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

[Wudang]

Many years ago Patrick Moore told listeners that due to the line up of planets there would be a drop in gravity. People contacted him saying how they'd floated around the kitchen etc. Details in his book Can You Speak Venusian, donated long ago.

 

[Puppycow]

You probably don't feel your body weight changing noticeably when you drink a beverage or eat a light meal, but that will affect your body weight far more than something as subtle as tidal forces from astronomical events. It's just too small a change to notice. Only the most sensitive scientific instruments could probably detect such miniscule changes in effective gravity.

 

[jadebox]

You probably don't feel your body weight changing noticeably when you drink a beverage or eat a light meal, but that will affect your body weight far more than something as subtle as tidal forces from astronomical events. It's just too small a change to notice. Only the most sensitive scientific instruments could probably detect such miniscule changes in effective gravity.

That reminds me of a question that I sometimes pose to smart kids ...

If I go on a diet and lose weight, how does the weight (fat) leave my body? The first answer they give is usually incorrect (and accompanied by a giggle).

 

[Helen]

83% here. Watched it on a beach facing west, with my visiting family, and a good time was had by all. Stuck around to watch the Perseids as well. Quite a show!

 

[steenkh]

83% here. Watched it on a beach facing west, with my visiting family, and a good time was had by all. Stuck around to watch the Perseids as well. Quite a show!

How long did you stick around to watch the Perseids? The sun went down at about 9, and proper darkness would only be after midnight?

Meteors are usually quite faint, so you must have had a terrific dark sky. I envy you. From Copenhagen only the brightest stars can be seen, and any meteors would have to unusually bright to be seen.

 

[Helen]

We were on a beach with very little light pollution, and stayed there until around 2, and the Perseids were quite spectacular from around midnight, when it got really dark, and until we left. But it is quite hard to get away from light pollution here as well, although not close to as difficult as in Copenhagen. My sister lives there, and she was quite envious...

I am still smiling - son et lumière, without the son, but with lots of the most amazing lumière!

 

[Armitage72]

Many years ago Patrick Moore told listeners that due to the line up of planets there would be a drop in gravity. People contacted him saying how they'd floated around the kitchen etc. Details in his book Can You Speak Venusian, donated long ago.

Similar to the reports of people's silverware spontaneously bending while they were watching Uri Geller perform on TV.

 

[PitPat]

Similar to the reports of people's silverware spontaneously bending while they were watching Uri Geller perform on TV.

Jeez, maybe I need to start watching porn.

 

[catsmate]

Many years ago Patrick Moore told listeners that due to the line up of planets there would be a drop in gravity. People contacted him saying how they'd floated around the kitchen etc. Details in his book Can You Speak Venusian, donated long ago.

Patrick Moore - Can You Speak Venusian (David & Charles) : Patrick Moore : Free Download, Borrow, and Streaming : Internet Archive

Patrick Moore ponders the various theories of flat earthers, channelers, crystal gazers, atlantism, Velikovsky and the like. A refreshing sceptical approach!

archive.org

 

[alfaniner]

How long did you stick around to watch the Perseids? The sun went down at about 9, and proper darkness would only be after midnight?

Meteors are usually quite faint, so you must have had a terrific dark sky. I envy you. From Copenhagen only the brightest stars can be seen, and any meteors would have to unusually bright to be seen.

It's not so much the dark that makes them more visible (I mean, once the sun's gone down completely it's not going to get any more dark, unless it's hazy, perhaps). But after midnight is recommended because that's when the Earth has rotated into the path of the dust particles, making the encounters much more likely. (Like driving into a snowstorm, vs. away from it.) That's how I remember it, anyway.

 

[steenkh]

It's not so much the dark that makes them more visible (I mean, once the sun's gone down completely it's not going to get any more dark, unless it's hazy, perhaps). But after midnight is recommended because that's when the Earth has rotated into the path of the dust particles, making the encounters much more likely. (Like driving into a snowstorm, vs. away from it.) That's how I remember it, anyway.

Astronomical darkness is defined to be when the sun is more than 18˚ below the horizon, which is something like two hours after the sun has set, but of course you can see meteors before that: there are just more to be seen during astronomical darkness. And of course, there should be no moon, but obviously that is not a problem on the night of a solar eclipse.

As for midnight being the time when the Earth is facing the direction of travel: I don't think so. Midnight is supposed to be about the time when you are facing directly away from the sun, and that is definitely not the direction of travel. The various meteor storms are named after the point from which they seem to originate, and that means that when the origin is highest in the sky, the night side is facing in the direction of travel. Does that give a better chance of seeing meteors? I don't think so. The paths of the meteors are longer when the origin is in the horizon, and I believe that gives you better chance of spotting them.

 

[rjh01]

That reminds me of a question that I sometimes pose to smart kids ...

If I go on a diet and lose weight, how does the weight (fat) leave my body? The first answer they give is usually incorrect (and accompanied by a giggle).

The answer is that you lose fat mostly by breathing it out as CO2. The other answer is that you piss it out. But the later only happens for the first few kilograms. And is the reason it is so easy to lose the first few kilograms.

 

[bigred]

I believe sweating is also part of it.

 

[rjh01]

I believe sweating is also part of it.

Yes. But only if you do more of it.

 

[Planigale]

The answer is that you lose fat mostly by breathing it out as CO2. The other answer is that you piss it out. But the later only happens for the first few kilograms. And is the reason it is so easy to lose the first few kilograms.

Yes as fats are mostly carbon and hydrogen, the only way out of the body is in the form of CO₂ and H₂O, by mass CO₂ will be most of the weight. Some water is also lost through breathing* as well as sweat and urine.

ETA
*Breathing will unconsciously increase when fasting / dieting to get rid of the extra CO₂

 

[Pixel42]

Conversely, when a plant grows it get most of that additional mass from the CO2 in the air, plus a bit from rain. It only gets a few nutrients from the soil.

 

[Puppycow]

Conversely, when a plant grows it get most of that additional mass from the CO2 in the air, plus a bit from rain. It only gets a few nutrients from the soil.

And a funny thing: air is mostly made of nitrogen, and plants need nitrogen, but I don't think most plants can get it directly from the air like they can with CO2. Which is why fertilizer generally contains nitrogen in some form that is usable by plants. I don't really know the details of plant biology, but I have wondered why plants can get their CO2 right out of the air, but not nitrogen, even though there's a lot more nitrogen in the air than CO2.

 

[The Great Zaganza]

There are bacteria that live near/in the roots of some plants, especially legumes, that can bind the nitrogen from the atmosphere.
Plants alone can't

 

[Wudang]

Yes. Old crop rotation cycles used to leave a field fallow every 4 years or so to allow nitrogen fixing plants (ie microorganism friendly as above) to grow and refresh the soil.

 

[Andy_Ross]

There are bacteria that live near/in the roots of some plants, especially legumes, that can bind the nitrogen from the atmosphere.
Plants alone can't

Clover being a well known one that most people don't think of as a legume. It's a popular fallow crop as it can be used as fodder and livestock can graze it.

With the recent rise in energy costs forcing up the price of nitrogen fertiliser, clover is becoming popular again.

Also popular with bees.

Clover - Wikipedia

en.wikipedia.org