If Only ...

[DaveH]

Talc

Gypsum

Calcite

Fluorite

Apatite

Orthoclase

Quartz

Topaz

Carborundum

Diamond

seems to be the correct list (didn't recall all of them from my geological period 15 years ago - had to do a bit of web searching to fill in a few gaps)

Looks right to me madannie, - looks like Doc. Dick taught us well lol

[DaveH]

Actually

Given the approximate diameter of Earth, and a comfortable man sized hole of 1.5 mts diameter,

I recon 22,500,00 cubic mts (22 500 000 000 ltrs) of it would be swallowed. (Give or take a bit for spillage ).

(But that's only if I correctly remember my sums from school)

Is that the volume to the Earth's centre or all the way through?

It is debateable weather the effects of gravity would only half fill the hole or completely fill it to the other side when the moving liquid finally came to rest.

[DaveH]

So, Mauna Kea gets its righful place as the tallest ...

That depends doesn't it.

It would still be the tallest (as it is now) but its height above sea level, which would be lowered by some of it going down the hole would be greater.

Although vox has calculated a very large volume it is likely that the volume of the oceans is so much bigger in comparison that the drop in sea level wouldn't be that great (especially as the hole is only 1.5 metres in diameter)

I suppose someone wants me to try and calculate exactly how much sea level would drop by

Assuming that the Earth is an oblate spheroid, ....POSSIBLY....

[vox]

Is that the volume to the Earth's centre or all the way through?

It is debateable weather the effects of gravity would only half fill the hole or completely fill it to the other side when the moving liquid finally came to rest.

All the way through. (not that it would be possible in reality)

I think that's what would happen because of the weight of the rest of the ocean above one side.

Wouldn't that make it shoot out the other side like a fountain until the pressure equalised. If it did then England would be flooded. The water would eventually drain back to the sea which would re fill the ocean and cause a constant flow.

(perhaps) :blink:

[DaveH]

All the way through. (not that it would be possible in reality)

I think that's what would happen because of the weight of the rest of the ocean above one side.

Wouldn't that make it shoot out the other side like a fountain until the pressure equalised. If it did then England would be flooded. The water would eventually drain back to the sea which would re fill the ocean and cause a constant flow.

(perhaps)

Once past the half way point gravity is already dragging the water back, only its momentum carries it past the centre.

By the time it reached the surface its momentum would be zero so I don't think you would get a fountain at this side.

However, like you, I think it would fill the entire hole as that water which had gone past the centre would not be able to return if water was continually flooding in at the other end.

But fluids are strange, if it was a highly viscous liquid (like treacle) it could go down the hole slowly enough to not overshoot the centre and effectively only fill half the hole.

[DaveH]

OK Stuart I'll leave this one for you as it gets rid of most the maths and introduces a solution using maps.

On a scale map of the south pacific locate my point given in the co-ordinates, measure from it to Tasmania (Lets say Hobart for accuracy of placement) and calculate the scale distance.

That would answer one of THYLACINE's questions about how far he would need to swim to get home after emerging from the hole.

Due to gravity of course, that whole would be drinking up half of the Pacific Ocean

Looks like I'm quicker with the advanced maths skills than Stuart is with the mapreading skills.

The hole emerges at 178 deg 30 min EAST and 53deg 22min SOUTH

Hobart, Tasmania is at 147 deg 19 min EAST and 42 deg 53 min SOUTH

Without frightening any more non - technical members I did a great circle calculation on this to calculate the shortest distance between these 2 points.

So without the working, the distance is 1592 miles that THYLACINE would have to swim to get home after emerging from hole through the centre of the Earth trip to Sheffield

Thats quite a long swim THYLACINE

Perhaps a 23 hour flight by British Airways or Quantas isn't too bad after all lol

[vox]

Once past the half way point gravity is already dragging the water back, only its momentum carries it past the centre.

By the time it reached the surface its momentum would be zero so I don't think you would get a fountain at this side.

However, like you, I think it would fill the entire hole as that water which had gone past the centre would not be able to return if water was continually flooding in at the other end.

But fluids are strange, if it was a highly viscous liquid (like treacle) it could go down the hole slowly enough to not overshoot the centre and effectively only fill half the hole.

But what about the initial weight of water above the hole ? Wouldn't that have an effect similar to pumping it in like a bicycle pump ?

[DaveH]

But what about the initial weight of water above the hole ? Wouldn't that have an effect similar to pumping it in like a bicycle pump ?

It would (that would be the pressure at the sea bed) and if the sea level did not drop significantly this force would be almost constant.

However, that pressure / force is created by Gravity pulling the water down onto the sea bed.

It's the same force that pulls it through the hole, and pulls it back once past the centre.

As Gravity seems to control all the force and motion in this little hypothetical model I still don't think it would shoot out of the other side and I stick by my initial comment.

Water always finds its own level they say.

If we assume that the Earth is a perfect sphere (ie it has a uniform radius) then water starts at sea level on one side and would finish at sea level on the other, both equal distances from the centre.

As Sheffield is significantly above sea level you would have to drill down a fair way even before you reached the water in the hole which was "spill through" from the Pacific.

[vox]

As Sheffield is significantly above sea level you would have to drill down a fair way even before you reached the water in the hole which was "spill through" from the Pacific.

Phew. Were safe from that possible cause of flooding then.

I'll sleep easy tonight Dave. lol

[DaveH]

Phew. Were safe from that possible cause of flooding then.

I'll sleep easy tonight Dave.

Not that safe vox, the reality would be much worse.

THYLACINE said we could ignore the 25,000 tons per square inch pressure and the 6000 degree temperature.

Water flooding into that hole would immediately be vapourised into steam (or at that temperatures even decomposed into hydrogen and oxygen).

The resulting expansion as the liquid turned to gas would generate collossal pressures, way in excess of the 25,000 tons per square inch.

That would create a hell of a hot water geyser at either end of that hole.

The largest recorded NATURAL explosion on record, which was bigger than a nuclear explosion, was the eruption of Krakatoa in Indonesia in 1883

This was caused by approximately 1 cubic mile (the official estimate) of sea water breaking into the volcanoes magma chamber and being vapourised to steam. With the volcanic vent blocked the whole island exploded, it could be heard hundreds of miles away, it triggered tsunamis which swept around the world and it threw so much ash into the upper atmosphere (the entire island) that it spread around the world and remained there for several years giving a series poor summers and bad weather due to "global dimming". The whole island was completely destroyed and dissapeared below sea level, - although it has reappeared since due to continuing volcanic activity in the area.

Now the water in our hole would dwarf this due to the greater scale, pressures and temperatures, and with the epicentre of the explosion being at the Eath's centre

Would the Earth itself survive these forces?

Or would they be sufficient to blast the entire world apart?

Sleep easy tonight vox! lol

[THYLACINE]

But what about the initial weight of water above the hole ? Wouldn't that have an effect similar to pumping it in like a bicycle pump ?

Thanks guys for the Journey to the Centre of the Earth, it was better than the film. Enjoyed all the calculation and speculation. Digging a hole through the centre of the earth, like many of mankinds grand theories will always remain a matter for conjecture. But at least I know I will have to take my trunks.

[DaveH]

Thanks guys for the Journey to the Centre of the Earth, it was better than the film. Enjoyed all the calculation and speculation. Digging a hole through the centre of the earth, like many of mankinds grand theories will always remain a matter for conjecture. But at least I know I will have to take my trunks.

Back to a more practical solution for you then THYLACINE.

In the 1980's there was a lot of interest in "Project HOTL" (Stands for HOrizontal Take off and Landing)

I believe even Richard Branson / Virgin Airways was interested in it, although it seems to have come to nothing, possibly because of cost.

It would involve a rocket powered aircraft (hence the horizontal take off and landing bit), a bit like a smaller, lower powered version of the space shuttle capable of suborbital flight and used for long haul passenger transport.

The riocket plane takes off like a normal jet aircraft but then climbs steeply out of the atmosphere to a height of about 80 miles.

When the rocket cuts out and you go into weightlessness it will have achieved around 16.000mph but have travelled only a couple of hundred miles.

It will now "coast" around the world to its destination. It is ballistic, it has effectively been "thrown" half way around the world.

The force which keeps it going and on course is, once again our old friend gravity.

16,000mph is a suborbital speed, it is not quite fast enough to go into orbit and it will start to fall back into the atmosphere about half way around the world from its starting point.

This will cause decelleration as the atmosphere is re-entered and with suitable reapplication of power it can be slowed down and flown conventionally like an aircraft for a standard landing.

As this is a subortal flight the time for half an orbit would be, as Bayleaf said earlier in this topic, about 45 minutes.

In fact, the publicity material for Project HOTL had bold statements such as, -

London Heathrow to Sydney Australia in just three quarters of an hour!

and

Take a day trip to Australia

(OK, so the total travelling time there and back is just an hour and a half so it is perfectly possible, but travelling across 10 time zones in just 45 minutes wouldn't half leave you suffering from jetlag)

If it had ever come to anything how about Sheffield to Hobart Tasmania in 50 minutes (or even an hour)?

You could have a day trip to Sheffield THYLACINE lol

[THYLACINE]

Back to a more practical solution for you then THYLACINE.

In the 1980's there was a lot of interest in "Project HOTL" (Stands for HOrizontal Take off and Landing)

I believe even Richard Branson / Virgin Airways was interested in it, although it seems to have come to nothing, possibly because of cost.

It would involve a rocket powered aircraft (hence the horizontal take off and landing bit), a bit like a smaller, lower powered version of the space shuttle capable of suborbital flight and used for long haul passenger transport.

The riocket plane takes off like a normal jet aircraft but then climbs steeply out of the atmosphere to a height of about 80 miles.

When the rocket cuts out and you go into weightlessness it will have achieved around 16.000mph but have travelled only a couple of hundred miles.

It will now "coast" around the world to its destination. It is ballistic, it has effectively been "thrown" half way around the world.

The force which keeps it going and on course is, once again our old friend gravity.

16,000mph is a suborbital speed, it is not quite fast enough to go into orbit and it will start to fall back into the atmosphere about half way around the world from its starting point.

This will cause decelleration as the atmosphere is re-entered and with suitable reapplication of power it can be slowed down and flown conventionally like an aircraft for a standard landing.

As this is a subortal flight the time for half an orbit would be, as Bayleaf said earlier in this topic, about 45 minutes.

In fact, the publicity material for Project HOTL had bold statements such as, -

London Heathrow to Sydney Australia in just three quarters of an hour!

and

Take a day trip to Australia

(OK, so the total travelling time there and back is just an hour and a half so it is perfectly possible, but travelling across 10 time zones in just 45 minutes wouldn't half leave you suffering from jetlag)

If it had ever come to anything how about Sheffield to Hobart Tasmania in 50 minutes (or even an hour)?

You could have a day trip to Sheffield THYLACINE

Dave, Been racking my brain, my humble library and the internet, your Project HOTL sounds like an essay I read some time ago about a mythical bird which did exactly what you describe above. The even gave this bird a name but I can't find it now. A ny ideas?

[DaveH]

Dave, Been racking my brain, my humble library and the internet, your Project HOTL sounds like an essay I read some time ago about a mythical bird which did exactly what you describe above. The even gave this bird a name but I can't find it now. A ny ideas?

Having read your reply I have tried to look it up again.

Part of the problem may have been that I spelt HOTOL wrong, - missing out an O which stands for "Off"

It's called project HOTOL not project HOTL.

With 25 years since the project was launched it seems to have completely disappeared without trace, just liked the famed aircraft the TSR2.

However, I am not making this up. There is a short reference to it here in a book I have from 1986 called "Frontiers of Space" published by WHSmith.

Don't know anything a bird though.

[DaveH]

Having read your reply I have tried to look it up again.

Part of the problem may have been that I spelt HOTOL wrong, - missing out an O which stands for "Off"

It's called project HOTOL not project HOTL.

With 25 years since the project was launched it seems to have completely disappeared without trace, just liked the famed aircraft the TSR2.

However, I am not making this up. There is a short reference to it here in a book I have from 1986 called "Frontiers of Space" published by WHSmith.

Don't know anything a bird though.

Found this on Wikipedia

Project HOTOL

It appears that the bird you are thinking of was a swallow.

[Bayleaf]

Found this on Wikipedia

Project HOTOL

It appears that the bird you are thinking of was a swallow.

Would that be an African swallow?

[DaveH]

Would that be an African swallow?

Don't know Bayleaf, - it just say a swallow on that Wikepedia link I found.

[RichardB]

Don't know Bayleaf, - it just say a swallow on that Wikepedia link I found.

Wot was its air-speed velocity ? :rolleyes:

[Bayleaf]

Thank you Richard!...

Courtesy of Monty Python and the Holy Grail....

GUARD #1: Where'd you get the coconut?

ARTHUR: We found them.

GUARD #1: Found them? In Mercia? The coconut's tropical!

ARTHUR: What do you mean?

GUARD #1: Well, this is a temperate zone.

ARTHUR: The swallow may fly south with the sun or the house martin or the plover may seek warmer climes in winter yet these are not strangers to our land.

GUARD #1: Are you suggesting coconuts migrate?

ARTHUR: Not at all, they could be carried.

GUARD #1: What -- a swallow carrying a coconut?

ARTHUR: It could grip it by the husk!

GUARD #1: It's not a question of where he grips it! It's a simple question of weight ratios! A five ounce bird could not carry a 1 pound coconut.

ARTHUR: Well, it doesn't matter. Will you go and tell your master that Arthur from the Court of Camelot is here.

GUARD #1: Listen, in order to maintain air-speed velocity, a swallow needs to beat its wings 43 times every second, right?

ARTHUR: Please!

GUARD #1: Am I right?

ARTHUR: I'm not interested!

GUARD #2: It could be carried by an African swallow!

GUARD #1: Oh, yeah, an African swallow maybe, but not a European swallow, that's my point.

GUARD #2: Oh, yeah, I agree with that...

ARTHUR: Will you ask your master if he wants to join my court at Camelot?!

GUARD #1: But then of course African swallows are not migratory.

GUARD #2: Oh, yeah...

GUARD #1: So they couldn't bring a coconut back anyway...

[clop clop]

GUARD #2: Wait a minute -- supposing two swallows carried it together?

GUARD #1: No, they'd have to have it on a line.

GUARD #2: Well, simple! They'd just use a standard creeper!

GUARD #1: What, held under the dorsal guiding feathers?

GUARD #2: Well, why not?

[DaveH]

Wot was its air-speed velocity ?

A lot slower than I thought Richard.

Originally it was supposed to be suborbital, around 15,000 mph, flight time to Australia would be 45 minutes

The Wikepedia link gives the speed as Mach 5 to Mach 7

If the speed of sound is around 760 mph then this equates to 3800 to 5320 mph

However that would still give a flight time to Australia of under 3 hours

Given that it takes under 3 hours to go from Sheffield to London on the train and people regularly do a "day trip" to London by rail

It means that THYLACINE would still be able to have his "day trip" home to Sheffield using HOTOL

Interestingly in the mid 1980's when Concorde was still flying (Mach 2 or 1500mph) I remember that one of the top prizes once offered on the quiz programme "Blockbusters" by Bob Holness was "A day trip to Egypt on Concorde"