Shields Up, Mr. Sulu! Cruising At 20% Speed Of Light Has Some Inherent Risks

Artist's impression of a directed-energy propulsion laser sail in action. Credit: Q. Zhang/

Back in April, Russian billionaire Yuri Milner and famed cosmologist Stephen Hawking unveiled Project Starshot. As the latest venture by Breakthrough Initiatives, Starshot was conceived with the aims of sending a tiny spacecraft to the neighboring star system Alpha Centauri in the coming decades.

Relying on a sail that would be driven up relativistic speeds by lasers, this craft would theoretically be capable of making the journey is just 20 years. Naturally, this project has attracted its fair share of detractors. While the idea of sending a star ship to another star system in our lifetime is certainly appealing, it presents numerous challenges.

Not one to shy away from any potential problems, Breakthrough Starshot has begun funding the necessary research to make sure that their concept will work. The results of their first research effort appeared recently in arXiv, in a study titled “The interaction of relativistic spacecrafts with the interstellar medium“.

Assessing the risks of interstellar travel, this paper addresses the greatest threat where relativistic speed is concerned: catastrophic collisions! To put it mildly, space is not exactly an empty medium (despite what the name might suggest). In truth, there are a lot of things out there on the “stellar highway” that can cause a fatal crash.

For instance, within interstellar space, there are clouds of dust particles and even stray atoms of gas that are the result of stellar formations and other processes. Any spacecraft traveling at 20% the speed of light (0.2 c) could easily be damaged or destroyed if it suffered a collision with even the tiniest of this particulate matter.

The research team was led by Dr. Chi Thiem Hoang, a postdoctoral fellow at Canadian Institute for Theoretical Astrophysics (CITA) at the University of Toronto. As Dr. Hoang told Universe Today via email:

“To evaluate the risks, we calculated the energy that each interstellar atom or dust grain transfers to the ship along the path of the projectile in the ship. This acquired energy rapidly heats a spot on the ship surface to high temperature, resulting in damage by reducing the material strength, melting or evaporation.”

In short, the danger of a collision comes not from the physical impact, but from the energy that is generated due to the fact that the spaceship is traveling so fast. However, what they found was that while collisions with tiny dust grains are very likely, collisions with heavier atoms that can do the most damage would be more rare.

Nevertheless, the damage from so many tiny collisions will certainly add up over time. And it would only take one collision with a larger particle to end the mission. As Dr. Hoang explained:

“We found that the ship would be damaged by collision with heavy atoms and dust grains in the interstellar medium. Heavy atoms, mostly iron can damage the surface to a depth of 0.1mm. More importantly, the surface of the ship is eroded gradually by dust grains, to a depth of about 1mm. The ship may be completely destroyed if encountering a very big dust grain larger than 15micron, although it is extremely rare.”

In terms of damage, what they determined was that each iron atom can produce a damage track of 5 nanometer across, whereas a typical dust silicate grain measuring just 0.1. micron across (and containing about one billion iron atoms) could produce a large crater on the ship’s surface.

Over time, the cumulative effect of this damage would pose a major risk for the ship’s survival. As a result, Dr. Hoang and his team recommended that some shielding would need to be mounted on the ship, and that it wouldn’t hurt to “clear the road” a little as well.

“We recommended to protect the ship by putting a shield of about 1 mm thickness made of strong, high melting temperature material like graphite.” he said. “We also suggested to destroy interstellar dust by using part of energy from laser sources.”

Starshot is the latest in a long line of directed energy concepts that owe their existence to Professor Phillip Lubin. A professor from the University of California, Santa Barbara (UCSB), Lubin is also the mind behind the Directed Energy Propulsion for Interstellar Exploraiton (DEEP-IN) project and the Directed Energy Interstellar Study.

These projects, which are being funded by NASA, seek to harness the technology behind directed-energy propulsion to rapidly send missions to Mars and other locations within the Solar System in the future. Long-term applications include interstellar missions, similar to Starshot.

Other interesting projects overseen by Lubin and the UCSB lab include the Directed Energy System for Targeting of Asteroids and exploRation (DE-STAR). This system calls for the use of lasers to deflect asteroids, comets, and other near-Earth objects (NEO) that pose a credible risk of impact.

In all cases, directed-energy technology is being proposed as the solution to the problems posed by space travel. In the case of Starshot, these include (but are not limited to) inefficiency, mass, and/or the limited speeds of conventional rockets and ion engines.

But the problems of interstellar travel don’t end with propulsion. Indeed, there are many safety hazards that have to be accounted for before any missions can be mounted. But as this recent study has shown, they are not insurmountable, and a mission to interstellar space could be performed if the proper precautions are taken.

Who knew the future of space travel would be every bit as cool as we’ve been led to believe – complete with lasers and shielding?

And be sure to enjoy this video from NASA 360, addressing directed-energy propulsion:

Further Reading: arXiv

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Professor Stephen Hawking Intends To Map The Known Universe

In honor of Dr. Stephen Hawking, the COSMOS center will be creating the most detailed 3D mapping effort of the Universe to date. Credit: BBC, Illus.: T.Reyes

Back in 1997, a team of leading scientists and cosmologists came together to establish the COSMOS supercomputing center at Cambridge University. Under the auspices of famed physicist Stephen Hawking, this facility and its supercomputer are dedicated to the research of cosmology, astrophysics and particle physics – ultimately, for the purpose of unlocking the deeper mysteries of the Universe.

Yesterday, in what was themed as a “tribute to Stephen Hawking”, the COSMOS center announced that it will be embarking on what is perhaps the boldest experiment in cosmological mapping. Essentially, they intend to create the most detailed 3D map of the early universe to date, plotting the position of billions of cosmic structures including supernovas, black holes, and galaxies.

This map will be created using the facility’s supercomputer, located in Cambridge’s Department of Applied Mathematics and Theoretical Physics. Currently, it is the largest shared-memory computer in Europe, boasting 1,856 Intel Xeon E5 processor cores, 31 Intel Many Integrated Core (MIC) co-processors, and 14.5 terabytes of globally shared memory.

The 3D will also rely on data obtained by two previous surveys – the ESA’s Planck satellite and the Dark Energy Survey. From the former, the COSMOS team will use the detailed images of the Cosmic Microwave Background (CMB) – the radiation leftover by the Big Ban – that were released in 2013. These images of the oldest light in the cosmos allowed physicists to refine their estimates for the age of the Universe (13.82 billion years) and its rate of expansion.

This information will be combined with data from the Dark Energy Survey which shows the expansion of the Universe over the course of the last 10 billion years. From all of this, the COSMOS team will compare the early distribution of matter in the Universe with its subsequent expansion to see how the two link up.

While cosmological simulations that looked at the evolution and large-scale structure of the Universe have been performed in the past – such as the Evolution and Assembly of GaLaxies and their Environments (EAGLE) project and the survey performed by the Institute for the Physics and Mathematics of the Universe at Tokyo University – this will be the first time where scientists compare data the early Universe to its evolution since.

The project is also expected to receive a boost from the deployment of the ESA’s Euclid probe, which is scheduled for launch in 2020. This mission will measure the shapes and redshifts of galaxies (looking 10 billion years into the past), thereby helping scientists to understand the geometry of the “dark Universe” – i.e. how dark matter and dark energy influence it as a whole.

The plans for the COSMOS center’s 3D map are will be unveiled at the Starmus science conference, which will be taking place from July 2nd to 27th, 2016, in Tenerife – the largest of the Canary Islands, located off the coast of Spain. At this conference, Hawking will be discussing the details of the COSMOS project.

In addition to being the man who brought the COSMOS team together, the theme of the project – “Beyond the Horizon – Tribute to Stephen Hawking” – was selected because of Hawking’s long-standing commitment to physics and cosmology. “Hawking is a great theorist but he always wants to test his theories against observations,” said Prof. Shellard in a Cambridge press release. “What will emerge is a 3D map of the universe with the positions of billions of galaxies.”

Hawking will also present the first ever Stephen Hawking Medal for Science Communication, an award established by Hawking that will be bestowed on those who help promote science to the public through media – i.e. cinema, music, writing and art. Other speakers who will attending the event include Neil deGrasse Tyson, Chris Hadfield, Martin Rees, Adam Riess, Rusty Schweickart, Eric Betzig, Neil Turok, and Kip Thorne.

Naturally, it is hoped that the creation of this 3D map will confirm current cosmological theories, which include the current age of the Universe and whether or not the Standard Model of cosmology – aka. the Lambda Cold Dark Matter (CDM) model – is in fact the correct one. As Hawking is surely hoping, this could bring us one step closer to a Theory of Everything!

Further Reading: Cambridge News

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Is Alpha Centauri The Best Place To Look For Aliens?

Project Starshot, an initiative sponsored by the Breakthrough Foundation, is intended to be humanity's first interstellar voyage. Credit:

For generations, human beings have fantasized about the possibility of finding extra-terrestrial life. And with our ongoing research efforts to discover new and exciting extrasolar planets (aka. exoplanets) in distant star systems, the possibility of actually visiting one of these worlds has received a real shot in the arm. Unfortunately, given the astronomical distances involved, not to mention the cost of mounting an expedition, doing so presents numerous significant challenges.

However, Russian billionaire Yuri Milner and the Breakthrough Foundation – an international organization committed to exploration and scientific research –  is determined to mount an interstellar mission to Alpha Centauri, our closest stellar neighbor, in the coming years. With the backing of such big name sponsors as Mark Zuckerberg and Stephen Hawking, his latest initiative (named “Project Starshot“) aims to send a tiny spacecraft to the Alpha Centauri system to search for planets and signs of life.

Consisting of an ultra-light nanocraft and a lightsail, the concept calls for a ground-based laser array to push the lightsail up to speeds of hundreds of kilometers an hour, towing the nanocraft into deep space. Such a system would allow the tiny spacecraft to conduct a flyby mission to Alpha Centauri in about 20 years after it is launched, which could then beam home images of possible planets, as well as other scientific data such as analysis of magnetic fields.

In essence, Starshot seeks to leverage recent technological developments to mount an interstellar mission that will reach another star within a single generation. As we explained in another article (“How Long Would It Take To Travel To The Nearest Star?“), using existing technology, it would take between 19,000 to 81,000 years for a spacecraft to make the trip to even the nearest star, depending on whether chemical rockets or ion engines were used.

Hence, the Foundation’s advisory board explored all potential methods for creating a craft that could travel at relativistic speeds – up to 20% the speed of light – so it could traverse the 4.37 light year distance in just 20 years. They determined that a tiny craft, roughly the size of a refrigerator magnet and weighing in the vicinity of a few grams, would be the best model for a spacecraft. They further determined that the best propulsion method would be laser-driven lightsail, which is not hampered by the limits of conventional methods.

With a massive ground-based laser directing the sail, the plan is to accelerate the nanocraft to its terminal velocity before it reaches a distance of about one million km from Earth (which is the limit to which the laser beam can be focused on the meter-scale sail). All told, the nanocraft will experience an acceleration of about 60,000 g (sixty-thousands times the force of Earth’s gravity, which works out to just under 600,000 m/s²).

As Professor Avi Loeb, the Frank B. Baird, Jr. Professor of Science at Harvard University and chairman of the Foundation’s Advisory Board, explained to Universe Today via email:

“{O]nly one offers a path forward: using beamed (laser) light to push a sail attached to a lightweight (gram-scale) smart payload (with a camera, transmitter and thrusters). This approach benefits from two major technological advances that were realized recently: miniaturization of electronics (developed by the cell phone industry) and the construction arrays of lasers that combine to make a very powerful and focused beam of light (developed by the defense industry). Interstellar travel is challenging, but based on these technological advances, we believe that there is a path forward without obvious show stoppers. The project is ambitious but doable.”

In addition to accomplishing the dream of countless generations (i.e. traveling to another star system), Breakthrough Starshot hopes to generate important supplementary benefits to astronomy in the meantime. Much like the Apollo Program of the 1960s, the Breakthrough Starshot program hopes to stimulate the development of technologies that will be beneficial here on Earth.

These include demonstrating proof-of-concept technology that will enable the exploration the solar system, the detection and study of Near Earth Objects (NEOs), and the benefits to material science that solar sail development will bring. The development of laser arrays will also have major implications for the science of optical systems, and the laser communication devices used on Starshot will likely lead to better communication with airplanes and satellites around Earth.

As Pete Worden, the Executive Director Project Breakthrough StarShot, told Universe Today via email:

“The project goals are to develop and demonstrate the technologies, particularly with respect to high power laser beaming technology and gram-class lightsail-craft that could enable humanity to send these craft to the nearest star system, Alpha Centauri within a generation.  We hope to mobilize the world’s expertise to make this possible.  The program will be an open international program.  Yuri Milner has provided our initial funding.  Renowned physicist Stephen Hawking and Facebook founder Mark Zuckerberg have joined Yuri Milner as the governing board of the project.”

Based on the Foundation’s best estimates, this project could achieve its goal of dispatching their interstellar traveler within a few decades time. And with a 20 some-odd year transit time, we could be gaining vital information about the nearest star system (including whether or not it has life-supporting exoplanets) by the 2050s or 2060s.

Naturally, there are still several engineering hurdles that would need to be overcome before Starshot can become a reality. For example, propelling a gram-scale spacecraft to 20% the speed of light will require a laser beam of that could generate about 100 Gigawatts of power over the course of a few minutes. The Project intends to build this laser array on the ground, simply because that would be much cheaper than building one in space.

This, in turn, creates the challenge of optical-blurring due to atmospheric turbulence. Using adaptive optics (measuring atmospheric effects and correcting for them) is believed to be able to compensate for that. Such a method has been tested on the scale of the largest telescopes (10 meters in diameter), but would need to be tested on a scale of 1 km before it can be considered feasible.

What’s more, there are plenty of doubts as to the missions intended target, not to mention the likelihood that the mission will succeed. For instance, while Alpha Centauri may be the nearest star, thus making it the natural choice for interstellar exploration, there is little reason to suspect we will find any exoplanets there.

Years back, astronomers announced the detection of a possible planet circling Alpha Centauri B with an orbital period of 3.24 days – which was named Alpha Cen Bb. However, subsequent examinations revealed that the detection of this exoplanet was the result of the window function (time sampling) of the original data. If we hope to find exoplanets, then we might need to look further afield – like Epsilon Eridani, a mere 10.5 light years away (which would result in a travel time of 55 years for the proposed nanocraft).

And, as Paul Gilster of Centauri Dreams points out, the concept presents numerous challenges that will require technical advances not currently in existence. For example, beyond the issue of laser power and adaptive optics, there are issues with the sail concept itself that are likely to prove difficult. Essentially, this comes down to the need for a balance to be struck between powerful lasers and a sail that is capable of withstanding them:

“Moreover, we have to design a sail that will ‘ride’ the beam rather than be blown off it, and one that will be so highly reflective that it will absorb less than 1/100,000th of the energy applied to it. These are problems that Robert Forward faced with his Starwisp design, a kilometer-wide ‘spider web’ of a sail driven by microwaves, with sensors scattered throughout the sail itself. It was Geoffrey Landis who would go on to show that as described, Starwisp would likely vaporize under the powerful beam meant to drive it to Alpha Centauri, causing a flurry of re-thinking of sail materials and design. But leaving the fuel at home is a powerful technique, and advances in technology may get us to the kind of materials that can withstand the photon torrent.”

Addressing the design called for by Breakthrough Starshot – a thin, round disc that is about the size of a picnic table in diameter, and which would have its entire electronics suite in the center – Gilster sees additional problems. “We’ve also got a problem in that concept,”  he says, “because Jim Benford has pointed out that a flat sail is not a good ‘beam-rider’ – we’ll likely have to look at the kind of curved sail designs both Jim and brother Gregory Benford have studied in lab work at the Jet Propulsion Laboratory.”

In the end, the only reason to send a probe to Alpha Centauri is because of its proximity. And mounting the mission will require that the Breakthrough Foundation and its supporters come up with new and innovative solutions to the hurdles they face. But given that the opportunities for research and exploration will still be abundant, the reasonable timelines involved, and the likelihood of success, the mission certainly appears to be doable.

Previous efforts by the Breakthrough Foundation’s include Breakthrough Listen, the largest scientist research program aimed at detecting transmissions from distant stars. These include monitoring for radio transmissions and optical laser transmissions using advanced instruments that are significantly more sensitive than anything currently in use, combined with advanced software and data analysis. The program will span 10 years and cost an estimated $100 million, surveying the 1,000,000 closest stars to Earth and the 100 closest galaxies to the Milky Way.

There’s also Breakthrough Message, a $1 million competition aimed at encouraging a global debate about the ethics and possible methods of communicating with possible intelligent beings beyond Earth. The competition is open, and the prize will be awarded to anyone who is able to design a message (in digital format) that best represents Earth and humanity to other civilizations.

And be sure to enjoy this video from the Breakthrough Foundation that illustrates the mission concept:

Further Reading: Breakthrough Initiatives

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Extinction Alert: Stephen Hawking Says Our Technology Might Wipe Us Out

Professor Stephen Hawking enjoying a lighter moment. Image credit: Zero G

If you’re thinking of having yourself cryogenically suspended and awakened in some future paradise, you might want to set your alarm clock for no later than 1,000 years from now. According to the BBC, Stephen Hawking will be saying this much in the 2016 Reith Lectures – a series of lectures organized by the BBC that explore the big challenges faced by humanity.

In Hawking’s first lecture, which will be broadcast on February 26th on the BBC, Hawking covers the topic of black holes, whether or not they have hair, and other concepts about these baffling objects.

But at the end of the lecture, he responded to audience questions about humanity’s capacity for self destruction. Hawking said that 1,000 years might be all we have until we meet our demise at the hands of our own scientific and technological advances.

As we have become increasingly advanced both scientifically and technologically, Hawking says, we will be creating “new ways that things can go wrong.” Hawking mentioned nuclear war, global warming, and genetically engineered viruses as things that could cause our extinction.

Nuclear War

Through the Cold War, annihilation at the hands of our own nuclear weapons was a real danger. The threat of a nuclear launch in response to a real or perceived threat was real. The resulting retaliation and counter-retaliation was a risk faced by everyone on the planet. And the two superpowers had enough warheads between them to potentially wipe out life on Earth.

The USA and the USSR have reduced their stockpiles of nuclear weapons in recent decades, but there are still enough warheads around to wipe us out. The possibility of a rogue state like North Korea setting off a nuclear confrontation is still very real. By the time Hawking’s 1,000 year time-frame has passed, we’ll either have solved this problem, or we won’t be here.

Global Warming

Earth is getting warmer, and though the Earth has warmed and cooled many times in its history, this time we only have ourselves to blame. We’ve been inadvertently enriching our atmosphere with carbon since the Industrial Revolution. All that carbon is creating a nice insulating layer around Earth, as it traps heat that would normally radiate into space. If we reach some of the “tipping points” that scientists talk about, like the melting of permafrost and the subsequent release of methane, we could be in real trouble.

Different climate engineering schemes have been thought up to counteract global warming, like seeding the upper atmosphere with reflective molecules, and having fleets of ships around the equator spraying sea mist into the air to partially block out the sun. Or even extracting carbon from the atmosphere. But how realistic or effective those counter-measures might be is not clear.

Genetically Engineered Viruses

As a weapon, a virus can be cheap and effective. There’ve been programs in the past to develop biological weapons. The temptation to use genetic science to create extremely deadly viruses may prove too great.

Smallpox and Viral Hemorrhagic Fevers have been weaponized, and as our genetic manipulation abilities grow, it’s possible, or even likely, that somebody somewhere will attempt develop even more dangerous viral weapons. They may be doing it right now.

There’s a ban on viral weapons, called the Biological and Toxin Weapons Convention signed in 1972. But, not everybody has signed it.

Artificial Intelligence

Hawking never mentioned AI in his talk, but it fits in with the discussion. As our machines get smarter and smarter, will they deduce that the only chance for survival is to remove or reduce the human population? Who knows. But Hawking himself, as well as other thinkers, have been warning us that there may be a catastrophic downside to our achievements in AI.

We may love the idea of driverless cars, and computer assistants like SIRI. But as numerous science fiction stories have warned us (Skynet in the Terminator series being my favorite,) it may be a small step from very helpful AI that protects us and makes our lives easier, to AI that decides existence would be a whole lot better without us pesky humans around.

The Technological Singularity is the point at which artificially intelligent systems “wake up” and become—more or less—conscious. These AI machines would start to improve themselves recursively, or build better and smarter machines. At this point, they would be a serious danger to humanity.

Drones are super popular right now. They flew off the shelves at Christmas, and they’re great toys. But once we start seeing drones with primitive but effective AI, patrolling the property of the wealthy, it’ll be time to start getting nervous.

Extinction May Have To Wait

As our scientific and technological prowess grows, we’ll definitely face new threats, just like Hawking says. But, that same progress may also protect us, or make us more resilient. Hawking says, “We are not going to stop making progress, or reverse it, so we have to recognise the dangers and control them. I’m an optimist, and I believe we can.” So do we.

Maybe you’ll be able to hit the snooze button after all.

Original Source: BBC News

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