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Warp Drive and ‘Star Trek’: Physics of Future Space Travel

Excerpts from article: For starters, the technical goals ceased to be just science fiction decades ago with a legacy of pertinent publications. To be clear, this does not mean that these breakthroughs are on the threshold of discovery. What it does mean is that these notions have advanced to where they are now problems that are able to be attacked. A graduate-level treatise, along with next-step research options, is available as the compilation “Frontiers of Propulsion Science” (AIAA, 2009). For the rest of us, here is a short version.

Image Credit: Namco Bandai

Faster-than-light engines

Compared to the distances between stars, lightspeed is slow. The neighboring star system nearest to us (Alpha Centauri) is more than four years away at light speed (as measured from the perspective of an external observer). The nearest habitable planet might be anywhere from 25 light-years to 200 light-years away. And, to consider meeting new aliens for each week’s episode, our ship would need a naive cruise speed of at least 25,000 times light speed. The word “naive” is used to remind us that we don’t really know what happens to time and space beyond lightspeed.

Wormholes and warp drives— approaches to FTL flight — are theoretically possible, but the theory has not yet advanced to guide their construction. These theories are based on Einstein’s theory of generalrelativity. The ongoing progress mostly focuses on the energy conditions — how to lower the energy required and how to create and apply the required “negative energy.” One conclusion we have already found is that wormholes are more energy-efficient at creating FTL than warp drive. For more, see Eric Davis’ “Faster-Than-Light Space Warps, Status and Next Steps” paper from last year’s 48th AIAA/ASME/SAE/ASEE Joint Propulsion Conference & Exhibit.

Recent news regarding the work of Harold “Sonny” White at NASA’s Johnson Space Center has been exaggerated. That work is an attempt to measure space-time distortions caused by the presence of negative energy. Unfortunately, I do not have an article to cite about that hypothesis or the methods being used, since such information has not (yet?) been published. Although Eric Davis is tracking this for the Tau Zero Foundation, we do not yet know enough to render judgment.

Quantum physics also presents tempting phenomena relevant to FTL questions. A number of phenomena, such as tunneling and entanglement, fall under the header of “quantum non-locality” — a term I learned from physicist John Cramer at the University of Washington, Seattle. Cramer’s attempt to test the possible time-paradox implications of such phenomena still remains incomplete. The last update I saw was “Status of nonlocal quantum communication test” presented by Cramer and his colleagues.

Control of gravitational and inertial forces

Picture your favorite fictional starship, where the crew is walking around normally, as if in a studio back on Earth. This means that the ship is providing a gravitational field for the comfort and health of the crew — in the middle of deep space where such fields do not exist. This would be a profound breakthrough! This hugely important feature often gets neglected in the shadow of the difficulty of achieving FTL. It is so ubiquitous in science fiction that many people do not even realize it’s there and the extent of its implications. Unfortunately, it does not yet have a cool-sounding name to help champion and convey its essence.

Given such an ability to create acceleration forces inside a spacecraft, it is not much of a leap of imagination to suggest that forces could be created outside a spacecraft too, thus moving the spacecraft through the universe. Such a nonrocket space drive would be a profound breakthrough.

But wait, there’s more. The physics of being able to manipulate gravitational and inertial forces also implies the ability to have “tractor beams” for moving distant objects, “shields” to deflect nearby objects, plus the ability to sense properties of space-time that we cannot yet even fathom.

Researchers have published more than one way to generate such acceleration fields, and both methods are theoretically consistent with Einstein’s general relativity (Robert Forward’s 1963 paper cited below, and the Levi-Civita effect). Both of those have daunting theoretical and implementation challenges, similar to warp drives and wormholes.

However, there is more than one way to approach this challenge, as I presented last year in “Space Drive Physics: Introduction & Next Steps” in the Journal of the British Interplanetary Society. That is the challenge that piques my professional interest. I’m revisiting the works of Eddington and Mach, to test a different formalism of the coupling between space-time (inertial frames) and electromagnetism that can be experimentally tested. Wish me luck.

Unprecedented energy storage and power usage

Interstellar flight — even when in the context of foreseeable technology — requires enormous amounts of energy, more prowess than humanity has yet achieved. On “Star Trek,” they use matter-antimatter to provide energy (antimatter is existing physics), by fully converting matter into energy. Think Einstein’s E=mc2. Our fantastical spacecraft will need at least that much energy, perhaps more.

Nuclear power is a reality that, if used for spaceflight, would greatly increase the extent of space activities using foreseeable technology. The power levels required for FTL flight, values which were once astronomically high, have improved with continued research to where they are now just fantastically daunting.

Other science fiction has cited quantum zero point energy as an ample energy source. Though quantum vacuum energy is rooted in credible theoretical and experimental approaches, that research is still too young to answer the wishes for ample energy conversion. Today, minuscule energy conversions are possible using tiny electrode gaps. Though these experiments are not energy extractors, they do serve as excellent tools to empirically explore this young topic in physics.

Sustainably peaceful society

An important element of “Star Trek” that went beyond technology is its society: creating a cooperative culture that can harness the power of starflight without killing themselves in the process. When considering the potency of the real energy levels required for starflight, that is critically important. This is not just a matter of inspiring fiction or feel-good notions. This is a matter of the survival of our species.

Although trends indicate that humanity is becoming more peaceful, overall, I am concerned that this challenge might turn out to be harder than creating the new physics for FTL and controllable gravity. The good news is that this is something we can all work toward by being more thoughtful about how each of us chooses to resolve conflicts of views, wants and needs.

(Full Article via SPACE)

Light and Dust in a Nearby Starburst Galaxy

Visible as a small, sparkling hook in the dark sky, this beautiful object is known as SDSS J082354.96+280621.6, or J082354.96 for short. It is a starburst galaxy, so named because of the incredibly (and unusually) high rate of star formation occurring within it.

One way in which astronomers probe the nature and structure of galaxies like this is by observing the behaviour of their dust and gas components; in particular, the Lyman-alpha emission. This occurs when electrons within a hydrogen atom fall from a higher energy level to a lower one, emitting light as they do so. This emission is interesting because this light leaves its host galaxy only after extensive scattering in the nearby gas — meaning that this light can be used as a pretty direct probe of what a galaxy is made up of.

Black Hole Firewall: Trouble On The Edge

Ever wondered what happens to things as they are consumed by the black hole, the left over matter of dead stars? For a time, it used to be okay to assume matter was destroyed once it entered into a black hole, spaghettified and all.. but it turned out that this couldn’t be further away from the truth. NewScientists Anil Ananthaswamy has a wonderful 3 page piece getting into full details of this history and what questions scientists are asking now. If you love black holes, this is a definite recommend. Although registration (completely free!) is required to view the whole article. It’s pretty insightful and accurately presents the problems currently being faced with how black holes do what they do:

“Paradoxes are good in physics,” reflects John Preskill. “They help to point the way towards important discoveries.” Quantum mechanics and Einstein’s theories of relativity offer plenty to choose from. There’s the cat that can be dead and alive at the same time. Or the Back to the Future-style time traveller who kills his own grandfather, rendering his own birth impossible. Or the twins who disagree on their age after one returns from a near light-speed trip to a neighbouring star. Each perplexing scenario forces us to examine the fine print of the problem, thereby advancing our understanding of the theory behind it. A case in point is Einstein, whose own theories came from trying to resolve the paradoxes of his time.

Image: Ring of fireSam Chivers

Now Preskill, a theoretical physicist at the California Institute of Technology in Pasadena, is scratching his head over the latest one to surface. Nicknamed the black hole firewall paradox, it comes about when you consider what happens to someone falling into a black hole.

With the nearest black hole more than 1000 light years away, the question is very much a theoretical one. Yet just by studying such a possibility, physicists are hoping to make a breakthrough in their efforts to combine general relativity and quantum mechanics into a theory of quantum gravity – one of the most intractable problems in physics today.

Black holes have long been fertile breeding grounds for paradoxes. Back in 1974, Stephen Hawking, along with Jacob Bekenstein of the Hebrew University in Jerusalem, Israel, famously showed that black holes are not entirely black. Instead, they radiate energy known as Hawking radiation comprising photons and other quantum particles – an agonisingly slow process that eventually causes the black hole to evaporate completely.

Hawking spotted a problem with this picture. The radiation seemed so random that he surmised it couldn’t carry any information about the stuff that had fallen in. So as the black hole evaporates, the information it holds must eventually disappear. Yet this is in direct conflict with a central tenet of quantum physics, which says that information cannot be destroyed. The black hole information paradox was born.

Over the decades, physicists have struggled with this paradox. Hawking thought that black holes destroyed information and the answer was to question quantum mechanics. Others disagreed. After all, Hawking’s idea came from his efforts to meld general relativity and quantum mechanics – a mathematical feat so elusive that he was forced to make approximations. Preskill even made a bet with Hawking that black holes don’t destroy information.

Several arguments suggest that Hawking was wrong. One of the most compelling comes from thinking about what happens as the evaporating black hole gets smaller and smaller. If information can’t escape or be destroyed, then more and more has to be stored in an ever-shrinking volume. But if this is the case, quantum theory says the probability for making a tiny black hole increases from virtually nothing to almost infinity wherever matter collides against matter. “You should have seen it at the Large Hadron Collider, you should have seen it at Fermilab, you should have seen it in tiny room-sized particle accelerators from the 1930s,” says Don Marolf, a theorist at the University of California in Santa Barbara (UCSB). “You should see it when you go and jump up and down on the grass.”

Obviously that hasn’t happened. The other possibility – that matter and the information it carries can leak out from a black hole – is unlikely. Any material that falls in would need to travel faster than light to escape the black hole’s fearsome gravity.

Perhaps, instead, the answer lies with the Hawking radiation itself. Maybe it isn’t so featureless. “A common reaction was that Hawking had simply been careless,” says Joseph Polchinski, also at UCSB. “It wasn’t that information was lost, it was that he hadn’t kept track of it enough.”

Yet all early efforts to do away with the paradox proved unsuccessful. “Hawking had identified a really deep problem,” says Polchinski.

As it happened, Hawking changed his mind in 2004, partly due to work by an Argentinian physicist called Juan Maldacena (see “Hawking’s change of heart”). Black holes don’t destroy information after all, he conceded. He honoured the bet he made with Preskill and presented him with an encyclopaedia of baseball, which Preskill likened to a black hole, because it was heavy and it took effort to get information out of it.

Into The Abyss..

[Full Article]

Star Birth in Cepheus

Watching starbirth isn’t easy: tens of millions of years are needed to form a star like our Sun. Much like archeologists who reconstruct ancient cities from shards of debris strewn over time, astronomers must reconstruct the birth process of stars indirectly, by observing stars in different stages of the process and inferring the changes that take place. Studies show that half of the common stars, including our Sun, formed in massive clusters, rich with young stars, from which they eventually escape. As part of his PhD thesis work, Thomas Allen, University of Toledo, has been observing such a region where stars are forming.

Cep OB 3b is rich young cluster located in the northern constellation of Cepheus. This image was created by combining individual images observed through four different filters on the 0.9 meter telescope at Kitt Peak: blue, visual (cyan), near infrared (orange) and an emission line of hydrogen (red).

The brightest yellow star near the center of the image is a foreground star, lying between us and the young cluster. The other bright stars are the massive young stars of the cluster that are heating the gas and dust in the cloud and blowing out cavities. Surrounding these massive cluster stars are thousands of smaller young stars that may be in the process of forming planetary systems.

J 900: Masquerading as a Double Star

The object in this image is Jonckheere 900 or J 900, a planetary nebula — glowing shells of ionised gas pushed out by a dying star.

Discovered in the early 1900s by astronomer Robert Jonckheere, the dusty nebula is small but fairly bright, with a relatively evenly spread central region surrounded by soft wispy edges.

Despite the clarity of this Hubble image, the two objects in the picture above can be confusing for observers. J 900’s nearby companion, a faint star in the constellation of Gemini, often causes problems for observers because it is so close to the nebula — when seeing conditions are bad, this star seems to merge into J 900, giving it an elongated appearance. Hubble’s position above the Earth’s atmosphere means that this is not an issue for the space telescope.

Astronomers have also mistakenly reported observations of a double star in place of these two objects, as the planetary nebula is quite small and compact.

Measuring the Universe More Accurately Than Ever Before

After nearly a decade of careful observations an international team of astronomers has measured the distance to our neighbouring galaxy, the Large Magellanic Cloud, more accurately than ever before. This new measurement also improves our knowledge of the rate of expansion of the Universe — the Hubble Constant — and is a crucial step towards understanding the nature of the mysterious dark energy that is causing the expansion to accelerate. The team used telescopes at ESO’s La Silla Observatory in Chile as well as others around the globe. These results appear in the 7 March 2013 issue of the journal Nature.

Image: This artist’s impression shows an eclipsing binary star system. Credit: ESO/L. Calçada

Astronomers survey the scale of the Universe by first measuring the distances to close-by objects and then using them as standard candles [1] to pin down distances further and further out into the cosmos. But this chain is only as accurate as its weakest link. Up to now finding an accurate distance to the Large Magellanic Cloud (LMC), one of the nearest galaxies to the Milky Way, has proved elusive. As stars in this galaxy are used to fix the distance scale for more remote galaxies, it is crucially important.

But careful observations of a rare class of double star have now allowed a team of astronomers to deduce a much more precise value for the LMC distance: 163 000 light-years.

“I am very excited because astronomers have been trying for a hundred years to accurately measure the distance to the Large Magellanic Cloud, and it has proved to be extremely difficult,” says Wolfgang Gieren (Universidad de Concepción, Chile) and one of the leaders of the team. “Now we have solved this problem by demonstrably having a result accurate to 2%.”

One Ring to Rule Them All

Galaxies can take many forms — elliptical blobs, swirling spiral arms, bulges, and discs are all known components of the wide range of galaxies we have observed using telescopes like the NASA/ESA Hubble Space Telescope. However, some of the more intriguing objects in the sky around us include ring galaxies like the one pictured above — Zw II 28.

Ring galaxies are mysterious objects. They are thought to form when one galaxy slices through the disc of another, larger, one — as galaxies are mostly empty space, this collision is not as aggressive or as destructive as one might imagine. The likelihood of two stars physically colliding is minimal, and it is instead the gravitational effects of the two galaxies that causes the disruption.

This disruption upsets the material in both galaxies, causing it to redistribute to form a dense central core, encircled by bright stars. All this commotion causes clouds of gas and dust to collapse and triggers new periods of intense star formation in the outer ring, which is thus full of hot, young, blue stars and regions that are actively giving rise to new stars.

The sparkling pink and purple loop of Zw II 28 is not a typical ring galaxy due to its lack of a visible central companion. For many years it was thought to be a lone circle on the sky, but observations using Hubble have shown that there may be a possible companion lurking just inside the ring, where the loop appears to double back on itself. The galaxy has a knotty, swirling ring structure, with some areas appearing much brighter than others.

NGC 3372

Distance: 7500 Light Years

Location: Carina

A bright photogenic patch of the southern Milky Way holds one of the most enigmatic and exotic stars known.

Image: Martin Matias Menrath Summary: Robert Gendler

Eta Carinae is the centerpiece and ionizing star of the great HII region, the Eta Carinae Nebula. The nebula itself spans some 260 light years across, about 7 times the size of the Orion Nebula. Massive is an understatement as the great star weighs in at some 100 to 150 solar masses and shines with the light output of 5 million suns.

As one of the most massive stars known, Eta Carinae pushes the theoretical limits on energy output of stars and has attracted much interest among astronomers trying to understand the physics of supermassive stars.

The young supergiant star ( only 2 to 3 million years old) pumps out as much energy in 6 seconds as our sun does in an entire year. Its prodigious stellar wind blows off the equivalent mass of Jupiter each year, exceeding our suns yearly rate of mass loss a 100 billion fold.

Globular Cluster Over a Hydrocarbon Sea

A hypothetical carbon planet orbits around a star which, itself, is located just beyond the outermost reaches of a globular cluster.

This cluster rises over the horizon, like some kind of giant moon lighting the night sky, with its shine reflected on the surface of a ocean made of hydrocarbons and carbon derivatives. — Caetano Julio Neto

NGC 922: Collisional Ring Galaxy

Why does this galaxy have so many big black holes? No one is sure. What is sure is that NGC 922 is a ring galaxy created by the collision of a large and small galaxy about 300 million years ago.

Image Credit: NASA, ESA; Acknowledgement: Nick Rose

Like a rock thrown into a pond, the ancient collision sent ripples of high density gas out from the impact point near the center that partly condensed into stars. Pictured above is NGC 922 with its beautifully complex ring along the left side, as imaged recently by the Hubble Space Telescope. Observations of NGC 922 with the Chandra X-ray Observatory, however, show several glowing X-ray knots that are likely large black holes.

The high number of massive black holes was somewhat surprising as the gas composition in NGC 922 — rich in heavy elements — should have discouraged almost anything so massive from forming. Research is sure to continue. NGC 922 spans about 75,000 light years, lies about 150 million light years away, and can be seen with a small telescope toward the constellation of the furnace (Fornax).