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[Elizabeth]

[Elizabeth]

[High Spy]

PULL UP, PULL UP

https://www.youtube.com/watch?v=2YNsCLFWi_g

[Dr. Shades]

At around 3.40am just outside the township of Bourke NSW on the Kamilaroi Highway, on the right when leaving town, my son and I were watching the stars and galaxies . . .

No, you were watching the stars and galaxY. Only one galaxy, Andromeda, is visible with the naked eye.

[Physics Guy]

The two Magellanic Clouds are dwarf galaxies, kind of suburbs of the Milky Way, which are probably visible to the naked eye from New South Wales. So is M31, though it's in the northern sky from down there.

The Milky Way itself is also a fair bit more spectacular in the Southern Hemisphere. It might be argued whether it counts as watching the galaxy when we are inside it, but we can watch most of the Milky Way from out on the edge. I think you could say you were watching a city if you were looking towards the downtown skyline from just inside the city limits.

So there are probably four galaxies that one can watch with the naked eye from Earth, in the Southern Hemisphere.

It's actually pretty hard to watch M31. It's such a faint smudge, even in a very dark sky, that it disappears if you look straight at it. The centers of our retinas have a lot of color-sensitive cone cells and not too many low-light-sensitive rod cells, so it's hard to see anything faint at night if you look straight at it. You have to kind of pay attention to things that you can only see in your peripheral vision. That trick can really help you not stub your toes in a dark room, and it can let you see the Andromeda galaxy. It's still frustrating to notice the faint smudge, look straight at it to see if it's really there, and find that it apparently isn't. Look a bit away, and it comes back. Tricky smudge.

[Dr. Shades]

It might be argued whether it counts as watching the galaxy when we are inside it, but we can watch most of the Milky Way from out on the edge.

Are you sure about that? From what I've read, "Our galaxy is roughly 100,000 light years across, and we can only see about 6,000 light years into the disk in the visible spectrum."

I think you could say you were watching a city if you were looking towards the downtown skyline from just inside the city limits.

I respectfully disagree. Everything I've read on the subject agrees that we're nowhere near the edge of the galaxy. More specifically, "The Solar System (and Earth) is located about 25,000 light-years to the galactic center and 25,000 light-years away from the rim. So basically, if you were to think of the Milky Way as a big record, we would be the spot that’s roughly halfway between the center and the edge."

[Physics Guy]

The Milky Way isn't a flat disc. Most of the stars are in a thick central blob, and the outer portion is not only thinner and less dense but swirled, with comparatively empty spaces between the spiralling arms. We're in the second-outermost swirl, with two or three inner swirls between us and the blob. So no, we're not quite at the city limits, but we're out in the sticks.

We can't resolve individual stars beyond something like 10,000 light years with the naked eye, because they're not bright enough. We can see much more distant collections of many stars, though, as blobs of light. That's why we can see M31, and why the Milky Way shows up to our eyes as a bright haze.

[Elizabeth]

Russian President Vladimir Putin commemorated the 61st anniversary of the first manned space flight, carried out by Soviet cosmonaut Yuri Gagarin and announced that Russia will be taking on an entirely different challenge for its next conquest. Putin intends to take the Russian Federation to the moon. An unmanned landing is intended to take place later this year, reviving the old Soviet lunar program as part of a collaboration with China to establish a moon base for long-term research operations.

[Res Ipsa]

Elizabeth, Universal Rule 10 states:

Do not EVER "link-and-run." If you post a link to something, always explain what's at the other end of the link, why it's important, and what you hope other readers / viewers learn from it. RULE OF THUMB: If it's not worth your time to describe it, then it's not worth our time to click on it.

Please explain why it's important to link Mein Kampf in the thread and what you hope other readers will learn from reading the text at your links.

Thanks.

[Physics Guy]

Wait, the problem with Mein Kampf is link-and-run? So it would be okay to post links to, say, child pornography, if we just explain what we hope other readers will learn from it?

Where the hell is the line? Do we even have one?