'Ere, where's the elephant then?

[FatLazyContractor]

Instead of flying thousands of miles to Australia, burning shed loads of fuel, I don't know why British Airways don't just fly straight up, I think space is about 50 miles away. Hang around in neutral for 12 hours until the Earth spins round, maybe hold a disco on board for the passengers then fly straight back down again.

+1

Also provide hummer truck "services". I will be one of their first customers.

[OwlHoot]

Poor old Copernicus.

Yes, his grave must be spinning round him

OH in "eppur si muove" mode

[VectraMan]

Early physicists ( or the equivalent ) identified a number of phenomenon that confirmed the rotation of the earth. Newton predicted that the rotation would cause an equatorial bulge and this was confirmed by physical measurement in the 18th Century.

Foucalts Pendulum is the classic practical experiment to demonstrate the earth is rotating.

You can see the effects of rotation in the Coriolis effect that means a projectile will veer to the right in the northern hemisphere and to the left in the southern relative to the point it was aimed at. This is something taken into account when plotting targets for long range gunnery such as sniper fire, naval gunfire and artillery fire.

I always thought physics glosses over this point. There's meant to be no such thing as absolute movement, as movement is always relative, and relative to me sat here near Oxford the earth is not rotating. Yet the things above prove that the earth is rotating, so it must be rotating relative to something; there must be an absolute. And therefore relatively is a load of old nonsense.

[VectraMan]

Instead of flying thousands of miles to Australia, burning shed loads of fuel, I don't know why British Airways don't just fly straight up, I think space is about 50 miles away. Hang around in neutral for 12 hours until the Earth spins round, maybe hold a disco on board for the passengers then fly straight back down again.

Except that wouldn't get you to Australia; only to places on the same latitude. So that's basically Canada and Russia.

[SpontaneousOrder]

I always thought physics glosses over this point. There's meant to be no such thing as absolute movement, as movement is always relative,

That's not true.
This only holds true in 'special' relativity (with the 'special' essentially meaning certain assumptions & caveats). In reality (which 'general' relativity models) the actual mover will have experienced a acceleration force at some point - hence things like the twin paradox not really being a paradox.

[SpontaneousOrder]

Instead of flying thousands of miles to Australia, burning shed loads of fuel, I don't know why British Airways don't just fly straight up, I think space is about 50 miles away. Hang around in neutral for 12 hours until the Earth spins round, maybe hold a disco on board for the passengers then fly straight back down again.

That's pretty much what the cleric was suggesting. Funnily enough, though, that exact same example demonstrates the rotation - spacebound vehicles launch near the equator, and head east, in order to gain enough speed to maintain orbit. If the earth didn't rotate it wouldn't matter what direction they flew in or at what lattitude they launched from.

[NotAllThere]

Rotational movement requires a force. Linear movement doesn't. The former is absolute, the latter relative.

Is the universe as a whole rotating and if so, can we determine its axis?

[DaveB]

Rotational movement requires a force. Linear movement doesn't. The former is absolute, the latter relative.

Is the universe as a whole rotating and if so, can we determine its axis?

Probably not, but then again it may be.

Is the Universe rotating?

Which doesn't seem to have moved on much from what Stephen Hawking wrote in 1968.

1969MNRAS.142..129H Page 129

[VectraMan]

Rotational movement requires a force. Linear movement doesn't. The former is absolute, the latter relative.

Where's the force coming from? And if it needs a force why doesn't the earth get tired and slow down?

[SpontaneousOrder]

Where's the force coming from? And if it needs a force why doesn't the earth get tired and slow down?

It's a virtual force made up of the real forces binding together the body which is rotating yet not flying apart. Just like centrifugal force on the fairground ride where the ground drops out id a virtual force (but of course real forces are involved). I.e. all of the forces balance out and the overall momentum of rotation is conserved.