We get questions every week about string theory and topics popularized by science fiction. Here's the problem. There's just no evidence. Each of these is based on wonderful and well-formed mathematical equations, or wishful thinking, but they're very hard (if not impossible) to test in the real Universe.

<strong><a href="http://media.libsyn.com/media/astronomycast/AstroCast-070409.mp3">Episode 31: String Theory, Time Travel, White Holes, Warp Speed, Multiple Dimensions, and Before the Big Bang (14.4 MB)</a></strong>

Read the full blog entry

Even more depressing than the episode about the sun killing off all life on Earth in a far distant future

We thought we'd pile it all into a single episode, just to get the pain over quickly for our listeners.

__________________
Fraser Cain
Publisher
Universe Today - Free space news delivered by email every weekday.

Fraser. Thank you. Pete.

__________________
A third rate theory forbids
A second rate theory explains after the fact
A first rate theory predicts...A. Lomonosov

It still means that starting from last Monday I still have to wait TWO WEEKS to get my Astronomy Fix though.

Keep up the good work and lets get back to the facts.

We get questions on string theory pretty much every day. We couldn't keep silent on the subject, but now people understand why we haven't done episodes on it, and probably won't.

__________________
Fraser Cain
Publisher
Universe Today - Free space news delivered by email every weekday.

Pamela is a star! Well, famous anyway. Well, an author, anyway. The April issue of Sky & Telescope has a book review she wrote. Presumably, she was paid for it. So that suggests fame AND fortune!

Yeah, i know. This has nothing to do with this show. In fact, i'm something like two months behind... but i didn't see a good spot to put in this announcement.

At the end of the program, Faser refers to all of the topics on the program as "mathematical theories." Are "mathematical theories" actually "theories?" I ask because this I believe this is a source of confusion to the layperson who argues that evolution is "just a theory." I understand what is necessary in science for an idea to be called a "theory," but it seems that scientists themselves use the word "theory" in other contexts all the time. "String Theory," for example, does not meet the criteria of a scientific theory and I wish people would start calling it String Hypothesis. However, it does meet the criteria of a mathematical theory. So is it correct to call it "String Theory?"

J. D.

The reason they call evolution a theory is because it cannot be tested and repeated, but the scientific evidence proves it to be true.

The only problem with your statement that I can find is the word "evidence".

You said there is none.

What you should have said is, "We have found no evidence".

"There's just no evidence" implies that you will never find any, and that draws a conclusion before the fact. And that in and of itself is not very scientific.

I can agree with that. We haven't found the evidence yet. The point of the show was to try and draw the distinction between popular theories that lack evidence, and the ones that are popular because of their evidence.

__________________
Fraser Cain
Publisher
Universe Today - Free space news delivered by email every weekday.

Very cool. I didn't type it to sound snippy. Inflection is tough with the written word.

I love your shows and only wish I didn't have to wait until Monday nights to get a half hour. +/-

Along with this webboard, your show, and a few other good podcasts, I am really learning alot.

Mostly that I just have more questions after listening.

Keep up the great work!

Thank you for making a show like this once in a while. These subjects are popular, not only in your e-mails but all of us who talk about, or teach astronomy will frequently encounter them.

String theory has been a favourite among European popular science magazines for a long time and even though it may not quite deserve to be associated with pure fiction like time travel or warp speed, I certainly understand why you put it there so as not to be forced to do an extra show on it.

A question: Would it be correct to quote Pamela saying that so far, no version of string theory has come up with even one prediction that, if it could be tested, would be a proof supporting string theory alone? That is to say that, as far as string theory is concerned, experimental science can not even get started since succeeding to prove one of the existing predictions would not prove anything at all.

A comment: Pamela is making a good point when saying that “Science has to explain why a ball I toss into the air goes up and comes down. Science does not have to be able to explain why I decided to throw the ball.” That well defines what science is and is not. As for the scientist and for the rest of us, those original questions might very well be important, that is: “Why was the ball tossed?” and “Who or what made that ball anyway?”. Those questions will always be around and should not be ignored but science is not the place to look for answers.

Forget about string theory. Try to scientifically experiment with quantum physics. It's all based on probablilities. How can you get a repeat in an experiment when you can't predict the outcome and get the same one twice in a row?

But that in and of itself becomes the evidence that something else is at work, so you put a name on it and try (with mathematics) to explain it.

You don't have to test it again... you already had an answer. Now you are explaining the answer.

"Every time I shoot this particle at that paper, the chance of it going to left, or right of the slits, or going through both is 100%, because I cannot predict which slit it will choose with any accuracy on a sub atomic level for any one choice."

I don't know if this is a good analogy, but string theory kind of sounds like the old theory of planetary motion that involved interlocking crystaline spheres to explain the complex motions of the planets. That mathematical theory explained the motions of the planets until we figured out the real reason for the complex motions (gravity, eliptical orbits, the whole "sun is the center of the solar system" controversy).

Martin

Quantum theory makes it impossible to predict the position and velocity of individual particles, but it makes astonishingly correct predictions about the Universe in general. It's bizarre, but it's correct. I love quantum theory because it battles your expectations and instincts at every turn. You have to turn off your intuition and just let your experiments guide you through understanding.

__________________
Fraser Cain
Publisher
Universe Today - Free space news delivered by email every weekday.

It is often suggested that the lack of time travelers visiting us today is very strong evidence against the possibility of it ever being feasible. Unfortunately, another possibility is that the human race will end before we can discover how to master the ability. Not a pleasing thought but there is certainly more than a remote chance it will happen.

There's also the possibility that time travellers have been visiting us, but that they have evolved to the point where we mistaken them for 'aliens'.

PLEASE TELL US ABOUT THOSE OTHER PODCASTS!!!

(sorry - I know this is completely off subject -
but I have started to listen to podcasts relatively lately,
and have great trouble to find anything even remotely as good as this show)

Well, there is Dark Matters which is done by some guy in Australia.
There is Explorations with Dr. Michio Kaku every Wednesday.
There is Bad Astronomy Q&A
uhm... 60 Second Science (updated every day)
Nova Science Now
Nasa's Jet Propultion Lab (most are video, but have some audio)
and Science Talk - The Podcast of Scientific American

I'm sure there tons more, but those are the ones I get right now. (Along with Coast to Coast). If you have i-Tunes, you can just go to the i-store and search under science and find whatever you want.

ALL of the ones I meantioned above (except Coast to Coast) are FREE.
You don't have to pay to use i-tunes. You only pay for premium services and podcasts.