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SETI (Search For Extraterrestrial Intelligence): Compendium / Miscellaneous

Those gold records were bolted to the outside of the spacecraft, so they've probably got lots of micrometeor scars and they're covered in interstellar dust. Not much can be extracted from a record after that.
OK, the playing side was facing the spaceship to protect the surface, but micrometeors can go straight through.


At least they weren't CD's. They's be screwed as soon as they were taken out their cases.
 
Didn't know where to put this:

Lots of buzz around this. Russian cosmonaut Anton Shkaplerov took routine samples from the outside of the International Space Station during a spacewalk. These samples were analyzed and found to contain bacteria that must have come from somewhere other than Earth or the ISS itself. "Bacteria that had not been there during the launch of the ISS module were found on the swabs," Mr. Shkaplerov told TASS Russian News Agency. "So they have flown from somewhere in space and settled on the outside hull." He made it clear that "it seems, there is no danger," and that scientists are doing more work to find out what they are. The Independent writes, "Finding bacteria that came from somewhere other than Earth would be one of the biggest breakthroughs in the history of science -- but much more must be done before such a claim is made."
 
Didn't know where to put this:

Lots of buzz around this. Russian cosmonaut Anton Shkaplerov took routine samples from the outside of the International Space Station during a spacewalk. These samples were analyzed and found to contain bacteria that must have come from somewhere other than Earth or the ISS itself. "Bacteria that had not been there during the launch of the ISS module were found on the swabs," Mr. Shkaplerov told TASS Russian News Agency. "So they have flown from somewhere in space and settled on the outside hull." He made it clear that "it seems, there is no danger," and that scientists are doing more work to find out what they are. The Independent writes, "Finding bacteria that came from somewhere other than Earth would be one of the biggest breakthroughs in the history of science -- but much more must be done before such a claim is made."
Excerpt C&P'd from tjhe article

Earlier this year, Russian scientists announced that the "Test" experiments had found a range of different organisms that had been brought up from Earth and seemed to be surviving by clinging onto the ISS's hull. They included plankton and bacteria that had been pulled up by a phenomenon that lifts micro-organisms up into the heights of the atmosphere.

How can Anton Shkaplerov be certain that this is not what happened?

Note please, that I am certain of anything at this point, but terrestrial contamination must be ruled out and from the part I quoted, I gather that this has not been done.

If it is not terrestrial in origin, it will indeed be a very major discovery.
 
Didn't know where to put this:

Lots of buzz around this. Russian cosmonaut Anton Shkaplerov took routine samples from the outside of the International Space Station during a spacewalk. These samples were analyzed and found to contain bacteria that must have come from somewhere other than Earth or the ISS itself. "Bacteria that had not been there during the launch of the ISS module were found on the swabs," Mr. Shkaplerov told TASS Russian News Agency. "So they have flown from somewhere in space and settled on the outside hull."
There is a school of astrobiology that holds that any bacteria found in low Earth orbit must have come from outer space, because there is 'no mechanism' that could lift them from Earth. Even if the bacteria are identical to Earth organisms, they 'must' have come from elsewhere. My daughter was taught by a lecturer that holds to this particular paradigm.

There is only one thing wrong with this idea - it is garbage. In low Earth orbit you are a few hundred kilometres from a massive blue planet that fills half the sky, and which is full of Earth-like bacteria. The next nearest possible source for such life is hundreds of thousands of kilometres away, and is effectively sterile. Where do you think these bacteria come from?
 
It's always 'twenty, twenty five years' down the road. No matter what it is.

INT21
 
My contention is that a 'sufficiently advanced' alien civilisation would last much longer than 100,000 years. The fact that few, or none, appear to have done so is a source of puzzlement.
 
Maybe there are but they have been studying our planet and think we may flood them with migrants. So they are keeping quiet.

INT21
 
There are a number of theories about what could be causing them.
They include a neutron star with a very strong magnetic field that is spinning very rapidly, two neutron stars merging together, and, among a minority of observers, some form of alien spaceship.
Let's examine the 'some form of alien spaceship' option for a bit. This might seem fantastical, but in fact it is one of the more sensible forms of interstellar propulsion available. If we assume that alien civilisations want to travel between the stars, but they can't find any magical 'warp drives' or 'wormholes', then they would be stuck with using real-life tech. What options are there?

Rocketry would be very problematic- to get a rocket up to interstellar speeds you'd need a fuel tank about 90 times as big as the payload, even using antimatter propulsion. The problem is that you have to accelerate the fuel and propellant in a rocket as well as the payload, which makes the system very inefficient. What we need is a system where the propellant and fuel are external to the rocket, so that the ship doesn't have to carry it along. The best option is beamed propulsion.

A beam of particles carrying momentum would be aimed at the back of the spacecraft, pushing it along; this allows the spacecraft to be very lightweight as it basically carries no fuel. The spacecraft could be shaped roughly like a kite or parachute. Some speculative designs of beam-propulsion use radio-waves or microwaves to propel a very large rectenna-like grid; this may be what we are seeing.
 
..A beam of particles carrying momentum would be aimed at the back of the spacecraft, pushing it along; this allows the spacecraft to be very lightweight as it basically carries no fuel. ..

So, a form of Solar Sail.

How does it slow down at it's destination ?

INT21.
 
..A beam of particles carrying momentum would be aimed at the back of the spacecraft, pushing it along; this allows the spacecraft to be very lightweight as it basically carries no fuel. ..

So, a form of Solar Sail.

How does it slow down at it's destination ?

INT21.
Good point that. Turn the sail round and make sure you're pointed at star?
 
Let's examine the 'some form of alien spaceship' option for a bit. This might seem fantastical, but in fact it is one of the more sensible forms of interstellar propulsion available. If we assume that alien civilisations want to travel between the stars, but they can't find any magical 'warp drives' or 'wormholes', then they would be stuck with using real-life tech. What options are there?

Rocketry would be very problematic- to get a rocket up to interstellar speeds you'd need a fuel tank about 90 times as big as the payload, even using antimatter propulsion. The problem is that you have to accelerate the fuel and propellant in a rocket as well as the payload, which makes the system very inefficient. What we need is a system where the propellant and fuel are external to the rocket, so that the ship doesn't have to carry it along. The best option is beamed propulsion.

A beam of particles carrying momentum would be aimed at the back of the spacecraft, pushing it along; this allows the spacecraft to be very lightweight as it basically carries no fuel. The spacecraft could be shaped roughly like a kite or parachute. Some speculative designs of beam-propulsion use radio-waves or microwaves to propel a very large rectenna-like grid; this may be what we are seeing.
The only (big) problem with that (if it worked) is that the spacecraft would have to fly in a dead straight line, all the way.
 
I think you would need to have a star of equal or greater particle output than the super laser that was pushing you away from your home planet..
Even if it was equal, you would need to start the deceleration at the halfway point in the trip.

Clearly you would want to accelerate to as high a velocity as possible to reduce the journey time to a minimum. If it took you, say, five years to get up to speed, it will take you five years to bleed off the speed at the end.

The other option is to have some conventional fuel and rocket system (or something as yet unknown) but only use it to slow down.

Just hope that the motor will fire up after years of not being used. Or you are in for a very long trip.

Pack lots of sandwiches.

INT21
 
...The only (big) problem with that (if it worked) is that the spacecraft would have to fly in a dead straight line, all the way.

Maybe not such a problem. But you would need to know where the destination planet would be at the calculated time of arrival.

Then you would be pushed by the beam in a straight line. A bit like 'aiming-off' in archery to allow for the cross wind.

Also the home planet would have to keep this high power laser running right up to the time you didn't need it. Five years in the example.

Celestial mechanics was never my strong point.

Isn't there a Solar Sail experiment being planned at the moment ?
 
I'd like to see the spaceship that could survive a beam that is detectable from billions of light years away.
 
I'd like to see the electricity bill for the laser.
 
I don't think the light beam propulsion is viable at all.
 
If 'they' are out there.....and many think 'they' have already been here...why haven't 'they' openly contacted us?
Some food for thought (other than the Prime Directive excuse...)...though I don't necessarily subscribe to either idea.
https://en.wikipedia.org/wiki/Fermi_paradox
 
..I don't think the light beam propulsion is viable at all...

It's probably viable for sending deep space probes out on years long very slow acceleration.

I doubt it can be used for space exploration though.

INT21.
 
Dr wu,

..why haven't 'they' openly contacted us? ..

Some people on Casebook would say they have ;)

Darn space Brothers, their everywhere.

INT21.

Ah well, going down stairs to watch the first of the new series of 'Death in Paradise'.

Catch y'all later.
 
Dr wu,

..why haven't 'they' openly contacted us? ..

Some people on Casebook would say they have ;)

Darn space Brothers, their everywhere.

INT21.

Ah well, going down stairs to watch the first of the new series of 'Death in Paradise'.

Catch y'all later.
Well...the people on Casebook aren't all playing with a full deck.
;)
No...getting serious for a moment...I meant openly regarding govts, etc..on a global level.....not abducting people and probing them.

ps: I watched the first 2 seasons of Death years ago...for some reason It didn't interest me after that.
 
2nd series was the best.

This new one seems like a bit of a space filler.

INT21.
 
I'd like to see the spaceship that could survive a beam that is detectable from billions of light years away.
There are two problems with beam propulsion, and this is one of them. The energy of the beam when it hits the ship would need to be equal to the energy that a rocket would have produced, if the ship had been propelled by a rocket; this allows the craft to accelerate exactly as if it were carring an inexhaustible supply of fuel. So the beam needs to be powerful enough to supply this energy at a distance. Because of the difficulty in focusing such a beam at a long distance, the beam would spread out and a significant fraction of the beam would miss the ship- this is what we might be detecting. An artificially focused beam of this kind might be detectable at millions of light years, depending on the focusing mechanism. But we'd need to be extremely lucky to detect suct a beam (unless they are very, very common).
 
.
How does it slow down at it's destination ?
And this is the second problem. Robert Forward (who was a big proponent of beamed propulsion) suggested sending two sails, the first one designed to double as a mirror which could then slow the second one down. This would require a very powerful, very tightly focused beam, which would be effective at interstellar distances - and which should be detectable at multi-million light-year distances. But there are a number of severe logistical problems with such a beam. Another thing to note is that a beam of this strength and accuracy would make a fantastically destructive weapon.
D001FA02.GIF
 
I'd like to see the electricity bill for the laser.
It would be very, very large. Charlie Stross has calculated that sending a payload the size of a Volkswagen to Alpha Centauri would cost the entire electricity budget of the Earth for a year. But remember that this is the most efficient way of doing it- to send a rocket, you'd have to accelerate the fuel and propellant as well, multiplying the total energy requirements by many orders of magnitude.
 
So at least we can agree that 'they' if they even exist and if they are interstellar travelers, don't use Solar Sails.

Back to the drawing board.

INT21
 
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