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A scientific fact/tidbit you recently learned that you thought was interesting

jadebox said:
Yes. Fat is lost mostly through carbon dioxide. So you breathe it out. That helps me understand one reason that losing weight is so difficult.
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Thunderfoot did a good vid about this a few years ago.
 
GlennB said:
Googling didn't help, so could you explain?

There's a lot more Ca and P in your body than K
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I've always heard this as CHON, carbon, hydrogen, oxygen, nitrogen. But I'm about as far from a biologist as anyone can be, so I'm not sure where potassium (K) fits in.
 
Wudang said:
Our eyes have 3 types of photoreceptors. Mantis shrimp have 12 including 1 infrared and 3 ultraviolet and see polarizes light. So they see many "colours" we can't conceptualise.
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No! Humans normally have four types of photoreceptors three colour receptors in cones, red, green, blue; and rods are non-colour specific (blue/green). Cones are predominantly around the centre of vision and provide detail, rods are dominant at the edge of vision and detect movement / changes in light and are low light sensitive, provide night vision. In particular light levels where all four photoreceptor contribute you may be able to see colours not normally visible.

Some women are tetra chromatic having an additional cone photoreceptor, this is related to the gene causing colour blindness in men. They can distinguish variations in colour not visible to normal humans.

Fun fact; humans retinas can detect near UV, the blue photoreceptors are sensitive to near UV, BUT the lens filters UV so no UV light gets to the retina to be seen. People who have had the lens removed can see into the UV spectrum.

https://www.bbc.com/future/article/20140905-the-women-with-super-human-vision

Second fun fact; humans can detect polarised light, it is thought the vikings may have used this ability to navigate.

https://www.ncbi.nlm.nih.gov/pmc/ar...s, humans are,carotenoids in the macula lutea.

How to see polarised light.

https://www.sciencedirect.com/science/article/pii/S0960982220318893
 
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The other thing with the shrimp is that the abundance of photoreceptors contrasts with basically no visual post-processing. We do a lot of post so when our red and blue receptors are both going off we perceive purple; apparantly the mantis shrimp does not do this and instead just has a dedicated receptor for each wavelength that is most important to it and that signal gets piped to its perception more or less directly.
 
This may be well-known to others, but I just learned that our sense of smell bypasses the thalamus:

Smell bypasses the thalamus, which Dalton calls the ‘consciousness detector.’

“(It goes) directly to the primary olfactory cortex, and that may be why we experience odors in a different way than we do other kinds of sensory stimuli,” Dalton said.

Because scent skips the thalamus, smells can enter our brains and attach to memories without us consciously registering or processing them. Research shows smell is the only sense that is active even while we sleep, or are in a coma.
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Source
 
ZirconBlue said:
This may be well-known to others, but I just learned that our sense of smell bypasses the thalamus:



Source
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"Research shows smell is the only sense that is active even while we sleep, or are in a coma."

How is it, then, that my alarm clock wakes me up?
 
GlennB said:
"Research shows smell is the only sense that is active even while we sleep, or are in a coma."

How is it, then, that my alarm clock wakes me up?
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The smell of bacon cooking in the morning wakes this mother ****** up more reliably than setting off an M-80 under my pillow.
 
GlennB said:
"Research shows smell is the only sense that is active even while we sleep, or are in a coma."

How is it, then, that my alarm clock wakes me up?
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I guess he meant that smell skips the reticular activation system which monitors senses and decides which ones to pass on while you are sleeping.

When I took psychology in college I was doing well on a test so when I came across the question "What does RAS stand for?" I answered with my name since those are my initials.

Whoever was grading the test had a sense of humor since my answer was marked as correct.
 
The Last of Us

There is a fungus, Ophiocordyceps unilateralis, that turns a species of ants or certain other insects into zombies (sort of). Hypoxanthine, sphingosine, and guanidinobutyric acid (which is similar in structure to gamma-aminobutyric acid) are among the compounds that may be part of how the fungus controls the ant's brain. I have never seen The Last of Us, but this is the fungus that inspired it.
 
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Some of you are going to say, I knew that.

I've known about the double slit experiment forever. What I didn't know, or didn't remember I'd heard until I was watching a science lecture tonight was that if you put a detector by the second slit to record if the photons are going through both slits then the interference pattern disappears.

I am fascinated and confused how observations can cause waveforms to collapse.
 
Surprised they were kept as pets. I know quite a few people that have been bitten by squirrels, they can be right vicious barstools when they are cornered. Would have thought the being bit by the wild ones would have been the more probable source of cross infection.
 
Darat said:
Surprised they were kept as pets. I know quite a few people that have been bitten by squirrels, they can be right vicious barstools when they are cornered. Would have thought the being bit by the wild ones would have been the more probable source of cross infection.
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Leprosy is an old infection in humans. Squirrels have human leprosy (and only in Britain), so it almost certainly went from humans to squirrels. All the mediaeval illustrations show squirrels as pets of women, perhaps they just don't like men! Leprosy is airborne spread by droplets from the airways, and probably needs prolonged exposure, so escaped or freed pet seems more likely. A squirrel catching it from biting a man seems less likely.
 
Darat said:
Surprised they were kept as pets. I know quite a few people that have been bitten by squirrels, they can be right vicious barstools when they are cornered. Would have thought the being bit by the wild ones would have been the more probable source of cross infection.
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You do know that squirrels were so named because they were owned by Squires and Earls, right?

Huh, that almost sounds reasonable.
 
Ryan O'Dine said:
You do know that squirrels were so named because they were owned by Squires and Earls, right?

Huh, that almost sounds reasonable.
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That's not right!
They were aquatic until the 1400's and were related to both squids and eels. The archaic pronunciation of squid was 'skwii'.
I read that on the internet, so I know it's true!
;)
 
welshdean said:
That's not right!
They were aquatic until the 1400's and were related to both squids and eels. The archaic pronunciation of squid was 'skwii'.
I read that on the internet, so I know it's true!
;)
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I think we're going to have to agree to disagree on this one (by which I mean, agree that you're wrong and disagree that I'm wrong).
 
This was supposed to be the case, Rising levels of CO2 in the atmosphere drive an increase in plant photosynthesis—an effect known as the carbon fertilization effect (Jan 27, 2022), but apparently plants find it harder to absorb carbon dioxide amid global warming (New Scientist, Aug 10, 2023):
A modeling study suggests that increases in photosynthesis have slowed since 2000, opposing previous research that said this effect would remain strong, helping to absorb CO2 from the atmosphere
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Sámi tribes, according to the Arktikum Science Museum in one of their exhibitions re the Aurora Borealis, believed that these spooky wavering lights in the northern winter sky were spirits and that these spirits were speaking to them. They would put all their worldly goods onto a sled and cover them over, out of some kind of fear of these supernatural events.

Of course, thanks to noticing the effect on a compass needle when the northern lights are active, scientists were able to ascertain that the lights were the result of geomagnetic phenomena.

When a solar storm comes toward us, some of the energy and small particles can travel down the magnetic field lines at the north and south poles into Earth's atmosphere. There, the particles interact with gases in our atmosphere resulting in beautiful displays of light in the sky. Oxygen gives off green and red light.

What Is an Aurora? - NASA Space Place

NASA Space Place (.gov)
https://spaceplace.nasa.gov › aurora
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Here's the thing. It wasn't until 2012 that an acoustics researcher at Aalto University recorded the 'voices' which were apx 70 metres above the ground during the appearance of the northern lights.

[Professor Unto K Laine] recorded hundreds of sound events in Fiskars where the temperature was at -20 °C. I selected the 60 loudest events, the sources of which were directly above the recording microphone array. The magnetic pulses that preceded these sounds proved that their sources were at an altitude of approximately 75 metres. On the same night, the Finnish Meteorological Institute carried out its own measurements, which proved that the inversion layer was located at the same altitude where these noises were born. The correlation between the strength of the magnetic pulses and the loudness of the sounds was also strong.
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So whilst people assumed the Sámi were just being superstitious, they knew about these northern light noises all the time.

The science behind the sounds is as follows:

According to the new inversion layer hypothesis, the popping and crackling sounds associated with the Northern Lights are born when the related geomagnetic storm activates the charges that have accumulated in the atmosphere's inversion layer causing them to discharge.

'Temperatures generally drops the higher the altitude. However, when temperatures are well below zero and, generally in clear and calm weather conditions during the evening and night, the cold is near the surface and the air is warmer higher up. This warm air does not mix, instead rising up towards a colder layer carrying negative charges from the ground. The inversion layer forms a kind of lid hindering the vertical movements of the charges. The colder air above it is charged positively. Finally, a geomagnetic storm causes the accumulated charges to discharge with sparks that create measurable magnetic pulses and sounds' Mr Laine, who is now a professor emeritus, explained.
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https://www.aalto.fi/en/news/acoustics-researcher-finds-explanation-for-auroral-sounds
 
I think I've heard it said that gravity is not a force.

Also the electromagnetic force and the weak force are actually the same force: the Electroweak force. So that would get it down to only two forces: The strong force and the electroweak force.
 
Puppycow said:
I think I've heard it said that gravity is not a force.

Also the electromagnetic force and the weak force are actually the same force: the Electroweak force. So that would get it down to only two forces: The strong force and the electroweak force.
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According to Einstein it is generated by the warping of space time. (My understanding of the science :blush:)


What happens at quantum level? :confused: Who knows.
 
Puppycow said:
I think I've heard it said that gravity is not a force.
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In a sense, yes. Force = mass * acceleration, but only if you're measuring acceleration from an inertial reference frame.

In a non-inertial reference frame, you can get all sorts of pseudo-forces like the centrifugal and coriolis force in rotating reference frames. These forces aren't real, they are artifacts of working in a non-inertial reference frame.

In general relativity, you actually cannot have global inertial reference frames, you can only have locally inertial reference frames. And a locally inertial reference frame is a free-falling reference frame. Objects not acted on by a force will follow a geodesic (the curved space equivalent of a straight line) through spacetime. So falling is a force-free activity, and gravity isn't a force. Other forces act on objects to accelerate them away from their geodesic, but gravity doesn't. Gravity warps spacetime to change what the geodesic is, but it doesn't push objects off their geodesic.
 
I recently learned (or re-learned yet again) that turtles don't live in their shell, they are their shell. Or rather the shell developed mainly from their ribs. Too many kids cartoons owning space in my brain.
 
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