Posts Tagged ‘‘Revelation Space’’

Radio 4 Next Monday on Possible Extraterrestrial Life

March 11, 2020

Next Monday, 16th March 2020, at 11.00 AM, Radio 4’s Out of the Ordinary is covering the subject of what aliens are probably like. The programme, ‘Aliens Are the Size of Polar Bears (Probably), has this brief description in the Radio Times:

Jolyon Jenkins concludes his series by hearing from astronomer Fergus Simpson, who predicts that if aliens exist they will be living on small, dim planets in small populations, have big bodies and be technologically backward.

This looks like a different take on the question of intelligent extraterrestrial life. Way back in the 1990s some of the astronomers involved in the hunt for it, such as SETI’s Seth Shostak, considered that aliens, if they exist, would probably be small, the size of Labradors. It’s also been an assumption of the search for intelligent aliens that the universe is old enough for alien civilisations to have arisen many times over, colonising space. Simpson’s suggestion that the aliens, if they’re out there, are probably technologically backwards, sounds like a solution to the Fermi Paradox. This was first proposed by the Italian-American physicist, Enrico Fermi, and runs: if the universe is old enough to have produced intelligent aliens, then why haven’t we found any? There are several solutions to the problem. One is that they don’t actually exist. Others are that space travel may be difficult, or that aliens don’t feel any need to expand into space. Or that advanced, technological civilisations destroy themselves in catastrophes like nuclear wars before they move outward across the Galaxy. Another solution is that they’re there, but keeping very quiet in case there are other, malign intelligences out there intent on their extermination.

This last solution is explored by the SF writer Alistair Reynolds in his novels Revelation Space, Redemption Ark and Absolution Gap. In this trilogy, humanity has expanded into space, only to be threatened by an ancient extraterrestrial menace – the Inhibitors. This is a machine culture that exists solely to destroy spacetravelling civilisations. Their reason is that millions of years ago, the Galaxy suffered a prolonged series of devastating wars as different species moved out into the Galaxy to claim territory from their rivals. In order to prevent further such wars occurring, the Inhibitors embarked on a long-term campaign of eradicating such civilisations. They aren’t enemies of intelligent life per se. Indeed, the whole policy is in order to protect such life, provided it remains confined to its home planet or solar system. But once it moves out into interstellar space, it becomes a target for eradication. And the Inhibitors themselves are quiet, dormant and so undetectable, until they discover their next prey, and wake up.

If aliens do live on small, dim planets, then they’d be difficult to discover with present astronomical techniques. Planets are too small for telescopes to detect normally, as they’re lost in the glare of their star, although some may later be seen through extremely high-power telescopes using very advanced optical techniques. And the planets that have been the easiest to discover are large worlds orbiting close to their suns. They’ve been detected because their gravitational pull has caused their stars to wobble as they orbit around them. Small planets further out would exert less force, and so caused smaller wobbles that may be difficult to detect. And if they’re technologically backwards, we would not be able to detect signs of their industrial and other activities, like radio or television transmissions, for example. If spacefaring civilisations do exist, at least close to us, then we should have detected signs of them by now. There was a paper in the Journal of the British Interplanetary Society suggesting that a light sail used within 30 light years of Earth would produce so much gamma radiation that we would be able to detect it. The fact that we haven’t may mean that such civilisations don’t exist. Simpson’s suggestion for the possible nature of extraterrestrial life is therefore one solution to the problem of the Fermi Paradox.

Scientists Invent Ion-Driven ‘Star Trek’ Plane

November 23, 2018

This is a fascinating piece from yesterday’s I newspaper, for the 22nd November 2018. It reports that Dr. Steven Barrett and his team at MIT have built an airplane that flies through channeling air underneath its wings using electrically charged wires hung below them.

The article, by John von Radowitz, on page 13, reads

A revolutionary electronic aircraft propulsion system inspired by Star Trek has been tested on a working model for the first time.

The five-metre wingspan glider-like plane has no propellers, turbines or any other moving parts, and is completely silent.

Instead, an “ionic wind” of colliding electrically charged air molecules provides the thrust needed to make it fly.

In the tests, the battery-powered unmanned aircraft, that weighs just five pounds, managed sustained flights of 60m at an average height of just 0.47m.

But its inventors believe that, like the early experiments of the Wright brothers more than 100 years ago, such small beginnings will eventually transform the face of aviation.

In the near future, ion wind propulsion could be employed to power quiet drones, the team predicts.

Further down the line, the technology could be paired with more conventional propulsion systems to produce highly fuel-efficient hybrid passenger planes.

Lead researcher Dr. Steven Barret, from Massachusetts Institute of Technology (MIT) in the US, said: “This is the first-ever sustained flight of a plane with no moving parts in the propulsion system.

“This has potentially opened new and unexplored possibilities for aircraft which are quieter, mechanically simpler, and do not emit combustion emissions.”

He revealed that he was partly inspi9red by the TV sci-fi series Star Trek. He was especially impressed by the show’s futuristic shuttle crafts that skimmed through the air producing hardly any noise or exhaust. “This made me think, planes shouldn’t have propellers and turbines,” said Dr. Barrett.
“They should be more like the shuttles in
Star Trek that have just a blue glow and silently glide.

The test aircraft, described in the journal Nature, carries an array of thin wires strung beneath the front end of its wings. A high-voltage current passed through the wires strips negatively charged electrons from surrounding air molecules.

This produces a cloud of positively charged ionized air molecules that are attracted to another set of negatively charged wires at the back of the plane.

As they flow towards the negative charge, the ions collide millions of times with other air molecules, creating the thrust that pushes the aircraft forward.

The article also said that

Test flights were made across the gymnasium at MIT’s duPont Athletic Centre, the largest indoor space the scientists could find.

The article also carried this diagram of the aircraft and its engine.

The illustration is entitled ‘How It Works’, and shows picture of the plane, with an arrow saying ‘Battery in fuselage’. There’s also a diagram of the electrically charged particles and the wires connected to the battery that the plane uses instead of a conventional engine.

The illustration’s notes read

Thin wires are strung under the front of the wing and thicker wires under the rear. When connected to a high voltage battery they act as electrodes. The thin positive electrode takes negatively charged electrons from air molecules, creating positive ions. The ions are attracted to the negative electrode at the rear and, as they flow towards it, they collide with neutral air molecules, creating thrust.

The plane reminds of me of the atmospheric aircraft in one of Alistair Reynold’s SF novels, Revelation Space, which fly through heating up the air below them. The propulsion system’s also related to the nuclear electric propulsion used, or proposed, for some spacecraft. This also uses an electrically charged grating to channel and increase the thrust of charged particles generated by a nuclear reactor. As I understand it, the amount of thrust generated by this type of rocket engine is small, but because it’s constant it can eventually build up over time so that the craft is flying at quite considerable speed.

An ion-driven plane is a fascinating concept, though it won’t be powering passenger craft just yet. But you wonder how many UFO sightings will be generated by the experimental and prototype craft which will be designed and built after this.