component in meat that cannot be replicated.

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Just Chat! / Re: Quality of discussions

« on: 25/08/2021 17:32:51 »

With the exception of racist and rape jokes, I think anything should be fair game in the Just Chat! section of this forum.

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Geology, Palaeontology & Archaeology / Are there mountains/mountain ranges that existed, but no longer do?

« on: 10/06/2021 00:59:50 »

Are there mountains we know of that once flourished the surface of the Earth, but have since disappeared?

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Physiology & Medicine / Re: Is it possible for a psychoactive drug to take effect within seconds?

« on: 02/06/2021 17:33:45 »

There was a case in Canada where an unstable woman named Cindy James, who obsessively alleged that she was being watched and harassed, wound up dead with her legs and arms bound together and a high dose of heroin in her system. The Canadian police declared it an obvious murder case, as someone with that amount of dope in their system could not tie themselves in such a way. Eventually, it was a journalist (not a physician) that pointed out that even if the drug was administered intravenously, it should have taken 10-15 minutes to reach her CNS. He then hired a woman matching the dead woman's age and physical characteristics to see if she could tie herself up the same way within 10 minutes. She was able to.

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Just Chat! / Re: MyHeritiage's

« on: 29/04/2021 00:01:00 »

If that is "attention" it's no wonder the US hasn't won a war since 1945.

I bet ten dollars you have a small penis.

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Just Chat! / Anyone believe Oliver Cromwell's rebellion was justified?

« on: 18/03/2021 04:54:30 »

In any of your opinion, did Cromwell have a legitimate beef against the Stewart king?
I think any king or leader that runs primarily based on his own conscience and doesn't pay much attention to consul and their people, meet the definition of despotism. I also believe it's beyond evil to see yourself as God's chosen. Both Cromwell and Charles I saw themselves as such.

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General Science / Re: Would you tell the world if you knew an asteroid was coming to Earth?

« on: 16/03/2021 01:39:54 »

David asks:

If you became aware that a significant-sized asteroid was likely to collide with the Earth in the not-too-distant future (say months rather than years) would you tell your colleagues or tell government officials or tell the world? Or would you just sell the family home and have a great holiday (assuming post Covid-19 conditions)?

What would you do?

Yes, because it is actually possible to stop them.

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Just Chat! / Do most men believe their penis is most important?

« on: 09/03/2021 16:28:58 »

Is there any evidence that most men value their penis over any other part of their body?

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General Science / Re: The journey to the red planet: does humanity need Mars colonisation?

« on: 26/01/2021 03:56:25 »

I honestly believe we would have more motive to go to Mars if there were beautiful, single women there.

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Just Chat! / Re: If you're a virgin, this is why you should NEVER admit to it...

« on: 19/12/2020 01:52:31 »

My bad... I posted this in the chemistry section by mistake. Meant it for "Just Chat!".