The no­tion of in­ter­stel­lar flight may not be so far fetched

Annapolis Valley Register - - NEWS - Gwynne Dyer’s new book is Grow­ing Pains: The Fu­ture of Democ­racy (and Work).

Want to be cheered up as we en­ter a new year? Okay, how’s this? It’s start­ing to look like in­ter­stel­lar travel may be pos­si­ble in a time frame that would be man­age­able for hu­man be­ings.

No, it’s not a cure for can­cer. But we know that we are bound to find that even­tu­ally, so long as our civ­i­liza­tion is not de­stroyed by war or global warm­ing or a ran­dom as­teroid strike. Un­til very re­cently, our un­der­stand­ing of sci­ence told us that travel even to the near­est stars will never be pos­si­ble.

That may still be true, for the an­swers are not all in yet. But last April the U.S. Na­tional Aero­nau­tics and Space Ad­min­is­tra­tion gave James Wood­ward and the Space Stud­ies In­sti­tute a Phase 2 grant un­der the NASA In­no­va­tive Ad­vanced Con­cepts pro­gram.

They got a Phase 1 grant in 2017 to work on their pro­posed space drive. They made enough progress to keep NASA happy and them­selves cred­i­ble, and they have now been funded to test new de­signs that in­crease the thrust pro­duced by their Mach Ef­fect Grav­ity As­sist (MEGA) drive. If that scales up sat­is­fac­to­rily, we will one day be able to build space­ships that go to the stars.

I must ad­mit that I re­ally en­joyed writ­ing that last line, for all my life I have been told that in­ter­stel­lar travel is only sci­ence fic­tion. Real space flight is ruled by Rus­sian sci­en­tist Kon­stantin Tsi­olkovsky’s clas­sic rocket equa­tion of 1903, which says that a rocket can get into space by ex­pelling enough of its mass (fuel) at high ve­loc­ity, but also says that the pay­load and/or the speed is strictly lim­ited.

More pay­load or more speed is pos­si­ble, but only by burn­ing more fuel. You must carry that fuel all the way from launch, which makes the ve­hi­cle heav­ier, which re­quires more fuel, and so on.

The “tyranny of the rocket equa- tion” is what makes space flight so ex­pen­sive, and in­ter­stel­lar travel by rocket im­pos­si­ble. For a manned space­ship to reach the near­est star (Prox­ima Cen­tauri, 4.2 light years), slow down again when it gets there, and do it all within one hu­man life­time, it would have to burn an amount of fuel roughly equal to the to­tal mass of the sun.

The fuel is the prob­lem, not the dis­tance. If you didn’t have to bring the fuel with you, send­ing a 400 kg. pay­load to Prox­ima Cen­tauri and put­ting it in or­bit around the most Earth-like planet would re­quire a few years’ ac­cel­er­a­tion at a mod­est 1g, a max­i­mum speed of 0.4c (four­tenths of light-speed, so no ma­jor rel­a­tivis­tic ef­fects), and a few years’ de­cel­er­a­tion at the far end. It would ar­rive in around 20 years.

All re­cent pro­pos­als for in­ter­stel­lar flight have there­fore aban­doned rock­etry and as­sumed ul­tra-light ve­hi­cles that carry large sails and are pushed by Earth-based lasers or by the so­lar wind. Two prob­lems: the push dies away be­fore they have trav­elled even one light year, and they have no way of stop­ping at their des­ti­na­tion.

So along comes Dr. James Wood­ward, who pub­lished his first peer-re­viewed ar­ti­cle on the Mach ef­fect in 1990, and Dr. Heidi Fearn, his col­league at Cal­i­for­nia State Univer­sity, Fuller­ton. They worked on the the­o­ret­i­cal physics of the Mach ef­fect, they built minia­ture mod­els of a space drive that doesn’t need to burn a pro­pel­lant and tested them, and grad­u­ally the space com­mu­nity be­gan to take them se­ri­ously.

NASA is cer­tainly tak­ing them se­ri­ously now. Con­trary to what some of their crit­ics claim, what they are do­ing does not vi­o­late fun­da­men­tal phys­i­cal laws like “ev­ery ac­tion must have an equal and op­po­site re­ac­tion.” How­ever, it does run con­trary to our daily ex­pe­ri­ence of those laws by ex­ploit­ing some of the more ar­cane as­pects of quan­tum physics.

I’d ex­plain the Mach ef­fect in greater de­tail, but I barely un­der­stand it my­self. Suf­fice it to say that their MEGA drive uses elec­tric­ity to pro­duce mass fluc- tu­a­tions within a block of metal, which in turn pro­pels the drive for­ward with­out burn­ing fuel. What is it push­ing against? All the rest of the mass in the uni­verse.

This isn’t a sure thing. There is still con­tro­versy over whether the ‘push’ is real, or just an elec­tri­cal or mag­netic ef­fect that cre­ates a false pos­i­tive. But NASA is will­ing to spend money on it, and a lot of other sci­en­tists are now fol­low­ing up on Wood­ward’s and Fearn’s work.

It would open the doors to the rest of the uni­verse for us. Ex­plo­ration, col­o­niza­tion, un­lim­ited re­sources, per­haps con­tact with other in­tel­li­gences – all of that be­comes much more pos­si­ble than it would if we must re­main for­ever con­fined to this one small plan­e­tary sys­tem. And, of course, it would make get­ting around this sys­tem a great deal eas­ier: the moon in four hours, Mars in two to five days, Jupiter in seven to eight days.

How’s that for ( po­ten­tially) good news?

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