First part here...
Its mission called for a trip to Barnard's star, some 5.9 light years distant.
Instead of nuclear bombs, the fusion-powered craft creates the propulsion on board in a reaction chamber.
The fuel pellets for the Daedelus class starship consisted of pellets composed of a deuterium-helium-3 mix.
These would have been ignited by what we call relativistic electron beams.
These are extremely high energy electrons that would have hit the deuterium-helium-3 pellets, caused them to fuse, and a huge amount of energy would be released.
The Daedelus design called for 250 of these pellets to be
released every second for over two years.
The spacecraft would have weighed 55,000 tons, most of
which would have been fuel.
The weight penalty for such a spacecraft would be high
but an advanced civilization could eliminate the problem by mining the hydrogen fuel during its interstellar journey.
Deuterium, or heavy hydrogen, exists in abundance on Earth,
notably in seawater, but helium-3 is a much rarer isotope.
In our Solar System, it can be found on the Moon and in vast
quantities on Jupiter and Saturn.
Scientists have proposed using huge hydrogen scoops to mine the helium-3 needed to cross the void of space.
So it's conceivable that if you had a craft that was powered
by nuclear fusion, you could go to another star system, and then use the hydrogen available from that star to refuel.
The self-contained fusion-powered spacecraft could avoid a huge weight penalty and reach speeds that could allow
near-star exploration in a reasonable time frame.
The max speed of a nuclear-powered fusion spacecraft-- Up to 15% of the speed of light.
Travel time from Earth to Alpha Centauri-- About 35 years.
The immense costs, the logistics, and even the politics of nuclear-powered spaceflight long ago caused humanity to
scrap any and all plans.
But a sufficiently advanced society could trade nuclear
propulsion for what seems like an impossible paradox--
Traveling at light speed without moving at all.
Can UFOs actually achieve the immense speeds required for interstellar travel?
One potential answer may be buried 30 feet beneath the
ground in America's heartland...
The Fermilab Tevatron Collider outside Chicago, Illinois.
Racing just below the speed of light, particles of protons and
anti-protons are launched in opposing directions.
They meet in a high energy collision.
The impact produces gamma rays-- The highest energy source known in the universe and potentially the key to interstellar travel.
The best way of making antimatter here on Earth is to
employ probably the most famous equation that Einstein taught us, which is E=mc^2, which tells us that for a certain amount of matter, we can get energy.
It's a great idea because it's incredibly efficient.
You essentially take all of the mass in those particles and
convert it into energy.
But how can antimatter exist in the universe if it must be artificially manufactured?
That's the question that Stefan H. from Philadelphia texted The Universe.
Stefan, antimatter definitely exists, and when it meets up
with normal matter, it explodes in a burst of electromagnetic radiation.
Now, we can make small bits of antimatter in laboratories, but we can also collect antimatter from space.
Some cosmic rays, which are charged, very energetic
particles coming from space, actually consist of antimatter.
Currently, the super-collider is the only practical way to produce antimatter.
And right now it's created in very small quantities.
If we could figure out a way to both create and store enough
antimatter, we would have a storable fuel which, when mixed
with ordinary matter, would liberate a huge amount of energy
at a rate way beyond what either fission or fusion can do.
Because we know antimatter exists and we know antimatter
can be created and stored, it is conceivable that an advanced
civilization could create and harness the power of antimatter
in sufficient quantities to create an antimatter rocket.
An antimatter ship could achieve unbelievable velocities, cruising just below light speed, nearly matching the speed of a star beam streaking across the galaxy.
Travel time from Earth to Alpha Centauri 4 1/2 light years distant-- About 5 years.
In human terms, the cost of creating enough antimatter
particles to power such a starship would be astronomical.
It might be affordable in alien currency, but an antimatter
spacecraft like this comes at a high price.
The gamma rays from antimatter propulsion are so dangerous, they could destroy the cell structure of any living beings aboard ship.
This starship would have to include an advanced shielding
mechanism to keep the crew alive.
And at such high rates of speed, there are equally destructive threats in the universe.
Space is pretty empty, but if you were moving close to the
speed of light, you'd need an extremely effective shielding
system that would allow you to be protected from interstellar
dust particles that would all but annihilate a spacecraft traveling that fast.
But if space debris is so dangerous, why not avoid it completely?
The solution might be one familiar to Star Trek fans, namely a starship that could achieve light speed without even moving.
In effect, one would create what is called a "warp bubble"--
The name taken straight out of science fiction-- And that would involve compressing a region of space-time in front of a spacecraft and expanding a region of space-time behind a
spacecraft while the spacecraft itself sat stationary inside this flat bubble.
So one would effectively be riding a wave of space-time.
A warp drive may seem like pure Sci-Fi fantasy...
But in 1994, a well-respected young physicist named Miguel Alcubierre published a serious proposal outlining how to travel in a controllable space warp.
There are huge obstacles to Alcubierre's warp-drive solution.
The biggest is called "dark energy"...
A cosmic phenomenon recognized in 2011 when three scientists were awarded the Nobel prize for proving its existence.
The simplest explanation that's been proposed for the
phenomenon of dark energy is that there's an intrinsic
property of space itself that makes it want to expand.
You can actually see it by looking at receding parts of the
universe and seeing that there's this extra acceleration component, but it isn't a stored energy source like solar energy or other kinds of energy.
And so it's not inconceivable-- It's not beyond the realms of possibility that some advanced civilization existing somewhere in the universe has learned how to harness dark energy to create an exotic form of propulsion.
But there's another obstacle to a workable warp drive.
The only known way to pull a spacecraft forward within a warp requires harnessing the intense energy of a black hole.
The sort of simple notion is somehow to make a very concentrated bit of matter, extremely concentrated, on the level which would cause a black hole.
If you could generate a black hole on a small scale, so to
speak, you could dangle it in front of the ship and use its
space distortion to sort of drag the ship along.
And exactly how fast could a warp drive tow an extraterrestrial spacecraft?
The clear implication of Alcubierre's work was that it should be possible, if you can make this design of a warp drive, to achieve speeds almost any multiple of the speed of light.
Travel time from Earth to Alpha Centauri aboard a light speed craft powered by a space warp-- About 4 1/2 years...
Or less, as long as everyone on board doesn't incinerate.
One problem with the Alcubierre drive is within that warp bubble, temperatures would rise to far hotter than the core of our Sun.
That's hot.
Just one more small problem to solve for the chance to reach planet Earth.
But what if such an alien spacecraft were to arrive in Earth's atmosphere, riding in a warp bubble, towed by a black hole?
It might not be the first mass-witness UFO sighting, but it would certainly be the last.
March 13, 1997...
Thousands of people witness an optical phenomenon
drifting across the Arizona skies.
Reports of a series of bright lights in geometric patterns are
widespread, including multiple sightings over Phoenix of a
craft up to a mile wide with lights winking on and off in sequence.
Reconstructing the events of that evening, the lights of the
Phoenix lights were almost certainly flares dropped by an
air force a-10 aircraft in conjunction with the human
tendency to envision a solid shape connecting them.
That's the best explanation for the Phoenix lights.
For many, the Phoenix lights incident was direct proof that a huge extraterrestrial craft had arrived.
Some even called it a mother ship.
The purpose of an extraterrestrial mother ship is fundamental to the theories of alien visitation.
It's the only way to bridge the vast distances of interstellar space.
The term "mother ship," I think, came into being around
the same time that "flying saucers" as a term came into being.
And I think the universal notion was you couldn't make an
interstellar trip in a person-sized craft.
You have to have something really large.
An apt earthly analogy of a mother ship is that of an aircraft carrier.
An aircraft carrier travels the vast distances across the
oceans, but its purpose is to transport smaller aircraft which
can then go on and engage in whatever their missions may be.
If the journey to Earth is long, on the order of centuries or even millennia, the mother ship would be much more
than just an aircraft carrier.
There's the generational or "ark ship," which is a very large spacecraft that is essentially an enclosed ecosystem, in which generations of inhabitants expect to be born, grow old, and die over the long period it takes the spacecraft to reach its ultimate destination.
Perhaps with technology, such as suspended animation, biological alien passengers could be put to sleep and revived after the vast journey.
Surviving such a journey would also mean surviving the
destructive energy powering the spacecraft itself.
One logical design solution, a cigar-shaped mother ship, is
precisely what many UFO witnesses claim to have seen.
For any advanced propulsion system, you would want to
situate the crew as far away as possible from the engine source.
So one possible design would be a very long, thin design, with
the engine located at one end of the spacecraft and then some
kind of truss connecting the crew section as far away as
possible so as to avoid damage from high-energy neutrons,
x-rays, or gamma rays from the advanced propulsion system.
If such ark ships have in fact visited planet Earth, the evidence would be overwhelming and undeniable.
Something all these exotic and advanced propulsion
technologies have in common is that they all radiate prodigious amounts of energy, and so we'd be able to see them, like beacons on a lighthouse, from sometimes light years away.
The concentrated emission of x-rays, gamma rays, or
subatomic particles would be suspicious, 'cause we don't see
that in our environment locally under any normal circumstances.
Beyond the obvious visual evidence, the physical effect of a mother ship approaching so close to the Earth's surface could be a terrifying form of apocalypse.
If, for whatever reason, this extraterrestrial technology or
civilization chose not to turn off their engines, it could be
catastrophic for life on Earth, as we would be bathed in
high-energy neutrons, x-rays, and gamma rays.
If it's something which is a version of a warp drive, then you're talking about space distortion, and you wouldn't want to be too close to any major mass, including the planet.
Such catastrophic visitations assume that aliens are willing to risk their own lives in interstellar space...
But there might be a better way.
They could stay at home...
And explore the cosmos using a race of thinking machines.
For many ardent believers in the UFO phenomenon, the Roswell, New Mexico, event in the summer of 1947 is the
defining alien encounter in human history.
In popular culture, the most lasting detail from the purported crash came from the descriptions of extraterrestrial bodies found at the scene.
In the ensuing decades, this vision of alien beings, known as
"the grays," became the accepted standard in science fiction and recurring alien-encounter reports.
The oversized heads may explain an expected feature in alien biology-- Greater intelligence.
The larger skulls would contain larger, more advanced brains compared to ours.
Mastering the profound challenges of interstellar travel would certainly require great intelligence, but might it require something that is beyond organic biology?
One area of science fiction where we might be making kind of
a big mistake is to assume that the aliens are biological, that they're living things.
I think that the possibilities for the kinds of organisms which might travel between the stars are really wide open.
And one possibility that has appeared on occasion in science fiction is machine intelligence.
According to a recent earthly equation known as Moore's Law, the number of transistors on a single computer chip doubles every 18 months, meaning computer processing speed doubles.
This trend has continued for more than half a century and
is expected to continue through 2020 or later.
The exponential explosion of processing speed is opening the
door on a staple of science fiction called "Artificial Intelligence."
So, if you invent a thinking machine, 100 years later, that machine is not only smarter than you are, it's smarter than all humans that have ever lived.
And that's the difference between artificial intelligence and real intelligence.
Artificial intelligence can evolve enormously faster.
But I think the form of AI that we find most both menacing
and promising is the kind of AI that could in fact do what
our brains can do, can think the way we can think.
At Stanford university's artificial intelligence laboratory,
the future of truly intelligent machines is rapidly approaching.
There are a few things that make AI difficult.
One is we don't really know yet how to make computers learn as effectively as humans can.
It seems that our computers today just aren't as fast as we
would like them to get to simulate the learning processes
that take place in the human brain.
To demonstrate early-stage artificial intelligence, Stanford students designed a fighting robot-- One that attempts to learn as it fights.
Okay, so what it's doing now-- It's trying to defend itself,
so it's reacting to your motion.
So, depending on how you move your sword, the robot will adapt to your motion and to your behavior.
How important a step on the road to true artificial
intelligence are robots like this, Torsten?
So here we are using artificial-intelligence methods, like learning methods, to adapt to the environment of the robot,
but we are still not at a stage where the robot is really thinking.
Today's computers are still far less intelligent than almost any human.
But in the future, I think computers could eventually reach, and maybe even surpass, human intelligence.
And if that's the case, imagine that each of us has a computer
in our wallet--a cell phone or wallet-- That was as smart as Einstein or even smarter.
How will civilization change, and what are the amazing things we could do then?
Advanced as it is on Earth, the fencing robot is but a crude analogy for the type of machine intelligence that could pilot an interstellar spacecraft.
The immense obstacles of space travel, including the sheer time scale and cosmic hazards, build a strong case that a race of intelligent machines will make first contact.
But honestly, if interstellar travel really takes place, it seems sort of reasonable to not send the biological beings.
I mean, they're fragile. They have finite lifetimes.
Just as NASA sends robotic probes to explore the Solar
System in advance of human explorers, our first contact with an alien civilization may be with its robotic probes.
Biologic being or AI super being?
Our vision of an extraterrestrial will remain mere speculation until first contact is made.
But how long will we wait?
And despite a lack of hard evidence, just how likely is the existence of another intelligent civilization?
Some believe it is highly likely that the universe teems with life.
The galaxy has been around for a long time.
The Solar System's been around for quite a long time, but the galaxy much longer.
And the stars in it-- Many of them are much older than the Sun and our Solar System.
So the chances are, if civilizations are out there, they've been around for longer than we have.
If they exist, say, for 100,000 years, then the chances are pretty good, I think, they will have learned to either
communicate across interstellar space or possibly travel.
Until first contact occurs, humanity will continue to scan the skies for UFOs.
None have been proven to be extraterrestrial craft so far,
but that does not rule out the possibility that humanity may
one day discover evidence of an intelligent civilization, either
in the far-flung heavens or much closer to home.
0 comments:
Post a Comment