If you fly fast enough in one direction can you reach space?

[JonnyFive]

Vipers said:

I wonder if the pyramid builders had this problem

They didn't think of the laws of physics and got on with it, theoretically.

[Engineer1]

Munter said:

Zad said:

You could indeed build a column of bricks high enough such that you would eventually reach zero-g (escape velocity). This is usually thought of the other way around though, that is to say launching a satellite way out beond the geostationary point, and dropping a rope from it which can then be climbed by a "space elevator".

http://en.wikipedia.org/wiki/Space_elevator

I see. We can't make the rope yet. That'd explain why we're not doing that.

We are working on it but space is a long way out so the length of the rope means that the weight of the rope would crush the rope at the bottom atleast with current materials that could be used for the rope.

[Oakey]

deeen said:

dr_gn said:

deeen said:

JonnyFive said:

Plus is 22236 miles random? Or is that the atmosphere edge?

It's the height for geostationary orbit. Atmosphere is much thinner than that, 75 miles.

I assumed the materials for the bricks came from earth, so ignored the gravitational effect of the pyramid. Don't know about the winch, maybe it got nicked by a bloke with a dag.

It's irrelevant where the bricks came from. The fact is that the top brick would be sitting upon the pyriamid itself. Since gravitational attraction is proportional to the inverse of the square of the distances between the centres of mass of the two objects, the top brick wouldn't "float" away at the same distance it would if it were in free space at that height above the earth, separated by nothing but the atmosphere.

Sorry didn't realise we were actually going to build this.

Ok yes the pyramid does have an effect, because it moves the centre of gravity of the Earth. So I could express it better by saying for the top brick to appear weightless, it needs to be about 26200 miles above the centre of gravity of the combined Earth + pyramid.

But it is relevant where the bricks come from, cos that many bricks will weigh about a zillion tons, so if you bring them from somewhere else (Mars, for example) you increase the mass of the Earth+pyramid and the geostationary orbit will be higher.

Wait.. what... we better be... I've got 100,000 house bricks on order for the end of next week. I was hoping we'd be well on with it before the month ends.

[Munter]

Oakey said:

Wait.. what... we better be... I've got 100,000 house bricks on order for the end of next week. I was hoping we'd be well on with it before the month ends.

Oh god. What have I started!

[deeen]

Well now I am a bit more sober, I have realised that the pyramid was a silly idea.

For a start, if the proportions were similar to the Egyptian ones, the base would not fit on the Earth.

So it's back to the single tower, then.
But 100,000 bricks? What were you thinking, man? That's only 4.5 miles! Get on the phone!

Don't worry, the top one will stay up there, then you can have all the others back afterwards.

[IainT]

deeen said:

Ok yes the pyramid does have an effect, because it moves the centre of gravity of the Earth. So I could express it better by saying for the top brick to appear weightless, it needs to be about 26200 miles above the centre of gravity of the combined Earth + pyramid.

But it is relevant where the bricks come from, cos that many bricks will weigh about a zillion tons, so if you bring them from somewhere else (Mars, for example) you increase the mass of the Earth+pyramid and the geostationary orbit will be higher.

Simple, just build a counterbalance pyramid on the other side assuming you're placing the pyramid on the equator.

[Camaro91]

I can just imagine the conversation at the builders merchants now...

"100,000 bricks please"

"Building a space pyramid are we sir?"