Well, I grouped you in with the crowd that seem to think governments only spy on their own citizens.

But I still feel that this method of tracking gives too little data for the effort needed to execute it. Not to mention sneaking it in to a 3GPP standard with this express intent. Not saying that it's impossible, but it does seem far fetched.

Sure. If they know the IMSI of the mobiles that the protesters are using in advanced. This attack gives the TMSI of the device, which is a temporary identifier, and will change when the mobile roams outside of the current location area.

Then they need to set up compromised base stations all over the city if they want to track this protester, and I am sure that there are easier ways to go about that.

Yes, an obscure error message that can be used to differentiate one UE from another, if you have already used a compromised base station to sniff earlier sessions, and which will give you an indication if that UE is in the area of your transmitter or not sounds just like the sort of nefarious flaw that the Men in Black Illuminati would work into an international standard to spy on the tinfoil community.

As a comment above already mentioned, the operator knows where you are, with a lot more precision than this attack gives, and most of them will happily share this data with the authorities, especially if a judge has OK'd it. This will, by the way, also give you voice and text intercepts, should you need them.

Personally, I find the "coolest" example of where we can see relativity and time dilation in effect to be GPS! To quote this site:

Always nice to see someone else who keeps in touch with assembly :)

And I have used this sig since at least 2005, and possible longer, but my memory is getting a bit fuzzy...

But it's not, exactly. Unless you are using LTE, voice calls are still set up as if they were circuit switched, including allocating resources throughout the network. Only data calls are handled as pure packet switched best effort calls.

But the biggest reason for separating voice call costs is probably that if you are calling someone who uses a different operator, your operator needs to pay for the use of that network (weather mobile or land line). At least around here, calling someone who is using the same operator is usually free, but calling someone using another operator will cost you a per minute charge.

No, you are correct. VoLTE (Voice over LTE) for the 4G networks is a pure VoIP type setup, but for UMTS and GSM systems, it works a bit differently. Of course, the actual data will still be carried in either IP packets or ATM cells, but the setup of the call is different.

For UMTS systems (which I am most familiar with), all calls are divided into either the Packet Switched (PS) domain, or the Circuit Switched (CS) domain.

The PS domain is normally "best effort", and is used for all data calls (including any VoIP client running on the UE), and works pretty much as you expect an IP network to. It is possible to set up connections with certain requirements on minimum and average bit rates, but in general, you get what is available, and your allocation can shift over time.

The CS domain, on the other hand, behaves like the old telephony systems, and is primarily used for voice calls. When you set up your call, the resources needed to provide the requested sustained bit rates are allocated from your UE all the way to the receivers UE. If such resources can not be allocated, the call setup will be refused. If the resources are available, you should, theoretically, be able to keep your connection indefinitely, without quality degradation. In reality, of course, there are cases where your call will be dropped or reduce in quality (e.g. if the cell you are in is full, and someone makes an emergency call).

The slices were made in 1955. The scans were made recently.

In actual transmission costs the data is cheap, but operators put many billions per year into infrastructure upgrades, license costs and the like, so it's not like selling wireless data is free money for the operator.

But yes, it's a profitable business.

That is exactly right. Each cell tower has 2 - 6 cells, the borders of which are usually measured somewhat approximately by the operator. So they know which cell you are in, which tells them the rough area around the cell tower that you are in.

They also have the ability to measure round-trip time for signals sent to your phone, giving a rough estimate of the distance from the tower to you, inside your cell (this actually becomes less accurate when signal reflection is an issue).

Finally, the cell phone constantly measures _all_ cells it can find. Not just the ones belonging to your operator, but other operators as well, including (if the phone is capable) 2G, 3G and 4G cells. All this is reported back to the radio network controller to assist with handover decisions between cells, so your operator (and thus anyone else with enough authority) can access this information.

Indeed. I haven't touched an MMO for many, many years (since I stopped playing Ultima Online), but I am seriously considering giving this one a try.

May take up to 22 years?

It will guaranteed never take less than 22 years. Never mind that even getting close to c is a wild dream at this time.

But if you did manage to get close to the speed of light, the trip would take ~22 years from an earth point of view, but for the people on the ship/whatever, the trip will be quite short. If you actually hit c (never mind that it is physically impossible), the trip would be instantaneous from the point of view of the travelers.

A more realistic scenario, if we pour a lot of money into propulsion research, might be to fly away at 10% c. That would lead to a trip take takes 220 years in earth-time, or 198 years in ship-time. Not exactly an easy trip to plan.

I think your post was very well written, but I just wanted to comment on this in particular:

This, for me, is the biggest "problem" with Slashdot today. A huge amount of posters go in for that "+5 Funny" post, and apart from articles on politics, it's hard to find much good discussion going on.

I remember when I first started reading Slashdot back in early 2000 (or could it have been late 1990's?). I used to save threads because they contained so much interesting information (especially about physics and astronomy). Maybe it's just me remembering things better than they actually were...

But seriously, try reading the comments for any article that has to do with Uranus. Or lasers. Or sharks. Or Russia. Or in fact most any article. "Funny" posts everywhere. The remainder is blatant trolls, whining about the EU/US, politicians, lawyers or accusing everyone of being employed by the company that they dared write anything positive about.

And on top that you have people modding funny comments as Insightful or Interesting, because "Funny mod doesn't give karma"

Thanks for the explanation. I must admit my particle physics is very weak (not that that will stop me from commenting..)

I can not remember ever having seen an example where an annihilation produces anything other than photons, but I guess it's usually simplified that way for us laymen. Anyways, it makes sense now that I think about it.

I think you are confusing "massive" and "strongly interacting".

The whole point of "dark matter" is that it interacts gravitationally with ordinary matter, but almost never in any other way. So, having massive dark matter particles means a higher gravitational field around them, but nothing else.

I agree with your other point however, that having two of these dark matter particles annihilating directly to a electron/positron pair seems.. strange. Normal matter/antimatter annihilations always (afaik) produce "energy" (i.e. photons).

But a good thing is that if annihilation of dark matter produces electron/positron pairs, then smashing electrons and positrons together in an accelerator should produce dark matter.