×

Announcing: Slashdot Deals - Explore geek apps, games, gadgets and more. (what is this?)

Thank you!

We are sorry to see you leave - Beta is different and we value the time you took to try it out. Before you decide to go, please take a look at some value-adds for Beta and learn more about it. Thank you for reading Slashdot, and for making the site better!

Comments

top

Quantum Physics Just Got Less Complicated

Khashishi Re:more simplifications and fewer cats, please (193 comments)

I think people are moving away from the Copenhagen interpretation to other interpretations such as consistent histories, decoherence, and many worlds. Bohmian interpretation is another option, but I find it inelegant and it doesn't hold too much sway.

Personally, I feel that consistent histories* is the best. In this interpretation, the cat is simply dead or alive. We don't know which until we check, but the cat's state didn't change when we opened the box. Note that whatever is enforcing consistency does not obey causality---the laws of quantum mechanics are essentially symmetric in time (more accurately CPT). In some sense, the future is "prewritten" though we have no way to measure it, and the current state of the universe is required to be consistent with the future state. So if the cat is dead in the future where the box is opened, it's already dead with the box closed.

I prefer the "block universe" depiction of the universe as a stationary 4D object, since it seems to be easiest to reconcile with relativity. Relativity of simultaneity makes no sense if the future isn't already written. We call this 4D universe object a history, and all the events in the history have to be consistent with laws of physics. It makes no difference if you think of the past causing the future or the future causing the past: they are just there and neither is created from the other. In the many worlds interpretation, every possible (e.g. consistent) history exists, but I think one is sufficient.

*I might be mistaken on what consistent histories is. My description is my personal interpretation, which might coincide with the definition of consistent histories.

2 days ago
top

Quantum Physics Just Got Less Complicated

Khashishi Re:Copenhagen interpretation != less complicated (193 comments)

There's no mysticism in quantum mechanics. It's pretty simple and mathematically consistent. All of the mysticism comes from popularizations of quantum mechanics. Bohmian mechanics is an unnecessary complicated interpretation of the same physical models.

2 days ago
top

The Dominant Life Form In the Cosmos Is Probably Superintelligent Robots

Khashishi Re:von Neumann probes (383 comments)

Of course, the engineering hurdles of a 100g probe sucking up Jupiter might be insurmountable...

2 days ago
top

The Dominant Life Form In the Cosmos Is Probably Superintelligent Robots

Khashishi Re:von Neumann probes (383 comments)

Travel time. The galaxy is some 100000 light years across. Using available fuels, what fraction of light speed can a probe hope to achieve? Let's suppose they run on DD fusion energy. The reaction gives off about 0.4% of the rest energy of the fuel, so a reasonable estimate of potentially attainable specific impulse is 0.004*c, assuming the probe is mostly fuel. Using Tsiolkovsky rocket equation, how fast can a probe reasonable reach? This depends on how much fuel the probe eats up at each stop. Assuming a probe mass of 100g, lets suppose the probe eats up a mass of Jupiter to create fuel at 10% efficiency at each stop. Well, that gives a delta v of ~.25*c. (Since there is a logarithm, the result doesn't change that much if we eat a sun or a saturn.) Useful cruise speed is half of that. Ok, that is still enough speed to conquer the galaxy in a few million years.

Multiplication factor: how many probes need to be sent out after each stop such that there is enough to spread over the galaxy in a reasonable time (there are ~10^11 stars). This is increased by the fact that many probes will fail to reach the destination for various reasons, so some redundancy is needed. We want to choose a multiplication factor such that the probes will cover the galaxy in approximately the same time as it takes for one probe to travel across the galaxy. Assume probes travel at 0.1*c, and it takes 10^6 years to traverse the galaxy. Let's assume a distance of 20 light years, or 200 travel years between stops. So we have 5000 stops in 10^6 years, so we need a multiplication factor of
f = 1.005 * redundancyFactor.
Ok, that's small enough to not make much difference in the resource needs.

Hmm, I intended to show that it was unfeasible, but it still looks like it might be physically possible, given extremely powerful probe technology.

2 days ago
top

Possible Dark Matter Signal Spotted

Khashishi Re:Whence Occam's Razor? (66 comments)

Keep in mind that what information comes out of journalists is typically 10 times more outrageous than any of the scientists' claims.

about two weeks ago
top

US Navy Authorizes Use of Laser In Combat

Khashishi Re:This might alienate anti-ISI* Muslims. (225 comments)

Silly rabbit, laws of war don't apply to dealing with unlawful combatants.

Also, lasers are fairly well collimated, so you'd have to aim directly at the person to blind them, and then I think they would have more problems than just blinding. You can also blind someone by shooting them in the eye with a gun, but for some reason it's ok as long as they have a good chance of dying outright.

about two weeks ago
top

NetHack: Still One of the Greatest Games Ever Written

Khashishi nethack has graphics (186 comments)

I know it's hip to play in text mode with vi keys, but you don't have to. Tile graphics mode has been around for a while now, and cursor keys have pretty much always been there. The article doesn't seem to indicate that.

about two weeks ago
top

NetHack: Still One of the Greatest Games Ever Written

Khashishi Re:Nethack needs an upgrade (186 comments)

Sounds like a decent premise for a new game inspired by Nethack. But it isn't Nethack, and multiplayer Nethack wouldn't work without massive changes.

about two weeks ago
top

Cisco Slaps Arista Networks With Suit For "Brazen" Patent Infringement

Khashishi Come on people (96 comments)

When I told you once, I told you a thousand times, and run Google translation by hand twice, and then run the grammar checker word.

If you copy a word for word, and then caught.

about two weeks ago
top

Uber Banned In Delhi After Taxi Driver Accused of Rape

Khashishi women are objects in India (180 comments)

I have a friend who got back from a trip to India. She was traveling in a group with some other women and one man. The taxi drivers would grab the women by the arms and force them in the car like luggage, and then talk with the man about where he would like to go (with his women). My friend had bruises on her arms from repeated grabs.

about two weeks ago
top

Displaced IT Workers Being Silenced

Khashishi silenced? (398 comments)

I'm having a bit of trouble feeling sorry for the 'victims' who chose to sell out here. If they are taking hush money, then they are complicit here.

about two weeks ago
top

The Ancestor of Humans Was an "Artist" 500,000 Years Ago

Khashishi unimpressed (59 comments)

I have higher expectations from proto-humans than some zigzag lines scratched into a shell. Come on, you really expect me to accept that as art?

about two weeks ago
top

Game Theory Analysis Shows How Evolution Favors Cooperation's Collapse

Khashishi Re:Academic Beclowining (213 comments)

Not (just) a perfectly logical person, but a perfectly logical selfish person. Altruism perplexed game theorists for years.

about three weeks ago
top

Game Theory Analysis Shows How Evolution Favors Cooperation's Collapse

Khashishi Re:Matters of Scale (213 comments)

Capitalism is about owning and trading things, not about making things. Certainly making things is a big part of owning them, and is a big drive of the capitalist model, but it is not a defining feature, as all societies make things. A defining feature is owning and trading things that are not (human) made, such as land, water rights, and the electromagnetic spectrum.

about three weeks ago
top

Montana Lawmakers Propose 85 Mph Speed Limit On Interstates

Khashishi Re:Federal Funding is not contingent on speed limi (525 comments)

As far as hitting wandering creatures goes, there is no real-world difference (in either chance or damages caused) between driving 60mph and 85mph

That statement goes against common sense and needs to be backed up with something.

about three weeks ago
top

Researchers Say the Tech Worker Shortage Doesn't Really Exist

Khashishi Re:The Same Game (454 comments)

Perhaps the solution isn't to pay workers more, but to pay CEOs less.

about a month ago
top

Laser Creates Quantum Whirlpool

Khashishi Re:I thought the distinction was arbitrary already (59 comments)

There are two types of mass: inertial mass and gravitational mass. As far as we know, these two are equivalent.
Inertial mass is the resistance to motion (change in velocity). In Newtonian terms, F = ma. In special relativity, F = dp/dt = d(gamma*m*v)/dt
So, you can define mass as long as you can define a velocity and acceleration.

Gravitational mass is associated with gravity. In Newtonian physics, F = -G*m1*m2/r^2. In general relativity, gravitational mass is equivalent to rest energy. Gravity is given by Einstein's field equations which depend on the stress-energy tensor, which is a 4x4 matrix. The [0,0] element of the matrix is the rest energy density, which is the gravitational mass density/c^2.

about a month ago
top

Laser Creates Quantum Whirlpool

Khashishi Re:I thought the distinction was arbitrary already (59 comments)

Unfortunately, the term matter isn't universally agreed upon. Let's look at the definitions in wikipedia:
1. Does it have mass and volume (occupies space)? A phonon has mass, and maybe has volume, but doesn't 'occupy space' because it is a boson.
2. relativity, has rest mass? Phonons don't fit the equation E^2 = m^2 c^4 + p^2 c^2, because they have nonlinear dispersion equations, so it doesn't really make too much sense to talk about them at rest. They aren't Lorentz invariant, since they depend on the velocity of the material they are traveling through.
3. Is it made of atoms. Phonons are not made of atoms.
4. Is it made of electrons and baryons. no.
5. Is it made of quarks and leptons? No

about a month ago
top

Laser Creates Quantum Whirlpool

Khashishi Re:I thought the distinction was arbitrary already (59 comments)

The term mass, without additional qualifications, means rest mass. Unusual definitions of mass ought to be clearly labeled, such as relativistic mass.

about a month ago

Submissions

top

Hackers steal 2 million tonnes of EU carbon credit

Khashishi Khashishi writes  |  more than 3 years ago

Khashishi (775369) writes "Taking advantage of the lax security systems in place, hackers stole some 475000 European Union carbon Allowances on 10 Jan through a variety of phishing attacks. The European Commission has closed the trading on 19 Jan, until at least 26 Jan, in order to beef up security measures. Is it a political statement, or just greed, that drove this act?"
Link to Original Source
top

Elan sues Apple over touchscreen patents

Khashishi Khashishi writes  |  more than 5 years ago

Khashishi (775369) writes ""TAIPEI (Reuters) — Taiwan chip designer Elan Microelectronics is suing Apple in the United States for what is says is infringement of two of its touchscreen technology patents by the MacBook, iPhone and iPod Touch.""
Link to Original Source
top

Giuliani predicts deadly earthquake, censored

Khashishi Khashishi writes  |  more than 5 years ago

Khashishi (775369) writes "Seismologist Giampaolo Giuliani claims to have predicted the deadly earthquake in L'Aquila, Italy, that killed at least 92 people. His attempts at warning the public were reported to the authorities and his warnings were censored to prevent public panic.

It must be noted that accurate earthquake prediction is not well-established within the science community, so what is the government's proper response?"

Link to Original Source
top

Supreme Court to rule on TV censorship

Khashishi Khashishi writes  |  more than 6 years ago

Khashishi (775369) writes "LA times and Associated Press report that the FCC v. Fox Television Stations case is being heard in the Supreme Court. The FCC policy would impose a heavy fine on use of "indecent" words on broadcast television, which Fox and others are claiming is a violation of free speech. The case was appealed after being ruled in Fox's favor in a federal appeals court in New York. Chief Justice John G. Roberts Jr. and Justice Antonin Scalia support the FCC policy of censorship."
Link to Original Source

Journals

Khashishi has no journal entries.

Slashdot Login

Need an Account?

Forgot your password?