Today I Learned

[fresh_42]

I wish I could find negative mass... and add a little to myself...

And think of the advantages in the grocery store!

 

[Simon Peach]

Something you better forget again immediately.

https://uk.news.yahoo.com/scientists-observe-liquid-apos-negative-135700638.html and I did say maybe

 

[OCR]

I wish I could find negative mass...

Won't you need to find some laters... firster ? .. .. lol

Scientists then use laters to kick the atoms around...

 

[OCR]

and I did say maybe

...Yup, you did.

 

[Borg]

today I learned that they may be negative mass

Something you better forget again immediately.

I think that he may be referring to this Science Daily article that came out last week - Physicists create 'negative mass'

Push it, and unlike every physical object in the world we know, it doesn't accelerate in the direction it was pushed. It accelerates backwards.

They are sensationalizing a bit but, interesting properties for what was created.

 

[jim hardy]

TIL that refrigerator "munion heaters" aren't electric anymore.
They intentionally apply heat around the doors to avoid annoying condensation and mold under the door gaskets. Last Sears i worked on was electric heating elements that you can switch off with an "energy saver' switch. But that was 1972.

Nowadays they run some of the hot side Freon tubing around the door jamb to warm it.
When the normal hot side (condenser) coils in the back get covered with dust or the fan stops, an inordinate amount of heat makes its way to the munion tubes in the doorjamb making the front of the fridge really hot to the touch.
That's a very nice feature because it alerts you that something needs attention.

My friend's wife noticed her fridge door area hot to the touch and sure enough, when we pulled it out and looked in the back the fan wasn't turning. The little fan motor was too hot to touch so while it was cooling down she ordered another.

I took it apart .

The front bearing was really tight but it came off the shaft with some oil and a hefty pull.
I soaked both bearings with the only oil i could find in the garage, automatic transmission fluid, and put it back together.

It's a happy fridge again.
I'll be very interested to learn how long the transmission fluid lube job lasts.

There's never a dull moment around old machinery.

old jim

 

[mfb]

Today I learned about Zagier's "one-sentence proof" that every prime p = 4k + 1 can be expressed as sum of two squares. It looks odd, and the involution comes out of nowhere, but it all fits together in an unexpected way.

 

[Farang]

Today I learned about Zagier's "one-sentence proof" that every prime p = 4k + 1 can be expressed as sum of two squares. It looks odd, and the involution comes out of nowhere, but it all fits together in an unexpected way.

What is pictured in your avatar?

 

[mfb]

Artist's impression of 1SWASP J1407b, probably a planet with a gigantic ring system.

 

[OCR]

it came off the shaft with some oil and a hefty pull.

Ok, now Jim, admit it... you used some magic too. .lol

There's never a dull moment around old machinery.

No truer statement can be made, however, as I get older, I'm starting to feel it's really not that bad to have... a dull moment. ..

 

[OCR]

Today I see...

Watching the sunrise outdoors statistically increases your odds of having a good day.

Oh...? I need a reference for that one....

And needing a nap after lunch.

I'll accept this as fact, though....

 

[DrGreg]

I think that he may be referring to this Science Daily article that came out last week - Physicists create 'negative mass'

They are sensationalizing a bit but, interesting properties for what was created.

When you follow the link to the journal abstract, you find it is really "negative effective mass", not "negative mass".

 

[Jonathan Scott]

When you follow the link to the journal abstract, you find it is really "negative effective mass", not "negative mass".

Sounds like the effect demonstrated by a helium balloon in an accelerating car.

 

[Aufbauwerk 2045]

Today I learned about a $400 internet-connected juice gizmo. Apparently you must subscribe to get whatever it is you get. Juice as a servce?

This gave me an idea. It should be possible to build a simple metal device that you put over your cup. It has a sort of cone-shaped thing in the middle and there are lots of sharp bits with holes. Sorry I haven't come up with the drawing yet.

Let's say you want some orange juice. You cut the orange in half. Then you place one half of the orange over the cone and push down while turning the orange. The juice comes out and falls through the holes into the cup.

I think this is a very green invention and I think it has great potential. It could even be advertised as "exercise your hands while making juice and keeping your planet healthy."

I don't suppose anyone has contacts with a good angel investor on this? I may need one soon anyway for my AI project.

 

[Aufbauwerk 2045]

p.s. in case someone already thought of my revolutionary green juicer technology, I could spruce it up with some LEDs and maybe a tiny video camera connected wirelessly to an app. I see great potential for this sort of video going viral on Youtube. You heard it here first, so I expect full credit if anyone monetizes this idea.

 

[phinds]

This gave me an idea. It should be possible to build a simple metal device that you put over your cup. It has a sort of cone-shaped thing in the middle and there are lots of sharp bits with holes

Can't tell if you're being tongue in cheek or not, but I assume you are. The first time I saw one of those was well over 60 years ago and I don't think they were particularly new then.

 

[Aufbauwerk 2045]

Can't tell if you're being tongue in cheek or not, but I assume you are. The first time I saw one of those was well over 60 years ago and I don't think they were particularly new then.

Yes, it's an apparently failed joke.

This is why I fail as a comedian. No matter what I say (or write) people think I'm being serious. That's why I need to just be deadly serious all the time.

Sigh.

 

[phinds]

Yes, it's an apparently failed joke.

This is why I fail as a comedian. No matter what I say (or write) people think I'm being serious. That's why I need to just be deadly serious all the time.

Sigh.

It may be more of an internet problem. I don't have it in person but sometimes do on forums. You lose most of the expressiveness we humans have when you do a post.

 

[newjerseyrunner]

This is some hard hitting science.

 

[phinds]

This is some hard hitting science.
View attachment 197217

Ah, dude ... you have WAY too much spare time on your hands

 

[Simon Peach]

to day I learned that APT supports zwo ASI1600mm-c

 

[mcknia07]

Today I learned, it's all too easy to make your spray lacquer finish run if you aren't extremely careful... Oops! Lesson learned the hard way. Just made myself a little bit more work than I had originally expected.

 

[collinsmark]

Today (well, yesterday) I learned about Dynamical Parallax, a method to estimate all sorts of good information about stars in a binary star system using only a limited set of observational data.

Using only [comparitively] easily observable parameters such as the binary system's orbital period, orbital angular separation (angular semi-major axis, as observed from Earth), and each star's apparent magnitude (brightness as seen from Earth), One can use Dynamical Parallax to accurately estimate the stars' actual masses, distance from Earth, and luminosities.

A quick guess might lead one to think that there is not enough information to solve such problems (lacking spectral information, etc): a close star system with small stars would be indistinguishable from a far away system with larger stars. Stellar Parallax works by exploiting the non-linear* relatiship between the stars' masses and corresponding luminosities -- that's what makes it work.

So yesterday I whipped up a program implementing the algorithm. It ignores relative eccentricity and assumes that the system's orbit is viewed flat on from Earth. I can live with that. The program requires inputs of the stars' relative magnitudes, the average angular separation of the stars along the line of their farthest/closest points of orbit (i.e., semi-major axis), and orbital period. It calculates the rest.

Here's a test case with Alpha Centauri that worked out pretty well:

For comparison, here are more accurate parameters (more accurate measuring techniques) from Wikipedia:

Distance: 4.37 light-year

Alpha Centauri A:
Mass: 1.1 M_☉
Luminosity: 1.519 L_☉
Absolute Magnitude: 4.38

Alpha Centauri B:
Mass: 0.907 M_☉
Luminosity: 0.5002 L_☉
Absolute Magnitude: 5.71

Pretty nifty. The crazy thing is this is the first time I've heard of dynamical parallax. Apparently astronomers have been using this technique for roughly a century.
----
*(The mass-luminosity relationship of a star is nonlinear up to about 20 solar masses, at which point Dynamical Parallax becomes less useful.)

 

[mfb]

It ignores relative eccentricity and assumes that the system's orbit is viewed flat on from Earth.

With circular orbits, our line of view doesn't matter.
The eccentricity is not hard to calculate if the position of the stars is tracked over one orbital period (or more precisely over a part of it).

 

[rootone]

Sean Carrol getting stuff nailed again.

 

[collinsmark]

With circular orbits, our line of view doesn't matter.
The eccentricity is not hard to calculate if the position of the stars is tracked over one orbital period (or more precisely over a part of it).

Yeah, the tricky part is those star systems who's line of semi-major axis is pointing more-or-less towards/away from Earth. In those cases, the system's semi-minor axis would appear (sort-of) to be the system's semi-major axis from Earth's perspective.

You can account and correct for that by carefully observing Doppler, etc., and being more careful about observing details of the orbit -- something a bit more complicated than simply observing the min/max angular separation alone. My program doesn't do any of that though. But I'm okay with it. For something I whipped up in a day, I'm happy with it.

 

[NascentOxygen]

TIL there are worms that can break down "non-biodegradeable" plastic (polyethylene). This discovery, like so many science discoveries before it, was serendipitous. This species of worms is well-known to beekeepers—the worms eat the wax comb inside beehives.

http://voices.nationalgeographic.co...o-breaking-down-plastic-beeswax-eating-worms/

 

[Aufbauwerk 2045]

Today I learned that after just one day of breaking the diet soda habit, I already feel better. No more diet soda for me. No more aspartame and/or sucralose. That makes several bad habits I've eliminated over the last year. These include Facebook, video games, and listening to talk radio.

"I am the Master of my fate,
I am the Captain of my soul."

 

[jim hardy]

Today I learned that after just one day of breaking the diet soda habit, I already feel better.

Don't be surprised if you experience cravings in next few days.
I tried to cut out sweets a year ago , only last three months have been successful. Took a whole year for the craving to subside.
Sugar is addictive. I don't know about addictive-ness of those artificial sweeteners because i never would eat them. Aspartame upsets my vision.

Good luck with eating healthy !
If you can't stream this , search on "Michael Pollan"
http://www.pbs.org/video/2365635287/

old jim

 

[Aufbauwerk 2045]

@jim hardy thank you for your comments. I know it's a struggle.

It was very hard to break myself of the pizza habit. I finally lost all craving for pizza, and in fact it now disgusts me.

I have a really fascinating diet book called Eat To Live by Dr. Joel Fuhrman. The only diet I was ever on that was successful was his strict diet. He backs up his diet with tons of references. I lost more than 20 lbs while eating as much as I wanted. The catch is I could only eat certain types of foods. It was a vegan diet. I ate lots of Romaine lettuce.

I was working from home at that time. Unfortunately it's too hard for me to stay on it when I'm working my current job. I plan to go back on it soon.

Among other things, he bans sweets. He explains that nature gives us our sweet tooth so we will enjoy eating fruit. He is all for eating fresh fruit. Although he does ban fruit juice from his strict diet. He emphasizes eating the whole fruit so we get the fiber and various other good bits from the fruit which are lost in juicing. I broke that rule sometimes.

One of my most interesting experiences was that once I had been off all meat for several weeks, I could no longer stand the smell. All I could think of was why I had been eating all that stinking, rotting animal flesh.

But sadly now that I'm not on the diet anymore, I have gone back to cheeseburgers. Disgusting.