Jason Carr ⋅ 20 Comments
Image Credit: Paramount
Image Credit: Paramount

Interstellar space travel is one of the most common themes of science fiction, but the question is, will it ever become reality?

With our current understanding of physics, propulsion methods and the limits of our technology, there is currently no practical way to travel to other stars and solar systems. NASA terminated its Breakthrough Propulsion Physics Program in 2003, stating that no further breakthroughs appeared to be imminent. What this ultimately means is that we should not be expecting to see travel to other stars become reality any time soon, if ever. NASA did recently announce that they will begin work on a Warp Drive…whether anything will come of that, only time will tell. I personally would like to see this happen in the private-sector but that’s certainly unlikely for the immediate future.

In most sci-fi stories, starships zip around the galaxy at speeds far exceeding that of light, the universal speed limit of 182,282 miles per second. The problem however is that the laws of physics state that absolutely nothing in the universe can travel faster than this (even though folks are trying to prove otherwise).

The Primary Issue – Distance

We know our own star simply as the Sun. The Sun is a star no different to billions of others in the Milky Way galaxy. To provide some important figures for reference, the Sun lies 93 million miles from away from Earth and it takes light eight minutes and twenty seconds to reach us.

Source: NASA
Source: R. Mewaldt & P. Liewer, JPL

The nearest star to Earth, other than the Sun, is Proxima Centauri of the Alpha Centauri triple-star system. It lies 4.24 light-years away, meaning that it takes 4.24 years for the star’s light to reach us.

The fastest launch speed achieved by mankind was that of the New Horizons robotic spacecraft which was launched at 36,373 miles per hour on its mission to the dwarf planet Pluto. The fastest man-made object is currently the Helios 2 solar space probe, travelling at 157,100 miles per hour. This speed was achieved by using gravitational assistance from the Sun. If the Helios 2 solar probe were to be sent directly towards Proxima Centauri, it would reach the star in approximately 18,000 years.

How Fast Can We Go?

There are technologies that exist which can achieve far greater speeds than those of space probes like Helios 2 or New Horizons.

One of these is nuclear pulse propulsion which basically uses nuclear explosions to power a rocket to incredibly high speeds. It seems plausible that such a spacecraft could reach speeds of around 5 percent of the speed of light, yet this would still take about 85 years to reach the nearest star. As demonstrated by the Project Orion effort of the mid-twentieth century, it is possible using only currently available technology. Of course, this speed is still too low, making it highly impractical. It is generally considered that, if a journey cannot be completed in considerably less than a human lifetime, it should not be started at all.

The only thing that is possible is to send out radio waves, traveling at the speed of light, to the stars. This allows us to send a message to Proxima Centauri for example, which would arrive in 4.24 years. Perhaps some day we will be able to send physical objects there at this rate.

Faster-than-Light (FTL)

Image Source: Nextbigfuture
Image Source: Nextbigfuture

Nothing can travel faster than light, as dictated by Einstein’s theories on relativity. 182,282 miles per second is the absolute speed limit. If practical interstellar travel is ever to become a possibility, we need to find a way around this speed limit.

To get around the FTL issue, sci-fi shows/movies/books often use things like warp drives that are capable of warping spacetime in such a way that it folds space. If this were possible, it would effectively enable FTL travel between two points. The Alcubierre drive, proposed in 1994, is the only serious attempt at theorizing a starship which travels faster than light. It does this by expanding space behind it and contracting space before it. The spacecraft travels in its own bubble at speeds slower than light. To put this in perspective, imagine a piece of paper with a point marked at each end. The shortest distance between these two points is a straight line, unless you fold the paper in half so that the two points meet each other directly.

The Alcubierre drive is highly theoretical and has one deal-breaking flaw – it requires something called exotic matter with negative mass, and this isn’t even known to exist.

The Bottom Line

Space Travel ConceptIf you could go back in time to the mid-nineteenth century and tell people that humanity was going to land on the moon in 1969, they would probably laugh at you. Since then, we have launched probes all over the Solar System and landed robotic spacecraft on the surfaces of Venus, Mars and Saturn’s moon, Titan. One thing is clear: Humanity’s potential is immense and science and technology are full of surprises. Interstellar travel may seem like a very long way off, but it will never become a reality if we don’t try.

One thing that is preventing many scientists from taking interstellar travel seriously is also the fact that we don’t really know where to start. There are countless stars out there, but until something truly interesting and worth visiting shows up, interstellar travel will remain a thing of science fiction. That being said, more than 850 planets have been discovered orbiting other stars and more are being confirmed every week. We are now learning that every star “up there” likely has a number of planets rotating around them (the same thing that happens in our neck of the universe). That’s a very, very large number of planets. It is likely just a matter of time before we find an Earth-like world out there in the lonely depths of space. Perhaps that will truly give humanity something to aim for resulting in a renewed interest in reaching the stars.


Ford, L., & Roman, T. (2000). Negative Energy, Wormholes and Warp Drive Scientific American, 282 (1), 46-53 DOI: 10.1038/scientificamerican0100-46

Hill, J., & Cox, B. (2012). Einstein’s special relativity beyond the speed of light Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences, 468 (2148), 4174-4192 DOI: 10.1098/rspa.2012.0340

González-Díaz, P. (2000). Warp drive space-time Physical Review D, 62 (4) DOI: 10.1103/PhysRevD.62.044005

Hansson, A. (2003). Project Orion: The Atomic Spaceship 1957–1965 Space Policy, 19 (2), 149-150 DOI: 10.1016/S0265-9646(03)00011-0

Endl, M., & Kürster, M. (2008). Toward detection of terrestrial planets in the habitable zone of our closest neighbor: proxima Centauri Astronomy and Astrophysics, 488 (3), 1149-1153 DOI: 10.1051/0004-6361:200810058

Additional Learning Resources:

Alpha Centauri Bb: An Interstellar Target?

[tt] Uploaded minds to the stars

What If NASA Could Figure Out the Math of a Workable Warp Drive?

Why we should send uploaded astronauts on interstellar missions

‘FTL’ tips: How to survive the dangers of interstellar travel

The downside of warp drives: Annihilating whole star systems when you arrive

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Posted in: Space + Physical Sciences ⋅ Tagged: Alcubierre drive, Breakthrough Propulsion Physics Program, Faster-than-light, Future, Helios, Milky Way, Pluto, Proxima Centauri, Science, Technology
http://twitter.com/jason_d_carr/status/281770459429761025/ Jason Carr (@jason_d_carr)
Will We Ever Really Travel to the Stars? http://t.co/PBJbEFax #space #exploration #astronomy #nextfrontier

http://www.landmaninsider.com Randy Young
Great article. I’ve heard about the “folding space” type theories, but never known what it was actually called. Now I do!

Jason Carr
Awesome! Thanks for reading Randy 🙂

http://jameswharris.wordpress.com Jim Harris
Jason I grew up believing in the final frontier and interstellar travel like it was a religion, but as I’ve learned more about science and the reality of the great distances between the stars I’ve become an atheist to my own beliefs.

We’ve never even been able to create a sustainable fusion reaction, so I find it very hard to believe we’ll ever create energy sources that can warp space. I’m not saying interstellar travel is impossible, I’m just saying it will be so hard that I’m not sure we’ll ever attempt it.

But there are other barriers that keep us on Earth that’s not like the physical barrier of the speed of light. After six manned missions to the Moon we essentially gave up on space travel. We’ve been going in LEO circles for forty years. We had the technology to colonize the Moon and Mars and we never used it. Most citizens of Earth see little reason to leave our planet, or spend the billions and trillions it will take.

I truly doubt we’ll ever have manned interstellar travel. I have great doubts about manned interplanetary travel. I think we’ll develop ever more powerful robots to travel in space for us, until space is colonized by AI beings. Interstellar travel is practical for machines, not biological creatures.

Jason Carr
Great thoughts Jim! I can’t say that I don’t hope you’re wrong on these points but like you, I am more inclined to believe that our best opportunities during the next 50 years likely lie within lunar, Mars, and low-orbit travel/missions.

James Sherridan
Like Jim I tend to think we’re a long long way off from interstellar travel. It’s a shame, especially considering how far tech has come over the past few decades. Guess it will take pending annihilation from a giant space body heading our way or some man-made disaster before we decide that this is a priority. Of course, by then it will be too late. Gotta love human behavior!

http://twitter.com/ProfAbelMendez/status/281928362165944321/ Prof. Abel Méndez (@ProfAbelMendez)
Will We Ever Really Travel to the Stars? http://t.co/rOVOVvyq

http://twitter.com/ResearchBlogs/status/282066611182112769/ ResearchBlogging.org (@ResearchBlogs)
Will We Ever Really Travel to the Stars? http://t.co/ko96jRyu

Hi Jason. I think that several of your assumptions are preventing you from seeing a solution to the problem of interstellar travel. The first assumption is that we need to get there within the lifetime of a person. If the purpose for such a mission were either science or colonization for he sake of colonization, I would agree. But if the reason is to ensure a back-up of the human species at distance, then the travel time is not the issue. Success in such a mission would come after the viable craft got far enough away from he solar system to be safe.

The second assumption (presumably) is that the humans on board would be awake. But if they were either in a state is suspended animation the the amount of time for them would not matter.

OK, so how practical would a slow boat with a frozen crew to Alpha Centauri be? Obviously, a slower ship is easier to construct than a fast ship. Likely, more conventional means of propulsion are likely easier than warping space which would probably require massive amounts of energy and probably mass.

As for the suspended animation, we can now sequence he genomes for all hibernating and freezable species for relatively cheap. There could be a breakthrough there. Scientists in Japan are able to use microwaves and freezing to freeze sizeable chunks of meat without creating ice crystals. So, there might be a breakthrough there.

Also, we are much further advanced towards ectogenesis and android parenting than many people realize. I have written a paper about such a concept. Just Google: “The EGR Mission” to see.

Jason Carr
Thanks for sharing your paper with me John (bookmarked).

Regarding your response. First, thanks for reading, I’m glad you’re here. Okay, you’re absolutely right…this post was written with the assumption that we can’t do it in a person’s lifetime (unless we figure out the whole relativity thing) but suspended animation is certainly another way to look at this. I’ve often written that this may be the way that advanced ETI civilizations may traverse the universe to reach us. It makes sense that this could apply to humans as well in the future. I’ll admit, I find the idea of cryogenics fascinating. I hadn’t read about the Japanese advancements you mention…I’ll look them up. Yours is certainly a valid argument however. If we could figure out how to make it work, it’s worthy of exploring further. My next question would of course be, who would we get to agree to go? Traveling to space with a reasonable expectation of surviving is one thing. But it seems to me that this (suspended animation) would be an even riskier route to take. We’d have to assume that a robot would successfully get us there in one piece and of course that the machine would wake us up. We’ve seen this in sci-fi and I like the idea of it. Do you feel that if we had the capability, we could find individuals that would be willing to leave knowing that it may be thousands and thousands of years before they return to Earth (if ever)? Finding such brave and noble explorers would be a tremendous thing…I just wonder if there are any left.

Interesting thoughts you’ve provoked and I have no doubt that I’ll now start watching advances more closely in this arena. Thanks so much John and I do hope you’ll continue to read/contribute in the future. I encourage everyone to read John’s article…interesting stuff: http://www.peregrinus-interstellar.net/index.php?option=com_content&task=view&id=135&Itemid=60

Well Mars One is planning on bringing prop;e on a one way trip to Mars, which is a desolate place to hang.

I think we could easily find people to go on a life long trip to be the hero of humanity.


Outstanding article. Very thought provoking. Thanks and keep up the good work! 🙂

http://twitter.com/astrosofista/status/284765718640197632/ Ricardo Montiel (@astrosofista)
¿Viajaremos alguna vez a las estrellas? http://t.co/TcA2uqkp – Sin novedades aparentes, todo sigue dependiendo del futuro

http://twitter.com/LorenaMarsh/status/286258811034013696/ @LorenaMarsh
Will We Ever Really Travel to the Stars? http://t.co/Ton2GzWW

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http://twitter.com/jphawkins2009/status/287271255688744960/ @jphawkins2009
Will We Ever Really Travel to the Stars? http://t.co/MOLahrEk

John Rogers
I believe we will, given time and a lot of patience and resources.

Yes we will !.

Mitar Tarabic – Serbian Prophet – dead 1899 – Has predicted –

Man will travel to other worlds to find lifeless deserts there, and still, God forgive him, he will think that he knows better than God himself. There, except the eternal peace of God, he will see nothing, but he will sense with his heart and soul all of God’s beauty and power. People will drive in rigs upon the moon and stars. They will look for life, but life similar to ours they will not find. It will be there, but they will not be able to understand it and see that it is life.

Further – the Bible has a very interesting prophesies in

Jeremia – chapter 31 verses –

35 Thus saith Jehovah, who giveth the sun for a light by day, and the ordinances of the moon and of the stars for a light by night, who stirreth up the sea, so that the waves thereof roar; Jehovah of hosts is his name:

36 If these ordinances depart from before me, saith Jehovah, then the seed of Israel also shall cease from being a nation before me for ever.

37 Thus saith Jehovah: If heaven above can be measured, and the foundations of the earth searched out beneath, then will I also cast off all the seed of Israel for all that they have done, saith Jehovah.

Comment – Yehovah who cant lie cant say – If You do something You will Never do – Then I Will do something I will never do.

That is – what Yehovah here says will come to pass.
This can only take place when Mankind travels to Outer Space.

Further –

Jeremia – chapter 33 verses –

19 And the word of Jehovah came unto Jeremiah, saying,

20 Thus saith Jehovah: If ye can break my covenant of the day, and my covenant of the night, so that there shall not be day and night in their season;

21 then may also my covenant be broken with David my servant, that he shall not have a son to reign upon his throne; and with the Levites the priests, my ministers.

22 As the host of heaven cannot be numbered, neither the sand of the sea measured; so will I multiply the seed of David my servant, and the Levites that minister unto me.

23 And the word of Jehovah came to Jeremiah, saying,

24 Considerest thou not what this people have spoken, saying, The two families which Jehovah did choose, he hath cast them off? thus do they despise my people, that they should be no more a nation before them.

25 Thus saith Jehovah: If my covenant of day and night stand not, if I have not appointed the ordinances of heaven and earth;

26 then will I also cast away the seed of Jacob, and of David my servant, so that I will not take of his seed to be rulers over the seed of Abraham, Isaac, and Jacob: for I will cause their captivity to return, and will have mercy on them.

Comment – Same interpretaition as above.


In the end gibberish that is what I read. Interpreted anyway anyone wants to.

Thats right – a coin has always two sides – as Reality !.