Amusing Science

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Anaxagoras
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Re: Amusing Science

Post by Anaxagoras » Thu Sep 26, 2019 10:49 am

This is a pretty cool discovery if you have a few minutes to read about it.

RECORD BREAKER: ASTRONOMERS FIND THE MOST MASSIVE NEUTRON STAR KNOWN. PROBABLY THE MOST MASSIVE ONE EVER

The neutron star is in a binary pair with a white dwarf and the plane of their orbits is edge on to us, so that the neutron star is occluded or occulted by the white dwarf each orbit. The orbital period is only 4-odd days. They say that its mass is almost at the theoretical upper limit of how massive a neutron star can be. Add a little bit more and it turns into a black hole.
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Re: Amusing Science

Post by Rob Lister » Thu Sep 26, 2019 11:34 am

So the Pulsar has a radius of ~15km with an angular velocity of ~500 rpm. That works out to a velocity of ~50,000,000 m/s. More than a tenth C. check my math.

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Re: Amusing Science

Post by Anaxagoras » Thu Sep 26, 2019 12:10 pm

If the body has a diameter of 30 kilometers, the circumference would be about 100 kilometers. It rotates 346 times per second. So if you paint a dot on the equator it would travel about 34,600 kilometers per second I think.
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Re: Amusing Science

Post by Abdul Alhazred » Thu Sep 26, 2019 3:44 pm

Anaxagoras wrote:
Thu Sep 26, 2019 10:49 am
This is a pretty cool discovery if you have a few minutes to read about it.

RECORD BREAKER: ASTRONOMERS FIND THE MOST MASSIVE NEUTRON STAR KNOWN. PROBABLY THE MOST MASSIVE ONE EVER

The neutron star is in a binary pair with a white dwarf and the plane of their orbits is edge on to us, so that the neutron star is occluded or occulted by the white dwarf each orbit. The orbital period is only 4-odd days. They say that its mass is almost at the theoretical upper limit of how massive a neutron star can be. Add a little bit more and it turns into a black hole.
So if (hypothetically of course) I were to spit on it, WHAM cosmic cataclysm just like that as it collapses into a black hole? 8)
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Re: Amusing Science

Post by Anaxagoras » Thu Sep 26, 2019 10:32 pm

Abdul Alhazred wrote:
Thu Sep 26, 2019 3:44 pm
Anaxagoras wrote:
Thu Sep 26, 2019 10:49 am
This is a pretty cool discovery if you have a few minutes to read about it.

RECORD BREAKER: ASTRONOMERS FIND THE MOST MASSIVE NEUTRON STAR KNOWN. PROBABLY THE MOST MASSIVE ONE EVER

The neutron star is in a binary pair with a white dwarf and the plane of their orbits is edge on to us, so that the neutron star is occluded or occulted by the white dwarf each orbit. The orbital period is only 4-odd days. They say that its mass is almost at the theoretical upper limit of how massive a neutron star can be. Add a little bit more and it turns into a black hole.
So if (hypothetically of course) I were to spit on it, WHAM cosmic cataclysm just like that as it collapses into a black hole? 8)
Hmm, it would probably take more mass than that. Maybe several Jupiters worth of mass actually. There's a margin of error to these calculations. I think the estimate is 2.14 solar masses and the theoretical upper limit is about 2.16 or 2.17. So 0.01 is actually 10 Jupiters worth of mass, because Jupiter is only 1/1000th the mass of the sun.

So yeah, everything is relative and "close to" on the cosmic scale like this doesn't really mean "close" on our puny human scale of reference. Our planet is like a mote of dust compared to some of the massive objects out there in the universe. Even mighty Jupiter is rather small compared to the sun, which is also not particularly large as far as suns go.
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Re: Amusing Science

Post by ed » Thu Sep 26, 2019 10:35 pm

Anaxagoras wrote:
Thu Sep 26, 2019 12:10 pm
If the body has a diameter of 30 kilometers, the circumference would be about 100 kilometers. It rotates 346 times per second. So if you paint a dot on the equator it would travel about 34,600 kilometers per second I think.
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Re: Amusing Science

Post by Witness » Fri Sep 27, 2019 12:14 am

To me neutron stars are even weirder than black holes (which are just geometry, in a way). Outside of an atomic nucleus a neutron is unstable and will decay to proton + electron + anti-neutrino (with an enormous, for a particle, half-life of slightly under 15 minutes).
And there gravity is strong enough to push the electron back "into" the proton.

NASA's take on them:
Internal structure of a neutron star

A neutron star is the imploded core of a massive star produced by a supernova explosion. A typical mass of a neutron star is 1.4 times the mass of the sun, with a radius of about 5 miles, and the density of a neutron.

The diagram below shows a slice of a neutron star. The rigid outer crust and superfluid inner core may be responsible for "pulsar glitches" where the crust cracks or slips on the superfluid neutrons to create "starquakes."

Notice the density and radius scales at left and right, respectively. The radius of a neutron star is slightly larger than Mt. Everest. But, according to astronomer and author Frank Shu, "A sugarcube of neutron-star stuff on Earth would weigh as much as all of humanity! This illustrates again how much of humanity is empty space."

Neutron stars can be observed as pulsars if they have strong magnetic fields.

Image
https://heasarc.gsfc.nasa.gov/docs/obje ... cture.html

It's of course g/cm3, not g/cm-3. (ed will convert to stones/yard3.)

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Re: Amusing Science

Post by Anaxagoras » Fri Sep 27, 2019 11:04 am



This one's mostly tongue in cheek but has some interesting facts about Mercury (the planet, that is).
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Re: Amusing Science

Post by robinson » Fri Sep 27, 2019 4:05 pm

wow
You never know what's going to happen, then some shit happens nobody saw coming, then later somebody says they knew it was coming, then some new shit happens nobody saw coming, rinse and repeat

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Re: Amusing Science

Post by Witness » Sat Sep 28, 2019 12:49 am

He uses a Fresnel lens to concentrate the sunlight. Named after Augustin-Jean Fresnel, typical romantic dude:

Image


Big ones made of glass are used in lighthouses:

Image


The principle is interesting: get rid of the unnecessary bulk by moving the curved surface nearer to the other one – without changing the angle, so you have to make circular cuts.

Image

The small ones you can buy at stationery shops are made of molded plastic, we've all seen them.

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Re: Amusing Science

Post by Bruce » Sun Sep 29, 2019 11:34 pm

Witness wrote:
Fri Sep 27, 2019 12:14 am
To me neutron stars are even weirder than black holes (which are just geometry, in a way).
I find it funny that you say that.

Neuron stars are things that can exist according to physics, but shouldn't because they are right on the edge of what is theoretically impossible.

Black holes on the other hand are theoretically impossible, unless you throw in the "event horizon" concept. That's the most fucked up thing that has come to be accepted the scientific community. This is a sphere of measurable volume, and calculatable mass, but everything inside of it is......impossible......or "unknowable", as the popular phrasing now goes. The laws of physics break down, infinite mass in zero volume, etc. Steven Hawking didn't invent this concept, but he accepted it and better defined everything mathematically everything that happens near black holes and on the surface of the event horizon. He did it so well that the majority of the scientific community stopped laughing about black holes and astronomers actually started looking for signs of them.

And now we have proof that impossible things exist. Makes you wonder how many other impossible things exist.
Such potential!

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Re: Amusing Science

Post by Abdul Alhazred » Sun Sep 29, 2019 11:42 pm

Bruce wrote:
Sun Sep 29, 2019 11:34 pm
... This is a sphere of measurable volume, and calculable mass ...
Calculable circumference and measurable mass.

But the diameter (and therefore the volume) is infinite. Or at least the space curvature asymptotically approaches infinity. There is no "bottom".

:coolspecs: :P :coolspecs: :P :coolspecs: :P :coolspecs: :P :coolspecs: :P :coolspecs: :P :coolspecs: :P :coolspecs: :P :coolspecs:
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Re: Amusing Science

Post by Witness » Mon Sep 30, 2019 12:07 am

Bruce wrote:
Sun Sep 29, 2019 11:34 pm
Black holes on the other hand are theoretically impossible
Why that?

As a historical note, a newtonian version has been predicted as early as 1783: Dark Star.

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Re: Amusing Science

Post by Bruce » Mon Sep 30, 2019 12:24 am

Witness wrote:
Mon Sep 30, 2019 12:07 am
Bruce wrote:
Sun Sep 29, 2019 11:34 pm
Black holes on the other hand are theoretically impossible
Why that?

As a historical note, a newtonian version has been predicted as early as 1783: Dark Star.
Never heard of dark star. Thanks for the link.
Such potential!

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Re: Amusing Science

Post by Witness » Mon Sep 30, 2019 12:27 am


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Re: Amusing Science

Post by Bruce » Mon Sep 30, 2019 12:29 am

Abdul Alhazred wrote:
Sun Sep 29, 2019 11:42 pm
Bruce wrote:
Sun Sep 29, 2019 11:34 pm
... This is a sphere of measurable volume, and calculable mass ...
Calculable circumference and measurable mass.

But the diameter (and therefore the volume) is infinite. Or at least the space curvature asymptotically approaches infinity. There is no "bottom".

:coolspecs: :P :coolspecs: :P :coolspecs: :P :coolspecs: :P :coolspecs: :P :coolspecs: :P :coolspecs: :P :coolspecs: :P :coolspecs:
That's an awesome point about the diameter. I never thought about that before. Starting to blow my mind the more I think about it. :shock:
Such potential!

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Re: Amusing Science

Post by Anaxagoras » Mon Sep 30, 2019 9:40 am

Bruce wrote:
Sun Sep 29, 2019 11:34 pm
Witness wrote:
Fri Sep 27, 2019 12:14 am
To me neutron stars are even weirder than black holes (which are just geometry, in a way).
I find it funny that you say that.

Neuron stars are things that can exist according to physics, but shouldn't because they are right on the edge of what is theoretically impossible.

Black holes on the other hand are theoretically impossible, unless you throw in the "event horizon" concept. That's the most fucked up thing that has come to be accepted the scientific community. This is a sphere of measurable volume, and calculatable mass, but everything inside of it is......impossible......or "unknowable", as the popular phrasing now goes. The laws of physics break down, infinite mass in zero volume, etc. Steven Hawking didn't invent this concept, but he accepted it and better defined everything mathematically everything that happens near black holes and on the surface of the event horizon. He did it so well that the majority of the scientific community stopped laughing about black holes and astronomers actually started looking for signs of them.

And now we have proof that impossible things exist. Makes you wonder how many other impossible things exist.
Black holes definitely don't have infinite mass, they have finite masses. I also think the laws of physics probably still hold even inside a black hole, it's just that there are some laws of physics that we just don't know about. We haven't discovered them yet, just as once upon a time we hadn't discovered General Relativity or Quantum Mechanics. Maybe we never will, but probably there's something.

They say that electron degeneracy pressure is what keeps white dwarfs from collapsing, and neutron degeneracy pressure is what keeps neutron stars from collapsing into black holes. Maybe there's something like that inside a black hole in the "singularity"? We can't be sure that the singularity is an infinitely small point, can we? Perhaps some as-yet unknown force comes into play inside a black hole.

We just have to accept that physicists are still working on the problem(s) and haven't figured everything out yet.
A fool thinks himself to be wise, but a wise man knows himself to be a fool.
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Re: Amusing Science

Post by Witness » Tue Oct 01, 2019 9:44 pm

The True Speed of Light© by gOD:


Time for an upgrade. :x

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Re: Amusing Science

Post by Witness » Wed Oct 02, 2019 9:58 pm

What Lives in Your Belly Button? Study Finds "Rain Forest" of Species

Thousands of bacteria found in navels. "It's quite beautiful," researcher says.

Rob Dunn and his team of ecologists aren't your average navel gazers. They're professional navel gazers, thank you very much, and their new study details the microbial contents of 60 volunteers' belly buttons.

The upshot? Belly buttons, it turns out, are a lot like rain forests.

[…]

Welcome to the Jungle

From 60 belly buttons, the team found 2,368 bacterial species, 1,458 of which may be new to science.

Some belly buttons harbored as few as 29 species and some as many as 107, although most had around 67. Ninety-two percent of the bacteria types showed up on fewer than 10 percent of subjects—in fact, most of the time, they appeared in only a single subject.

One science writer, for instance, apparently harbored a bacterium that had previously been found only in soil from Japan—where he has never been.

Another, more fragrant individual, who hadn't washed in several years, hosted two species of so-called extremophile bacteria that typically thrive in ice caps and thermal vents.

[…]

In the meantime, the lab has kicked off pilot studies for their next citizen-science spectacular: Armpit-pa-looza.
https://www.nationalgeographic.com/news ... alth-dunn/

Original source: https://journals.plos.org/plosone/artic ... ne.0047712

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Re: Amusing Science

Post by Bruce » Thu Oct 03, 2019 9:27 am

Hilarious and correct.

Image
Such potential!