Category Archives: Physics

Science Fiction, Without the Fiction: Warp Drive


Today’s Music: Delta Spirit – People C’mon

“Engage, warp factor 9.”
“Jump to lightspeed.”
“Prepare the hyperdrive.”

If you read or watch science fiction, all of those phrases are familiar to you. In fact, variations on that theme are so well known, that we are complicit in ignoring the fact that it can’t be done.
We let ourselves be fooled by mystical explanations of “anti-matter” and “holes in the space-time continuum”.

Until now.

Harold White
Follow me! I know the way!

White’s work is based on the math and ideas of Miguel Alcubierre, who came up with the equations for warp drive. But he thought it would take an energy source the size of Jupiter to do it.
While working on the equations one day, White realized that if the shape of the field generator was changed, it could be done with an energy mass of about 1600 pounds.
That’s less than the weight of the bookbag I used to carry!

Here’s the oversimplified version of how it works:
The engine (referred to as an Alcubierre Drive) would warp the space around it. The space behind would be expanded, pushing the craft forward. The space in front would be contracted.

That’s it.
Now here’s the kicker: The speed of light is an absolute. Nothing can go faster than it.
But because of loopholes in Einsteins theory of relativity, the light barrier isn’t broken relative to the changed shape of space.

The practical upshot is that a trip to Alpha Centauri (4.3 light years away (that’s 4.3 years of constant travel at the speed of light!) could be done in…wait for it…two weeks.

I’ve waited on line at the DMV for longer than that.

So practically, what does that mean? Well, nothing really. It’s all still theoretical.
White is in a lab right now, trying to generate micro disturbances in space to see if they are measurable.
The math holds up, but it remains to be seen if (and how well) it can be applied in real life.

It’s so obvious…maybe…


I hope it can. I bet there’s great skiing on Pluto
But I only have a few days off…

The first article I saw, from io9, The article from Time.
And an abstract of White’s paper, with a link to the pdf of the whole thing.

Advertisements

The Uncertainty Principle


Today’s Music: They Might Be Giants – Particle Man

The Heisenberg Uncertainty Principle refers to measuring the position and speed of tiny particles in the quantum physics world. It states that the more precisely one property is measured, the less precisely the other can be controlled, determined, or known.
For those of you expecting a waggish post relating to why I always lose socks in the laundry, or why I can never find my keys, sorry to disappoint. While those are both interesting topics deserving of further attention, I’m actually going to stick with physics here.

I’m not a scientist. My math skills are adequate but unimpressive. But science, and quantum physics in particular fascinate me. The search for an explanation of the universe, from it’s largest phenomena to it’s smallest appeals to the tinkerer in me.
And while I knew what the Uncertainty Principle said, I never quite grasped the meaning.
Finally, someone explained it to me in a way I could understand.

It's not really there...

Right now, you’re able to see this because photons (light particles) are bouncing off whatever screen you’re looking at and reflecting onto your eyes.

Now think about the size of a photon vs. the size of your screen. there’s no comparison. Your screen is bombarded by photons, but because of the size difference, the constant barrage makes no difference.

Now shrink it down. Say to the size of an electron.

Objects on your monitor are MUCH smaller than they appear.

The photon and the electron are not that dramatically different in size. In fact, they are close enough, that the momentum of the photon that bounces off the electron is enough to move the electron, like you being bumped in a crowd during, say, a rush hour train commute.

So, the Uncertainty Principle (simplified) says you can either know the Speed of the electron OR it’s Position.
If I figure out the speed of the electron, I’ve done this by bombarding it with photons. How fast the electron passes through the photons tells me how fast it’s moving.
But since each photon that hits the electron changes it’s position a bit, I don’t know exactly where it is. To note it’s speed more accurately, I have to hit it with more photons, bouncing it around even more.

Going the other way, say I want to know where the electron is. So I tap it with just one photon. That will give the least bounce against the electron. So now I know where it is.
But because there is only the one (or other very small amount) of photons, I can’t track the speed of the photon.
I can only know one or the other.
Still with me? No shame if you’re not. Honestly, I first heard of the Uncertainty Principle in high school, and it’s taken me to the start of middle-age before I understood what it meant.

The explanation that cleared it up for me came from Dr. Brian Greene’s eminently readable The Elegant Universe. Seriously, there is very little math in the book, and some of the analogies are hilarious.

So, back to the Principle.
Since only one condition (speed or position) can be known at a time, only the probability of the other can be measured. If the speed is known, then I can only say that the electron is between a probably range here and there.
If I know where the electron is, I can only say it’s going between a probable range of this fast and that fast.

Albert Einstein (the guy with the hair) famously said “God does not play dice with the universe”. He never agreed with the uncertainty principle because it relied on probability instead of a solid “it’s going this fast, and it’s here”.

Do I look uncertain to you?!?

Now, all these years later, I finally have some idea of what the hell he’s talking about.
How cool is that?

****EDIT – If anyone sees anything wrong in the above, please correct me in the comments and I’ll update the post!!!  Thanks.