On January 10 2016 03:55 Epishade wrote: What will happen to video evidence when a program such as Photoshop is released that would allow you to seamlessly alter videos as to be unable to discern real life from CGI content?
You mean in a courtroom? That's a good question, although plenty of things used as case evidence are already bullshit, such as the unreliability of eyewitness testimony, the unreliability of lie detector tests, etc. I'm not sure if tampered video evidence will make a significant difference.
Even fingerprints are basically interpreted by the technician based upon outside information you give him. The issues with evidence accepted by courts are somewhat horrifying. Once a narrative has been built the evidence is shaped by it.
How? All a fingerprints analyst does is to compare a given fingerprint with another fingerprint coming from a database. Sounds pretty straight-forward to me.
On January 10 2016 03:55 Epishade wrote: What will happen to video evidence when a program such as Photoshop is released that would allow you to seamlessly alter videos as to be unable to discern real life from CGI content?
You mean in a courtroom? That's a good question, although plenty of things used as case evidence are already bullshit, such as the unreliability of eyewitness testimony, the unreliability of lie detector tests, etc. I'm not sure if tampered video evidence will make a significant difference.
Even fingerprints are basically interpreted by the technician based upon outside information you give him. The issues with evidence accepted by courts are somewhat horrifying. Once a narrative has been built the evidence is shaped by it.
How? All a fingerprints analyst does is to compare a given fingerprint with another fingerprint coming from a database. Sounds pretty straight-forward to me.
Like many of the techniques used by law enforcement, it's not as reliable as they like to pretend.
On January 10 2016 03:55 Epishade wrote: What will happen to video evidence when a program such as Photoshop is released that would allow you to seamlessly alter videos as to be unable to discern real life from CGI content?
You mean in a courtroom? That's a good question, although plenty of things used as case evidence are already bullshit, such as the unreliability of eyewitness testimony, the unreliability of lie detector tests, etc. I'm not sure if tampered video evidence will make a significant difference.
Even fingerprints are basically interpreted by the technician based upon outside information you give him. The issues with evidence accepted by courts are somewhat horrifying. Once a narrative has been built the evidence is shaped by it.
How? All a fingerprints analyst does is to compare a given fingerprint with another fingerprint coming from a database. Sounds pretty straight-forward to me.
It's not that simple. They're also given context and a suspect in mind to test against. You're right that it should be as simple as "does this contextless fingerprint match any in our database" but like any science it is limited by the scientists themselves. In trials the same fingerprints will be ruled out by some technicians and identified as the suspect by others based on nothing but the context also provided.
There are? Pretty much all of our long-range stuff has nuclear reactors on board. A lot of stuff in space has ion thrusters for propulsion, which once again uses the power from a nuclear reactor.
If you mean "blows up nukes behind the ship to propel it", you might want to take a look into "Project Orion". The main reasons are a) bad publicity and b) international laws against nuclear weapons in orbit.
On January 10 2016 03:55 Epishade wrote: What will happen to video evidence when a program such as Photoshop is released that would allow you to seamlessly alter videos as to be unable to discern real life from CGI content?
You mean in a courtroom? That's a good question, although plenty of things used as case evidence are already bullshit, such as the unreliability of eyewitness testimony, the unreliability of lie detector tests, etc. I'm not sure if tampered video evidence will make a significant difference.
Even fingerprints are basically interpreted by the technician based upon outside information you give him. The issues with evidence accepted by courts are somewhat horrifying. Once a narrative has been built the evidence is shaped by it.
How? All a fingerprints analyst does is to compare a given fingerprint with another fingerprint coming from a database. Sounds pretty straight-forward to me.
Like many of the techniques used by law enforcement, it's not as reliable as they like to pretend.
On January 10 2016 12:27 Simberto wrote: There are? Pretty much all of our long-range stuff has nuclear reactors on board. A lot of stuff in space has ion thrusters for propulsion, which once again uses the power from a nuclear reactor.
If you mean "blows up nukes behind the ship to propel it", you might want to take a look into "Project Orion". The main reasons are a) bad publicity and b) international laws against nuclear weapons in orbit.
nah, i meant why isnt nuclear powered ships gonna be feasible for interstellar travel. Not enough acceleration? why do we really on gravitational sling shots and solar panels for the probes. genuine question.
On January 10 2016 12:27 Simberto wrote: There are? Pretty much all of our long-range stuff has nuclear reactors on board. A lot of stuff in space has ion thrusters for propulsion, which once again uses the power from a nuclear reactor.
If you mean "blows up nukes behind the ship to propel it", you might want to take a look into "Project Orion". The main reasons are a) bad publicity and b) international laws against nuclear weapons in orbit.
nah, i meant why isnt nuclear powered ships gonna be feasible for interstellar travel. Not enough acceleration? why do we really on gravitational sling shots and solar panels for the probes. genuine question.
I've read some stuff and heard more about solar sails and eliminating or reducing carrying fuel from space craft all together or at least limiting it to maneuvering.
As to why there isn't one yet, I would imagine it has to do with not having a space craft that doesn't need to come back down. We still need that massive payload to get into orbit. I suspect that when/if we have some ships that are basically at the ISS crew's disposal that would be an option. Simberto raises a good point as well though, treaties about nuclear material in man made space craft could write out the option for the time being.
On January 10 2016 03:55 Epishade wrote: What will happen to video evidence when a program such as Photoshop is released that would allow you to seamlessly alter videos as to be unable to discern real life from CGI content?
You mean in a courtroom? That's a good question, although plenty of things used as case evidence are already bullshit, such as the unreliability of eyewitness testimony, the unreliability of lie detector tests, etc. I'm not sure if tampered video evidence will make a significant difference.
Even fingerprints are basically interpreted by the technician based upon outside information you give him. The issues with evidence accepted by courts are somewhat horrifying. Once a narrative has been built the evidence is shaped by it.
How? All a fingerprints analyst does is to compare a given fingerprint with another fingerprint coming from a database. Sounds pretty straight-forward to me.
It's not that simple. They're also given context and a suspect in mind to test against. You're right that it should be as simple as "does this contextless fingerprint match any in our database" but like any science it is limited by the scientists themselves. In trials the same fingerprints will be ruled out by some technicians and identified as the suspect by others based on nothing but the context also provided.
Easy case (matching of a full fingerprint against a database) is done through automated systems (regardless of context) and is reliable enough (usually guaranteed to have false matches les than 0,1% of the time or something like that). Experts may be asked to confirm the match on screen display, but it's no big deal. There is never an issue on a case of this type.
Issues arise when scene fingerprint quality is low. On a crime scene, you will rarely have a bloody hand squarely set on a flat surface or a glass that has been neetly picked up and set down. What the automated system works with are partial fingerprints, distorted by the way finger was pressed, degraded by movement (if finger slipped), and representing only part of the finger.
In those cases, the AFIS are usually configured to display a given number of candidates (say 10), with matching scores. It's up to the expert at his desk to make a decision based on a low quality partial image and the reference print of those candidates. The decision is then subject to human interpretation and may lead to errors.
On January 10 2016 12:27 Simberto wrote: There are? Pretty much all of our long-range stuff has nuclear reactors on board. A lot of stuff in space has ion thrusters for propulsion, which once again uses the power from a nuclear reactor.
If you mean "blows up nukes behind the ship to propel it", you might want to take a look into "Project Orion". The main reasons are a) bad publicity and b) international laws against nuclear weapons in orbit.
Nuclear fission reactors (cooled chain reaction) in space have been very rare (mainly USSR with TOPAZ reactors during cold war days). What we use commonly are nuclear generators (using the heat of natural radioactive decay in a radioactive mass).
Usual power source for satellite ion thrusters are solar panels, not nuclear generators or reactors.
On January 10 2016 12:27 Simberto wrote: There are? Pretty much all of our long-range stuff has nuclear reactors on board. A lot of stuff in space has ion thrusters for propulsion, which once again uses the power from a nuclear reactor.
If you mean "blows up nukes behind the ship to propel it", you might want to take a look into "Project Orion". The main reasons are a) bad publicity and b) international laws against nuclear weapons in orbit.
Nuclear fission reactors (cooled chain reaction) in space have been very rare (mainly USSR with TOPAZ reactors during cold war days). What we use commonly are nuclear generators (using the heat of natural radioactive decay in a radioactive mass).
Usual power source for satellite ion thrusters are solar panels, not nuclear generators or reactors.
True, i was talking about the heat generators on things like the Voyager probes.
On January 10 2016 12:27 Simberto wrote: There are? Pretty much all of our long-range stuff has nuclear reactors on board. A lot of stuff in space has ion thrusters for propulsion, which once again uses the power from a nuclear reactor.
If you mean "blows up nukes behind the ship to propel it", you might want to take a look into "Project Orion". The main reasons are a) bad publicity and b) international laws against nuclear weapons in orbit.
nah, i meant why isnt nuclear powered ships gonna be feasible for interstellar travel. Not enough acceleration? why do we really on gravitational sling shots and solar panels for the probes. genuine question.
You are conflating things. Gravitational Slingshots are routes, not engines. And they are amazing because they give you Delta V for free. That is really good if you want to do stuff in space, and until we develop engines that are so overpowered that they have Delta V to spare, using Gravitational Slingshots is a good idea. Solar panels are also not engines, but a power source (It is where the probe gets its electricity from). Some probes use Electricity for propulsion via Ion Thrusters.
Solar panels are also not the same as solar sails, which someone else talked about earlier, which use photon pressure from the sun to accelerate a craft. Both have the problem that the further away from the sun you get, the less sunlight there is, making them less effective with the square of the distance to the sun (And thus probably not very good for interstellar missions)
So far, we are not doing ANYTHING interstellar, all we do is stuff in the solar system (Ignore the "Voyager has left the solar system" stuff that comes up every few years, they are still insanely far away from any other solar system, so we can safely talk about us not doing any interstellar missions). And for interstellar missions, acceleration is usually not very relevant, as you have enough time to accelerate anyways because everything will take ages no matter what you do with current tech. What you care about is fuel efficiency, since you can't really refuel in space and thus you have to take every gram of fuel with you from the start (And also spend more fuel to speed up that fuel, etc...)
And as far as i know, the best (theoretical) engine for interstellar travel that people have come up with so far is still the Orion craft, which i mentioned in my previous post. Which is based on having really big suspension systems, and then blowing up nuclear bombs behind you to accelerate. Theoretically, such a ship, build mostly with tech that was available in the 60s, could be able to reach Alpha Centaury in ~ a hundred years +-, which is some orders of magnitude better than anything else we have come up with so far.
Okay, I get your point. Assuming interplanetary (is that even a word) travel, wouldnt nuclear powered ships be better? Why do we have to crash probes if we can have them orbit or travel in-between planets?
We crash probes when they are done with their job, because it would be very expensive to design them to land anywhere, and we don't want lots of trash in orbit that crashes into other stuff we launch. Any time you travel somewhere, that uses up some fuel. It is expensive to put stuff (including fuel) into space.
Where we get our energy from doesn't help with this either, because so far the only way we have found to propel stuff in space is to throw stuff out the back of the craft really fast. So whenever you want to do any maneuver in space, you need to throw something out the back, all of which you needed to take into space to begin with, and you only have limited amounts of stuff to throw out with on your probes, which means at some point you want to trash them. And at that point it is probably useful if there is not a lot of radioactive stuff on them.
Do we really have the tech to build a nucledar-bomb-ship? The theory is sounds I guess, but the materials to build a ship that will have nukes going off behind it all the time, but not break?
Even if we had, it must be ridiculously expensive, and you probably need ships of a certain size, as you can't build tiny atomic bombs (right?). The technology simply isn't viable as it is now. Much cheaper and easier to use chemical fuel.
I also don't understand why we would change the trajectories if we change fuel?
As far as i know, the tech was (mostly) there in the 60s, albeit only theoretically. Apparently you could build nuclear bombs down to 0.03 kilotons or equal to ~30 tons of TNT in the 60s. Lots of fascinating information here.
Basically, Orion craft are cheaper and more effective than chemical crafts, but you really don't want to blow up lots of nukes in the atmosphere to launch something, so you would probably want to at least launch it chemically into orbit. And currently there is a ban on nuclear explosions in space which prevents any research in orion craft, which makes a lot of nerds like me very sad, because Orion seems like the only practical way of interstellar travel we have with current technology, and going to other stars is amazing.
At some point, if you have excess Delta-V, you could change the trajectory of an interstellar mission because you want to save time. Doing gravity assists at Jupiter costs time, but saves fuel. If time is more important than fuel, you might skip them.
On January 12 2016 00:58 SoSexy wrote: Any tips on what to do on VERY long flights? Reading, music, etc. but when u have something like 18 hours on a plane I dunno :S
Depending on the airline, most will have you squared away with some decent videos to watch. When I came back from China this Summer, unable to sleep for whatever reason, I stayed up finished The Martian by Andy Weir and watched the Jinx in its entirety.
In flight entertainment is pretty decent these days, otherwise sleep aids can be helpful to pass some chunk of time if you have trouble like I do sleeping on a flight.
Otherwise, just be sure to get up once in a while 18 hours completely stationary is a recipe for an emergency landing.
EPT
