Tau Ceti's planets nearest around single, Sun-like star

BBC ^ | 19 December 2012 Last updated at 00:32 ET | Staff

[Red Badger]

The nearest single Sun-like star to the Earth hosts five planets - one of which is in the "habitable zone" where liquid water can exist, astronomers say.

Tau Ceti's planetary quintet - reported in an online paper that will appear in Astronomy and Astrophysics - was found in existing planet-hunting data.

The study's refined methods of sifting through data should help find even more far-flung worlds.

The star now joins Alpha Centauri as a nearby star known to host planets.

In both those cases, the planets were found not by spying them through a telescope but rather by measuring the subtle effects they have on their host stars' light. Continue reading the main story

In the gravitational dance of a planet around a star, the planet does most of the moving. But the star too is tugged slightly to and fro as the planet orbits, and these subtle movements of the star show up as subtle shifts in the colour of the star's light we see from Earth.

This "radial velocity" measurement is a tricky one; stars' light changes also for a range of other reasons, and requires picking out the specifically planetary component from all this "noise".

Now, Hugh Jones of the University of Hertfordshire and colleagues have refined their "noise modelling" in order to subtract it, and thereby see the smallest signals hiding in the data - starting with Tau Ceti.

[Red Badger]

An artist's impression shows the five-planet system; from there, our Sun appears in the constellation Bootes

[Red Badger]

exoplanet ping!...............

[struggle]

Hey folks, let’s solve FTL travel and build a rocket and get off this stupid planet already. Someone call Bob Lazar.

[struggle]

Hey folks, let’s solve FTL travel and build a rocket and get off this stupid planet already. Someone call Bob Lazar.

[Vaquero]

THIS IS CETI ALPHA FIVE! Ceti Alpha Six exploded six months after we were left here. The shock shifted the orbit of this planet and everything was laid waste. ‘Admiral’ Kirk never bothered to check on our progress. It was only the fact of my genetically-engineered intellect that allowed us to survive

[staytrue]

Does anyone remember where Khan (maker of Corinthian leather in Chrysler cars) is marooned ?

[Red Badger]

Space and space travel will not be conquered using rockets.
It will be done by Time Machines.......

[Mr. K]

I like Bob Lazaar

He does NOT sound like a lunatic- I have listened to him and he has never said anything incorrect about the physics (and I have a bachelors degree in physics)

They can find no record of him at the school he claims he attended, but no other school has a record of him either- yet he obviously has post-graduate education in Physics

He makes a lot of sense too- and they asked him things about groom lake like “where is the lunch room” and “what color tiles are in the bathroom” and he made drawings and consistantly explained things over and over.

You can’t make up stuff like that and keep it straight- he just sounds totally credible to me

[Red Badger]

http://www.e-reading.org.ua/chapter.php/82002/20/Azimov_-_Asimovs_Mysteries.html

[cripplecreek]

[Red Badger]

I think I’ve been there!.........of course all exoplanets tend to look alike after a while.......

[Vaquero]

see 5

[GonzoGOP]

This is interesting because Tau Ceti is close enough that an Orion drive probe could reach there in around four hundred years. Still not a fast run but when talking about interstellar travel this is about as far as you can go and still have any hope that the probe will still be functional when you get there. Dyson actually worked out the design for a ship that could get up to .033C using existing (1960s) technology.

I don't think there is any chance we would actually build or send send such a probe. First it would cost close to the US GNP to build the thing. Second the fuel for the engine would be several hundred thousand nuclear bombs. Finally a 400,000 ton Orion drive starship plays hell with the launch facilities.

[Red Badger]

To conquer interstellar space, first you must conquer time............

[allmendream]

According to Star Trek - most exoplanets look amazingly like Southern California!

And almost all aliens look like humans but with a small useless facial variation and a single exaggerated social or biological feature.

[GonzoGOP]

To conquer interstellar space, first you must conquer time............

Is patience a way of conquering time? A large asteroid ark with an Oriion or nuclear salt-water drive could transport people to another star. Of course the people who arrive would be the great great grandchildren of the people who departed. However when you consider that by the time we would attempt such an adventure humanity would have been living in big orbital space colonies like the O'Neill cylinder and Bernal sphere. So for them the idea of living their lives in an artificial environment would not seem at all strange.

[gymbeau]

I think Tau Ceti featured in Barbarella, but I can’t remember much more about it than Hanoi Jane’s naked breasts.

Cheers,
Jim

[mdmathis6]

I don’t know how the nuclear explosion thing would work in space without air or medium to get super heated to “push” the ship up to speed. The orion drive uses sequential explosions of Nukes to ‘push’ the ship but with nothing to heat up in space to create a shock wave to further propel the ship, how dose such a drive work? Is it the quick flashes of light and radiation from the nuke fireballs pushing against the shieded drive plate over a period of years even decades, that they expect to provide the momentum?

Drive lasers and concentrated beams of charged particles operating continuously over months might be a better bet as while the initial accelation forces are small, overtime the craft will attain enormous velocities at “c” or close to it since acceleration, while tiny in force is continous until the whole craft is traveling as fast as the photons leaving the drive engines.

[GonzoGOP]

I don’t know how the nuclear explosion thing would work in space without air or medium to get super heated to “push” the ship up to speed.

These are not your run of the mill H-bombs. The bomb's geometry and materials focused the X-rays and plasma from the core of nuclear explosive to hit the reaction mass. A bomb with a cylinder of reaction mass expands into a flat, disk-shaped wave of plasma when it explodes. A bomb with a disk-shaped reaction mass expands into a far more efficient cigar-shaped wave of plasma debris. The cigar shape focuses much of the plasma to impinge onto the pusher-plate.

In effect each bomb would be a nuclear shaped charge. The propellant medium is partially provided by the material of the explosive itself converted to extremely hot plasma by the explosion. However the majority of the plasma is created by a cone of plastic which not only is converted to plasma, but does not become radioactive like a metallic filler would. Some of the original designs used tungston because it gave more thrust, but it also would have been expensive and more importantly created a vast amount of fallout from the launch.

[GonzoGOP]

Drive lasers and concentrated beams of charged particles operating continuously over months might be a better bet as while the initial acceleration forces are small, overtime the craft will attain enormous velocities at “c” or close to it since acceleration, while tiny in force is continuous until the whole craft is traveling as fast as the photons leaving the drive engines.

There are two problems with the drive lasers. First you have to build them, and that isn't something we know how to do. They require vast amounts of orbital infrastructure (in contrast a city sized Orion could be surfaced launched if you can get it past the EPA). Finally in order to decelerate you need drive lasers on the other end.

Stopping an Orion wouldn't be easy either. Nuclear bombs have a use by date, and after a few hundred years they aren't going to go bang any more. So the ship would need to have some way of reprocessing the tritium pits used to detonate the bombs used for the deceleration phase. A NSW engine would work for deceleration. The problem with those isn't getting them going, it is keeping them under control. If any of the fuel leaks it immediately goes critical. When you remember that we are talking about a corrosive liquid that you need to store for four centuries the problem starts to become clear.

A beamed energy craft may be the answer to intersteller colonization as their top speed is vastly higher than a nuclear salt-water rocket or Orion drive. The top end is actually limited to less than .5 c because since the photon is only going at c it hits with less force as the ship goes faster and faster. In addition when the photon reflects off the sail it carries energy away with it. Still .5 c is a heck of a lot faster than the .035 c that is the limit for an Orion or NSW engine. Considering human life spans a 40 year trip is a lot more attractive than a 400 year trip. You also don't have to share your ship with a portable Chernobyl as you would with a NSW drive.

So when you find someplace you want to go send ahead a robot ship with a laser. Then when it is in place you send the colonists on a much faster light sail craft.