Manned missions into space -- a waste? - Page 2

xouper · 15th January 2004, 05:57 AM

I'm with epepke on this issue. It's an issue I feel very strongly about. As a kid I always wanted to be an astronaut. I got as far as becoming a pilot, but my uncorrected vision disqualified me from going any further.

I don't find any merit at all in the opinions expressed by the Kevin Lowe's of the world.

Larspeart · 15th January 2004, 06:42 AM

Epepke is dead on in my view of the situation. I read his posts and found myself nodding my head.

I posted this in another thread, but after reading this one, it seems more then appropriate for a re-post here. . .

"I think that the problem is that humans have become weak and timid. The slightest mention of danger or possible loss of life sends people running. Look at the ENOURMOUS risks of the true explorers from humankinds' past.

The Polynesians who got into a CANOE and rowed their way without a rudder or a sail hundreds/thousands of miles with only a hope that they'd find anything.

Columbus, etc who took big, complex ships not designed to go into deep, open seas into the big unknown to find a faster route to Asia.

The explorers of the New World, running into new and sometimes hostile cultures.

The men who maped the seas, the oceans, the continents and the islands of the world inthe 1500-1700's.

The brave and hardy fellows who trekked across the wasteland of Antarctica JUST to do it first.

And WHY? George Mallory, who 1st climbed Mt. Everest said it best. "Because it is there."

Thousands of lives risked and lost, but with great purpose. Without men and women like that, we'd know NOTHING about the planet we live on, the people in it, or much of anything else. I can't stand the attitude of 'Why bother?' or the 'But what about the risks' mentality we have nowadays hamstringing innovaton and discovery."

Humans are stagnating with the kinds of attitudes that some of you have. The fatalistic notion that 'we're never getting off this rock' seems both ignorant and insane to me. WE ALREADY HAVE gotten off 'this rock'. Now, the next step to to find a way to STAY off of it. Get some people living on Mars.

Not only do i want to be alive to watch the 1st person walk on Mars, but I want to live to see the 1st baby BORN on Mars. I want to watch the first soccer game played on Mars.

The timid, repressed, blaise, cost-conscious attitude that I see in people nowadays scares me, because it shows that many of us feel that we as a species have 'peaked'. I dread that thought.

hgc · 15th January 2004, 06:58 AM

Quote:

Originally posted by Larspeart
Epepke is dead on in my view of the situation. I read his posts and found myself nodding my head.

I posted this in another thread, but after reading this one, it seems more then appropriate for a re-post here. . .

"I think that the problem is that humans have become weak and timid. The slightest mention of danger or possible loss of life sends people running. Look at the ENOURMOUS risks of the true explorers from humankinds' past.

I don't see it this way. It's not an issue of timidity. I do think that with the advancement of civilization and societal structures, life has become more stable and predictable, and hence the perceived value of life has gone up, at least in some parts of the world.

Quote:

The Polynesians who got into a CANOE and rowed their way without a rudder or a sail hundreds/thousands of miles with only a hope that they'd find anything.

Columbus, etc who took big, complex ships not designed to go into deep, open seas into the big unknown to find a faster route to Asia.

The explorers of the New World, running into new and sometimes hostile cultures.

The men who maped the seas, the oceans, the continents and the islands of the world inthe 1500-1700's.

The brave and hardy fellows who trekked across the wasteland of Antarctica JUST to do it first.

All those people went places that could readily support human life -- you know, in the warm and loving Earth atmosphere.

Quote:

And WHY? George Mallory, who 1st climbed Mt. Everest said it best. "Because it is there."

Thousands of lives risked and lost, but with great purpose. Without men and women like that, we'd know NOTHING about the planet we live on, the people in it, or much of anything else. I can't stand the attitude of 'Why bother?' or the 'But what about the risks' mentality we have nowadays hamstringing innovaton and discovery."

Humans are stagnating with the kinds of attitudes that some of you have. The fatalistic notion that 'we're never getting off this rock' seems both ignorant and insane to me. WE ALREADY HAVE gotten off 'this rock'. Now, the next step to to find a way to STAY off of it. Get some people living on Mars.

Not only do i want to be alive to watch the 1st person walk on Mars, but I want to live to see the 1st baby BORN on Mars. I want to watch the first soccer game played on Mars.

The timid, repressed, blaise, cost-conscious attitude that I see in people nowadays scares me, because it shows that many of us feel that we as a species have 'peaked'. I dread that thought.

I see no evidence of this human stagnation and timidity of which you speak. By your formulation, it would seem that if you can dream it, but our society is not geared up to meet the challenge, then we're timid.

All the dreaming and non-necessary exploring that you and I both love are luxuries afforded by the accomplishment of civilization in allowing that not every human must be occupied full time with basic survival. And they do contribute even more to civilized advancement. But that doesn't make every dream realistic or valid. Soccer games on Mars are not realistic. And expenditures on that goal are going to take away so many possibilities for real space exploration.

Morchella · 15th January 2004, 07:33 AM

Gerald K. O'Neill, "The Colonization of Space", Physics Today September 1974, p. 32.
Gerard K. O'Neill, "The High Frontier", William Morrow and Co., NY, 1977; Anchor Books (Doubleday) 1982.
O'Neill, Gerard K.; Driggers, G.; and O'Leary, B.: New Routes to Manufacturing in Space. Astronautics and Aeronautics, vol. 18, October 1980, pp. 46-51.

That's not science fiction or pipe dreams, pal. And people like O'Neill are far from being woowoos. [/b][/quote]

So you dredged up one proponent. So what. No. I have never read any O'Niell. It seems his work is kind of old don't you think. Did he mention that the closest star is 3 light years away and the possibility that there is a habitable planet there is less than one in a billion. Did he account for the fact that we cannot ever approach the speed of light?
Go fire up your DVD and watch another Star Wars movie again, dork.

Bluegill · 15th January 2004, 07:41 AM

Quote:

woo woo

Quote:

dork

What's with the attitudes around here? We should behave like Federation envoys, not Klingons! Captain Picard would not approve, regardless of your views on boldly going etc. Whether or not whe're sharing a whole planet or sharing a three-year ride in a metal can, I think we need a little civility.

juryjone · 15th January 2004, 07:43 AM

While I applaud epepke's statement, and the wonderful way he expressed it, I've got to say that I don't think humanity is in any danger of losing its explorers. When Columbus sailed the ocean blue, Mallory climbed that big rock that was in his way, and, yes, when Tom Hanks and Kevin Bacon had that bit of trouble on Apollo 13, the vast majority of people on this earth were more likely to have said something like what Kevin Lowe has expressed (probably in the same harsh terms). There will always be people who oppose change.

And there will always be costs associated with change. Yes, manned exploration is currently costly. And how are reductions in cost acheived? Through economies of scale. The first, and second, and tenth manned mission will always be costly, whether it's done now or a millenium from now. It is only by repeatedly sending missions that the cost will go down.

If I were asked to go on a Mars mission today, I would go, risk be damned. However, I think I'm with those that would like to see robotic missions become more effective and more cost-efficient before we try to force the technology onward to manned exploration. If Columbus had had the technology to send an unmanned ship around the world, just to confirm his suspicions that there was a route to India there, before going himself and risking his life and the life of his men, don't you think he would have? We have the technology to look before we leap - why not use it? That's not losing the spirit of exploration - that's just plain common sense.

hgc · 15th January 2004, 07:44 AM

Quote:

Originally posted by Bluegill

What's with the attitudes around here? We should behave like Federation envoys, not Klingons! Captain Picard would not approve, regardless of your views on boldly going etc. Whether or not whe're sharing a whole planet or sharing a three-year ride in a metal can, I think we need a little civility.

Thank you, Bluegill. The appropriate place for unmitigated insults is a lifegazer thread.

Graham · 15th January 2004, 07:45 AM

Quote:

Originally posted by Morchella

So you dredged up one proponent. So what. No. I have never read any O'Niell. It seems his work is kind of old don't you think. Did he mention that the closest star is 3 light years away and the possibility that there is a habitable planet there is less than one in a billion. Did he account for the fact that we cannot ever approach the speed of light?
Go fire up your DVD and watch another Star Wars movie again, dork. [/b]

Aren't you the unpleasant little person?

Here's a few more book sto be going on with, though I expect you're much too cool to actually read any of them:

# Entering Space: Creating a Spacefaring Civilization by Robert Zubrin (Paperback)

# Spacefaring: The Human Dimension by Albert A. Harrison (Paperback)

# The Starflight Handbook : A Pioneer's Guide to Interstellar Travel by Eugene F. Mallove (Author), Gregory L. Matloff (Author) (Hardcover)

# The Space Elevator: A Revolutionary Earth-to-Space Transportation System by Bradley C. Edwards, Eric A. Westling (Paperback)

# The Millennial Project: Colonizing the Galaxy in Eight Easy Steps by Marshall T. Savage, Arthur Charles Clarke (Introduction) (Paperback)

Btw, I fail to see how one could watch "another movie again", dork or otherwise.

Graham

Skeptical Greg · 15th January 2004, 08:20 AM

Quote:

Originally posted by hgc

Soccer games on Mars are not realistic. ......

And no computer will ever need more than 640k of RAM...

xouper · 15th January 2004, 08:33 AM

Quote:

Morchella: So you dredged up one proponent. So what. No. I have never read any O'Niell. It seems his work is kind of old don't you think.

I cited O'Neill to show that serious investigations into the science, technology, and economics of space colonization predates Star Wars movies. But O'Neill certainly isn't the only one. Far from it. It was a hint to the wise to research the subject further and see what else has been said.

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Go fire up your DVD and watch another Star Wars movie again, dork.

And that pretty much sums up your intellectual contribution to this thead.

hgc · 15th January 2004, 08:39 AM

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Originally posted by Diogenes

And no computer will ever need more than 640k of RAM...

If I'd made that prediction, I'd take responsibility for it. As it stands, computers don't need anything. Humans need computers to have more RAM so they can play games.

Skeptical Greg · 15th January 2004, 09:02 AM

Quote:

Originally posted by hgc
If I'd made that prediction, I'd take responsibility for it. As it stands, computers don't need anything. Humans need computers to have more RAM so they can play games.

And I have no doubt that you would.. ( take responsibility for it... )

I hope you got my point, that what may seem realistic or not today, could be realistic next week, or a joke to think that it wasn't ( realistic ) 20 years from now.. .. And the sooner we go to work on it, the sooner it will happen, whether you are talking about eradicating world hunger or going to Mars..

The solving of social problems does not seem to be as conducive to applied research as technological ones.. However, technological breakthroughs usually manage to favorably impact social problems when properly applied..

Note, that the technology already exists to end world hunger, has for some time, and it hasn't happened..
Why should one expect that delaying manned space exploration for any length of time, will in some way facillitate a more rapid solution to social problems...

Wile E. Coyote · 15th January 2004, 09:23 AM

While it is true that manned expeditions require a lot of life support whereas unmanned ones do not, it is not quite true to say that the life support is a waste.

Advances in life support systems for hostile environments benefit many different fields, such as: ecology, recycling, biology, energy efficiency, medicine, nutrition, psychology, etc.

There are things which can be learned only by humans placed in an environment, supported by technology designed to suit them. Ecologically, we could potentially learn a lot from a human colony on the Moon or Mars.

hgc · 15th January 2004, 09:32 AM

Quote:

Originally posted by Diogenes

And I have no doubt that you would.. ( take responsibility for it... )

I hope you got my point, that what may seem realistic or not today, could be realistic next week, or a joke to think that it wasn't ( realistic ) 20 years from now.. .. And the sooner we go to work on it, the sooner it will happen, whether you are talking about eradicating world hunger or going to Mars..

...

Yes I did. But then I don't think that all claims about what will one day be possible/practical are equally reasonable. I think that it's unreasonable to think that we'll be able to colonize space without supplying the colonizers with almost all their supplies from Earth.

But then I've not read any of the literature other than that by O'Neill. I've got more to learn, and this new initiative will push me to read the other sources mentioned in this thread. In the meantime, I remain skeptical of the viability of the plan.

hgc · 15th January 2004, 09:34 AM

Quote:

Originally posted by Wile E. Coyote
While it is true that manned expeditions require a lot of life support whereas unmanned ones do not, it is not quite true to say that the life support is a waste.

Advances in life support systems for hostile environments benefit many different fields, such as: ecology, recycling, biology, energy efficiency, medicine, nutrition, psychology, etc.

There are things which can be learned only by humans placed in an environment, supported by technology designed to suit them. Ecologically, we could potentially learn a lot from a human colony on the Moon or Mars.

I agree we could learn a lot of value. I would prefer to start with successful bio-dome type experiments here on Earth.

edited to add: and then we can send Paulie Shore off planet.

patnray · 15th January 2004, 09:41 AM

Quote:

Originally posted by Wile E. Coyote
While it is true that manned expeditions require a lot of life support whereas unmanned ones do not, it is not quite true to say that the life support is a waste.

Advances in life support systems for hostile environments benefit many different fields, such as: ecology, recycling, biology, energy efficiency, medicine, nutrition, psychology, etc.

There are things which can be learned only by humans placed in an environment, supported by technology designed to suit them. Ecologically, we could potentially learn a lot from a human colony on the Moon or Mars.

Name one thing that we could learn from humans on Mars we couldn't learn from robots.

"Ecologically" we could learn as much, or more, from a colony on the moon or a larger space station as we could from a colony on Mars...

Also, any realistic plan for a manned mission to Mars requires a slew of sophisticated robot spacecraft, rovers, and chemical processing systems. Since they are necessary, shouldn't developing them be a priority?

But once they are develooped, we come back to my question: what could humans accomplish that they couldn't?

patnray · 15th January 2004, 09:52 AM

Quote:

Originally posted by Correa Neto
Right now, unmanned probes are cheaper and involve very little risk of human lives being lost, but our robotic ships are not smart enough to make repairs, take last minute decisons, improvise, etc. Apollo 13 and Mir are examples of the differences a crew can make when it comes to save the day. An EVA can open a jammed antenna, fix leaking conduits, an astronaut can manually land the ship, correcting an imperial/metric system mistake, fix short-circuited wires, etc. A crewed ship can, if needed, make great changes on the mission profile, for example.
Sure, unmanned vessels are less complex, smaller, etc., but they are alo less flexible.

When the high gain (high speed) antenna system failed in one of the Voyager spacecraft (due to the failure of a single capacitor), ground controllers completely reprogrammed the systems, devised a more compact image compression scheme, invented new ways to aim and focus the cameras, changed mission parameters to make more memory available for storing images, and used a much slower transmission system to return the images to earth. The key is designing robust, flexible, and redundant systems.

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The day will come when our machines will be smart enough for all of this. But untill this day, some goals are better achieved with manned ships.

That day will come when we focus our attention on it. And such sophisticated machines will be absolutely necessary to support manned missions to Mars.

Name a goal that could be better achieved with a manned ship...

15th January 2004, 09:54 AM

Quote:

Originally posted by hgc
I'm a big fan of space exploration and research, but I'm starting to question the value and viability of manned missions.

So much of what we do in space can be accomplished robotically. Is it worth the extra effort to support human life out there? If we were able to devote those same resources to replacing direct human activity with remote controlled or programmed robotic activity, might we reap more benefits?

I imagine so. Yes I agree that manned missions are not worth it.

Quote:

If the end-game is to establish a brighter future for mankind when the Earth becomes too crowded or otherwise unlivable, I say get your head out of the sci-fi clouds and face reality: we've go no other home than the surface of this planet, and that's probably forever.

I don't agree with this. I think that earth like planets might be relatively common in the Universe. Perhaps there is another "earth" within 20 light years which we could inhabit, providing there is no other intelligent life forms living there comparable or exceeding our own intelligence (a reasonable supposition). I think that some of us could get to such a planet within the next 1000 years

Wile E. Coyote · 15th January 2004, 09:56 AM

Quote:

Originally posted by patnray

Name one thing that we could learn from humans on Mars we couldn't learn from robots.

What it feels like to be standing on Mars.

xouper · 15th January 2004, 09:59 AM

Quote:

patnray: Name one thing that we could learn from humans on Mars we couldn't learn from robots.

What it's like to live there. Sometimes humans want to experience things first hand. For example, I certainly wouldn't send a dildo in to do a man's job.

Edited to add: I see Coyote beat me to it.

hgc · 15th January 2004, 10:01 AM

Quote:

Originally posted by Interesting Ian
...

I don't agree with this. I think that earth like planets might be relatively common in the Universe. Perhaps there is another "earth" within 20 light years which we could inhabit, providing there is no other intelligent life forms living there comparable or exceeding our own intelligence (a reasonable supposition). I think that some of us could get to such a planet within the next 1000 years

Yes, I also suspect there are other "Earth-like" planets. But how much like Earth would be necessary to support human life? The variables are so numerous as to drastically reduce our chances of finding such a place, even among 1,000,000 known lush green planets. Add to that the practical problem of the universal speed limit, and we'd have a hell of a time getting there even if we could find it.

I think that humans would sooner evolve into Martians than we'll find another Earth.

15th January 2004, 10:10 AM

Quote:

Originally posted by epepke
I guess I disagree with just about everybody.

Manned space exploration is valuable because I want to go. If I don't get to go, I want someone to go.

The reason I want to go is that I am a human.

Gorillas feed their community. Jackdaws gather toys. Cats mark their territories. Every creature lives, breathes, eats, eliminates, reproduces, dies.

I'm one of those creatures, but I'm also a human, and we explore. That's what we do. "We choose to do these things, not becuase they are easy, but because they are hard."

I think there's a great deal of danger these days in losing our humanity. When we decide that the only value of science is make some pill to give someone two more years of life watching Friends reruns, or we decide that the only value of space exploration is to fill up a disc with data as cheaply as possible, or we decide that the only value of learning is to get a better job and put more cholesterol on the table, we cut off bits of ourselves and throw them away. At the end of this process, we all may be healthy and long-lived and sane and sensible and comfortable. And we will be apes with cell phones, nothing more.

We will be like Nietzsche's Last Man. We will neither live where it is too hot nor too cold. Work will be regulated, lest it become a burden, and so will leisure, lest it become like work. We will be content. So says the Last Man, and blinks.

I don't know about you all, but I didn't evolve the biggest neocortex in the history of the planet so that I could do that.

A nice emotional outburst epepke

I think probably most people would agree with you. On the other hand I think that we should settle for unmanned missions for the next 50 years or so until technology improves and we have more of an idea where the interesting stuff lies through the unmanned missions. A man on mars by 2020? No, but maybe by about 2069.

15th January 2004, 10:14 AM

Quote:

Originally posted by hgc
Yes, I also suspect there are other "Earth-like" planets. But how much like Earth would be necessary to support human life? The variables are so numerous as to drastically reduce our chances of finding such a place, even among 1,000,000 known lush green planets. Add to that the practical problem of the universal speed limit, and we'd have a hell of a time getting there even if we could find it.

I think that humans would sooner evolve into Martians than we'll find another Earth.

I would have thought that earth like planets wouldn't be all that uncommon. What variables do you have in mind? As for the Universal speed limit we could maybe travel very close to the speed of light. Thus a journey of 20 light years might only take a few months ship time.

Hexxenhammer · 15th January 2004, 10:32 AM

Quote:

Originally posted by hgc
Yes, I also suspect there are other "Earth-like" planets. But how much like Earth would be necessary to support human life? The variables are so numerous as to drastically reduce our chances of finding such a place, even among 1,000,000 known lush green planets. Add to that the practical problem of the universal speed limit, and we'd have a hell of a time getting there even if we could find it.

I think that humans would sooner evolve into Martians than we'll find another Earth.

With the variety of environments that humans can live in on THIS planet without much technology, from sea level to the highest mountains, and above the arctic circle to the equator, I think we'd do ok on a sufficiently earth-like planet. The speed limit is a problem, but we could get a good fraction of light speed going and with advances in life support maybe the astronauts would be spry at very old ages if it took years to get somewhere.

hgc · 15th January 2004, 10:33 AM

Quote:

Originally posted by Interesting Ian

I would have thought that earth like planets wouldn't be all that uncommon. What variables do you have in mind? As for the Universal speed limit we could maybe travel very close to the speed of light. Thus a journey of 20 light years might only take a few months ship time.

Variables like the temperature gradients; chemical composition of the Earth, seas and atmosphere; weather patterns; incoming radiation from the local star; other life already resident; and so on.

I don't know how we would accelerate up to close to the speed of light, but I'll allow that it's theoretically possible for the sake of this discussion. But tell me more about this "ship time."

hgc · 15th January 2004, 10:40 AM

Quote:

Originally posted by Hexxenhammer
With the variety of environments that humans can live in on THIS planet without much technology, from sea level to the highest mountains, and above the arctic circle to the equator, I think we'd do ok on a sufficiently earth-like planet. The speed limit is a problem, but we could get a good fraction of light speed going and with advances in life support maybe the astronauts would be spry at very old ages if it took years to get somewhere.

Yes, humans appear to be tremendously adaptable, given that we can live just about anywhere on Earth. But the variety of environments here on just this planet is nothing like the variety of environments on all the possible life-supporting planets within some theoretical striking distance (allowing we could do some sort of trip to planets in this section of the Milky Way). All the land regions of this planet might just as well be considered to be quite similar if viewed from the perspective of an imaginary being whose been around the galaxy a bit. To say "we'd do ok on a sufficiently earth-like planet," is a tautology, given that sufficiently means humans could survive there, in this context.

15th January 2004, 10:51 AM

Quote:

Originally posted by Morchella

So you dredged up one proponent. So what. No. I have never read any O'Niell. It seems his work is kind of old don't you think. Did he mention that the closest star is 3 light years away and the possibility that there is a habitable planet there is less than one in a billion.

Hi Morchello,

I'm a "woo woo" BTW.

Anyway, the nearest star is 4.2 light years away, not 3 light years away. It's true that it is very unlikely that there is a habitable planet there, but this is because I believe it is a binary star system

I do not see that habitable planets should be all that rare. Perhaps you could provide some reasons why you think this?

Quote:

Did he account for the fact that we cannot ever approach the speed of light?

Why can't we?

patnray · 15th January 2004, 10:57 AM

Quote:

Originally posted by Wile E. Coyote

What it feels like to be standing on Mars.

That is not a fact about Mars, it is a fact about human feelings. Don't get me wrong, though, I, too, would love to experience that. Very romantic. But it will probably only be experienced by a hand full to a few dozen people at the most. Aside for such subjective experiences, what objective facts can we learn from manned missions that we can't learn from unmanned missions?

Skeptical Greg · 15th January 2004, 11:00 AM

Quote:

Originally posted by Interesting Ian

.....providing there is no other intelligent life forms living there comparable or exceeding our own intelligence (a reasonable supposition).

So, in this case, we turn around and return to Earth?

Hexxenhammer · 15th January 2004, 11:01 AM

Quote:

Originally posted by hgc
I don't know how we would accelerate up to close to the speed of light, but I'll allow that it's theoretically possible for the sake of this discussion. But tell me more about this "ship time."

Ian's not off here (I'm amazed too

) As long as the ship's "gas pedal is down" it could probably get a good percentage of light speed going. I suppose limited by things like mass, fuel supply etc...things that take math and people smarter than me to figure out. When you get halfway to where you're going, turn around and start slowing down by firing the engines again.

Anyone know what % lightspeed a ship that uses conventional physics could get to? My wild-@$$ed guess is 20-35%. I reserve the right to be very, very wrong.

hgc · 15th January 2004, 11:03 AM

Quote:

Originally posted by Interesting Ian

Why can't we? [ever approach the speed of light]

You have to put in energy to get acceleration. The amount of fuel that would be required to accelerate to that velocity would be a whole hell of a lot more than we have available. Don't forget that you have to decelerate too.

Hexxenhammer · 15th January 2004, 11:04 AM

Quote:

Originally posted by Diogenes

So, in this case, we turn around and return to Earth?

No that's when we fire the death rays while broadcasting "We come in peace."

15th January 2004, 11:10 AM

Quote:

Originally posted by hgc
Variables like the temperature gradients; chemical composition of the Earth, seas and atmosphere; weather patterns; incoming radiation from the local star; other life already resident; and so on.

If we consider a star similar to our own, and we discover a planet similar in size to our own at a comparable distance from its parent star, would it not be the case that there is a good chance it will turn out earthlike? If not then why not?

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I don't know how we would accelerate up to close to the speed of light,

The application of force. This could be exactly the same as the gravitational force so that the astronauts would have normal weight. The spaceship could accelerate for half its journey to a given star, then decelerate for the other half of the journey.

Quote:

but I'll allow that it's theoretically possible for the sake of this discussion. But tell me more about this "ship time." [/b]

Einsteins special theory of relativity. From the astronauts perspective, if they travel very close to the speed of light, instead of the star being 20 light years away, it might, say, only be 1 light year away

patnray · 15th January 2004, 11:22 AM

Quote:

Originally posted by Hexxenhammer

Anyone know what % lightspeed a ship that uses conventional physics could get to? My wild-@$$ed guess is 20-35%. I reserve the right to be very, very wrong.

Mass increases as the velocity increases and becomes infinite at the speed of light. It would take an infinite amount of energy to accelerate even one milligram to the speed of light.

My very rough calculations show mass increasing about 25% at half the speed of light and about 50% at 3/4 the speed of light.

Using conventional (inertial thrust) means, how fast could one go (and still be able to stop at the other end of the journey)? Inertial thrust requires mass to accelerate in the opposite direction and energy to accelerate it. If you carry the mass you will eventuall eject along with you you will have to accelerate that mass, too. I remember some science fiction stories invloving a kind of space jet that scoops up gas and dust particles and accelerates those to produce thrust without having to carry the mass along. Given a sufficient supply of energy and a very long time to accelerate, I think maybe 5% to 10% of c might be possible...

patnray · 15th January 2004, 11:28 AM

To put things in perspective, the Mars lander traveled about 0.0038% the speed of light as it left earth (about 7 miles/second)...

Hexxenhammer · 15th January 2004, 11:42 AM

Quote:

Originally posted by patnray
Given a sufficient supply of energy and a very long time to accelerate, I think maybe 5% to 10% of c might be possible...

I guess we'll just have to invent hyperdrive.

Psiload · 15th January 2004, 11:44 AM

Quote:

Originally posted by Wile E. Coyote

What it feels like to be standing on Mars.

It would feel exactly like standing in the middle of a Wal Mart in a stuffy, uncomfortable spacesuit.

Oh, did you mean feel in the emotional sense? Like how it felt when you got a gold star, and a smiley face on a third grade spelling test?

Aren't there less expensive ways to stroke our egos?

15th January 2004, 11:49 AM

Quote:

Originally posted by hgc
Why can't we? [ever approach the speed of light]
--------------------------------------------------------------------------------

You have to put in energy to get acceleration. The amount of fuel that would be required to accelerate to that velocity would be a whole hell of a lot more than we have available. Don't forget that you have to decelerate too.

Recall that I didn't propose a trip now, but rather sometime within the next 1000 years. I don't know how one would acquire the energy, but I'm unconvinced that it will be an insurmountable problem if we experience the same rate of technological progress over the next 1000 years as we have done over the past 300 years. Maybe energy can be extracted from the empty vacuum of space, or maybe we could get sufficient amounts of energy by matter getting directly converted into energy, or maybe we could somehow utilise the use of anti-matter. Hell, I don't know.

How would the denizens of 1000 AD have proposed getting to Mars?

Skeptical Greg · 15th January 2004, 12:10 PM

Quote:

Originally posted by Interesting Ian

How would the denizens of 1000 AD have proposed getting to Mars?

A sufficiently long ladder, perhaps?

patnray · 15th January 2004, 12:23 PM

It isn't just a question of finding a source of energy. Relativity places some severe constraints because mass increases as velocity increases...

The human cargo also places some constraints. Extreme acceleration is not an option. Acceleration must be limited to something around 1 g.

Here's a puzzle for those with time on their hands: Assume you have a space ship with an unlimited energy supply and a non-inertial propulsion system that can produce 1 g of acceleration when the mass of the ship equals the rest mass. Assume the mass of the ship does not change except for the relativistic increase due to velocity. How long would it take (measured by an observer on earth) to get to a star 10 light years away (remember you can only accelerate for half the journey, then you must deccelerate)?

15th January 2004, 05:57 AM	#41
xouper Banned Join Date: Jan 2002 Posts: 2,189	I'm with epepke on this issue. It's an issue I feel very strongly about. As a kid I always wanted to be an astronaut. I got as far as becoming a pilot, but my uncorrected vision disqualified me from going any further. I don't find any merit at all in the opinions expressed by the Kevin Lowe's of the world.
xouper Banned Join Date: Jan 2002 Posts: 2,189

15th January 2004, 06:42 AM	#42
Larspeart Muse Join Date: Feb 2003 Posts: 581	Epepke is dead on in my view of the situation. I read his posts and found myself nodding my head. I posted this in another thread, but after reading this one, it seems more then appropriate for a re-post here. . . "I think that the problem is that humans have become weak and timid. The slightest mention of danger or possible loss of life sends people running. Look at the ENOURMOUS risks of the true explorers from humankinds' past. The Polynesians who got into a CANOE and rowed their way without a rudder or a sail hundreds/thousands of miles with only a hope that they'd find anything. Columbus, etc who took big, complex ships not designed to go into deep, open seas into the big unknown to find a faster route to Asia. The explorers of the New World, running into new and sometimes hostile cultures. The men who maped the seas, the oceans, the continents and the islands of the world inthe 1500-1700's. The brave and hardy fellows who trekked across the wasteland of Antarctica JUST to do it first. And WHY? George Mallory, who 1st climbed Mt. Everest said it best. "Because it is there." Thousands of lives risked and lost, but with great purpose. Without men and women like that, we'd know NOTHING about the planet we live on, the people in it, or much of anything else. I can't stand the attitude of 'Why bother?' or the 'But what about the risks' mentality we have nowadays hamstringing innovaton and discovery." Humans are stagnating with the kinds of attitudes that some of you have. The fatalistic notion that 'we're never getting off this rock' seems both ignorant and insane to me. WE ALREADY HAVE gotten off 'this rock'. Now, the next step to to find a way to STAY off of it. Get some people living on Mars. Not only do i want to be alive to watch the 1st person walk on Mars, but I want to live to see the 1st baby BORN on Mars. I want to watch the first soccer game played on Mars. The timid, repressed, blaise, cost-conscious attitude that I see in people nowadays scares me, because it shows that many of us feel that we as a species have 'peaked'. I dread that thought.
Larspeart Muse Join Date: Feb 2003 Posts: 581	__________________ "Anyone who is willing to trade liberty for security deserves neither security nor liberty."- Benjamin Franklin

15th January 2004, 07:33 AM	#44
Morchella Scholar Join Date: Dec 2002 Location: Lake Tahoe Posts: 62	Gerald K. O'Neill, "The Colonization of Space", Physics Today September 1974, p. 32. Gerard K. O'Neill, "The High Frontier", William Morrow and Co., NY, 1977; Anchor Books (Doubleday) 1982. O'Neill, Gerard K.; Driggers, G.; and O'Leary, B.: New Routes to Manufacturing in Space. Astronautics and Aeronautics, vol. 18, October 1980, pp. 46-51. That's not science fiction or pipe dreams, pal. And people like O'Neill are far from being woowoos. [/b][/quote] So you dredged up one proponent. So what. No. I have never read any O'Niell. It seems his work is kind of old don't you think. Did he mention that the closest star is 3 light years away and the possibility that there is a habitable planet there is less than one in a billion. Did he account for the fact that we cannot ever approach the speed of light? Go fire up your DVD and watch another Star Wars movie again, dork.
	__________________ Dog be with you.

15th January 2004, 07:43 AM	#46
juryjone Refusing to be confused by facts Join Date: Mar 2002 Posts: 879	While I applaud epepke's statement, and the wonderful way he expressed it, I've got to say that I don't think humanity is in any danger of losing its explorers. When Columbus sailed the ocean blue, Mallory climbed that big rock that was in his way, and, yes, when Tom Hanks and Kevin Bacon had that bit of trouble on Apollo 13, the vast majority of people on this earth were more likely to have said something like what Kevin Lowe has expressed (probably in the same harsh terms). There will always be people who oppose change. And there will always be costs associated with change. Yes, manned exploration is currently costly. And how are reductions in cost acheived? Through economies of scale. The first, and second, and tenth manned mission will always be costly, whether it's done now or a millenium from now. It is only by repeatedly sending missions that the cost will go down. If I were asked to go on a Mars mission today, I would go, risk be damned. However, I think I'm with those that would like to see robotic missions become more effective and more cost-efficient before we try to force the technology onward to manned exploration. If Columbus had had the technology to send an unmanned ship around the world, just to confirm his suspicions that there was a route to India there, before going himself and risking his life and the life of his men, don't you think he would have? We have the technology to look before we leap - why not use it? That's not losing the spirit of exploration - that's just plain common sense.
	__________________ "Humanity is slipping into the void of ignorance while you cheer and wave." - Tirdun, in reference to geggy and the 9/11 conspiracy theorists

15th January 2004, 07:45 AM	#48
Graham Graduate Poster Join Date: Dec 2002 Posts: 1,465	Quote: Originally posted by Morchella So you dredged up one proponent. So what. No. I have never read any O'Niell. It seems his work is kind of old don't you think. Did he mention that the closest star is 3 light years away and the possibility that there is a habitable planet there is less than one in a billion. Did he account for the fact that we cannot ever approach the speed of light? Go fire up your DVD and watch another Star Wars movie again, dork. [/b] Aren't you the unpleasant little person? Here's a few more book sto be going on with, though I expect you're much too cool to actually read any of them: # Entering Space: Creating a Spacefaring Civilization by Robert Zubrin (Paperback) # Spacefaring: The Human Dimension by Albert A. Harrison (Paperback) # The Starflight Handbook : A Pioneer's Guide to Interstellar Travel by Eugene F. Mallove (Author), Gregory L. Matloff (Author) (Hardcover) # The Space Elevator: A Revolutionary Earth-to-Space Transportation System by Bradley C. Edwards, Eric A. Westling (Paperback) # The Millennial Project: Colonizing the Galaxy in Eight Easy Steps by Marshall T. Savage, Arthur Charles Clarke (Introduction) (Paperback) Btw, I fail to see how one could watch "another movie again", dork or otherwise. Graham
Graham Graduate Poster Join Date: Dec 2002 Posts: 1,465	__________________ The wages of sin are death, but by the time taxes are taken out, it's just sort of a tired feeling. - Paula Poundstone

15th January 2004, 06:58 AM	#43
hgc Penultimate Amazing Join Date: Jun 2002 Posts: 12,988	Quote: Originally posted by Larspeart Epepke is dead on in my view of the situation. I read his posts and found myself nodding my head. I posted this in another thread, but after reading this one, it seems more then appropriate for a re-post here. . . "I think that the problem is that humans have become weak and timid. The slightest mention of danger or possible loss of life sends people running. Look at the ENOURMOUS risks of the true explorers from humankinds' past. I don't see it this way. It's not an issue of timidity. I do think that with the advancement of civilization and societal structures, life has become more stable and predictable, and hence the perceived value of life has gone up, at least in some parts of the world. Quote: The Polynesians who got into a CANOE and rowed their way without a rudder or a sail hundreds/thousands of miles with only a hope that they'd find anything. Columbus, etc who took big, complex ships not designed to go into deep, open seas into the big unknown to find a faster route to Asia. The explorers of the New World, running into new and sometimes hostile cultures. The men who maped the seas, the oceans, the continents and the islands of the world inthe 1500-1700's. The brave and hardy fellows who trekked across the wasteland of Antarctica JUST to do it first. All those people went places that could readily support human life -- you know, in the warm and loving Earth atmosphere. Quote: And WHY? George Mallory, who 1st climbed Mt. Everest said it best. "Because it is there." Thousands of lives risked and lost, but with great purpose. Without men and women like that, we'd know NOTHING about the planet we live on, the people in it, or much of anything else. I can't stand the attitude of 'Why bother?' or the 'But what about the risks' mentality we have nowadays hamstringing innovaton and discovery." Humans are stagnating with the kinds of attitudes that some of you have. The fatalistic notion that 'we're never getting off this rock' seems both ignorant and insane to me. WE ALREADY HAVE gotten off 'this rock'. Now, the next step to to find a way to STAY off of it. Get some people living on Mars. Not only do i want to be alive to watch the 1st person walk on Mars, but I want to live to see the 1st baby BORN on Mars. I want to watch the first soccer game played on Mars. The timid, repressed, blaise, cost-conscious attitude that I see in people nowadays scares me, because it shows that many of us feel that we as a species have 'peaked'. I dread that thought. I see no evidence of this human stagnation and timidity of which you speak. By your formulation, it would seem that if you can dream it, but our society is not geared up to meet the challenge, then we're timid. All the dreaming and non-necessary exploring that you and I both love are luxuries afforded by the accomplishment of civilization in allowing that not every human must be occupied full time with basic survival. And they do contribute even more to civilized advancement. But that doesn't make every dream realistic or valid. Soccer games on Mars are not realistic. And expenditures on that goal are going to take away so many possibilities for real space exploration.

15th January 2004, 07:41 AM	#45
Bluegill Graduate Poster Join Date: Oct 2002 Location: Louisville Posts: 1,188	Quote: woo woo Quote: dork What's with the attitudes around here? We should behave like Federation envoys, not Klingons! Captain Picard would not approve, regardless of your views on boldly going etc. Whether or not whe're sharing a whole planet or sharing a three-year ride in a metal can, I think we need a little civility.

15th January 2004, 07:44 AM	#47
hgc Penultimate Amazing Join Date: Jun 2002 Posts: 12,988	Quote: Originally posted by Bluegill What's with the attitudes around here? We should behave like Federation envoys, not Klingons! Captain Picard would not approve, regardless of your views on boldly going etc. Whether or not whe're sharing a whole planet or sharing a three-year ride in a metal can, I think we need a little civility. Thank you, Bluegill. The appropriate place for unmitigated insults is a lifegazer thread.

15th January 2004, 08:20 AM	#49
Skeptical Greg Agave Wine Connoisseur Join Date: Jul 2002 Location: Just past 'Resume Speed' Posts: 12,873	Quote: Originally posted by hgc Soccer games on Mars are not realistic. ...... And no computer will ever need more than 640k of RAM...
	__________________ " Somewhere between Jesus dying on the cross, and a giant bunny hiding eggs,there seems to be a gap in information. " Stan - Southpark Prove your computer is not a wimp ! Join the JREF Folders ! Team 13232

15th January 2004, 08:33 AM	#50
xouper Banned Join Date: Jan 2002 Posts: 2,189	Quote: Morchella: So you dredged up one proponent. So what. No. I have never read any O'Niell. It seems his work is kind of old don't you think. I cited O'Neill to show that serious investigations into the science, technology, and economics of space colonization predates Star Wars movies. But O'Neill certainly isn't the only one. Far from it. It was a hint to the wise to research the subject further and see what else has been said. Quote: Go fire up your DVD and watch another Star Wars movie again, dork. And that pretty much sums up your intellectual contribution to this thead.
xouper Banned Join Date: Jan 2002 Posts: 2,189

15th January 2004, 08:39 AM	#51
hgc Penultimate Amazing Join Date: Jun 2002 Posts: 12,988	Quote: Originally posted by Diogenes And no computer will ever need more than 640k of RAM... If I'd made that prediction, I'd take responsibility for it. As it stands, computers don't need anything. Humans need computers to have more RAM so they can play games.

15th January 2004, 09:02 AM	#52
Skeptical Greg Agave Wine Connoisseur Join Date: Jul 2002 Location: Just past 'Resume Speed' Posts: 12,873	Quote: Originally posted by hgc *If I'd made that prediction, I'd take responsibility for it. As it stands, computers don't need anything. Humans* need computers to have more RAM so they can play games.** And I have no doubt that you would.. ( take responsibility for it... ) I hope you got my point, that what may seem realistic or not today, could be realistic next week, or a joke to think that it wasn't ( realistic ) 20 years from now.. .. And the sooner we go to work on it, the sooner it will happen, whether you are talking about eradicating world hunger or going to Mars.. The solving of social problems does not seem to be as conducive to applied research as technological ones.. However, technological breakthroughs usually manage to favorably impact social problems when properly applied.. Note, that the technology already exists to end world hunger, has for some time, and it hasn't happened.. Why should one expect that delaying manned space exploration for any length of time, will in some way facillitate a more rapid solution to social problems...
	__________________ " Somewhere between Jesus dying on the cross, and a giant bunny hiding eggs,there seems to be a gap in information. " Stan - Southpark Prove your computer is not a wimp ! Join the JREF Folders ! Team 13232

15th January 2004, 09:23 AM	#53
Wile E. Coyote Critical Thinker Join Date: Dec 2002 Posts: 342	While it is true that manned expeditions require a lot of life support whereas unmanned ones do not, it is not quite true to say that the life support is a waste. Advances in life support systems for hostile environments benefit many different fields, such as: ecology, recycling, biology, energy efficiency, medicine, nutrition, psychology, etc. There are things which can be learned only by humans placed in an environment, supported by technology designed to suit them. Ecologically, we could potentially learn a lot from a human colony on the Moon or Mars.

15th January 2004, 09:32 AM	#54
hgc Penultimate Amazing Join Date: Jun 2002 Posts: 12,988	Quote: Originally posted by Diogenes And I have no doubt that you would.. ( take responsibility for it... ) I hope you got my point, that what may seem realistic or not today, could be realistic next week, or a joke to think that it wasn't ( realistic ) 20 years from now.. .. And the sooner we go to work on it, the sooner it will happen, whether you are talking about eradicating world hunger or going to Mars.. ... Yes I did. But then I don't think that all claims about what will one day be possible/practical are equally reasonable. I think that it's unreasonable to think that we'll be able to colonize space without supplying the colonizers with almost all their supplies from Earth. But then I've not read any of the literature other than that by O'Neill. I've got more to learn, and this new initiative will push me to read the other sources mentioned in this thread. In the meantime, I remain skeptical of the viability of the plan.

15th January 2004, 09:34 AM	#55
hgc Penultimate Amazing Join Date: Jun 2002 Posts: 12,988	Quote: Originally posted by Wile E. Coyote While it is true that manned expeditions require a lot of life support whereas unmanned ones do not, it is not quite true to say that the life support is a waste. Advances in life support systems for hostile environments benefit many different fields, such as: ecology, recycling, biology, energy efficiency, medicine, nutrition, psychology, etc. There are things which can be learned only by humans placed in an environment, supported by technology designed to suit them. Ecologically, we could potentially learn a lot from a human colony on the Moon or Mars. I agree we could learn a lot of value. I would prefer to start with successful bio-dome type experiments here on Earth. edited to add: and then we can send Paulie Shore off planet.

15th January 2004, 09:41 AM	#56
patnray Graduate Poster Join Date: Mar 2002 Location: San Jose, CA Posts: 1,008	Quote: Originally posted by Wile E. Coyote While it is true that manned expeditions require a lot of life support whereas unmanned ones do not, it is not quite true to say that the life support is a waste. Advances in life support systems for hostile environments benefit many different fields, such as: ecology, recycling, biology, energy efficiency, medicine, nutrition, psychology, etc. There are things which can be learned only by humans placed in an environment, supported by technology designed to suit them. Ecologically, we could potentially learn a lot from a human colony on the Moon or Mars. Name one thing that we could learn from humans on Mars we couldn't learn from robots. "Ecologically" we could learn as much, or more, from a colony on the moon or a larger space station as we could from a colony on Mars... Also, any realistic plan for a manned mission to Mars requires a slew of sophisticated robot spacecraft, rovers, and chemical processing systems. Since they are necessary, shouldn't developing them be a priority? But once they are develooped, we come back to my question: what could humans accomplish that they couldn't?

15th January 2004, 09:52 AM	#57
patnray Graduate Poster Join Date: Mar 2002 Location: San Jose, CA Posts: 1,008	Quote: Originally posted by Correa Neto Right now, unmanned probes are cheaper and involve very little risk of human lives being lost, but our robotic ships are not smart enough to make repairs, take last minute decisons, improvise, etc. Apollo 13 and Mir are examples of the differences a crew can make when it comes to save the day. An EVA can open a jammed antenna, fix leaking conduits, an astronaut can manually land the ship, correcting an imperial/metric system mistake, fix short-circuited wires, etc. A crewed ship can, if needed, make great changes on the mission profile, for example. Sure, unmanned vessels are less complex, smaller, etc., but they are alo less flexible. When the high gain (high speed) antenna system failed in one of the Voyager spacecraft (due to the failure of a single capacitor), ground controllers completely reprogrammed the systems, devised a more compact image compression scheme, invented new ways to aim and focus the cameras, changed mission parameters to make more memory available for storing images, and used a much slower transmission system to return the images to earth. The key is designing robust, flexible, and redundant systems. Quote: The day will come when our machines will be smart enough for all of this. But untill this day, some goals are better achieved with manned ships. That day will come when we focus our attention on it. And such sophisticated machines will be absolutely necessary to support manned missions to Mars. Name a goal that could be better achieved with a manned ship...

15th January 2004, 09:54 AM	#58
Interesting Ian Guest Posts: n/a	Re: Manned missions into space -- a waste? Quote: Originally posted by hgc I'm a big fan of space exploration and research, but I'm starting to question the value and viability of manned missions. So much of what we do in space can be accomplished robotically. Is it worth the extra effort to support human life out there? If we were able to devote those same resources to replacing direct human activity with remote controlled or programmed robotic activity, might we reap more benefits? I imagine so. Yes I agree that manned missions are not worth it. Quote: If the end-game is to establish a brighter future for mankind when the Earth becomes too crowded or otherwise unlivable, I say get your head out of the sci-fi clouds and face reality: we've go no other home than the surface of this planet, and that's probably forever. I don't agree with this. I think that earth like planets might be relatively common in the Universe. Perhaps there is another "earth" within 20 light years which we could inhabit, providing there is no other intelligent life forms living there comparable or exceeding our own intelligence (a reasonable supposition). I think that some of us could get to such a planet within the next 1000 years
Interesting Ian Guest Posts: n/a

15th January 2004, 09:56 AM	#59
Wile E. Coyote Critical Thinker Join Date: Dec 2002 Posts: 342	Quote: Originally posted by patnray Name one thing that we could learn from humans on Mars we couldn't learn from robots. What it feels like to be standing on Mars.

15th January 2004, 09:59 AM	#60
xouper Banned Join Date: Jan 2002 Posts: 2,189	Quote: patnray: Name one thing that we could learn from humans on Mars we couldn't learn from robots. What it's like to live there. Sometimes humans want to experience things first hand. For example, I certainly wouldn't send a dildo in to do a man's job. Edited to add: I see Coyote beat me to it.
xouper Banned Join Date: Jan 2002 Posts: 2,189

15th January 2004, 10:01 AM	#61
hgc Penultimate Amazing Join Date: Jun 2002 Posts: 12,988	Re: Re: Manned missions into space -- a waste? Quote: Originally posted by Interesting Ian ... I don't agree with this. I think that earth like planets might be relatively common in the Universe. Perhaps there is another "earth" within 20 light years which we could inhabit, providing there is no other intelligent life forms living there comparable or exceeding our own intelligence (a reasonable supposition). I think that some of us could get to such a planet within the next 1000 years Yes, I also suspect there are other "Earth-like" planets. But how much like Earth would be necessary to support human life? The variables are so numerous as to drastically reduce our chances of finding such a place, even among 1,000,000 known lush green planets. Add to that the practical problem of the universal speed limit, and we'd have a hell of a time getting there even if we could find it. I think that humans would sooner evolve into Martians than we'll find another Earth.

15th January 2004, 10:10 AM	#62
Interesting Ian Guest Posts: n/a	Quote: Originally posted by epepke I guess I disagree with just about everybody. Manned space exploration is valuable because I want to go. If I don't get to go, I want someone to go. The reason I want to go is that I am a human. Gorillas feed their community. Jackdaws gather toys. Cats mark their territories. Every creature lives, breathes, eats, eliminates, reproduces, dies. I'm one of those creatures, but I'm also a human, and we explore. That's what we do. "We choose to do these things, not becuase they are easy, but because they are hard." I think there's a great deal of danger these days in losing our humanity. When we decide that the only value of science is make some pill to give someone two more years of life watching Friends reruns, or we decide that the only value of space exploration is to fill up a disc with data as cheaply as possible, or we decide that the only value of learning is to get a better job and put more cholesterol on the table, we cut off bits of ourselves and throw them away. At the end of this process, we all may be healthy and long-lived and sane and sensible and comfortable. And we will be apes with cell phones, nothing more. We will be like Nietzsche's Last Man. We will neither live where it is too hot nor too cold. Work will be regulated, lest it become a burden, and so will leisure, lest it become like work. We will be content. So says the Last Man, and blinks. I don't know about you all, but I didn't evolve the biggest neocortex in the history of the planet so that I could do that. A nice emotional outburst epepke I think probably most people would agree with you. On the other hand I think that we should settle for unmanned missions for the next 50 years or so until technology improves and we have more of an idea where the interesting stuff lies through the unmanned missions. A man on mars by 2020? No, but maybe by about 2069.
Interesting Ian Guest Posts: n/a

15th January 2004, 10:14 AM	#63
Interesting Ian Guest Posts: n/a	Re: Re: Re: Manned missions into space -- a waste? Quote: Originally posted by hgc Yes, I also suspect there are other "Earth-like" planets. But how much like Earth would be necessary to support human life? The variables are so numerous as to drastically reduce our chances of finding such a place, even among 1,000,000 known lush green planets. Add to that the practical problem of the universal speed limit, and we'd have a hell of a time getting there even if we could find it. I think that humans would sooner evolve into Martians than we'll find another Earth. I would have thought that earth like planets wouldn't be all that uncommon. What variables do you have in mind? As for the Universal speed limit we could maybe travel very close to the speed of light. Thus a journey of 20 light years might only take a few months ship time.
Interesting Ian Guest Posts: n/a

15th January 2004, 10:32 AM	#64
Hexxenhammer Malleus Malefactorum Join Date: Jul 2003 Posts: 2,124	Re: Re: Re: Manned missions into space -- a waste? Quote: Originally posted by hgc Yes, I also suspect there are other "Earth-like" planets. But how much like Earth would be necessary to support human life? The variables are so numerous as to drastically reduce our chances of finding such a place, even among 1,000,000 known lush green planets. Add to that the practical problem of the universal speed limit, and we'd have a hell of a time getting there even if we could find it. I think that humans would sooner evolve into Martians than we'll find another Earth. With the variety of environments that humans can live in on THIS planet without much technology, from sea level to the highest mountains, and above the arctic circle to the equator, I think we'd do ok on a sufficiently earth-like planet. The speed limit is a problem, but we could get a good fraction of light speed going and with advances in life support maybe the astronauts would be spry at very old ages if it took years to get somewhere.
	__________________ Georgia's board of education approved the plan that allows teachers to keep using the word 'Evolution' when teaching biology. Though, as a compromise, dinosaurs are now called 'Jesus Horses.'--Jimmy Fallon on Weekend Update "I mean, if you buy into a religion, you're pretty much kissing good by(sic) critical thinking, aren't you?" --Riddick. Amen to that, brother. Gamers! Ultimate RPG Thread has a new home at skepticalcommunity! Check it out!

15th January 2004, 10:33 AM	#65
hgc Penultimate Amazing Join Date: Jun 2002 Posts: 12,988	Re: Re: Re: Re: Manned missions into space -- a waste? Quote: Originally posted by Interesting Ian I would have thought that earth like planets wouldn't be all that uncommon. What variables do you have in mind? As for the Universal speed limit we could maybe travel very close to the speed of light. Thus a journey of 20 light years might only take a few months ship time. Variables like the temperature gradients; chemical composition of the Earth, seas and atmosphere; weather patterns; incoming radiation from the local star; other life already resident; and so on. I don't know how we would accelerate up to close to the speed of light, but I'll allow that it's theoretically possible for the sake of this discussion. But tell me more about this "ship time."

15th January 2004, 10:40 AM	#66
hgc Penultimate Amazing Join Date: Jun 2002 Posts: 12,988	Re: Re: Re: Re: Manned missions into space -- a waste? Quote: Originally posted by Hexxenhammer With the variety of environments that humans can live in on THIS planet without much technology, from sea level to the highest mountains, and above the arctic circle to the equator, I think we'd do ok on a sufficiently earth-like planet. The speed limit is a problem, but we could get a good fraction of light speed going and with advances in life support maybe the astronauts would be spry at very old ages if it took years to get somewhere. Yes, humans appear to be tremendously adaptable, given that we can live just about anywhere on Earth. But the variety of environments here on just this planet is nothing like the variety of environments on all the possible life-supporting planets within some theoretical striking distance (allowing we could do some sort of trip to planets in this section of the Milky Way). All the land regions of this planet might just as well be considered to be quite similar if viewed from the perspective of an imaginary being whose been around the galaxy a bit. To say "we'd do ok on a sufficiently earth-like planet," is a tautology, given that sufficiently means humans could survive there, in this context.

15th January 2004, 10:51 AM	#67
Interesting Ian Guest Posts: n/a	Quote: Originally posted by Morchella So you dredged up one proponent. So what. No. I have never read any O'Niell. It seems his work is kind of old don't you think. Did he mention that the closest star is 3 light years away and the possibility that there is a habitable planet there is less than one in a billion. Hi Morchello, I'm a "woo woo" BTW. Anyway, the nearest star is 4.2 light years away, not 3 light years away. It's true that it is very unlikely that there is a habitable planet there, but this is because I believe it is a binary star system I do not see that habitable planets should be all that rare. Perhaps you could provide some reasons why you think this? Quote: Did he account for the fact that we cannot ever approach the speed of light? Why can't we?
Interesting Ian Guest Posts: n/a

15th January 2004, 10:57 AM	#68
patnray Graduate Poster Join Date: Mar 2002 Location: San Jose, CA Posts: 1,008	Quote: Originally posted by Wile E. Coyote *What it feels* like to be standing on Mars.** That is not a fact about Mars, it is a fact about human feelings. Don't get me wrong, though, I, too, would love to experience that. Very romantic. But it will probably only be experienced by a hand full to a few dozen people at the most. Aside for such subjective experiences, what objective facts can we learn from manned missions that we can't learn from unmanned missions?

15th January 2004, 11:00 AM	#69
Skeptical Greg Agave Wine Connoisseur Join Date: Jul 2002 Location: Just past 'Resume Speed' Posts: 12,873	Re: Re: Manned missions into space -- a waste? Quote: Originally posted by Interesting Ian .....providing there is no other intelligent life forms living there comparable or exceeding our own intelligence (a reasonable supposition). So, in this case, we turn around and return to Earth?
	__________________ " Somewhere between Jesus dying on the cross, and a giant bunny hiding eggs,there seems to be a gap in information. " Stan - Southpark Prove your computer is not a wimp ! Join the JREF Folders ! Team 13232

15th January 2004, 11:01 AM	#70
Hexxenhammer Malleus Malefactorum Join Date: Jul 2003 Posts: 2,124	Re: Re: Re: Re: Re: Manned missions into space -- a waste? Quote: Originally posted by hgc I don't know how we would accelerate up to close to the speed of light, but I'll allow that it's theoretically possible for the sake of this discussion. But tell me more about this "ship time." Ian's not off here (I'm amazed too ) As long as the ship's "gas pedal is down" it could probably get a good percentage of light speed going. I suppose limited by things like mass, fuel supply etc...things that take math and people smarter than me to figure out. When you get halfway to where you're going, turn around and start slowing down by firing the engines again. Anyone know what % lightspeed a ship that uses conventional physics could get to? My wild-@$$ed guess is 20-35%. I reserve the right to be very, very wrong.
	__________________ Georgia's board of education approved the plan that allows teachers to keep using the word 'Evolution' when teaching biology. Though, as a compromise, dinosaurs are now called 'Jesus Horses.'--Jimmy Fallon on Weekend Update "I mean, if you buy into a religion, you're pretty much kissing good by(sic) critical thinking, aren't you?" --Riddick. Amen to that, brother. Gamers! Ultimate RPG Thread has a new home at skepticalcommunity! Check it out!

15th January 2004, 11:03 AM	#71
hgc Penultimate Amazing Join Date: Jun 2002 Posts: 12,988	Quote: Originally posted by Interesting Ian Why can't we? [ever approach the speed of light] You have to put in energy to get acceleration. The amount of fuel that would be required to accelerate to that velocity would be a whole hell of a lot more than we have available. Don't forget that you have to decelerate too.

15th January 2004, 11:04 AM	#72
Hexxenhammer Malleus Malefactorum Join Date: Jul 2003 Posts: 2,124	Re: Re: Re: Manned missions into space -- a waste? Quote: Originally posted by Diogenes So, in this case, we turn around and return to Earth? No that's when we fire the death rays while broadcasting "We come in peace."
	__________________ Georgia's board of education approved the plan that allows teachers to keep using the word 'Evolution' when teaching biology. Though, as a compromise, dinosaurs are now called 'Jesus Horses.'--Jimmy Fallon on Weekend Update "I mean, if you buy into a religion, you're pretty much kissing good by(sic) critical thinking, aren't you?" --Riddick. Amen to that, brother. Gamers! Ultimate RPG Thread has a new home at skepticalcommunity! Check it out!

15th January 2004, 11:10 AM	#73
Interesting Ian Guest Posts: n/a	Re: Re: Re: Re: Re: Manned missions into space -- a waste? Quote: Originally posted by hgc Variables like the temperature gradients; chemical composition of the Earth, seas and atmosphere; weather patterns; incoming radiation from the local star; other life already resident; and so on. If we consider a star similar to our own, and we discover a planet similar in size to our own at a comparable distance from its parent star, would it not be the case that there is a good chance it will turn out earthlike? If not then why not? Quote: I don't know how we would accelerate up to close to the speed of light, The application of force. This could be exactly the same as the gravitational force so that the astronauts would have normal weight. The spaceship could accelerate for half its journey to a given star, then decelerate for the other half of the journey. Quote: but I'll allow that it's theoretically possible for the sake of this discussion. But tell me more about this "ship time." [/b] Einsteins special theory of relativity. From the astronauts perspective, if they travel very close to the speed of light, instead of the star being 20 light years away, it might, say, only be 1 light year away
Interesting Ian Guest Posts: n/a

15th January 2004, 11:22 AM	#74
patnray Graduate Poster Join Date: Mar 2002 Location: San Jose, CA Posts: 1,008	Re: Re: Re: Re: Re: Re: Manned missions into space -- a waste? Quote: Originally posted by Hexxenhammer Anyone know what % lightspeed a ship that uses conventional physics could get to? My wild-@$$ed guess is 20-35%. I reserve the right to be very, very wrong. Mass increases as the velocity increases and becomes infinite at the speed of light. It would take an infinite amount of energy to accelerate even one milligram to the speed of light. My very rough calculations show mass increasing about 25% at half the speed of light and about 50% at 3/4 the speed of light. Using conventional (inertial thrust) means, how fast could one go (and still be able to stop at the other end of the journey)? Inertial thrust requires mass to accelerate in the opposite direction and energy to accelerate it. If you carry the mass you will eventuall eject along with you you will have to accelerate that mass, too. I remember some science fiction stories invloving a kind of space jet that scoops up gas and dust particles and accelerates those to produce thrust without having to carry the mass along. Given a sufficient supply of energy and a very long time to accelerate, I think maybe 5% to 10% of c might be possible...

15th January 2004, 11:28 AM	#75
patnray Graduate Poster Join Date: Mar 2002 Location: San Jose, CA Posts: 1,008	To put things in perspective, the Mars lander traveled about 0.0038% the speed of light as it left earth (about 7 miles/second)...