Thread: October 14, First Contact

Originally Posted by juroara

nitsuj, you come off as a very negative person that only thinks of things as being impossible unless it is already possible today

if everyone thought like you there would be no progress. we would just stick our heads in the mud and shit on it

Uhm, no. Some things will be possible in the future, I just don't think ships that travel at light speeds the size of a truck is possible, EVER. The majority of videos of aliens show them flying in the aircraft, not teleporting, not going through wormholes, flying. If they're flying at supersonic/hypersonic speeds, that's too slow to reach the nearest star, let alone another galaxy. They need to travel at the speed of light, and maybe if they had infinite fuel, it'd be possible, but given the size that most ships in the videos are, unless they get 1,000,000 lightyears to the gallon, they're not coming to earth.

Originally Posted by juroara

someone has to think outside of the box. someone has to imagine the impossible. scientists, inventors have to dream of impossible things for progress to be made

I doubt they think of impossible things to make. As far as I know, no one ever said traveling at the speed of sound was impossible or anything. I'm pretty sure scientists have a fairly good idea of what's possible, and what isn't, by using physics and maths.

Originally Posted by juroara

earthlings are tiny little specks of dust in the greatness of the universe. its a extremely naive to think our tiny little specks of scientists have discovered everything there is to be known - and that we understand all there is and ever will be to space travel. to say its impossible for any alien race to travel great distances at great speeds, in RELATIVE short times - is NAIVE.

So far, traveling at light/superluminal speeds IS impossible, so I don't see what's so naive about it. Sure, there might be life out there like us, but I highly doubt they're traveling to places lightyears away from them.

Originally Posted by juroara

you are saying you know for a sure of that which we do not know. its just soo much more honest to just be open and say "I don't understand it"

Why say that when I've yet to be shown an aircraft the size of a one-passenger plane going at or faster than 186,000 miles per second?

Originally Posted by juroara

just let go. think OUTSIDE OF YOUR BOX. its okay. its funner on the other side of possibilities. life is more positive. the future has a brighter outlook. you see more options in life.

can you or can you not accept, that something you don't currently understand can still be possible?

I haven't had a reason to accept aliens traveling at or faster than light is possible. I also haven't had a reason to accept that Abraxas from Fantastic Four is aiding them in their galactic travels.

Also, if they do exist, why don't they come into contact with us? They're supposedly been coming for hundreds/thousands/millions of years, so why haven't they came into contact?

Originally Posted by drewmandan

Again, I don't believe those things in the videos are aliens. I think most of them are frisbees. When I envision a ship that goes 0.99c, I think of a ship miles long that is mostly fuel.

I edited my post earlier with quotes and links to the articles.


EDIT: I'll just post them in here.

EDIT:

Here's some things I found:

http://en.wikipedia.org/wiki/Faster_than_light#Tachyons

In special relativity, while it is impossible to accelerate an object to the speed of light, or for a massive object to move at the speed of light, it is not impossible for an object to exist which always moves faster than light. The hypothetical elementary particles that have this property are called tachyons. Their existence has neither been proven nor disproven, but even so attempts to quantise them show that they may not be used for faster-than-light communication.[15] Physicists sometimes regard the existence of mathematical structures similar to Tachyons arising from theoretical models and theories as signs of an inconsistency or that the theory needs further refining.[16]

http://www.wonderquest.com/ftl.htm

Q: Why is it impossible to go faster than light? (Manuel, Someplace, World)

A: It is impossible for any object to achieve the speed of light by a mechanical acceleration, which, indeed, makes going faster than light also impossible by such means. Suppose we try to accelerate an object of rest mass, m, that's traveling at a velocity, v, up to the speed of light, c — what happens? We can't do it because we would need an infinite amount of energy, as the relativistic energy equation (below) shows: When v = c, the energy, E, required is infinite.



That's not, however, the end of the story. There's nothing in this equation that proves it's impossible to go faster than light by some other means.

For example, particles that might have always been going faster than light. Thus, they need not reach the speed of light to get faster than light. We have never found such particles (called tachyons), but that doesn't mean they don't exist. Perhaps, the big bang created some tachyons, and some remain from that ancient event.

"Articles claiming to have found experimental evidence for tachyons spring up from time to time in the literature, but none have lasted long or held up to critical scrutiny," says physicist Rod Nave, professor at George State University.

Theory is not encouraging, even if it doesn't rule out the possibility of faster than light travel. Einstein's theory of special relativity says, if a particle goes faster than light, then time becomes an imaginary number (the square root of a negative number). And "we haven't a clue what that means," says Nave.

"Relativity is so counter-intuitive" it's good to have conceptual anchors to stop us from floating too far adrift. Nave throws these two out to keep his classes from taking their speculations too seriously:

* Light speed (c = 186,282 mi/s = 299 792 km/s, in a vacuum) is the speed limit of the universe.
* "When you talk about speeds faster than c, that is science fiction, not science." Because there is no experimental evidence.

http://www.projectrho.com/rocket/rocket3v.html

Originally Posted by The Light-Speed Barrier.

No, this is not like the "sound barrier", it is much more fundamental.

That old spoil-sport Einstein created his theory of General and Special Relativity. Before that, Newtonian physics predicted that if your spacecraft burnt X amount of fuel, it would be accelerated by a velocity of Y, always. Which makes common sense.

Relativity says that may be true at normal velocities, but it doesn't hold at speeds close to the speed of light "c". At those speeds, burning X amount of fuel will accelerate your spacecraft by less than Y, i.e., to accelerate by Y, you need to burn more than X fuel.



And to move at the speed of light, you'd need an infinite amount of fuel. And more than infinity if you want to move faster. Since it is impossible to burn an infinite amount of fuel it is impossible to move at the speed of light, let alone faster.

Every single FTL drive you read about in science fiction is some clever way to avoid the light speed barrier.

http://www.physicsguy.com/ftl/html/F...l#chap:barrier

Chapter 7: The First Problem: The Light Speed Barrier

In this section we discuss the first thing (and in some cases the only thing) that comes to mind for most people who consider the problem of faster than light travel. I call it the light speed barrier. As we will see by considering ideas discussed in Part I , Chapter 1 of this FAQ, light speed seems to be a giant, unreachable wall standing in our way. I note that various concepts for FTL travel may deal with this problem, but here we simply want to talk about the problem in general.


7.1 Effects as One Approaches the Speed of Light

To begin, consider two observers, A and B. Let A be here on Earth and be considered at rest for now. B will be speeding past A at a highly relativistic speed as he (B) heads towards some distant star. If B's speed is 80% that of light with respect to A, then tex2html_wrap_inline878 for him (as defined in Section 1.4 ) is 1.6666666... = 1/0.6. So from A's frame of reference, B's clock is running slow and B's lengths in the direction of motion are shorter by a factor of 0.6. If B were traveling at 0.9 c, then this factor becomes about 0.436; and at 0.99 c, it is about 0.14. As the speed gets closer and closer to the speed of light, A will see B's clock slow down infinitesimally slow, and A will see B's lengths in the direction of motion becoming infinitesimally small.

In addition, If B's speed is 0.8 c with respect to A, then A will see B's energy as a factor of tex2html_wrap_inline878 larger than his rest-mass energy (Note, I use an equation for energy here defined in Section 1.5, Equation 1:8 ):

(Eq 7:1)


where m(B) is the mass of observer B. At 0.9 c and 0.99 c this factor is about 2.3 and 7.1 respectively. As the speed gets closer and closer to the speed of light, A will see B's Energy become infinitely large.

Obviously, from A's point of view, B will not be able to reach the speed of light without stopping his own time, shrinking to nothingness in the direction of motion, and taking on an infinite amount of energy.

Now let's look at the situation from B's point of view, so we will now consider him to be at rest. First, notice that the sun, the other planets, the nearby stars, etc. are not moving very relativistically with respect to the Earth; so we will consider all of these to be in the same frame of reference. Remember that to A, B is traveling past the earth and toward some nearby star. However, in B's frame of reference, the earth, the sun, the other star, etc. are the ones traveling at highly relativistic velocities with respect to him. So to him the clocks on Earth are running slow, the energy of all those objects becomes greater, and the distances between the objects in the direction of motion become smaller.

Let's consider the distance between the Earth and the star to which B is traveling. From B's point of view, as the speed gets closer and closer to that of light, this distance becomes infinitesimally small. So from his point of view, he can get to the star in practically no time. (This explains how A seems to think that B's clock is practically stopped during the whole trip when the velocity is almost c. B notices nothing odd about his own clock, but in his frame the distance he travels is quite small.) If (in B's frame) that distance shrinks to zero as his speed with respect to A goes to the speed of light, and he is thus able to get there instantaneously, then from B's point of view, c is the fastest possible speed.

From either point of view, it seems that the speed of light cannot be reached, much less exceeded. This, then, is the "light speed barrier", but most concepts people have in mind for producing FTL travel explicitly deal with this problem (as we will see). However, the next problem isn't generally as easy to get away with, and it probably isn't as well known among the average science fiction fan.