PF Random Thoughts

Jimmy Snyder

Sometimes I laugh at what I read, but it's pretty rare. In this case I simply don't get the joke. Did rootx see the lights of an airplane at the airport 10 km away and then wonder to himself if he would have been able to see them if visibility was 1 km?

I live 50 km from Phila International, but directly under the incoming flight path, 10 km up. Jetliners pass by about 1 a minute and when it's dark I have no trouble to see their headlights. Unless, of course, visibility is only 9.999... km. I think this answers rootx's question. If you can't see the headlights then they don't do any good.

Or was he asking whether the headlights on a plane improve the visibility of other objects for the plane's pilot? I don't think they do regardless of visibility conditions.

What does visibility measure anyway. Does 1 km visibility mean that objects at that distance are at the threshold between visible and invisible? Or is it the distance at which an object can be seen clearly. What does clearly mean in this context? If visibility is 1 km and there are two objects, one with headlights and the other without, do you need to see them both, or is one enough?

AlephZero

The strobe lights are normally on whenever the a/c engines are running. On the ground, they are a warning to keep clear of engine exhaust or propellor wash, and that a stationary a/c might start to move without warning! In the air, a flashing strobe is easier to see than a steady light, and at night it is obviously an artificial light and not a star, etc.

Landing lights are steady and not strobed because reflections from the a/c's own flashing ligths can be disorienting to the pilot when flying through cloud or mist.

Landing lights are so other people can see you - especially at a small airstrip operating under visual flight rules, where there may be a radio operator on the ground but no formal air traffic control system.

Incidentally, commercial aircraft cabin lights are usually dimmed for takeoff and landing, to avoid a side-on view of the aircraft being mistaken for its landing lights.

zoobyshoe

I don't often drink juice. Mostly I eat the whole fruit, in binges, according to what's available at the time. At this season you can't get strawberries or cherries. The oranges aren't very good, so I'm down to apples and bananas for a while. They seem to get those right all ear round.

turbo

I drink cold-pressed apple cider form local orchards. Not a big fan of juices, though.

dkotschessaa

Spent a large part of the day being fascinated by the physics of the dippy bird that I got for Christmas as a whimsical gift.

Then the cat happened.

farewell, dippy...

-Dave K

Borg

I guess my day has been a little more productive. I bought an Arduino Uno controller yesterday. I've been having fun learning how to program it and wire up the circuits.

dkotschessaa

LOL. That's awesome. Reminds me of the old radio shack kits I had when I was a kid. I don't think they have them anymore. Radio Shack sucks now.

Borg

The last time that I tried this was several years ago. That was a PIC microcontroller that you had to practically know binary to program it. I had heard that the Arduino was easier to program and it is. The Arduino's programming languange is very similar to Java which is much easier for me. The big difficulty for me now should just be the circuits - figuring out the right transistor took over an hour.

Astronuc

Srinivasa Ramanujan's Century-Old Secrets Unlocked
http://news.yahoo.com/mathematicians...171554694.html

Now that's an amazing story.

In case anyone is interested - Ken Ono's paper - UNEARTHING THE VISIONS OF A MASTER: HARMONIC MAASS FORMS AND NUMBER THEORY
http://mathcs.emory.edu/~ono/publica...v/pdfs/114.pdf

and

RAMANUJAN’S UNPUBLISHED MANUSCRIPT ON THE PARTITION AND TAU FUNCTIONS WITH PROOFS AND COMMENTARY
http://www.math.wisc.edu/~ono/reprints/044.pdf

an interesting perspective on the story of Ramanujan -
http://www.3quarksdaily.com/3quarksd...ramanujan.html

Borek

Speaking of playing with things - I got my Raspberry Pi few days ago. Turns out it can work as a HTPC with a minimum effort. Fascinating.

Borg

The White House has a section to allow people to create petitions. I would love to hug the person that came up with this petition. I created an account just to sign it.

Petition to legally recognize Westboro Baptist Church as a hate group.

HeLiXe

mmmm raspberry pi! Where is PengPeng when you need him?

Borek

Let's say 40+, sounds better, doesn't it?

OmCheeto

I misread that. I thought you created that petition!

The huggable person's name is Grant.

They've gotten a few signatures since then

And, oh my, 281,922-281,826 = 96 people have signed it while I was in the process of signing it. 96 signatures in a very brief moment.

Someone should make a graph of signatures per brief moment over time.

I love graphs. And I would assume people now know my feelings for hate groups.

edward

The way it has been explained to me is that the Westboro Baptist Church is hateful because they can't have sex standing up. Being Old School Baptist means, no dancing is allowed, and having sex standing up looks too much like dancing.

The members should go for some kind of therapy; All three of them.

Evo

They're already considered a hate group. I'm sure they're already on FBI and other enforcement watch lists. I'm not aware of any special legal hate group status. ? I'm not really sure what the petition is supposed to be doing, although it's nice to show they're not popular.

rootX

I skimmed through wiki but didn't find anything about government considering them a hate group.
http://en.wikipedia.org/wiki/Westbor...eme_Court_case

I wonder what "hate group" even means in the US when there is no restriction on speech IIRC.