Science Fiction
Dictionary
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
 |
Mirrors For Gravitational Waves
Is it possible to have a surface that could reflect gravitational waves? In a recent paper, Stephen J. Minter, Kirk Wegter-McNelly and Raymond Y. Chiao speculate that thin superconducting films would be highly reflective mirrors for gravitational microwaves.
This is the basis on which a gravitational wave can interact with a superconducting sheet. “Quantum delocalization causes the Cooper pairs of a superconductor to undergo non-geodesic motion relative to the geodesic motion of its ionic lattice,” says Chiao and buddies.
They speculate that this difference in motion causes the sheet to absorb energy from the gravitational wave and then re-radiate it as gravitational wave travelling in the opposite direction–in other words specular reflection.
The new idea comes from considering what happens to a superconducting sheet when a gravitational wave passes by. The Cooper pairs within the sheet are quantum objects governed by the uncertainty principle and so cannot have specific trajectory: they are entirely delocalised. On the other hand, the ions that make up the crystal structure of the superconductor are not delocalised and so can move along a geodesic trajectory when a gravitational wave passes.
(How superconducting sheets could reflect gravitational waves [MIT article])
(Diagram of gravitational wave mirror)
Science fiction fans may well reflect on this research, since they've seen similar ideas more than a century ago. In his 1901 novel The First Men in the Moon, H.G. Wells wrote about a material called "cavorite" that was opaque to gravitation.
On the 14th of October, 1899, this incredible substance was made!
Oddly enough, it was made at last by accident, when Mr. Cavor least expected it. He had fused together a number of metals and certain other things - I wish I knew the particulars now ! - and he intended to leave the mixture a week and then allow it to cool slowly...
..."You are quite clear that the stuff is opaque to gravitation, that it cuts off things from gravitating towards each other? "
"Yes," said I. "Yes."
(Read more about Wells' Cavorite)
Once it becomes clear that Cavorite is "impervious to gravitation", the two men design a spherical spacecraft with special features that would allow them to steer the craft.
"You would go off in a straight line--" I stopped abruptly. "What is to prevent the thing traveling in a straight line into space for ever?" I asked. "You're not safe to get anywhere, and if you do--how will you get back?"
"I've just thought of that," said Cavor. "That's what I meant when I said the thing is finished. The inner glass sphere can be air-tight, and, except for the manhole, continuous, and the steel sphere can be made in sections, each section capable of rolling up after the fashion of a roller blind. These can easily be worked by springs, and released and checked by electricity conveyed by platinum wires fused through the glass. All that is merely a question of detail. So you see, that except for the thickness of the blind rollers, the Cavorite exterior of the sphere will consist of windows or blinds, whichever you like to call them. Well, when all these windows or blinds are shut, no light, no heat, no gravitation, no radiant energy of any sort will get at the inside of the sphere, it will fly on through space in a straight line, as you say. But open a window, imagine one of the windows open. Then at once any heavy body that chances to be in that direction will attract us--"
I sat taking it in.
"You see?" he said.
"Oh, I see."
"Practically we shall be able to tack about in space just as we wish. Get attracted by this and that."
(Wells' Cavorite)
This question of how gravitation might affect a sphere coated with a material that reflects gravity waves is particularly interesting, given recent questions about the behavior of Gravity Probe B, a orbiting experiment consisting of four perfectly round spheres, that spin rapidly and thus behave like gyroscopes. Each sphere has a thin superconducting coating.
The four gyroscopes in GP-B are the most perfect spheres ever made by humans. These ping pong-sized balls of fused quartz and silicon are 1.5 inches across and never vary from a perfect sphere by more than 40 atomic layers.
(Space.com)
(Spherical gyroscope used in Gravity Probe B)
If there were an obvious interaction between a superconducting films and gravitational waves, wouldn't Gravity Probe B have picked them up somehow? After all, in his previous paper Chiao says that a superconducting sphere is the perfect shape for a graviational wave antenna.As it turns out, the experiment has been throwing out anomalous results ever since it was launched. The team has puzzled over them for years now and lately come to the conclusion that they are the result of some imperfections in the shape of the spheres. This seems rather unlikely given the testing regime that Gravity Probe B underwent during its tortuous history.
Could the real cause of Gravity Probe B's problems be reflections from passing gravitational waves?
(If superconducting sheets reflected gravitational waves...)
Read more at If superconducting sheets reflected gravitational waves..., How superconducting sheets could reflect gravitational waves and Laboratory-scale superconducting mirrors for gravitational microwaves (pdf); read more about Gravity Probe B in NASA Collects Gravity Data to Test Einstein's Theory. Thanks to Winchell Chung for the tip and sf reference for this story.
Scroll down for more stories in the same category. (Story submitted 3/24/2009)
Follow this kind of news @Technovelgy.| Email | RSS | Blog It | Stumble | del.icio.us | Digg | Reddit |
Would
you like to contribute a story tip?
It's easy:
Get the URL of the story, and the related sf author, and add
it here.
Comment/Join discussion ( 3 )
Related News Stories - (" Space Tech ")
Is China Mining Helium-3 On The Moon's Farside?
'...for months Grantline bores had dug into the cliff.' -
Solitary Black Hole Wanders In Space
'...the Hole is something like a vortex or a whirlpool?' - Frank K. Kelly, 1935.
Spaceplane From Virgin Atlantic
'ZARNAK, YOU'RE TO COMMAND A SCOUTING EXPEDITION --- FIND OUT WHAT THIS IS ALL ABOUT!'
Taikonauts Exercise In China's Tiangong Space Station
'Joe got out the gravity-simulator harnesses...' - Murray Leinster, 1953.
Technovelgy (that's tech-novel-gee!) is devoted to the creative science inventions and ideas of sf authors. Look for the Invention Category that interests you, the Glossary, the Invention Timeline, or see what's New.
Science Fiction
Timeline
1600-1899
1900-1939
1940's 1950's
1960's 1970's
1980's 1990's
2000's 2010's
Current News
LLM 'Cognitive Core' Now Evolving
'Their only check on the growth and development of Vulcan 3 lay in two clues: the amount of rock thrown up to the surface... and the amount of the raw materials and tools and parts which the computer requested.'
Has Elon Musk Given Up On Mars?
'There ain't no such thing as a free lunch.'
Bacteria Turns Plastic Into Pain Relief? That Gives Me An Idea.
'I guess there's nobody round this table who doesn't have a Crosswell [tapeworm] working for him in the small intestine.'
When Your Child's Best Friend Is An AI
'Figments of his mind in one sense, of course, for he had shaped them...'
China's Drone Mothership Can Carry 100 Drones
'So the parent drone carries a spotter that it launches...'
Drones Recharge In Mid-Air Like Jets Refuel!
'...nurse drones that would cruise around dumping large amounts of power into randomly selected pods.'
Australian Authors Reject AI Training Of Llama
'It's done with a flip of the third joint of the tentacle on the down beat.'
Is China Mining Helium-3 On The Moon's Farside?
'...for months Grantline bores had dug into the cliff.'
Maybe It's Too Soon To Require Autonomous Mode
'I hope all those other cars are on automatic,' he said anxiously.
Is Agentic AI The Wrong Kind Of Smartness?
'It’s smart enough to go wrong in very complicated ways, but not smart enough to help us find out what’s wrong.'
Heat Waver - The First Ever Combo Solar Collector And Wind Turbine
'...like a spray of tulips mounted fanwise.'
Tesla 'Fleet Response Agents' Bolster FSD Autonomy
'You hate the whole idea that some bored drone pusher in a remote driving centre has got your life... in his hands.'
Mori3 Autonomous Shapeshifting Robot
'My homeland is being threatened by the Replicators. Thus far all attempts to stop them have failed.'
Tesla Seeks 'Tesla Robotaxi' And 'Robobus' Trademarks Ignoring Prior Art
'A robobus had just rolled up to the curb.'
Scary Grid Safety Robots
'The ultimate horror for our paranoid culture...'
Does AI Provide A Way Forward For Talk Therapy
'And there in the next room by the sofa sat a familiar suitcase, that of his psychiatrist Dr. Smile.'
