Naked Science Forum

Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: Seany on 05/04/2008 21:55:02

Title: If we Built a Building BIG enough, could we sense Earth's rotation?
Post by: Seany on 05/04/2008 21:55:02
If we Built a Building Big enough...

Would we be able to feel the rotation of the earth??

[diagram=330_0]
Title: Re: If we Built a Building BIG enough, could we sense Earth's rotation?
Post by: neilep on 05/04/2008 21:58:42
Now why d'ya wanna go and make the Earth into A Ping Pong bat ?

 [ Invalid Attachment ]






...bear in mind we'd have to use up half the Earth to make the materials for it !!


Title: Re: If we Built a Building BIG enough, could we sense Earth's rotation?
Post by: Seany on 05/04/2008 22:01:04
Now why d'ya wanna go and make the Earth into A Ping Pong bat ?

 [ Invalid Attachment ]





...bear in mind we'd have to use up half the Earth to make the materials for it !!




Yes.. Now it does look like a ping pong bat.. [:P]

Well.. I was just wondering.. Would it still be long enough for us to feel the rotation of the earth?
Title: Re: If we Built a Building BIG enough, could we sense Earth's rotation?
Post by: neilep on 05/04/2008 22:04:55
Have ewe really drawn it to scale  ?


The top three quarters will be in outer space and will be dull and boring....they'll have no atmosphere !! *le groan* [;D] [;D]
Title: Re: If we Built a Building BIG enough, could we sense Earth's rotation?
Post by: Seany on 05/04/2008 22:09:28
Have ewe really drawn it to scale  ?


The top three quarters will be in outer space and will be dull and boring....they'll have no atmosphere !! *le groan* [;D] [;D]

Maybe not to scale!! But how tall would it have to be for us to feel the rotation?
Title: Re: If we Built a Building BIG enough, could we sense Earth's rotation?
Post by: neilep on 05/04/2008 22:12:58
Have ewe really drawn it to scale  ?


The top three quarters will be in outer space and will be dull and boring....they'll have no atmosphere !! *le groan* [;D] [;D]

Maybe not to scale!! But how tall would it have to be for us to feel the rotation?

LOL...I refer this question to people who actually can let ewe know !!

...as much as I luff playing at being klevur I need too many lucozade tablets to maintain the illusion that I actually know something !!
Title: Re: If we Built a Building BIG enough, could we sense Earth's rotation?
Post by: Seany on 05/04/2008 22:17:49
LOL LOL...

But do you think we could ever feel the rotation, however high the building was?.. Or would the speed of rotation have torn the building apart?
Title: Re: If we Built a Building BIG enough, could we sense Earth's rotation?
Post by: neilep on 05/04/2008 22:21:23
LOL LOL...

But do you think we could ever feel the rotation, however high the building was?.. Or would the speed of rotation have torn the building apart?

LOL *help....he's still asking me klevur stuff*

*swallows a whole bottle of the glucose drink and a handful of glucose tablet chasers*

I think......the building would not be torn apart unless it was so tall it hit the moon !!....as far as feeling the rotation....well...put it like this...it would still take 24 hours to make one rotation !....I think it would be slight if at all !!


*gawwwd help me that I hope I made some sense*

LOL
Title: Re: If we Built a Building BIG enough, could we sense Earth's rotation?
Post by: Make it Lady on 05/04/2008 22:25:10
If you could feel the earth's rotation wouldn't it be good to put a revolving restaraunt at the top of the tower block. That would make you so giddy.
Title: Re: If we Built a Building BIG enough, could we sense Earth's rotation?
Post by: Seany on 05/04/2008 22:31:06
LOL LOL...

But do you think we could ever feel the rotation, however high the building was?.. Or would the speed of rotation have torn the building apart?

LOL *help....he's still asking me klevur stuff*

*swallows a whole bottle of the glucose drink and a handful of glucose tablet chasers*

I think......the building would not be torn apart unless it was so tall it hit the moon !!....as far as feeling the rotation....well...put it like this...it would still take 24 hours to make one rotation !....I think it would be slight if at all !!


*gawwwd help me that I hope I made some sense*

LOL

But the circumference  is much bigger!
Title: Re: If we Built a Building BIG enough, could we sense Earth's rotation?
Post by: neilep on 05/04/2008 22:37:24
LOL LOL...

But do you think we could ever feel the rotation, however high the building was?.. Or would the speed of rotation have torn the building apart?

LOL *help....he's still asking me klevur stuff*

*swallows a whole bottle of the glucose drink and a handful of glucose tablet chasers*

I think......the building would not be torn apart unless it was so tall it hit the moon !!....as far as feeling the rotation....well...put it like this...it would still take 24 hours to make one rotation !....I think it would be slight if at all !!


*gawwwd help me that I hope I made some sense*

LOL

But the circumference  is much bigger!


"Hi There,

Sheepy can not come to the forum right now cos he has expired after an overdose of Lucozade. Please leave a message for Klevur peeps to answer ."


 [ Invalid Attachment ]


Title: Re: If we Built a Building BIG enough, could we sense Earth's rotation?
Post by: Seany on 05/04/2008 22:49:02
LOL LOL...

But do you think we could ever feel the rotation, however high the building was?.. Or would the speed of rotation have torn the building apart?

LOL *help....he's still asking me klevur stuff*

*swallows a whole bottle of the glucose drink and a handful of glucose tablet chasers*

I think......the building would not be torn apart unless it was so tall it hit the moon !!....as far as feeling the rotation....well...put it like this...it would still take 24 hours to make one rotation !....I think it would be slight if at all !!


*gawwwd help me that I hope I made some sense*

LOL

But the circumference  is much bigger!


"Hi There,

Sheepy can not come to the forum right now cos he has expired after an overdose of Lucozade. Please leave a message for Klevur peeps to answer ."


 [ Invalid Attachment ]




LOL LOL..  Very cute dead sheepy [;)]

OK Neil. I shall wait [;)]
Title: If we Built a Building BIG enough, could we sense Earth's rotation?
Post by: another_someone on 06/04/2008 04:45:49
Rather depends on where you built the building - putting a tower block over the north pole (maybe the south pole might be on firmer ground) would have no effect on caused by the rotation of the Earth at all that would not be noticable at ground level.

I am assuming your project is to be on the equator.

Indeed, building up would both reduce the effect of gravity, and increase the effects of rotation; but given that the surface of the Earth is already over 6,000Km above the centre, and the atmosphere is only about 120Km thick (the top of mount Everest is only about 8.5Km up), so to build to the edge of space would still only add about 2% to the distance between the the top of the building and the centre of the Earth.

More interesting would be that as you build up, you would have longer hours of daylight.
Title: If we Built a Building BIG enough, could we sense Earth's rotation?
Post by: neilep on 06/04/2008 07:34:21
Seany............if you build it, they will come  !



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

*quick quiz*...who does ?
Title: If we Built a Building BIG enough, could we sense Earth's rotation?
Post by: Seany on 06/04/2008 09:05:08
Rather depends on where you built the building - putting a tower block over the north pole (maybe the south pole might be on firmer ground) would have no effect on caused by the rotation of the Earth at all that would not be noticable at ground level.

I am assuming your project is to be on the equator.

Indeed, building up would both reduce the effect of gravity, and increase the effects of rotation; but given that the surface of the Earth is already over 6,000Km above the centre, and the atmosphere is only about 120Km thick (the top of mount Everest is only about 8.5Km up), so to build to the edge of space would still only add about 2% to the distance between the the top of the building and the centre of the Earth.

More interesting would be that as you build up, you would have longer hours of daylight.

That is very interesting!!
Title: If we Built a Building BIG enough, could we sense Earth's rotation?
Post by: Seany on 06/04/2008 09:05:46
Seany............if you build it, they will come  !



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

*quick quiz*...who does ?

I do not get it.. LOL
Title: If we Built a Building BIG enough, could we sense Earth's rotation?
Post by: Soul Surfer on 06/04/2008 10:43:45
what do you mean by "feel the rotation of the earth".  If you mean like sitting on a roundabout going round fast enough you get pushed away from the centre.  Sometimes called the centrifugal force.

The answer is you can "feel" it now if you have a spring balance that is sensitive enough.  You don't need a tall building to get you further from the centre.  If you measure a weight at (or near) the pole and then take it to the equator and measure the same weight again it will be a bit less on the spring balance because of the extra centrifugal force.  If you used a lever balance with weights it would not show any difference because the weights would be affected in exactly the same way.

If by feel you mean sense an effect on your body it is very unlikely unless you went right out into space and orbited the earth when you would probably notice that you were in zero gravity because in an orbiting satellite the attraction of the earth is exactly balanced by the centrifugal force of the orbit.

Now if you built a really tall structure on the equator and went so far out that the centrifugal force balanced the weight of the structure  you could build a "space elevator".  Such structures have been proposed and may just be possible using the very strongest materials on a planet like the earth.
Title: If we Built a Building BIG enough, could we sense Earth's rotation?
Post by: Seany on 06/04/2008 11:48:58
But to make a "Space elevator" wouldn't you need like half the materials in the Earth??

And yes, I do mean "feel" as in the roundabout movement thing..

Thanks for the detailed answer!
Title: If we Built a Building BIG enough, could we sense Earth's rotation?
Post by: Soul Surfer on 06/04/2008 12:18:37
No  the suggestion is that it should be a strip of carbon fibre material in tension only a metere or two wide a few centimetres thick and about 35 thousand miles long
Title: If we Built a Building BIG enough, could we sense Earth's rotation?
Post by: lyner on 06/04/2008 12:38:41
It may be worth pointing out that, on the top of the building, you would still be going around in a circular path so there would be no 'pulsing force'. Eveything on the Earth would be rotating round the centre of mass of Earth plus building. By effectively altering the shape of the Earth you would have shifted the CM a tiny bit. (A REALLY tiny bit!)
Title: If we Built a Building BIG enough, could we sense Earth's rotation?
Post by: Seany on 06/04/2008 12:47:53
If the building was 35km tall.. And I was on the toppest floor in a room.. would I be stuck onto one side of the room, because of the earth rotating?
Title: If we Built a Building BIG enough, could we sense Earth's rotation?
Post by: lyner on 06/04/2008 12:49:28
Quote
If by feel you mean sense an effect on your body it is very unlikely unless you went right out into space and orbited the earth when you would probably notice that you were in zero gravity because in an orbiting satellite the attraction of the earth is exactly balanced by the centrifugal force of the orbit.
There is only one distance at which the forces exactly balance out and that distance is the distance of the satellite's centre of mass.  That is the only distance at which the gravitational attraction is exactly what is needed to produce the appropriate central force to keep the craft in its orbit. On parts of the satellite away from the Earth, there is a small net  force 'outwards' and on parts on the side of Earth there is a small net force 'inwards'. What you really have, in an orbiting craft, is microgravity and not zero gravity.
This is the same effect that causes two tidal bulges of the seas around the Earth.
If your satellite were very flexible, it would stretch in the same way, making it elongated along the radius of the orbit; wierd.
Title: If we Built a Building BIG enough, could we sense Earth's rotation?
Post by: lyner on 06/04/2008 12:52:56
If the building was 35km tall.. And I was on the toppest floor in a room.. would I be stuck onto one side of the room, because of the earth rotating?
No -  there is no tangential acceleration - you are going in a circle at uniform speed. You would just 'feel' a bit lighter. 35km wouldn't be anything like enough to get a different measure of weight. You could measure the difference in G field, though, through general relativistic  effects on time (search on the Mossbauer effect, for instance).
Title: If we Built a Building BIG enough, could we sense Earth's rotation?
Post by: Seany on 06/04/2008 12:53:33
How much less would you weigh?
Title: If we Built a Building BIG enough, could we sense Earth's rotation?
Post by: graham.d on 06/04/2008 13:15:30
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.
Title: If we Built a Building BIG enough, could we sense Earth's rotation?
Post by: Seany 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?
Title: If we Built a Building BIG enough, could we sense Earth's rotation?
Post by: Madidus_Scientia 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)
Title: If we Built a Building BIG enough, could we sense Earth's rotation?
Post by: graham.d 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.
Title: If we Built a Building BIG enough, could we sense Earth's rotation?
Post by: Carolyn 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! [:)]
Title: If we Built a Building BIG enough, could we sense Earth's rotation?
Post by: Make it Lady 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. 
Title: If we Built a Building BIG enough, could we sense Earth's rotation?
Post by: lyner on 06/04/2008 21:37:37
How much less would you weigh?
****** all.
Title: If we Built a Building BIG enough, could we sense Earth's rotation?
Post by: Make it Lady on 06/04/2008 22:25:14
What units are you working in here?
Title: If we Built a Building BIG enough, could we sense Earth's rotation?
Post by: Seany 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!! [:D]
Title: If we Built a Building BIG enough, could we sense Earth's rotation?
Post by: Seany 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!
Title: If we Built a Building BIG enough, could we sense Earth's rotation?
Post by: Karen W. 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!!
Title: If we Built a Building BIG enough, could we sense Earth's rotation?
Post by: Karen W. 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!
Title: If we Built a Building BIG enough, could we sense Earth's rotation?
Post by: Karen W. 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!
Title: If we Built a Building BIG enough, could we sense Earth's rotation?
Post by: another_someone 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.
Title: If we Built a Building BIG enough, could we sense Earth's rotation?
Post by: lyner on 07/04/2008 10:57:37
What units are you working in here?
firkins?
Title: If we Built a Building BIG enough, could we sense Earth's rotation?
Post by: Seany 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!
Title: If we Built a Building BIG enough, could we sense Earth's rotation?
Post by: Seany 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!! [;D]
Title: If we Built a Building BIG enough, could we sense Earth's rotation?
Post by: Make it Lady 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.
Title: If we Built a Building BIG enough, could we sense Earth's rotation?
Post by: Make it Lady 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!! [:D]

Whoever you build it for will come. I'll come.
Title: If we Built a Building BIG enough, could we sense Earth's rotation?
Post by: Make it Lady 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!! [;D]

I think health and safety would have a field day.
Title: If we Built a Building BIG enough, could we sense Earth's rotation?
Post by: Bored chemist 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.
Title: If we Built a Building BIG enough, could we sense Earth's rotation?
Post by: Madidus_Scientia on 08/04/2008 09:59:49
Haha yeah you would too, didn't think of that
Title: If we Built a Building BIG enough, could we sense Earth's rotation?
Post by: Titanscape 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.
Title: If we Built a Building BIG enough, could we sense Earth's rotation?
Post by: lyner 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 (http://www.thenakedscientists.com/forum/index.php?topic=11878.0)
Title: If we Built a Building BIG enough, could we sense Earth's rotation?
Post by: Emetsipe 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.

Database Error

Please try again. If you come back to this error screen, report the error to an administrator.
Back