Does Life Exist

[JurijD]

THE SPINNING SHIP PROBLEM:

The 3 problems I saw mentioned here about using rotational inertia to replace gravity were:

1. movements of astronauts *inside* would "distabilize" the ship and cause it to stop rotating properly
2. as humans aren´t a point object as high school physics would like us to believe a thing called the Corelious force develops when you rotate them on the inside of a wheel like structure of a radious not big enough compared to the size of the person inside.
3. even though inertia gives us 1 g and minimum corelious force we still experience muscle atrophy and "back stress"

My thoughts on these:
1. If we look closely at Newtons laws of motion we see that every action as a reaction... so what could be the "worst" disturbance an astronaut could cause to a rotating wheel? The absolute worst would be for him to run in the same direction the wheel is spinning... that way his legs would push the wheel in the opposite direction on the spinning motion and tend to slow it down... but the funny thing is that the moment this astronaut stopped running the wheel would start spinning at the same speed as it did in the beginning because there is a little thing called rotational inertia conservation which states that in any inclosed system (a spaceship and its occupats) the rotational inertia of the whole system cannot be changed by internal forces of the system... you can bounce all you want inside but you won´t change anything.

2. The obvious solution to this issue is to build a wheel that has a radious more than 100x the normal height of a person (heeh... big, yes... very big) althugh this might be impractical and almost impossible to do now it might be in the future... but sadly its the only solution physics offers us for now...

3. I´m pretty sure this is the result of insufficient inertia and persisting differential (Corelious) forces in a wheel not big enough or not spinning fast enough. Because if we had a big wheel with almost no differential forces and a g inertial acceleration at the ouer rim... we would´t be able to set it apart from normal gravity. (it´s not only simulated... it´s exactly the same as normal gravity in all it´s affects... you just have to have a wheel big enough to eliminate the differential forces)

[narf poit chez BOOM]

theologically, i've heard that their are microbes in volcanos. so if god put life there, he probably put it on other planets.

250,000,000,000 planets in our galaxy and something like 300,000 galaxies seems like a great waste of space to me otherwise. i mean 75,000,000,000,000,000 stars, since ours is a medium galaxy...it's not if, it's where.

[ August 09, 2003, 09:32: Message edited by: narf poit chez BOOM ]

[deccan]

Warning: Potentially controversial and offensive material, especially to people with strong religious / spiritual beliefs.

It should be obvious that as a fan of SEIV, MOO, Star Trek, Star Wars etc., I enjoy the idea and fantasy of huge starships moving across interstellar distances. But I have to say that I don't believe that it'll ever be anything more than a fantasy. The immense physical / energy problems is one thing. The economic cost / benefit rationale of such an endeavor is another. But perhaps the most overlooked obstacle to such a vision is that humanity may not stay in its current form for every long.

At the very least, one would expect severe genetic / bionic modifications to function optimally in a spaceship, because the energy costs of genetically / bionically modifying a human being is so much less than the costs of moving a ship at respectable velocities. A good example would be the type of modifications described in the short story "Spirey and the Queen" by ALastair Reynolds. This surely puts paid to the Star Trek vision of future space travel.

But why be so conservative? It's likely that within the near future, we could have fully conscious, fully sentient artificial intelligences. Rather than being wholly alien and hostile, as in "Matrix" or "Terminator", I think that the likeliest scenario would be something similar to Walter Jon Williams' story "Daddy's World" , i.e. they'll just be like us, being our offspring. Once conscious software has fully legal rights, I expect that people will start designing, rearing and interacting with software children instead of biological children. A spaceship carrying conscious software has very notable advantages over one that must carry biological lifeforms. In Greg Egan's "Diaspora" for example, "polises" that are physically only about the size of a shoebox, but containing untold billions of independent software persons in VR environments, multiply backed up and constantly updated with similar units with old-fashioned EM communications, creep across the galaxy.

Instead of sending huge colony ships across the galaxy, how about sending non-intelligent software controlled robots to build the necessary sensory, power, construction and communications infrastructure on distant worlds, and then sending future humans to inhabit them in the form of encoded EM radiation. After all, if materialism is true, then person-hood is nothing but data.

[Atrocities]

If you rule out evolution and the religious factors, what could be some other possibilities for how we came to be on this planet?

I am sorry, I do not believe that we evolved from apes and monkies nor do I believe that we were "POOOOF" created. I think there is truth in both however, but no substantial answers.

If we did develop on this world, then yes it is likely, however remote, that life could develop on other worlds. I Subscribe the theory that we are a unique side effect of a lot of rare occurances that lead to our being. I do not believe that the universe is teaming with life and the evidence to date supports this depressing view.

But if we did not evolve on this planet, and were not magically created by some super being calling itself GOD (Government of Domocracy or General Operations Director) then a whole new avenue of possiblities opens. It is this theory that we came from somewhere else that holds the most hope for imagination and coversation for me.

[JurijD]

Originally posted by Atrocities:
I am sorry, I do not believe that we evolved from apes and monkies nor do I believe that we were "POOOOF" created.

You´re right... humans (Homo Sapiens) didn´t evolve from apes and monkeys but from lower primates. Apes and monkeys have a totally different evolutional branch than modern humans.

But since I get the distinct feeling that you really wanted to say that humans didn´t evolve from lower hominids in the way generally accepted by modern science:


Australopithecus Afarensis --> Australopithecus Africanus --> Homo Habilis --> Homo Ergaster --> (Homo Erectus) --> Homo Heidelbergensis --> Homo Sapiens


but rather came about by some other way... (not by a pooof as you say)... I have to urge you to reconsider because human origins are a most accurately researched field of peleoantrophology and a more recent proof of its correctness is that evolutionary trees drawn up by examining bone reamins and anatomical similarities are in complete agreement with the trees drawn by mDNA analysis and genome compression analysis. It is very very rare that two totally different methods give so very similar results; in affect confirming one another. So the human evolution tree is here to stay. We don´t need any aliens or gods to complete the picture, in reality there is no such thing as a "missing link" so often popularized by the media... we have all the important "links" already, now we just add a few "nodes" to the tree every now and then. but the general structure will only get more detailed and won´t change in any radical way.

P.S.: And for those who think humans are the pinnacle of evolution I have to add that about 1 million years ago there were about 3 different fully developoed humanoid races living on this planet. For the evolutionary line is not a linear thing as I drawn it up there but has many other branches and "tree tops" other than our own. More importantly not one of these other hominid species was better developed than the other, we just got lucky that our ancestors were able to drive the other two off their teritories and push them into extiction.


My Conclusion:
So if you consider our ancestors intelligent (some 1M year ago) than the other two races were also intelligent. So we don´t really have to look out there for signs of alien intelligence, we have a perfect example than it can (and did) happen more than once here on Earth and so I´m pretty sure it also happened somewhere else.


[ August 09, 2003, 13:46: Message edited by: JurijD ]

[JurijD]

Originally posted by Atrocities:
But if we did not evolve on this planet, and were not magically created by some super being calling itself GOD (Government of Domocracy or General Operations Director) then a whole new avenue of possiblities opens. It is this theory that we came from somewhere else that holds the most hope for imagination and coversation for me.

You do realize that this statement is a paradox in itself, don´t you?

Because if we did come from somewhere else how did life get started there? (evolution?) And if it somehow managed to overcome the vast distance of space and landed on our planet it most surely landed somewhere else too... because the odds of life being created and then migrating to only one other planet in the universe are next to nothing... it would be against the laws of mathematics and nature fur such a thing to happen... so if you think about it, if you propose that life came from somewhere out of this earth then you also propose that the universe is full of life becasue the odds of it only comming here are not to be considered... so your argument contradicts what you said earlier about you believing the universe is empty of life (or thar life is very rare).

[ August 09, 2003, 13:55: Message edited by: JurijD ]

[Ruatha]

Technology for manned mission to mars?

Urlorama (whoa, am I even beating Thermo on amount quoted???):

Soviet plans for manned mission to Mars

http://news.bbc.co.uk/2/hi/science/nature/876112.stm
http://nssdc.gsfc.nasa.gov/planetary...mars_crew.html

http://ares.jsc.nasa.gov/HumanExplor...CS/EIC036.HTML


[7]....of the late 1940s when he and his fellow specialists from the German rocket program worked for the U.S. Army at Fort Bliss, Texas, and White Sands Providing Ground, New Mexico, testing improved Versions of the V-2 missile, von Braun wrote a lengthy essay outlinings a manned Mars exploration program. Published first in 1952 as "Das Marsprojekt; Studie einer interplanetarischen Expedition" in a special issue of the journal Weltraumfahrt, von Braun's ideas were made available in America the following year. 4

Believing that nearly anything was technologically possible given adequate resources and enthusiasm, von Braun noted in The Mars Project that the mission he proposed would be large and expensive, "but neither the scale nor the expense would seem out of proportion to the capabilities of the expedition or to the results anticipated.'' Von Braun thought it was feasible to consider reaching Mars using conventional chemical propellants, nitric acid and hydrazine. One of his major fears was that spaceflight would be delayed until more advanced fuels became available, and he was reluctant to wait for cryogenic propellants or nuclear propulsion systems to be developed. He believed that existing technology was sufficient to build the launch vehicles and spacecraft needed for a voyage to Mars in his lifetime.



[105] A key component of early Space Shuttle plans was its linkage to a possible mission to Mars as the next major NASA undertaking. During 1967 and 1968, the Atomic Energy Commission (AEC) reached key milestones in propulsion on the road to Mars. In tests in Nevada, the AEC conducted successful demonstrations of nuclear reactors built for use in rocket propulsion and showed that its contractors were ready to develop a flight-rated engine suitable for piloted missions to that planet.


One morning in early September 1969 I had to leave the senior staff meeting early to go see the Vice President. Peter Flanigan had alerted me that Agnew's Space Advisory Committee [sic] was about to make some recommendations to the President that Flanigan knew Nixon could not live with. Peter had been unsuccessful in dissuading the President's science advisor, Lee DuBridge, from agreeing with the staff of Agnew's Advisory Committee that there should be a very costly manned mission to the planet Mars in 1981. So Flanigan had asked for a meeting with Agnew, the ex-officio chairman of the committee, in the hope that we could persuade him to kill it.

Sketches of Von Brauns Mras expedition proposal.

In the 1960's, as NASA was designing spaceships to go to the moon, more Mars mission designs continued to be studied including a "Concept for a Manned Mars Expedition with Electrically Propelled Vehicles" devised in 1962, by scientists at NASA’s Marshall Space Flight Center in Alabama.

This mission, planned for the 1980s, included five ships and a crew of fifteen. The scientists and engineers planning this mission considered the possible loss of some of the ships during the voyage, believing the mission could continue even if two of the five ships were lost. This way of thinking about risk is reminiscent of early long sea voyages and the fleets sent to make them. One of the Mars ships could even be used as an emergency return vehicle with the entire crew onboard (albeit "under crowded conditions"). This ship design utilized nuclear electric propulsion and the radiation shelter was made of graphite and metal. For more shielding the scientists placed water and oxygen tanks around the crew module as well as the fuel tanks, an idea still under consideration today!


In 1986, another Mars mission scenario was designed for NASA’s Jet Propulsion Laboratory. This plan was called 'The Case for Mars: Concept Development for a Mars Research Station'. This mission had as its overall goal a permanently manned scientific base using Martian resources to supply consumables, including propellant. This mission used a heavy lifting launch vehicle and three modules that would create artificial gravity. The spacecraft is constructed in Earth orbit and is a "cycler" continually going between the two planets. The Mars trip takes an average of six months with each crew living on the surface for about 25 months at a time. Each crew is relieved by another crew ensuring a permanent habitation of the planet

In 1993, The NASA Exploration Program Office launched the Mars Exploration Study Project and produced a Mars Design Reference Mission, that owes much to the Mars Direct mission plan. The spacecraft are not built in Earth orbit and there is no prior lunar base built for testing. This mission employs a heavy-lift launch vehicle to send the crew and cargo to Mars. The transit times are short and there are long Mars surface stays. In-situ resources are used to make fuel for the return journey and the habitat used to travel to Mars is the same as the one the crew lives in on the surface.

In 1997, a second reference mission, The Human Exploration of Mars, was prepared by the Mars Exploration study team at the NASA Johnson Space Center after the possible discovery of microbial life on the Martian meteorite was announced. Based on the previous reference mission, it called for the establishment of a Mars Program Office; the development of human quarantine and sample handling protocols (to protect Earth from contamination by possible Martian microorganisms); and making the program international from its inception.

In 2001, human Mars exploration plans were put on hold and NASA refocused on the space shuttle, the construction of the International space station and research on lunar exploration.

A number of studies have outlined vigorous space programs, many quite similar to the President's recent initiative. While these programs differ somewhat in content and schedule, they are surprisingly consistent regarding the near-term level of funding required. Based on our own review, we believe that a reinvigorated space program will require real growth in the NASA budget of approximately 10 percent per year (through the year 2000) reaching a peak spending level of about $30 billion per year (in constant 1990 dollars) by about the year 2000. Such a program will:

* provide for the basic infrastructure to operate NASA, the recommended Science program, the recommended and expanded Technology program, a Mission to Planet Earth, a new start on a phased and evolutionary heavy lift launch vehicle and a reconfigured Space Station; and
* provide sufficient funds to begin laying the foundation for lunar and Mars missions on a schedule that will permit real progress and significant periodic technical achievements leading to a manned Mars mission in approximately 30 years, i.e., Mission from Planet Earth.

China denies plans on manned misison to Mars (Why did I include this link? I don't know)

[ August 09, 2003, 14:38: Message edited by: Ruatha ]