UFO'S of UAP'S, ASTRONOMIE, RUIMTEVAART, ARCHEOLOGIE, OUDHEIDKUNDE, SF-SNUFJES EN ANDERE ESOTERISCHE WETENSCHAPPEN

Experts assemble at the "Star Wars: The Science Awakens" panel at New York Comic Con Oct. 8, 2016. (Left to right: Janey Tracey, Christopher Mahon, Mara Wood, Travis Langley, Charles Liu, Eliot Sirota, Monique Renee)
**Credit: Sarah Lewin/Space.com**

1. Do lightsabers make sense scientifically?

Charles Liu, an astrophysicist at The City University of New York College of Staten Island, said the main issue with lightsabers is how much energy would be required. His explanation assumed lightsabers would be made of plasma.

"If you build plasma up to a high enough energy, they [lightsabers] actually can have a physical reaction with one another," Liu said. "So if you could contain superpowerful plasma in these magnetic bottles, or something, and they knock against one another, they might actually be able to release noise and a physical resistance."

"The problem is, if you have that much power and ability to confine that much plasma, you don't want to leave it in a stick — you want to blast and level a city with it," he added.

With today's technology, it would not be possible to get that much power into such a small, portable package, said Christopher Mahon, a writer at science/sci-fi website Outerplaces.com. It'd need about 100 times the power density of a cellphone, which isn't currently possible, he said.

"And look what happened when Samsung tried to make a slightly more powerful battery," Liu joked, referring to the company's recently recalled Note 7 smartphone. (Hint: They exploded.)

A lightsaber could be a beam of plasma shaped like a donut, circling in on itself and maybe controlled by some sort of black hole in the handle with adjustable strength, the panelists said. But even then, the plasma would give off way more excess radiation, spraying the surroundings with light and particles, unless it was somehow siphoned off into some other dimension, they said.

The group also discussed whether the Force was necessary for someone to operate a lightsaber, which would help explain any nonscientific functioning of the weapon. But Han Solo uses a lightsaber, and his connection to the Force is unclear, psychologist and "Talking Comics" podcast host Mara Wood pointed out. Ultimately, it's probably that the Force makes people better lightsaber users but isn't crucial to the weapon's function. [Is a Real Lightsaber Possible? Science Offers a New Hope]

2. Would Kylo Ren's lightsaber slice up his arms?

Eliot Sirota, a visual-effects artist and filmmaker, recalled when the internet freaked out over the first "The Force Awakens" trailer because it featured two short mini-beams coming out of the sides of villain Kylo Ren's lightsaber.

As it turns out, the design is more practical than one might expect, assuming lightsabers themselves actually worked. Sirota cited weapons expert Steve Huff, who had been on this same panel in the past.

Huff tested the design: He built a foam model of Kylo Ren's weapon and put chalk on the blades, covering every part of the light beams' surface to reflect how every edge is a cutting edge. Then, he tested the model out with a German longsword fighting style that featured similarly shaped swords. When he went through a series of movements from that fighting style, he didn't get any chalk on the wrists of his black gloves, indicating he wouldn't have cut his body.

Therefore, people with the Force who were well trained, like Jedi and Kylo Ren, would likely have nothing to fear from their own weapon, he said.

"That's also some security about somebody else just picking up your weapon, because they turn their hand slightly, and the hand goes to the floor," added Travis Langley, editor and lead writer of the book "Star Wars Psychology: Dark Side of the Mind" (Sterling, 2015).

3. Do droids have rights?

Droids, like Luke Skywalker's companions R2D2 and C3PO, are beloved characters in the "Star Wars" movies, but most characters seem to treat them with complete disregard. It's unclear what rights droids have in "Star Wars" society, the panelists noted, if they have any at all.

"I'm a droid-rights advocate," Sirota said. "They're just disposable … [Scavengers] go out and just find them in the sand, and fix them up, sort of, and sell them off like a garage sale."

That behavior can seem jarring to audiences because the droids seem to be sentient, or they at least simulate sentience. After all, they seem to come up with original thoughts, meeting an artificial intelligence criterion called the Lovelace test, Mahon said. The Lovelace test evaluates whether an artificial being has creativity, and is an alternative to the Turing test (which evaluates whether it can pass as human). Moreover, the droids of the "Star Wars" universe have personalities that are more complex than anyone would probably program (such as C3PO's strange, complaining nature).

The characters in "Star Wars" seem to diverge in how they treat droids, the panelists noted: Skywalker family members seem to treat them well, but otherwise, they're pretty much viewed as machines.

"In the galaxy at large, these are tools," Sirota said. "These are microwave ovens, essentially." [Makers of 'Star Wars' BB-8 Droid Toy Promise Hidden Tricks]

A major exception, the panelists added, is cyborgs — characters who are part human and part machine, who seem to be treated as fully human. But where do you draw the line?

"Darth Vader is probably the perfect example of that," Langley said — he's transformed by and reliant on cybernetic implants, which could account for some of the drastic changes to his personality over the course of his storyline.

And perhaps we shouldn't be surprised to find that the ethical concerns in the "Star Wars" universe can be different from those facing humans on Earth. This is, after all, a civilization that relies on cloned human soldiers.

"There may be some ethical differences in the 'Star Wars' universe, given that we discuss the sentience of droids and it doesn't seem to be a topic [there]," said Monique Renee, who dresses in costume as part of the 501st and Rebel Legions and is studying zoology, biology and paleontology. "Cloning people might just be something they do there that we might not."

4. How would travel through hyperspace work?

The panelists' response to hyperspace is to cite string theory, a real-world framework that attempts to describe physics in terms of tiny, vibrating one-dimensional strings which exist in many more dimensions than we can sense. Essentially, if something like the string-theory universe were real, Mahon said, ships could travel largely through other dimensions — mostly outside of known space-time, but still leaving a "mass shadow," like a ghost, in their wakes).

"People are trying to develop a theory that explains our physics, here — not with four dimensions but with 10," Liu said. An 11-dimensional structure would tie them all together, he added — and by moving outside of our usual dimensions " you can literally jump back into any point in space-time," he said.

That might even explain the widely varying times it takes people to get around in the "Star Wars" universe, Liu added. For some string theories, the universe isn't uniform in all dimensions, so it could take longer to get to certain locations than to others.

5. Do planet-destroying lasers make sense?

"NO," Liu declared, the superweapons do not make sense.

"First of all, if you hit a planet with an energy beam — and this is true for Red Matter in the 'Star Trek' reboot also — you don't wind up with a planet going KABOOM! like that … What happens instead is, you get a rupture, but then gravity pulls everything back down again." ['Watch WIRED Smash an Epic LEGO Star Destroyer & Trek Alum Explain 'Star Wars']

Moreover, under the universal laws of physics, it would not be possible to funnel a star's energy into a planet without it immediately turning into a star itself, the panelists said.

If a planet were somehow vaporized, it would ultimately mess with the orbits of other planets in the system, Liu added. For instance, if Earth were turned to rubble, it would eventually become a ring system around the sun and, in turn, slowly change Mars' and Venus' orbits a bit. Saturn's rings, for instance, are held in place by shepherd moons that keep the rings from deviating.

6. Would destroying the Death Star ruin the economy?

An audience member brought up a theory, discussed by The Film Theorists on YouTube: that the destruction of the Death Star superweapon would be devastating to the galactic economy. The panelists, however, doubted that would be the case.

"A couple of astronomers and NASA technicians have said 'Star Wars' is the land of infinite fuel, because all the starships can go pretty much anywhere," Mahon said. "If you're dealing with star systems with thousands of planets across a galaxy, the resources are just incalculable. And the Galactic Empire loves superweapons; that's one of their big things. So they probably have the logistics system in place to make it happen."

"The Empire as a government doesn't care about how everyone else is doing; they just take what they want," Sirota added. "Let's just go to a planet and strip-mine it and take all their resources, and — 'Oh, sorry guys, see you later; we're going to go build a Star Destroyer.'" [Photos: 'Star Wars and the Power of Costume' Exhibition]

7. Is "Star Wars" science fiction or fantasy?

Janey Tracey, managing editor of Outerplaces.com, said this question puts "Star Wars" fans in a bind: It's either fantasy, or you have to accept midi-chlorians as real (the widely disliked biological explanation for the Force given in the series' prequel movies). Part of the reason people disliked that narrative turn, the panelists said, was that viewers didn't feel the need to understand the science behind the Force to appreciate the movies' storylines.

"'Star Wars' is really apart from something like 'Star Trek,' for me, because you look at 'Star Trek,' and the science is just so important to the fans and the creators," Renee said. "[In] 'Star Wars,' the science is more of a framework to hang the story off of. It really wasn't quite as important. It's there; it's just meant to explain what's going on, and you suspend your disbelief and just go with it."

That discussion raised another question: "Why has their science advanced so little in 1,000 years?" Langley asked. The panelists speculated that the dark days of the universe could have stalled technological development, as in Earth's Middle Ages, or perhaps the existence of the Force itself made technology irrelevant. After all, when the Force was weak, the technological Empire rose. [10 Real Alien Worlds That Resemble 'Star Wars' Planets]

"Star Wars" "could be science fiction, science fantasy, real — it just isn't necessarily human," Liu said later in the panel. "The fact that they look human is utterly coincidental if they're that far away and it's that long ago."

Ultimately, though, "Star Wars" is based on a traditional "hero's journey" narrative — the heroic quests that come up again and again in mythology around the world. Series' creator George Lucas purposely followed that format, the panelists said, and it's part of the reason the movies resonate so immediately with an audience (and also why people thought "The Force Awakens" ripped off "A New Hope"; both films hewed to that narrative.) "Star Trek," on the other hand, focuses on humanity's overall journey into the future.

"'Star Wars' is the hero's journey," Sirota said. "'Star Trek' is the human journey."

Email Sarah Lewin at slewin@space.com or follow her @SarahExplains. Follow us @Spacedotcom, Facebook and Google+. Original article on Space.com.

Where Is the Rest of the Universe? — **Much of the universe is made of of matter that we can't see.**
**Credit: agsandrew / Shutterstock.com**

Most of the universe is made up of "stuff" that is invisible, possibly intangible and interacts with other things only via the force of gravity. Oh, yes, and physicists don't know what the stuff is or why it makes up so much of the universe — some four-fifths of its mass.

They call it dark matter.

So where is this mysterious stuff that makes up such a huge chunk of our universe, and when will scientists find it?

First, though, how do we know it's even out there?

Dark matter was first hypothesized in the 1930s when Swiss astronomer Fritz Zwicky realized that his measurements of the masses of galaxy clusters showed some of the mass in the universe was "missing." Whatever was making galaxies heavier, it didn't give off any light, nor did it interact with anything else except via gravity.

Vera Rubin, in the 1970s, found that the rotation of galaxies was not following the predictions of Newton's laws of motion; the stars in galaxies (notably Andromeda) all seemed to be orbiting the center at the same speed, rather than those farther out moving more slowly as theories of gravity said they should. Clearly, something was adding mass to the outer parts of galaxies, something nobody could see. [Does the Universe Have an Edge?]

Other pieces of evidence came from gravitational lensing, which happens when the gravity of a large object bends the light waves around that object. Per Albert Einstein's theory of general relativity, gravity bends space (like a sumo wrestler might deform the mat he is standing on), so light rays bend around massive objects even though light itself is massless. Observations indicated that there wasn't enough visible mass to bend the light by as much as it was bending around certain galaxy clusters — in other words, the galaxies were more massive than they should be.

Then there is the cosmic microwave background (CMB), the "echo" of the Big Bang, and supernovas. "What the CMB tells you is that the universe is spatially flat," said Jason Kumar, a professor of physics at the University of Hawaii. "Spatially flat" means that if you were to draw two lines across the universe, they would never meet, even if those lines were a billion light-years across. In a steeply curved universe, those lines would meet at some point in space.

Researchers then calculated how much matter the universe must have in order to be flat and produce the amount of normal matter (also calledbaryons) observed in the universe.

"I ask myself, 'Is the amount of matter I have equal to baryonic matter, and it's not," Kumar said.

There's now little dispute among cosmologists and astronomers that dark matter exists. Yet it seems unaffected by light, and it isn't charged like electrons or protons are. So far it has eluded direct detection.

"That's kind of the mystery," Kumar said. There are may ways scientists have tried to "see" dark matter – either via its interactions with normal matter or looking for particles that dark matter might become. "Those experiments are going to keep getting better, and don't seem to have any hiccups so far as they go to better detectors."

What we know it isn't

A number of theories have come and gone as to what dark matter is. One of the first was logical enough: The matter was hidden within massive astrophysical compact halo objects, or MACHOs, such as neutron stars, black holes, brown dwarfs and rogue planets. They don't emit light (or they emit only very little), so they are effectively invisible to telescopes. [The 9 Biggest Unsolved Mysteries in Physics]

Yet surveys of galaxies looking for small distortions in the light of background stars produced by a MACHO passing by — called microlensing events — couldn't account for the amount of dark matter around galaxies, or even a significant portion of it. "MACHOs seem as ruled out as ever," said Dan Hooper, an associate scientist at the Fermi National Accelerator Laboratory in Illinois.

Dark matter doesn't appear to be clouds of gas that telescopes wouldn't see, either. Diffuse gas would absorb light from the galaxies that are farther away, and on top of that, ordinary gas would re-emit radiation at longer wavelengths – there'd be a massive radiation of infrared light in the sky. Since that doesn't occur we can rule that out as well, Kumar said.

What it might be

Weakly interacting massive particles, or WIMPs, are some of the strongest contenders to explain dark matter. WIMPs are heavy particles — about 10 to 100 times heavier than a proton — that were produced during the Big Bang, though just small quantities are left today. These particles interact with normal matter via gravity or the weak nuclear force. More massive WIMPs would move more slowly through space, and therefore be "cold" dark-matter candidates, while lighter ones would move faster, and be "warm" dark matter. [Wacky Physics: The Coolest Little Particles in Nature]

One way to find them is in "direct detection" experiments, such as the Large Underground Xenon (LUX) experiment, which is a container of liquid xenon in a South Dakota mine. If a xenon nucleus seems to "bounce" with no explanation, that would be a candidate for getting hit with a dark-matter particle. The magnitude of the bounce would give an idea of the new particle's mass. But Hooper said that LUX hasn't seen anything yet.

Another way to see the WIMPs might be particle accelerators. Inside accelerators, atomic nuclei smash into each at near the speed of light, and in the process that energy of the collision gets turned into other particles, some new to science. So far, though, particle accelerators haven't detected anything that looks like a dark matter candidate, either.

Results from both direct detection and particle accelerators, however, have placed limits on the size and mass of this hypothetical dark-matter particle, Kumar said. The sensitivity of LUX is down to 200 MeV, or about a fifth of a proton's mass, and it could theoretically see particles as heavy as 1 TeV, which is comparable to some types of quarks. Since LUX saw nothing so far, that could well mean that dark matter isn't in that range.

Kumar said that it's possible that WIMPs are really heavy, and because they are so massive there just aren't that many of them, meaning the chance they'll hit a xenon atom is small.

Another possibility: axions. These subatomic particles could be detected indirectly by the kinds of radiation they emit as they annihilate or as they decay into other kinds of particles, or appear in particle accelerators. Yet there hasn't been any direct evidence of axions, either.

Since detecting heavy, slow-moving "cold" particles, like WIMPs or axions, hasn't yielded results yet, some scientists are looking at the possibility of lighter, faster-moving particles, which they call "warm" dark matter. There has been a renewed interest in such a dark-matter model after scientists found evidence of an unknown particle, using the Chandra X-ray Observatory, in the Perseus cluster, a group of galaxies about 250 million light-years from Earth. The known ions in that cluster produce certain X-ray emission lines, and in 2014, scientists saw a new "line" that may correspond to an unknown lightweight particle, Nicola Menci, an astrophysicist at Italy's National Institute for Astrophysics (INAF), told Live Science in an email.

If dark-matter particles are light, scientists are going to have a difficult time detecting them directly, said Tracy Slatyer, a physicist at MIT. Slatyer has proposed new kinds of particles that might make up dark matter.

"Dark matter with [a] mass below about 1 GeV is really hard to detect with conventional direct detection experiments, because they work by looking for the unexplained recoils of atomic nuclei… but when the dark matter is much lighter than the atomic nucleus, the recoil energy is very small," Slatyer said. Protons — a hydrogen nucleus — can't be any lighter than about 938 MeV, so a particle that weighs in the keV range would be 1,000 times lighter. "Think bouncing a ping-pong ball off a bowling ball; the bowling ball doesn't move very much," she said.

Slatyer said there is a lot of research being done on how to find dark-matter particles if current methods fail. Using "superfluid" liquid helium, semiconductors and even breaking of chemical bonds in crystals, are among the ideas being floated.

Kumar said one reason dark matter is so mysterious is precisely that physicists feel that they understand, to a point, how the Big Bang nucleosynthesis ― the origins of matter ― worked. The Standard Model, which predicted the Higgs boson, has been very successful so far, so unless they've all been really wrong about something fundamental it's odd that nobody has managed to detect a dark-matter particle yet.

If, for example, dark-matter particles are very different from what many current models predict, it's possible that particle accelerators wouldn't have seen it. Accelerators like the Large Hadron Collider are better at seeing things that interact with the strong nuclear force, which decay into other particles.

"If that's the way your dark matter works it's a great machine to find it," he said. "But if there isn't a heavier particle like that it's harder."