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Jenny
738001.  Mon Aug 30, 2010 5:36 pm Reply with quote

St John, New Brunswick, has reversing waterfalls, unlikely as that sounds - I've seen them.

 
Jenny
738002.  Mon Aug 30, 2010 5:39 pm Reply with quote

Reddy's post 737773 on internal decapitation might be another 'impossible' as well.

 
PDR
738008.  Mon Aug 30, 2010 6:07 pm Reply with quote

A vectored-thrust VTOL aeroplane can simultaneously get 8,600lbs of vertical thrust and 5,000lbs of forward thrust (a total of 13,600lbs) from a single engine that is only developing 10,000lbs of thrust with the nozzles inclined 60 degrees downwards. So 3,600lbs of "free thrust" appears in an impossible burst of geometric obstinacy...

If seperate lift and thrust engines were used this would not be possible, and it's the primary reason for the choice of the single-engined vectored thrust layout for the Harrier (still the world's only effective operational VTOL fast jet). Hawker's marketing department once tried to brand it "Geometric Thrust Augmentation", but it never caught on. The real benefit comes in the STOL and ski-jump performance rather than actual VTOL performance.

NALOPKT(&EFGAS)

PDR

 
Spud McLaren
738017.  Mon Aug 30, 2010 8:00 pm Reply with quote

I'm sure this applies to many combinations, but one I remember from Arthur Mee's Children's Encyclopedia was that you can take a pint of an alcohol and mix it with a pint of water, but the resulting mixture will occupy only 1.92 pints.

 
Zebra57
738019.  Mon Aug 30, 2010 8:12 pm Reply with quote

Spud wrote "No rivers run uphill", while this is basically true there are situations when the impossible occurs.

Between December 1811and February 1812 the massive New Madrid Earthquakes were reported to have reversed the flow of the River Mississippi.

 
RLDavies
738045.  Tue Aug 31, 2010 4:37 am Reply with quote

Zebra57 wrote:
Spud wrote "No rivers run uphill", while this is basically true there are situations when the impossible occurs.

Between December 1811and February 1812 the massive New Madrid Earthquakes were reported to have reversed the flow of the River Mississippi.

Oh, that reminds me of a quibble I had with the show. When discussing the New Madrid earthquake many series ago, the redoubtable Mr Fry pronounced the town as if it was the Spanish city of Mahd-RID. But, as anyone from Missouri will tell you, it's MADD-rid.

And it was indeed a dem'd big earthquake. Rang the church bells in Boston.

 
Spud McLaren
738076.  Tue Aug 31, 2010 5:51 am Reply with quote

Zebra57 wrote:
Spud wrote "No rivers run uphill", while this is basically true there are situations when the impossible occurs.

Between December 1811and February 1812 the massive New Madrid Earthquakes were reported to have reversed the flow of the River Mississippi.
But that's running backwards, or (more accurately) in the opposite direction from that which it normally takes - not "uphill". The lie of the land altered. The water still flowed from one location to a slightly lower one, it's just that the slightly lower one was formerly the slightly higher one. In fact

"There were temporary river waterfalls where the Mississippi ran backwards during 1811-12 earthquakes. It happened early on Feb. 7, 1812, when a thrust fault created a sudden dam several feet high in the bottom of the river loop near New Madrid.

The main section involved was from island 10 northward about 10 miles to island 8. It lasted for a few hours, though the new dams/waterfalls lasted for a few DAYS, and ruined several flatboats."

from http://showme.net/~fkeller/quake/mississippi_river_ran_backward.htm


In effect, a dam was suddenly created and the water backed up. That's completely different from defying gravity and flowing uphill. You can get water to flow uphill, but either by use of specific additives, or under lab conditions.

 
Jenny
738174.  Tue Aug 31, 2010 9:54 am Reply with quote

RLDavies wrote:
When discussing the New Madrid earthquake many series ago, the redoubtable Mr Fry pronounced the town as if it was the Spanish city of Mahd-RID. But, as anyone from Missouri will tell you, it's MADD-rid.


And Madrid in Maine is pronounced MADE-rid, Vienna is pronounced Vy-EN-na, and Calais pronounced CAL-us to rhyme with palace.

Edited for typo.


Last edited by Jenny on Thu Sep 16, 2010 3:17 pm; edited 1 time in total

 
Neotenic
743671.  Thu Sep 16, 2010 5:08 am Reply with quote

When telephones were impossible

There's also this, apparently from an item in a New York paper in 1868;

Quote:
A man has been arrested in New York for attempting to extort funds from ignorant and superstitious people by exhibiting a device which he says will convey the human voice any distance over metallic wires so that it will be heard by the listener at the other end. He calls this instrument a telephone. Well-informed people know that it is impossible to transmit the human voice over wires.

 
PDR
743674.  Thu Sep 16, 2010 5:24 am Reply with quote

They were quite right - it is impossible. No human voice ever gets past the menu system...

PDR

 
Flash
743678.  Thu Sep 16, 2010 5:44 am Reply with quote

Neo - my spidey sense reckons that Popular Science was either the victim or the perpetrator of a hoax, there. An interesting thing, though: if you scroll up a couple of pages from the 1928 article you link to, there's a description of a working fax machine (under the title "Shorthand sent by telephoto", top of p72).

 
brunel
743693.  Thu Sep 16, 2010 6:39 am Reply with quote

Spud McLaren wrote:
Zebra57 wrote:
Spud wrote "No rivers run uphill", while this is basically true there are situations when the impossible occurs.

Between December 1811and February 1812 the massive New Madrid Earthquakes were reported to have reversed the flow of the River Mississippi.
But that's running backwards, or (more accurately) in the opposite direction from that which it normally takes - not "uphill". The lie of the land altered. The water still flowed from one location to a slightly lower one, it's just that the slightly lower one was formerly the slightly higher one. In fact

"There were temporary river waterfalls where the Mississippi ran backwards during 1811-12 earthquakes. It happened early on Feb. 7, 1812, when a thrust fault created a sudden dam several feet high in the bottom of the river loop near New Madrid.

The main section involved was from island 10 northward about 10 miles to island 8. It lasted for a few hours, though the new dams/waterfalls lasted for a few DAYS, and ruined several flatboats."

from http://showme.net/~fkeller/quake/mississippi_river_ran_backward.htm


In effect, a dam was suddenly created and the water backed up. That's completely different from defying gravity and flowing uphill. You can get water to flow uphill, but either by use of specific additives, or under lab conditions.


I've heard that the Amazon river does actually flow uphill towards the end of the river. In this particular section, the increase in elevation is very small - perhaps one or two metres in every thousand - but, because the amount of water flowing in the river is so large, the effects of the Coriolis force outweigh that of the effects of gravity, and force the flow uphill.
I am afraid that, at the moment, I have been unable to substantiate the claim, nor been able to prove that it would be possible.

 
PDR
743710.  Thu Sep 16, 2010 7:56 am Reply with quote

I think you're refering to the "Casiquiare"(sp?) which from memory is a natural canal that links the Amazon with another river (my brain says it's the Orinoco, but it has been increasingly error-prone over the last few years so don't quote me on it).

IIRC there is something rather strange about the Casiquiare in the way it appears to cross the dividing feature between two drainage systems (which should involve water effectively flowing up hill, but I can't remember the details).

But I'm not sure that Coriolis has anything to do with it - coriolis force force is a "fictitious" force and so should be confined to Booker Prize submissions and expense claims...

:0)

PDR

 
brunel
743734.  Thu Sep 16, 2010 8:52 am Reply with quote

PDR wrote:
I think you're refering to the "Casiquiare"(sp?) which from memory is a natural canal that links the Amazon with another river (my brain says it's the Orinoco, but it has been increasingly error-prone over the last few years so don't quote me on it).

IIRC there is something rather strange about the Casiquiare in the way it appears to cross the dividing feature between two drainage systems (which should involve water effectively flowing up hill, but I can't remember the details).

But I'm not sure that Coriolis has anything to do with it - coriolis force force is a "fictitious" force and so should be confined to Booker Prize submissions and expense claims...

:0)

PDR

Fair enough - I only reported the anecdote as it was given to me at the time, and because of other commitments, I had never got round to researching the comment to see if it was true.

 
Jaster
767531.  Thu Dec 16, 2010 9:34 am Reply with quote

How about the Onyx River in Antarctica ?

It flows inland not towards the sea
It's dry most of the time
Sometimes it does not reach it's outflow in Lake Vanda (which has no outflow)
It's only fed by meltwater not rain/snowfall since it is in Wright Valley a dry valley where it has not rained for at least a few thousand years ...

 

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