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Drake's equation

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samivel
54326.  Wed Feb 22, 2006 7:53 am Reply with quote

Is it too long?

 
dr.bob
54329.  Wed Feb 22, 2006 7:58 am Reply with quote

Gray wrote:
What a strange coincidence - I've just this minute come across that book as the origin of the concept of Dyson Spheres.


Errrmmmmm

Wasn't Freeman Dyson the origin of the concept of Dyson Spheres? Hence the name.

Or are you suggesting he pinched the idea from a book?

 
Tas
54393.  Wed Feb 22, 2006 9:40 am Reply with quote

or from a vacuum cleaner?

:-)

Tas

 
Quaintly Ignorant
54401.  Wed Feb 22, 2006 10:02 am Reply with quote

Within Gray's link it does state:

Quote:
Dyson acknowledged that the inspiration for his scheme came from Olaf Stapledon's Star Maker:


Freeman Dyson is a quite interesting chap what with the
Dyson Shell = http://en.wikipedia.org/wiki/Dyson_sphere,
Dyson Tree = http://en.wikipedia.org/wiki/Dyson_tree and his work on
Nuclear Propulsion = http://en.wikipedia.org/wiki/Project_Orion and nothing whatever to do with vacuum cleaners or washing machines. :-)

 
Tas
54412.  Wed Feb 22, 2006 10:16 am Reply with quote

Nuclear Propulsion in Space.

Now there is an interesting idea. Once the vehicle is in space, wouldn't it be more effective to use Nuclear power to provide thrust, for initial speeds and then slingshot around various moons and planets? I'm not sure about using mini bombs for thrust, but there must be some way to use this?

Whilst I am on about this, wouldn't it also be more effective to launc a vehicle from outside the Earths gravity? I am sure more speed would be produced if the 'ship' had it's fuel ferried up to it, and it was then launched from orbit?

Anyone wanna chat about this? Or should I make it another thread?

:-)

Tas

 
Tas
54413.  Wed Feb 22, 2006 10:18 am Reply with quote

Dyson Spheres:

The only problem I could see with this, would be the tremendous radiation problems, especially with any sort of solar ejection...still, I guess one would get a helluva tan!

:-)

Tas

 
Quaintly Ignorant
54437.  Wed Feb 22, 2006 10:55 am Reply with quote

On Nuclear Propulsion:

Launching a nuclear pulse rocket from earth is entirely possible but I think a polar launch site wold be required to avoid human contamination. Antartica would be perfect. Leaving aside the problems of getting the craft up there, project Orion is the closest humans have come to large scale space operations. It is said one Orion mission would be enough to establish a permanent moon-base. We could get to Pluto and back inside a year.

Quote:
The Orion nuclear pulse rocket design has extremely high performance. Orion nuclear pulse rockets using nuclear fission type pulse units were originally intended for use on interplanetary space flights. Orion rockets using nuclear fusion pulse units were intended for use on interstellar space flights.

The top cruise velocity that can be achieved by a thermonuclear Orion starship is about 8% to 10% of light velocity. An atomic (fission) Orion can achieve perhaps 3%-5% of the speed of light. A nuclear pulse drive starship powered by matter-antimatter pulse units would be theoretically capable of obtaining a velocity of from 50% to 80% of the speed of light.


The technology to build these things has existed since the 1950's but the nuclear tensions arising from the cold war put paid to them. Carl Sagan, thorough genius that he was proposed that the worlds stock of nuclear weapons would be perfect for this use. Project Daedalus was to be a robotic interstellar probe to Barnard's Star that would travel at 12% of the speed of light. In 1989, an improved version of the original Daedalus design was created by the U.S. Navy in Project Longshot; the main design difference was that Daedalus relied on the fusion reaction being able to power the ship as well, whereas in Longshot the external reactor provided this power.

Now that Russia has lost much of its influence and nuclear tensions aren't so high, for the moment, a ressurection of these projects should be in order.

 
Quaintly Ignorant
54440.  Wed Feb 22, 2006 10:58 am Reply with quote

Tas wrote:
Dyson Spheres:

The only problem I could see with this, would be the tremendous radiation problems, especially with any sort of solar ejection...still, I guess one would get a helluva tan!

:-)

Tas

Most science fiction portrays the sphere as an enclosed structure but Dyson had in mind asteroid sized colonies dotted around the star at similar distances. Although actually building a sphere around a sun would be pretty cool.

 
Tas
54453.  Wed Feb 22, 2006 11:10 am Reply with quote

Wouldn't a Dyson sphere get very hot, rather than be cool? Or at least glow with Simpson-raditaion?

:-)

Tas

 
dr.bob
54811.  Thu Feb 23, 2006 9:19 am Reply with quote

Quaintly Ignorant wrote:
Launching a nuclear pulse rocket from earth is entirely possible but I think a polar launch site wold be required to avoid human contamination.


Leaving aside for a moment the problem of non-human contamination, I think even humans will experience plenty of contamination once the rocket gets up into the high atmosphere and carries on chucking nuclear bombs out the back.

Freeman Dyson is definitely an extremely clever man and, like most extremely clever people, is ever so slightly unhinged :)

 
Tas
54831.  Thu Feb 23, 2006 9:48 am Reply with quote

So, why not launch the rocket in a conventional manner, and then pulse blast away to your hearts content when suitably far away?

:-)

Tas

 
Quaintly Ignorant
54852.  Thu Feb 23, 2006 10:34 am Reply with quote

The worry is flooding the Van Haalen (sp) belt with radiation. We are, for the moment at least, well protected by Earth's magnetic field.

"There is a fine line between genius and insanity; I have erased this line."

 
Tas
54854.  Thu Feb 23, 2006 10:36 am Reply with quote

Hang on a sec....if the Van Allen Radiation Belt can handle solar eruptions (flares are sooooo 70s!), surely a few small nukes should cause a worry?

Or is it the specific types of radiation that cause the problem?

:-)

Tas

 
Quaintly Ignorant
54940.  Thu Feb 23, 2006 3:12 pm Reply with quote

I think it becomes a problem for future manned space-flight. Although, it may be possible to clean out lots of the belt with focused nuclear blasts.

 
dr.bob
55070.  Fri Feb 24, 2006 5:19 am Reply with quote

Tas wrote:
Hang on a sec....if the Van Allen Radiation Belt can handle solar eruptions (flares are sooooo 70s!), surely a few small nukes should cause a worry?


No, once you're past the Van Halen (excellent name! :) belts and into space there's no problem. I was just drawing attention to the problems of detontaing several large nuclear devices in the upper atmosphere. That will probably cause significant problems in the environment, especially if it becomes a regular way of launching spacecraft.

 

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