The speed of light, c,  is 299,972,458 m/s, or ~300,000km/s.

So c ? 0.3 * 10^6 km/s.

At minimum, Pluto is 4284.7 * 10^6 km from Earth, and at maximum it is 7528.0 * 10^6 km from Earth. [1]

So at it's minimum distance from Earth, it would take 4284.7/0.3 = 14282.3 s = 238.0 min ? 4 hr to reach at the speed of light.

At it's maximum distance, it would take 7528.0/0.3 = 25093.3 s = 418.2 min ? 7 hr to reach at the speed of light.

That's not terrible.

But the best we've achieved in terms of spacecraft speeds is probably the Helios probes, which reached a speed of about  70.22km/s which is a mere 0.000234c, or a paltry 0.0234% of the speed of light. Note that this was an unmanned craft, was not meant to escape our solar system, and was achieved with the help of the Sun's gravity. What's impressive is that this was accomplished back in the mid 1970's.  [2]

At that speed, it would take the Helios probes about 16,949.5 hr = 706.2 days = 1.9 years to reach Pluto, at it's minimum distance from Earth.

In terms of leaving our solar system, the Voyager 1 is probably the fastest spacecraft, also unmanned, reaching speeds of 17.26km/s, which is a mere 0.0000575c, or 0.00575% the speed of light. Voyager 1 was launched in 1977.  [3] Voyager 1 was able to achieve these speeds by gravity slingshot (or gravity assist) which requires a particular alignment of planets that don't occur that often.

At that speed, it would take Voyager 1 about 68,956.8 hr = 2,873.2 days = 7.9 years to reach Pluto, at it's minimum distance from Earth.

But Pluto is barely the end of our solar system; far from it. The Oort Cloud defines the outer boundary of our solar system, roughly 50,000 AU (Astronomical Units, where 1AU ? mean distance from the Earth to the Sun) from the Sun, which is roughly one light year. That is, traveling at the speed of light, it would take about a year to reach from Earth.

At Voyager 1's speeds, this is more like ~18,000 years!

But these are old spacecraft, right? Our spacefaring technology must have improved over the past 40-odd years.

There have been a number of projects trying to improve these speeds. Project Orion is one, started in 1958 and since abandoned, driven by nuclear explosions to propel the craft from behind to speeds ranging from 19 to 31km/s. At it's best, while in theory it could achieve speeds much greater than the Voyager 1, it still pales against the speed of light. The more recent (mid 2000's)  Mini-Mag Orion seems to be the project's spiritual successor.

Project Longshot was an endeavor similar to Project Orion from 1988, hoping to achieve impressive speeds of ~13,411km/s, roughly 4.5% the speed of light.

From 1973 to 1978, there was also Project Daedalus, hoping to achieve a maximum speed of 12% the speed of light.

More recently, there is Project Icarus, which started in 2009, functioning as a spiritual successor to Daedalus. There's also the 100 Year Starship project between DARPA and NASA, which hopes to achieve interstellar travel within the next century.

But in general, these projects are focused on unmanned space travel — probes and other remote-controlled devices. When humans are introduced, a number of other problems crop up, from surviving at those speeds to providing livable environments to protection from cosmic rays and radiation and so on.

And what about other, more sci-fi-esque workarounds and loopholes? What about wormholes and Einstein-Rosen bridges and antimatter rockets and blackholes and so on? There are plenty of those.

One interesting proposed means of travel is the Alcubierre drive, which is basically like surfing through space. Space is collapsed and expanded on opposing ends such that it forms a "wave", propelling a "bubble" that contains the spacecraft. The result of this manipulation of space is that the bubble can arrive at another point faster than light, while the spacecraft never exceeds the speed of light within the bubble. But at present, these largely seem to be fantasy, requiring a lot of fragile bits to fit together just right.

If interstellar travel does materialize within our lifetime, I imagine it won't be as fantastic as science fiction tends to portray it. Perhaps we'll see great, slow-moving barges or junks transporting large groups of people over multi-generational journeys, but I guess that's fantastic in it's own way.

Note: This post contains SPOILERS! If you're interested in this game, go play it first and then revisit this post.

Spec Ops: The Line plays much like a novella, like the Joseph Conrad tale to which it will always and inevitably be compared. It's relatively short for a game, but delivers its message in a dense and potent gut-punch.

In The Line, near-future Dubai has been all but buried underneath catastrophic sandstorms that left the city's inhabitants stranded. Colonel John Konrad of the 33rd Battalion volunteered himself and his troops to stay behind and help evacuate the city. You play Captain Martin Walker, leader of a three-man Delta Force squad sent to investigate Dubai after receiving a distress signal from Konrad. (For a more in-depth plot summary, the Wikipedia entry is good)

Naturally, the game has greater depth than this plot might imply. As Russ Pitts writes in Polygon's great behind-the-scenes look:

It is a game about a city at risk of being swallowed by nature and a man at risk of being swallowed by the weight of his own horrible acts. It is a shooter in which the innocent bystanders are as much a part of the story as you are, and telling the good guys from the bad is practically impossible.

The game itself is a bit of an anomaly - it's actually part of a franchise ( the Spec Ops franchise), which I've never played before, but I get the impression that this game's development and evolution is quite unique from its sibling titles. It's gameplay isn't particularly sophisticated, even for shooters. In fact, it can feel quite frail at times - ammo is sparse, you die quickly, and the cover system is pretty wonky. Some take the stance that this less-than-gratiftying gameplay is intentional, and I have to agree. The game functions as much as a criticism on the shooter genre that glorifies war as much as it is on the brutality of war itself. The frightened look on Walker's face as you're on the brink of death was hard for me to ignore. An unlike other war-focused franchises (e.g. Call of Duty), you're not fighting ambiguously Eastern European villains bent on destroying the world or unambiguously evil Middle Eastern terrorists set on bringing the west to its knees. You're fighting fellow American soldiers and the twisted machinations of your own brittle, guilt-gnawed mind. That you're fighting American soldiers manages to make the fact that you're killing people more evident (foreign soldiers are easier to otherize). You mercilessly execute these soldiers for a pittance in much-needed ammunition - a drop of water in the desert - and you can often see the fear in their eyes as you do it. It can be a pretty jarring experience.

In spite of its subpar gameplay (or in addition to, if you interpret it like I do), The Line's drawing of the narrative, and use of immersion and simple decision-making is so compelling that this game is hard to put down. There are only a few decision-making points in the game, but each is heavy, bearing solid ethical and moral ambiguities that can compel you to question your own sense of justice and belief in what's right. For instance, the decision to either leave Riggs to suffer a slow painful death or mercifully kill him - Riggs having just damned the whole city to thirst - led to a discussion on justice in the modern age, tit-for-tat punishment, and the bitterness of post-massacre suicides. Games like this are powerful, and to me indicate the artistic potential of the medium.

The most important and most discussed event in The Line is the white phosphorus scene. In this scene, Walker makes the call (the player has no say) to blanket an entrenched group of the 33rd with white phosphorus, believing that they took a large group of refugees hostage. After the troops had been cleared, Walker and his squad find amongst the devastation that what they thought to be a cluster of enemy combatants was actually the refugees they were looking for, now charred and blackened from the white phosphorus.

It's easy to be critical about the forced hand here. But technically, it's hard to be truly critical about it - making an event so crucial to the plot optional would possibly mean spinning out a completely different alternate plot. Which would be neat, but maybe impractical for this game, and against its intent. But perhaps that this pivotal moment is without choice is what makes decisions so much more powerful afterwards. Walker, to cope with his crime, begins to posit imaginary decisions - such as the two hanging criminals - in the hopes of offering himself an opportunity at redemption, a chance to make the right choice. But ultimately, and tragically, he still denies himself from the most important decision he has - to leave Dubai and save his squad, or to ruthlessly press on deeper into the city and his madness.

In general, however, the game has a lot of great touches that maybe deserve greater analysis. The deeper you descend into Walker's tragic deceit, the innocuous loading screen tips give way to dark and doubtful introspection - a glimpse at the player's own lucidity that tunnel-visioned Walker does not have the benefit of. During the white phosphorus sequence, the sense of calm on Walker's reflected face is startling and disturbing on a second playthrough, knowing what he's actually doing on that monitor. It could be interesting to think about the decision to do an over-the-shoulder shooter rather than a first-person shooter like Call of Duty or Battlefield. At first thought, it seems to me that an FPS could have made the gameplay even more immersive, but it might have been equally important to see Walker's expressions as he fought.But these are all opinions of someone who has been fortunate enough to never have seen real war firsthand. What would a real soldier think of The Line? Game critic Kris Ligman had a friend, a Marine that served two tours in Iraq, give his thoughts on the game during two playthroughs. Both his takes are worth a read.

Take One

In the first take he points out issues in general with games that implement decision-making systems. He also figures out the twist early on (and to be honest, it is a maybe overused plot device) - if I'd figured it out that early, I think that would have ruined a lot of the weight of the decisions that followed. They would have felt arbitrary and meaningless, as it would be apparent that Walker was careening toward his own inevitable destruction. For this game to be successful, the player needs to be as much in the dark as Walker - Walker, in his state after the white phosphorus incident, is mentally incapable of seeing the truth of his situation. You - the player - have to think you're doing the sensible, rational thing just as much as Walker does, so that your realization of (self-)deception is just as damning as Walker's. According to Walt Williams, lead writer of the game, one of your final choices is to just stop playing (that is, to let your Konrad hallucination count to five and kill you). In this light, this choice can be interpreted in a lot of ways - Walker finally giving up, or the player refusing to cross his or her "line" and play along with these disturbing decisions.

Take Two

The second take seems to mostly be concerned with technical inaccuracies (there seem to be quite a few), but his reflection/summary at the end is a good look at the game in the context of today's American conflicts, and the nature of heroism:"This [cognitive] dissonance arises from the idea that everyone is the hero of their own story. No one truly believes themselves to be the villain. This game makes you the villain."

This observation points out The Line's sharpest criticism of similar war games, and perhaps of human nature in general. In other war titles, it's always a given that the player is the hero. But is that a reasonable assumption to make? As the "hero", you're killing countless amounts of people, and these games often fail to put such acts under sufficient ethical scrutiny. And in our own lives, how many of us fall victim to the blind conviction of our own actions, believing them to be unambiguously justified, assuming that we'd do no wrong (because if it were wrong, we wouldn't do it)?

For some time now, there's been a great deal of buzz about "mobile". Despite the hubbub surrounding mobile, it seems that a lot of applications of "mobile" have just been a direct translation of web/desktop products to smartphones, which doesn't take full advantage of the platform's potential.

At the highest level, mobile allows us to bring the interconnectedness we've come to love, but that's confined to computers (in the laptop/desktop sense), to the rest of the world. Mobile technologies enable us to create a digital layer upon the physical world, making tangible the intangible information embedded in all physical objects. Your smartphone will become your ambassador to this digital world, communicating with this digital layer and translating it into useful, human-comprehendable output.

Here are the broader mobile trends and potentials that I've noticed:

Literal Input

With the increase of software pseudo-intelligence and the proliferation of alternate input devices on mobile devices (most notably the camera, which of course isn't really all that new, but also other sensors), mobile devices (and computers in general) will be capable of understanding increasingly literal input.

As it stands now, there exists a gap between our information needs and the queries we end up forming to (hopefully) express those needs in a way a computer can understand. With computers becoming better at "doing what humans are good at", this gap will shrink. Computers will be able to digest direct and literal input, creating an altogether more fluid and enjoyable mobile experience. In fact, we've already been seeing this for awhile with technologies such as Google Goggles and Word Lens (though current technology often leaves something to be desired). With Google Goggles, for instance, instead of having to translate a physical object into a manually-inputted word query into a search engine, the application can directly "understand" the visual input of the object itself.

Context-Aware Automation/Prediction

With increasingly "intelligent" software - perhaps fruits of the latest "big data"/data science/etc craze - we can expect these interactions to require less and less of our personal guidance and management, and for them to become more automated and predictive.

This is something that Google is already tackling with Google Now, which is capable of learning your behaviors and tries to predict what information you need based on your current context.

The implications of such technology are pretty huge, perhaps we'll see some realization of "machine augmented cognition" where mobile devices function like an auxiliary brain, remembering things for us, handling small tasks for us automatically, and knowing when to do all this without needing our managing or guidance.

It's worth noting that context-aware automation & prediction leapfrogs over literal input because you are presented with your information before you've even formed your information need!

Device modularity through accessory ecosystems

Mobile is not a single-device experience. Right now the current mobile experience is pretty centralized around, if not exclusively focused on, your smartphone. But we'll see more external (and wearable) sensors that extend the capabilities of our smartphones. Functioning as inputs, our smartphones will communicate with these sensors and translate their streams into something useful and informative to a person. This is already emerging with personal health monitoring devices such as Jawbone UP, Nike+ FuelBand, FitBit, etc.

The adoption of these sensors reflects how people are becoming more and more interested in turning to the objective reality that data describes as a means of informing personal betterment and self-management. Is this indicative of a broader "computer infallibility" trend where we form greater and greater distrust in our own subjective experiences and evaluations, and instead fill this void with an increasing reliance on the objective "truth" (perhaps more appropriately "fact" but really just "data") of computers?

In general though, such a network of sensors allows us to automate what used to rely on manual input and/or memory to a level of granularity that we could not hope to realistically achieve on our own. We wouldn't even necessarily need to ever be exposed to the raw data but instead just have the data pre-processed into what's most relevant to us, such as broader trends or simply suggestions on what to do next.

These sensors could also empower "invisible computing". Currently, the process of documenting an experience necessarily interrupts the experience (unless documenting the experience is the experience which certainly can be the case - think "Instagram"), but with such a network of sensors this documentation can happen subtly in the background. This allows us to return to the pre-smartphones-everywhere experience of experiences where experiencing the experience meant just experiencing it.

Increasingly layperson-friendly computer interaction paradigms

These other trends lend to a broader one of increasingly layperson-friendly computer interaction paradigms (and this isn't really contained to mobile). Computing interaction could more directly correlate with physical metaphors/analogues that most people find more intuitive. We'll have to make less special considerations when using computers, such as having to edit our queries so that a computer may understand them. Things will just work as the average person would expect them to.

For instance, file transfer amongst computers typically requires going through a router. To people unfamiliar with computers, that doesn't really sound logical - if a computer can connect with things wirelessly, why not to another computer? Why does it have to go through something else to get there? Less technical folk can take it on faith that it just has to work that way, but that's never satisfactory for anyone.

With the proliferation of WiFi Direct, however, computers can directly connect with each other, in a way that makes a lot more sense to the layperson. Adding an interaction that allows "moving" physical gestures (such as "pushing" the file to another computer) makes the whole experience that more intuitive.

Of course, as it typically is with technology, there's a whole mess of things that could go wrong. There's always potentially disruptive implications of a new technology or usage pattern at a broader scale. For instance, these wearable sensors have controversial implications in a society where ubiquitous recording is often treated as a crime or as an infringement upon rights (see the EyeTap McDonalds scandal).

With wearable sensors there's also the potential for cultural and social resistance (think of the negative reputation of Bluetooth headsets), but I haven't really seen that myself with these latest health monitoring devices.