# The Naked Scientists Forum

### Author Topic: If we Built a Building BIG enough, could we sense Earth's rotation?  (Read 17271 times)

#### Seany

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##### If we Built a Building BIG enough, could we sense Earth's rotation?
« Reply #25 on: 06/04/2008 13:40:36 »
Look up Foucault's pendulum. There is one in the Pantheon in Paris and I remember there used to be one in the science museum in London. This senses the earth's rotation. Also, as mentioned in the question on tides, in the Northern hemisphere, the tidal range on North facing coasts is higher than on South facing coasts because of the Coriolis force.

On the tall building (at the equator) issue, the downward force (your weight) gets less as you ascend the building. This is only partly due to you moving away from the earth and gravity getting less as a result, but also due to it being balanced by you being in orbit. When you get to a height of about 35,786 km above the earth (I know that is quite a tall building) you will be in a geostationary orbit and you will be weightless.

Now this bit is cool..

But if I am 35,785km above the Earth.. Would I not be weightless?

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##### If we Built a Building BIG enough, could we sense Earth's rotation?
« Reply #26 on: 06/04/2008 15:49:23 »
You may feel the earths rotation as you were rising in a lift (if the lift was fast enough) from the bottom to the top of the building, because you would be gaining rotational speed as you rose. But as sophiecentaur said, once at the top you are not accelerating, so you will not feel it. Just as you don't feel it right now, even though you are travelling at about 1600km's an hour relative to the centre of the earth (if you were near the equator). And the earth itself is travelling about 107232 km's per hour around the sun.

And you don't need to be at geostationary orbit to experience weightlessness, any orbit will do. geostationary orbit just refers to the height a satellite needs to be to stay directly above 1 point on the earths surface while it is orbiting. (because at lower heights the satellite needs to move faster to stay in orbit)
« Last Edit: 06/04/2008 16:03:27 by Madidus_Scientia »

#### graham.d

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##### If we Built a Building BIG enough, could we sense Earth's rotation?
« Reply #27 on: 06/04/2008 16:26:55 »
Yes, but we are talking about being at the top of a building, so by definition (if the building is attached to the ground) the orbit is geostationary. Anyone on this floor (at 35,786km high) would be weightless.

#### Carolyn

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##### If we Built a Building BIG enough, could we sense Earth's rotation?
« Reply #28 on: 06/04/2008 18:15:55 »
Seany............if you build it, they will come  !

Hmmm...you may not know what I'm referring too !!

*quick quiz*...who does ?

He should build it in a Field of Dreams!

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##### If we Built a Building BIG enough, could we sense Earth's rotation?
« Reply #29 on: 06/04/2008 18:58:43 »
Seany............if you build it, they will come  !

Hmmm...you may not know what I'm referring too !!

*quick quiz*...who does ?

In case you're interested Seany, this is from a film called 'Field of Dreams.' Kevin Cosner builds a baseball pitch in the middle of nowhere because he knows if he does famous baseball stars that have died will come back and play baseball there. A very weird film and very American in idealism. Love Kevin though.

I think your building would be fun as lots of people would be able to experience a slight weightlessness. I doubt you would feel the Earth move though, unless I was there.

#### lyner

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##### If we Built a Building BIG enough, could we sense Earth's rotation?
« Reply #30 on: 06/04/2008 21:37:37 »
How much less would you weigh?
****** all.

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##### If we Built a Building BIG enough, could we sense Earth's rotation?
« Reply #31 on: 06/04/2008 22:25:14 »
What units are you working in here?

#### Seany

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##### If we Built a Building BIG enough, could we sense Earth's rotation?
« Reply #32 on: 07/04/2008 00:07:55 »
Seany............if you build it, they will come  !

Hmmm...you may not know what I'm referring too !!

*quick quiz*...who does ?

He should build it in a Field of Dreams!

I still don't get whoo will come!!

#### Seany

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##### If we Built a Building BIG enough, could we sense Earth's rotation?
« Reply #33 on: 07/04/2008 00:08:50 »
Seany............if you build it, they will come  !

Hmmm...you may not know what I'm referring too !!

*quick quiz*...who does ?

In case you're interested Seany, this is from a film called 'Field of Dreams.' Kevin Cosner builds a baseball pitch in the middle of nowhere because he knows if he does famous baseball stars that have died will come back and play baseball there. A very weird film and very American in idealism. Love Kevin though.

I think your building would be fun as lots of people would be able to experience a slight weightlessness. I doubt you would feel the Earth move though, unless I was there.

Thank you for clearing this up!

#### Karen W.

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##### If we Built a Building BIG enough, could we sense Earth's rotation?
« Reply #34 on: 07/04/2008 00:56:33 »
Seany............if you build it, they will come  !

Hmmm...you may not know what I'm referring too !!

*quick quiz*...who does ?

Its "Kevin Costner," in "Field of dreams..."  Good Good movie! YAYYYYYY!  I know that one!!

#### Karen W.

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##### If we Built a Building BIG enough, could we sense Earth's rotation?
« Reply #35 on: 07/04/2008 00:57:37 »
Seany............if you build it, they will come  !

Hmmm...you may not know what I'm referring too !!

*quick quiz*...who does ?

In case you're interested Seany, this is from a film called 'Field of Dreams.' Kevin Cosner builds a baseball pitch in the middle of nowhere because he knows if he does famous baseball stars that have died will come back and play baseball there. A very weird film and very American in idealism. Love Kevin though.

I think your building would be fun as lots of people would be able to experience a slight weightlessness. I doubt you would feel the Earth move though, unless I was there.

Thank you for clearing this up!

Whoops.. I missed this post...! But A great movie indeed!

#### Karen W.

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##### If we Built a Building BIG enough, could we sense Earth's rotation?
« Reply #36 on: 07/04/2008 00:59:20 »
His father wanted to play pro ball and he had a chance to see his father again as a man.. playing ball in the  field he built.. with all the deceased people that came back to play!...... I liked it a lot!

#### another_someone

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##### If we Built a Building BIG enough, could we sense Earth's rotation?
« Reply #37 on: 07/04/2008 00:59:48 »
I think your building would be fun as lots of people would be able to experience a slight weightlessness. I doubt you would feel the Earth move though, unless I was there.

But might I recommend not using the stairs to get to the top.

#### lyner

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##### If we Built a Building BIG enough, could we sense Earth's rotation?
« Reply #38 on: 07/04/2008 10:57:37 »
What units are you working in here?
firkins?

#### Seany

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##### If we Built a Building BIG enough, could we sense Earth's rotation?
« Reply #39 on: 07/04/2008 12:31:33 »
His father wanted to play pro ball and he had a chance to see his father again as a man.. playing ball in the  field he built.. with all the deceased people that came back to play!...... I liked it a lot!

I have not seen it!

#### Seany

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##### If we Built a Building BIG enough, could we sense Earth's rotation?
« Reply #40 on: 07/04/2008 12:32:07 »
I think your building would be fun as lots of people would be able to experience a slight weightlessness. I doubt you would feel the Earth move though, unless I was there.

But might I recommend not using the stairs to get to the top.

Well I reckon 35,000km walk upstairs should be good for fitness!!

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##### If we Built a Building BIG enough, could we sense Earth's rotation?
« Reply #41 on: 07/04/2008 18:17:57 »
What units are you working in here?
firkins?

My Friend, Andrea Hill, married a guy called Ian Firkin. She was going to have a double barreled name but realised it was a bad idea.

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##### If we Built a Building BIG enough, could we sense Earth's rotation?
« Reply #42 on: 07/04/2008 18:19:09 »
Seany............if you build it, they will come  !

Hmmm...you may not know what I'm referring too !!

*quick quiz*...who does ?

He should build it in a Field of Dreams!

I still don't get whoo will come!!

Whoever you build it for will come. I'll come.
« Last Edit: 07/04/2008 18:20:41 by Make it Lady »

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##### If we Built a Building BIG enough, could we sense Earth's rotation?
« Reply #43 on: 07/04/2008 18:21:56 »
I think your building would be fun as lots of people would be able to experience a slight weightlessness. I doubt you would feel the Earth move though, unless I was there.

But might I recommend not using the stairs to get to the top.

Well I reckon 35,000km walk upstairs should be good for fitness!!

I think health and safety would have a field day.

#### Bored chemist

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##### If we Built a Building BIG enough, could we sense Earth's rotation?
« Reply #44 on: 07/04/2008 19:34:58 »
Why?
http://www.hse.gov.uk/myth/

Anyway,
Am I right in thinking that if you buils a building taller than geostationary orbit (ignoring the practical imposibility) would you have to change which side you carpeted at the geostationary orbit height?
Inside you would put the carpet on the side nearest earth. Oustide that geostationary orbit, you would need to put the carpets on the side further from earth because at that range the centrifugal force would be greater than gravity and you would be flung out rather than held down.

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##### If we Built a Building BIG enough, could we sense Earth's rotation?
« Reply #45 on: 08/04/2008 09:59:49 »
Haha yeah you would too, didn't think of that

#### Titanscape

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##### If we Built a Building BIG enough, could we sense Earth's rotation?
« Reply #46 on: 13/04/2008 14:24:07 »
Years ago I dreamt of that, a building on the equator, so rigid and tall that it did not touch the ground. Due to the Earth's rotation and thus the building's long upper parts it holds up the weight of the lower part by tensile strength.

Made of carbon fibre, or ceramic fibre.

that is the projected future means to enter orbit.

Up there you would feel no gravity, and at the top reverse gravity.

#### lyner

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##### If we Built a Building BIG enough, could we sense Earth's rotation?
« Reply #47 on: 15/04/2008 12:38:47 »
We did the 'space elevator' to death not long ago. I still like the idea.
http://www.thenakedscientists.com/forum/index.php?topic=11878.0
« Last Edit: 15/04/2008 12:40:28 by sophiecentaur »

#### Emetsipe

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##### If we Built a Building BIG enough, could we sense Earth's rotation?
« Reply #48 on: 23/04/2008 02:18:37 »
in regards to the space elevator, I've read about actual proposals to make one and they think carbon nanotubes would be able to withstand the forces involved, however i'm concerned about the fact that if you did have this counterweight far out in space wouldn't it, over time, affect the earth's orbit? I would think you would have to have two at the equator that were exactly on the other side of the earth of each other to balance it out.

#### The Naked Scientists Forum

##### If we Built a Building BIG enough, could we sense Earth's rotation?
« Reply #48 on: 23/04/2008 02:18:37 »