Voyager 1, now 17 light hours from Earth, continues to be my touchstone when asked about getting to Alpha Centauri — and in the last few days, I’ve been asked that question a lot. At 17.1 kilometers per second, Voyager 1 would need 74,000 years to reach the blistering orb we now believe to be orbiting Centauri B. Voyager 1 is not the fastest thing we’ve ever launched — New Horizons at one point in its mission was moving with greater velocity, though no longer, and the Helios II Solar probe, no longer functional, reaches about 70 kilometers per second at perihelion. But Voyager 1 will be our first craft to reach interstellar space, and it continues to be a measure of how frustratingly far even the nearest stars happen to be.
Cautionary notes are needed when a sudden burst of enthusiasm comes to these subjects, as it seems to have done with the discovery of Centauri B b. What we need to avoid, if we’ve got our eyes on long-term prospects and a sustained effort that may take centuries to succeed, is minimizing the challenges of an interstellar journey. Making it sound like a simple extension of existing interplanetary missions would create a public backlash once the real issues become clear. Better to be straightforward, to note the vast energy budget needed by an interstellar mission, the conundrum of propulsion, the breathtaking scope of the distances involved.
Image: The night sky above Mt. John Observatory in New Zealand, where a second active hunt for Alpha Centauri planets has taken place. This and a third Centauri project, Debra Fischer’s work at the Cerro Tololo Inter-American Observatory (Chile), give us hope that Centauri B b may be confirmed in the near future. Note the Southern Cross (just above and to the right of the dome), with Alpha and Beta Centauri the two stars to its left. Alpha Centauri (the leftmost bright star) is a triple system made up of Centauri A, Centauri B and Proxima Centauri. Credit: Fraser Gunn.
Marc Millis told Alan Boyle just after the Centauri B b discovery that manned missions were almost certainly not going to be our first attempts to reach the stars. We can work out scenarios where the global economy grows to the point where a civilization moving into the Solar System can afford to build huge laser installations that could propel a lightsail to perhaps ten percent of the speed of light. Get up to that kind of velocity and you make the Centauri crossing in less than half a century, but only for a flyby. Deceleration is another matter, and even if, as Robert Forward showed, there may be ways to decelerate a lightsail at destination, the mission then extends to at least a century and, given our assumptions, perhaps a good deal more.
So we’re likely talking about robotic probes which, given the development time needed to create and launch them, would probably be ‘manned’ by an extremely sophisticated artificial intelligence. In the same article, astrobiologist Dirk Schulze-Makuch (Washington State) told Boyle that an interstellar mission could be seen as part of a roadmap that developed incrementally:
“The roadmap that we have takes a grand perspective, with the objective to scout out our own solar system first, put a permanent human presence on Mars, look at asteroids, and really work first on our own solar system before we take the next step to an extrasolar planet.”
And as I’ve speculated here on more than one occasion, a developmental model like this may take a more gentle trajectory than we’ve previously assumed. A civilization that masters living in nearby space by developing large habitats that can house thousands may eventually branch off from its Earthbound human roots to thrive in the places between planets and stars. Generations may indeed live and die in such habitats not because of a specific mission constraint but as a matter of choice. And if this occurs, a mission to a nearby star may be an organic extension of space living, its destination motivated by long-term curiosity rather than any plans of settlement.
Centauri B b is hardly a compelling target for any kind of mission, but the enthusiasm it has already generated points to the latent exploratory impulse that may be triggered if we do find a habitable world somewhere among the Centauri stars. In another recent piece on the discovery, Ian O’Neill quotes Robert Freeland, deputy project leader for Project Icarus, the ongoing re-design of the 1970s Project Daedalus starship study. Like me, Freeland is pondering how the public would react to the next round of Centauri discoveries, assuming such are made:
“I have often imagined the day when scientists directly image an Earth-like extra-solar planet. We would be able to determine the planet’s atmosphere and surface temperature from its spectrum, and we would thus know whether it might be able to sustain life as we know it. I suspect that once such a discovery hits the news, people worldwide are going to demand that we send a probe to determine whether the planet has life (of any type) and/or could be suitable for human habitation. If the latter proves true, then a manned mission would eventually follow.”
A lot can happen, of course, between the surging interest such a discovery would create and the realization of how tough a mission like this would be. But Freeland is surely right that Centauri B b is a warning shot that tells us we’ll be finding much more about this system in the not so distant future. While it is true that the HARPS spectrograph that made the recent discovery possible is capable of detecting planets no smaller than four Earth masses in the habitable zone of Centauri B, Stéphane Udry (Observatoire de Genève) said in the recent news conference that ESO was already working on technologies that would extend that range down to one Earth mass.
Image: An artist’s impression of Centauri B b. Credit: Adrian Mann.
Meanwhile, supported by the Planetary Society, Debra Fischer (Yale University) has been working on a separate search for Alpha Centauri planets, one she recently discussed with Bruce Betts. Fischer notes how faint the 0.5 m/s signal seen by the Geneva team is and points to the need to confirm the discovery. Her team, which has been talking with the HARPS researchers, has been analyzing its own dataset and running simulations to test detectability. Says Fischer:
“Our best data set for aCenB begins in June 2012, when we completed some stability upgrades to the new spectrograph (CHIRON) that we built for the 1.5-m CTIO telescope (with NSF MRI funding). Our precision since the upgrade matches the HARPS precision, but yields a 5-month string of data compared to the 5-year time baseline of data from HARPS.”
And she adds:
“We are in an excellent position to follow-up, but that will likely require an intensive search over the prospective orbital period of 3.24d when the star rises again in January 2013.”
Would the discovery of a habitable zone planet around Centauri B, perhaps occurring some time in the next ten years, have the effect Freeland believes it would? Given the state of our technology, we couldn’t get off an interstellar mission any time soon, but I would like to think that such a finding would be a spur to research that might turn interstellar studies from a back-burner activity into a more visible and better funded effort. We need to advance the technologies that will help us with in-system projects, from long-term life support to advanced robotics. And we can hope that eventually, a Solar System-wide civilization may emerge that will have the strategies and the energy budget to consider a close-up look at such a distant, tantalizing target.
No, it is not a problem of quantum mechanics. Merely of its interpretation.
Since it concerns merely interpretation, there is no cost, no measurable effects, no physical relevance whatsoever. No FTL, either.
Yes, so you have said, and so you are (not even) wrong. There is nothing unclear about the fact that there is no such thing as “simultaneous”. You are drawing the word out of a hat, to make a meaningless statement.
“No, it is not a problem of quantum mechanics. Merely of its interpretation.”
And what are the interpretations of quantum mechanics?
The hypothesis regarding the reality described by the formalism of the quantum mechanics.
“Since it concerns merely interpretation, there is no cost, no measurable effects, no physical relevance whatsoever.”
If you take the many worlds interpretation to be correct (as you do) – meaning you take it to correspond to reality -, then the universe dividing itself with every wave function collapse IS real, a part of reality.
And the enormous cost of the many worlds interpretation (breaking every known physical law) is also real.
If you take the many worlds interpretation to be nothing more than an intellectual exercise, corresponding to nothing real – why did you bring it up, anyway?
“No FTL, either.”
There is FTL transmission of noise (useless information). Entanglement is just that.
“There is nothing unclear about the fact that there is no such thing as “simultaneous”. You are drawing the word out of a hat, to make a meaningless statement.”
Really? Then what is the word “simultaneous” doing in relativity, Eniac?
I guess Einstein was fond of making meaningless statements.
In a POV, you have an simultaneity – it is far from meaningless a concept.
In two POVs, you have two different simultaneities – and this is what would allow travel back in time if you could travel FTL (or simultaneous) in one of these POVs.
Another interesting point is that there has been some recent research regarding the capability of entanglement influence to occur not only across spacial distances, but temporal as well. Below is an article, but there are more on web.
You misunderstand the concept of “interpretation” of quantum mechanics. It is not about what is real, it is about what reality means. In saying “… correspond to reality”, you implicitly assume there to be one identifiable, objective, reality. What both relativity and quantum mechanics are showing us is that instead, like simultaneity, reality cannot be objective It depends on the identity of the observer.
Every one of us is familiar with the concept that there is more than one future, yet we do not worry about the enormous amounts of energy that are wasted if many of those futures do not come to pass. You need to realize that your present once was one of many futures. What, in your opinion, happened to all the others? Did they vanish in a puff of smoke? The answer is: they are as “real” as ever (or never). We merely lost sight of them, because they are no longer part of our timeline.
JoeP: Interesting article. Note that no-one (not the author, nor anyone else according to him) is claiming that Victor’s decision somehow “causes” the earlier correlation. The closest he comes is here:
This is pretty close to my own feelings about the matter. I try to make sense of it, but I do not get very far, as you can tell from my clumsy attempts above….
Maybe I’ll try reading the paper that he is talking about.
“You misunderstand the concept of “interpretation” of quantum mechanics. It is not about what is real, it is about what reality means.”
Yes – and you think the many-worlds interpretation is what reality means, expressed in QM mathematics.
This is what I said in my previous post – with a different formulation.
“In saying “… correspond to reality”, you implicitly assume there to be one identifiable, objective, reality. What both relativity and quantum mechanics are showing us is that instead, like simultaneity, reality cannot be objective It depends on the identity of the observer.”
Yes, Eniac, in quantum mechanics, every state has a probability of occurring which is not 100%. In other words, it is not 100% certain, as with newtonian physics, but exists in a kind of limbo.
“Every one of us is familiar with the concept that there is more than one future, yet we do not worry about the enormous amounts of energy that are wasted if many of those futures do not come to pass. You need to realize that your present once was one of many futures. What, in your opinion, happened to all the others? Did they vanish in a puff of smoke? The answer is: they are as “real” as ever (or never). We merely lost sight of them, because they are no longer part of our timeline.”
With Newton, there was only a state, but that state was 100% certain, it had 100% existence.
With quantum mechanics, there are all possible states, but none of these states have a 100% probability/existence, only all together reach 100%.
The futures you mention, these quantum states do not exist; each is in a limbo between newtonian existence and non-existence, each has only a probability.
These probabilities go down or up, disappear, etc. This does not break any law of physics; indeed, it IS the law of physics.
So yes, the probability/possibility of alternate futures can disappear without breaking any physical law – and disappears.
You seem to take a potential future as if it had a newtonian 100% certain existence – and you wonder how it could disappear. And you have no problem with breaking all fundamental conservation laws/etc just to have them stay. But, Eniac, there is nothing newtonain about them.
I gave the paper a read (if you read the comments Arstechnica following it) there is a link given to the preprint I think. The comments section is also quite interesting.
One more point I’d like to make is that there is indeed an objective reality, even though we do not understand it — and may never understand it fully.
There are various interpretations of QM and other physical theories and these are essentially models and mathematics that attempt to describe the behavior of reality. One interpretation will mesh with reality better than the others and it will take more empirical experiments to get closer to the better model.
Often we find that equations describe behavior quite well. The does not always give us a good understanding of the actual mechanism behind things. For example, one may use Newtonian level physics to describe celestial mechanics and get results that correlate quite well to actuals. In these equations, the effects of gravity are considered instantaneous — when we now know this to be almost certainly wrong due to the work of Einstein and gravity being considered the effects of space curvature, propagating at the speed of light.
So which theory correlates more closely to the physical reality of nature? Obviously relativity does — and it was for this and several other key points that were experimentally verified over time.
The fact that relativity and QM contain ideas that support things like locality, uncertainty, probability, and entanglement does not imply that Reality itself is mutable or that the underlying system/mechanics is somehow off limits, unimportant, or not knowable.
Forget Alpha Centauri B – Neil deGrasse Tyson found the location of Superman’s planet of origin, Krypton!
and speaking of astronomy ….
A prominent astrophysicist has pinned down a real location for Superman’s fictional home planet of Krypton.
Krypton is found 27.1 light-years from Earth, in the southern constellation Corvus (The Crow), says Neil deGrasse Tyson, director of the American Museum of Natural History’s Hayden Planetarium in New York City. The planet orbits the red dwarf star LHS 2520, which is cooler and smaller than our sun.
Tyson performed the celestial sleuthing at the request of DC Comics, which wanted to run a story about Superman’s search for his home planet.
The new book — Action Comics Superman #14, titled “Star Light, Star Bright” — comes out Wednesday (Nov. 7). Tyson appears within its pages, aiding the Man of Steel on his quest.
“As a native of Metropolis, I was delighted to help Superman, who has done so much for my city over all these years,” Tyson said in a statement. “And it’s clear that if he weren’t a superhero he would have made quite an astrophysicist.”
You’ll have to read “Star Light, Star Bright” to find out just how Superman and Tyson pinpoint Krypton. For amateur astronomers who want to spot the real star LHS 2520 in the night sky, here are its coordinates:
Right Ascension: 12 hours 10 minutes 5.77 seconds
Declination: -15 degrees 4 minutes 17.9 seconds
Proper Motion: 0.76 arcseconds per year, along 172.94 degrees from due north
Superman was born on Krytpon but was launched toward Earth as an infant by his father, Jor-El, just before the planet’s destruction. After touching down in Kansas, Superman was raised as Clark Kent by a farmer and his wife.
Now Superman will apparently know exactly where he came from.
“This is a major milestone in the Superman mythos that gives our super hero a place in the universe,” DC Entertainment co-publisher Dan DiDio said in a statement. “Having Neil deGrasse Tyson in the book was one thing, but by applying real-world science to this story he has forever changed Superman’s place in history. Now fans will be able to look up at the night’s sky and say, ‘That’s where Superman was born.’”
What is this star’s magnitude? I am willing to bet it is not visible with unaided vision. And as for fans looking up in the night sky to see the place where Superman was born, they will have to be in the Southern Hemisphere to do so at all, as that is where Corvus the Crow is located.
As for that red sun, apparently it was called Rao and was either a red dwarf or red supergiant (no big difference, right?) about 50 light years from Earth – when it wasn’t being placed in another galaxy,though whoever was writing the issue that day probably meant a solar system.
And just in case you wanted to know more about Krypton itself:
Inconsistencies and retconning – where would comics be without them?