e no­tion of in­ter­stel­lar ight may not be so far fetched

Truro Daily News - - OPINION - Gwynne Dyer Gwynne Dyer’s new book is Grow­ing Pains:

Want to be cheered up as we close out the past 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 nd 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.

at 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.

ey got a Phase 1 grant in 2017 to work on their pro­posed space drive. ey 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 E ect 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 ction. 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.

e “tyranny of the rocket equa­tion” is what makes space ight 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.

e 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 e ects), and a few years’ de­cel­er­a­tion at the far end. It would ar­rive in around 20 years.

So along comes Dr. James Wood­ward, who pub­lished his rst peer­re­viewed ar­ti­cle on the Mach e ect in 1990, and Dr. Heidi Fearn, his col­league at Cal­i­for­nia State Univer­sity, Fuller­ton. ey worked on the the­o­ret­i­cal physics of the Mach e ect, 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.

I’d ex­plain the Mach e ect in greater de­tail, but I barely un­der­stand it my­self. Suf­fice it to say that their MEGA drive uses elec­tric­ity to pro­duce mass uc­tu­a­tions 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. is isn’t a sure thing. There is still con­tro­versy over whether the ‘push’ is real, or just an elec­tri­cal or mag­netic e ect 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 ve days, Jupiter in seven to eight days.

How’s that for (po­ten­tially) good news?

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