h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

A note about the Great Wall/space thing. This is another fallacy that won't go away. I process imagery from space, taken by astronauts using normal cameras and lenses. Plenty of man made objects can be seen from space: roads, buildings, irrigation patterns, to name a few. There's also those brilliant projects off the coast of Dubai which are quite striking from orbit and much more distinct than the Great Wall.

Some variants stipulate that the Great Wall is the only man made object visible from the moon's surface. Apparently (after a quick google) this is the original version. This was stated in a 1932 edition of Ripley's Believe it or not. Well, don't. It's not visible from the moon's surface. At it's widest it's only a little over 9 meters which isn't much from 363,000 kilometers distance.

i believe also that the substantial part of the wall is only a small section of it. most of it is really no more than a small wall of ordinary proportions.

i also think this one appeared way back in the thread somewhere.

~*~The Milky Way and Andromeda galaxy are on a collision course. In about 3 billion years, the two galaxies will collide.~*~

Really? That would be interesting to see. And I'm given to understand that the sun will swell to the point of incinerating the Earth in about 5 billion. Is it possible that the collision (which I know would take at least millions of years in itself) could affect that somehow?

I'm just finishing a week of night shifts,
I've got a week off now,
I have a fridge full of beer


Taff
agent of kaos

Holy crap... we have U numbers in the 9 millions or more now.

Will Smith turned down the role of Neo in The Matrix. Instead he starred in Wild Wild West.


Yes, the one with the forty foot tall robot spider.

http://www.youtube.com/watch?v=vgYhLIThTvk&feature=related
Kevin Smith talking about Superman and the giant spider (20 min).

"And I'm given to understand that the sun will swell to the point of incinerating the Earth in about 5 billion. Is it possible that the collision (which I know would take at least millions of years in itself) could affect that somehow?"

For one thing, the sun won't be in the Milky Way anymore, but in a new elliptical galaxy created by the merger with the Andromeda galaxy. But I think we get cooked anyway.

As I read it, in all likelihood life on earth wouldn't necessarily be affected by the two galaxies "colliding", due to the immense distances between the stars.

I didn't think so. But not being an astronomer, I thought maybe there'd be some bizarre gravity effects from all the new interactions between them.

~*~Will Smith turned down the role of Neo in The Matrix. Instead he starred in Wild Wild West. Yes, the one with the forty foot tall robot spider.~*~

I like that movie.

-If you fall from a plane with no parachute, it's better to land in a forest than in the sea.-

Only if you prefer that your remains be eaten by bears than by sharks.

-A note about the Great Wall/space thing-

It's well known that there are only three man made objects visible from space. One is the Great Wall and the other is Pamela Anderson.

if matter in the universe is being flung outwards at great speed from the big bang, how comes it to be that large bodies like galaxies are colliding? i understand there would be some relatively minor changes in direction of big things but given the distances involved...

this is a serious question. if i fling a handful of rice away from me i might expect grains to be frequently colliding in the vicinity of my hand, but not once they have travelled a distance from me.

Interesting. Shouldn't this question be the basis of a thread of its own?

If the universe is expanding it's the AVERAGE distance between everything and everything else that's increasing. The imperfection in the texture from near the beginning that allowed matter to form in the first place also meant that there would be clumpiness in gravity as well. The galaxies are flying away from the centre but still can be attracted to each other.
As well, consider if two galaxies are moving away from the centre more or less on the same radial, the outer one is slowed down by the inner one which is speeded up. Again they would eventually collide.

thank you. a very clear and concise explanation.

given the massive velocities involved with this, (scuze the pun) are these variations to hubble flow explainable by the known masses of the objects concerned, or is dark matter necessary for the explanation?

A good question.

I have a question that I'm not sure I can state properly, but ... I understand that if we look at Hubble photos of "deep space", we are seeing the early universe. Meaning galaxies that existed in the first billion or less years after the Big Bang. My question: that light that is arriving at the Hubble's cameras, where has it been for the last 12 billion or so years? Presumably somewhere between the Big Bang and the Hubble. So is the universe expanding FASTER than the speed of light ... but then the light would NEVER catch up?

Steve K., forever stranded in a Newtonian universe.

i can answer this only because i have just come from wiki. you are referring i think to olber's paradox, the resolution of which is summed up here. http://en.wikipedia.org/wiki/Hubble_flow

which leads me to a piece of uselessness.

olber's paradox was frst resolved by, of all people, edgar allan poe.

Time magazine's "Man of the Year" for 1938 was Adolf Hitler.

The Dallas Morning News' man of the year 2007 was "The Illegal Immigrant".