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The Dot in .mars
Skynet writes "CNN has a really cool interview with Chad Edwards, manager of the Mars Network Office, about NASA's desire to improve telecommunications to and from Mars. They plan to get a 1MBps link up by 2007. They also discuss the possibility of multiple Internets spread throughout solar system, all interconnected. Very interesting discussion."
d00d! w3 0wn j00! @ll y0r r0v3r R b3l0ng 2 us!1! PH34R 0UR M4D SK1LLZ!!!!
Basically, latency and bandwidth have nothing to do with each other. The reason we perceive latency to affect bandwidth on the internet is because the internet requires acknoledgements for every n packets. That means that if you have a high latency, it'll take awhile for the ACK to come back and thus you slow down the transmission. If you design a protocol that takes into account that an ACK takes 8 minutes to arrive, you can get full bandwidth at high latency. You could even use TCP, if you expand the sliding window to allow it to send, say, 16 minutes worth of packets without requiring an ACK. It would suck for telnet, but streaming data (which is what NASA wants to do) would be fine.
Go Badgers! -- #include "std/disclaimer.h"
Just imagine being on Mars and being unable to read /. for a whole week because Earth and Mars are on opposite sides of the sun. Will you be tough enough to survive it?
#naabhaprzrag, #sverubfr-000, #agi-fcbafberq, negvpyr[pynff*=' negvpyr-ary-'] { qvfcynl: abar !vzcbegnag; }
No what you do is get a very long noodle, you put a Rabbi on one end and touch the other end with a bit of pork or shrimp, I believe Tryef is in fact faster than light. So now you have a faster than light signaling system.
How you streach a noodle from Earth to Mars is left as an exercize for the reader.
Erlang Developer and podcaster
*shudder* I apologize for the word "Ameriocentric."
.ge, it's .de for Deutchland.
.ma domain? or would that suggest that residents of Massachusetts, USA, are not of this Earth?
s .h tml for further reading.
When domain names were drawn up for nations, we used ISO 3166, which was agreed upon by people who don't only speak English. Germany isn't
Granted, we don't know the Latin spelling of what Martians call their home planet (nevermind their native tounge), but I find it hard to believe that "Mars" is the only name for that particular moving star in the sky.
Italian, Spanish, Romanian: "Marte"
Czech: "Smrtonos"
Arabic (the language that many stars are named in) "Merrikh"
Hebrew: "Ma'adim"
Mandarin: "Huoxing"
Japaneese: "Kasei"
Most languages seem to agree on using an "M" sound to start the word. Perhaps we should use the
http://www.seds.org/nineplanets/nineplanets/day
So why don't you read the article, then?
Of course, you're absolutely right about the latency. But latency doesn't adversely affect, for example, the transmission of pictures, geological data, or even streaming video.
Jules
-- Any sufficiently advanced technology is indistinguishable from a perl script.
bash-2.04$ ping -i 100000 pathfinder.mars
PING pathfinder.mars (208.56.123.4): 56 data bytes
request timed out
request timed out
request timed out
64 bytes from 208.56.123.4: icmp_seq=3 ttl=245 time=86603.712 ms
request timed out
request timed out
Would be kinda cool to set up a quake2 server at mars, even thou the ping would suck.....
Feed the need: Digitaladdiction.net
I'm sorry, but having 4 or 5 probes on an extremely high-latency link, probably not directly connected to the Internet, does not qualify to be part of the Internet. It will be decades before anything beyond low earth orbit will attain enough connectivity to really become connected to the Internet.
Don't get me wrong, I'm fascinated by NASA's Deep Space Network and everything, but we're not there yet. Hell, even the combined bandwidth of all low earth orbit satellites is miniscule compared to ground links.
[an error occurred while processing this directive]
* we do not increase the rtt estimate. rto is initialized
* from rtt, but increases here. Jacobson (SIGCOMM 88) suggests
* that doubling rto each time is the least we can get away with.
* In KA9Q, Karn uses this for the first few times, and then
* goes to quadratic. netBSD doubles, but only goes up to *64,
* and clamps at 1 to 64 sec afterwards. Note that 120 sec is
* defined in the protocol as the maximum possible RTT. I guess
* we'll have to use something other than TCP to talk to the
* University of Mars.
So maybe we're a while off, eh?
-----
Somehow I don't see this as all so wonderful...
Mars is going to get broadband before I do out here in the stix, damn!
It's NOT fair I tell you...
If it don't GO... chrome it. ~ Frank Banks
This is actually quite an insightful question.
The problem is that when you tug on a rope what you actually do is send a "wave" of compression and stretching down the rope, and it takes time for the wave to reach the other end and be felt.
The same happens if you push on a rod.
The speed of this wave is determined by the stiffness and mass of the rope or rod. The stiffer and lighter, the faster it travels. So, you say, make your rod or rope stiff enough and light enough and it should travel faster than light!
In fact you can't do that. The stiffness of a rope or rod is determined by the strength of the forces between the atoms that make it up, which are determined by electromagnetic effects (same as light). The fact that these effects only transmit information between the atoms at the speed of light puts an absolute limit of how stiff a rope or rod you can make, and ensures that the waves always travel slower than light.
Chad Edwards, when asked about the possibility of online gaming to Mars, said that they were concerned about high ping times. Edwards did say that they are confident, however, that their ping times will be lower than those currently enjoyed by players on Blizzard's battle.net service.
You have probably read something somewhere about the EPR paradox and the Aspect experiments, which are key ingredients in discussions about the interpretation of quantum mechanics. This is a delicate subject, even many physicists will make errors when trying to explain it. I will also, I am sure, but I count someone will correct me (I actually hope somebody skilled in foundations of QM will comment on this, I am only an experimental nuclear physicist).
EPR (Einstein, Podolsky and Rosen) considered a correlated pair of particles with spin. E.g. when a neutral pion (spin zero) decays into two photons, the spins of the two photons must be opposite (conservation of angular momentum). Spin is always measured along a polarization axis, with only two possible answers, say + and -.
In the case where both spins are measured along the same axis you know what the measurement will read as soon as you know one of them, namely the opposite. If the two axes are under an angle, quantum mechanics gives a simple formula for the probability that the measurements will give opposite answers (cos^2 of half the angle between the axes, or so).
If you would assume that the actual direction of the polarization was already determined in the middle (when the pion decayed), then you can show that this probability distribution must have a certain property (the illustrious 'Bell inequality'), which is *not* fulfilled by the quantum mechanical prediction. Then Aspect actually tried it out (and it is a very difficult experiment) and lo & behold, QM was right and hence the 'actual spins' (which is a vague concept) are *not* determined in the middle but at the moment of the measurement, and hence the information about the *other* measurement travels faster than light, instantaneous even.
The sad point to note for your superluminal lasercommunication is that you cannot *influence* the information. It is Nature who decides the direction of the spins. So the answer to your question is 'No, in that fashion you cannot communicate faster than light'. Information can be superluminal, influence cannot. For communication you need to be able to influence the information.
With your measurement you can predict what the other would measure if the polarization axis there would be chosen (anti)parallel to yours. You cannot tell from your (measurements) the direction of the other polarization axis, which is what you were suggesting. If, for instance, one (the sender) would keep its polaxis constant and the other (the receiver) would do a series of measurements with the (wrong) idea that due to the correlation you should see an angular dependence; well then, pity, you would measure in any angle + and - equally often (with some random deviations). The QM correlation only tells you whether the other one will measure the same or the opposite, if you would *already*know* the other axis.