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20 December 2007

Does the Southern Hemisphere always get a better view of the night sky? Duelling theories on Internet Relay Chat.


On IRC last night I told Phrost that when I went to the Australian desert to see Halley's Comet, the night sky above the Southern Hemisphere presents a much denser, richer star field than the night sky above the Northern Hemisphere.

He said that was just a seasonal phenomenon because of when I was there, that if I went back six months later it would reverse.

I said No, the Southern Hemisphere always sees a denser star field because of the orientation of the Plane of the Ecliptic (Earth's orbit around the Sun) relative to where the Solar System is within the disk of our galaxy, the Milky Way.


He sent me a diagram of his theory (Top) and I sent him a diagram of my theory (Bottom). I'm Droog4. He used itty-bitty font, so click and it gets bigger and easier to read.

My astronomy is a little rusty, see Note 1. If you actually KNOW what's going on here, Leave A Comment. As usual, just explain the Science, don't take the opportunity to call Phrost and Droog4 idiots.

This may be the last piece of my Refrigerator Art which I create on MSPaint, 'cause last night I downloaded Paint.Net, a free souped-up version cooked up by students at the University of Washington, with some assistance from Microsoft. I couldn't use Paint.net before because it wouldn't run under my old OS, WindowsME (Miserable Enema). But apparently Paint.net can do all the nifty tricks that Adobe Photoshop can do. Adobe Photoshop costs U$975.

In Alice Springs, one of the local amateur astronomers who loaned us tourists their fancy telescopes was the lawyer for the local Aborigines, and he said the Aborigines thought the Comet was a nasty old man throwing rocks down on the Earth, and they just wanted the Comet to go away fast.

Most of the other amateur astronomers were US employes of Pine Gap, a.k.a. "The Golf Ball Factory," a supersecret electronic intelligence eavesdropping facility near Alice run by the NSA (No Such Agency).

The Southern skies really are spectacular and rich with fascinating objects. It's like looking up at the sky from another planet.

8 comments:

Mike Stone said...

I'm no Astronomer by any means, but if I were to guess, I'd say that it has more to do with light extinction than how many stars there are to look at. Both locations have plenty of stars in all directions. Most of the constellations in the night sky are visible in both hemispheres. We actually mostly face into the center of the Milky Way, which is why we see that really neat stripe of lighter sky.

That being said, I think you're both kind of right. The night sky in the southern hemisphere is always going to be brighter because there is a lower human population. Less humans, less pollution, clearer sky. There are also times of the year that this is going to be better than others due to the Earth's location in it's orbit.

Vleeptron Dude said...

Wow. I don't know if you're right about either of your theories, but you've managed to crash your Space Taxi into *2* profoundly Big and Interesting matters.

1. Something that's deeply important to me, the loss of our human heritage of Clear Night Skies. And decades before Al Gore came galloping over the hill to save the Earth over Global Warming and Climate Change, the International Dark-Sky Association (notice the hyphen)

www.darksky.org

has been battling Light Pollution by trying to get cities to shift to kinds of industrial lighting which don't screw up our ability to look to the skies at night.

DON'T GET ME STARTED ABOUT THE NEW PRISON IN SPRINGFIELD VERMONT DOWN THE ROAD from the mountaintop kids and amateur astronomy summer camp Stellafane!!! Real interesting bunch of people:

http://stellafane.org/

Oh but anyway,

2. Both locations have plenty of stars in all directions.

You've smashed right into my Fave Astronomy Thang:

Obler's Paradox!

If everywhere you look, you see a star ... if sooner or later in the vast or perhaps even infinite universe there's light coming at you from a star in every direction ...
WHY IS THE SKY DARK AT NIGHT? If starlight is coming to Earth from every direction, why isn't the night bright as the day?

Obler never figured out the answer, but he won a whole Pizza with sausage & mushrooms for figuring out such a dynamite question! By his argument, which nobody in his era could poke a hole in, the night sky really SHOULDN'T BE DARK!!!

But a century or so after he died, somebody finally won the Pizza and answered it! The Answer is Very Subtle!

Anonymous said...

Light pollution is another interesting theory... it makes sense. The West.. especially the eastern seaboard where Droog and I live, is always polluted. Often times, you can't even see through the smokey skies.

Also.. I don't think that the milky way is close to the the galactic center either, which supports both our theories.

Why is the sky black? I think that while light does travel from millions of light years away, a lot of is degraded through stratospheric debris. This is just my theory but I think that the furthest (and weak) light sources become so weakened that they are unable to penetrate earth's atmosphere. Meanwhile, objects as large and close as our sun have no problem doing so... just a thought.

Vleeptron Dude said...

Hey hey hey hey phrost! Is it final exam time? Well, I always had my priorities during exam week. I always used to take the subway from the Bronx down to Greenwich Village and hang out at music clubs when I should have been studying.

This is a way cool thread. No pizza for you, that's not the solution to Obler's Paradox.

I've cooked up a Scheme to get The Real Answer to the Southern/Northern Hemisphere star density problem. I'm going to send an e-mail to some poor innocent Astronomer at a very prestigious optical observatory in the middle of the Australian Outback. I'll whine and beg for him to explain it to us in Very Small Words.

I bugged a Japanese comet expert who was dumb enough to post his e-mail addie on his site, and he very kindly took the time to e-mail me and explain why a particular big bright comet would never come back again in our lifetime. So I might get lucky with another expert.

I mean, what better things does a PhD astrophysicist have to do than explain simple space crap to dopes on Vleeptron?

Vleeptron Dude said...

or maybe I'll ask THIS GUY:

http://vleeptronz.blogspot.com/2007/07/things-to-do-in-local-group-when-youre.html

Mike Stone said...

Uh, the easy answer is that the sky is not black. Humans just have piss poor night vision. There's light all around us, even when it's "dark". It's just that the light is to faint for our lame ass optics to register, or it's outside of our favorite wavelengths. There's a reason that our cats have no problems navigating around those obstacles I insist on bashing my shins on or tripping over. And it's not that they memorized the room when the light was on.

Vleeptron Dude said...

That may be the easy answer, but it's not The Answer to Olber's Paradox!

Betcha Wikipedia has it, just hold on, I'll hose it up and pose it.

It's reallllllly interesting. Because Olber was right -- the night sky shouldn't be dark, because there's a star sending light to the Earth from every possible direction.

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